DETERMINING CORRELATION BETWEEN AIR TEMPERATURE
AND SOLAR RADIATION AT WEST SHOA ZONE, GINDEBERET
WOREDA, KACHISE METEOROLOGICAL STATION
M.Sc. Graduate Project
By
LEMMA TUFA AMESSA
October, 2015
HARAMYA UNIVERSITY
DETERMINING CORRELATION BETWEEN AIR TEMPERATURE
AND SOLAR RADIATION AT WEST SHOA ZONE, GINDEBERET
WOREDA, KACHISE METEOROLOGICAL STATION
A graduate project submitted to school of Post graduate program
directorate
(College of Natural and Computational Science, the Department of
physics)
HARAMAYA UNIVERSITY
In partial Fulfillment of the requirements for the degree of Master of
Science in Physics (Environmental physics)
By
Lemma Tufa Amessa
October, 2015
Haramaya University
ii
Post graduate program directorate
HARAMAYA UNIVERSITY
As a graduate project advisor, I certify that I have read and evaluated this graduate
project prepared under my guidance, by Lemma Tufa, entitled “Determining
correlation between Air temperature, and solar radiation at West Shoa Zone,
Gindeberet Woreda, Kachise meteorological station’’
I recommend that it is submitted as fulfillment of the graduate project requirement.
Dr Gelana Amente
___________
Advisor
Signature
__________
Date
As members of the board of examiners, we certify that we have read, evaluated the
Graduate project prepared by Lemma Tufa and examined the candidate. We recommend
that the graduate project be accepted as fulfilling the requirement for the degree of
Master of Science in Physics (Environmental Physics)
____________________
Name of chairperson
____________________
___________
Signature
__________
Date
_________
_________
Name of Internal Examiner
Signature
Date
_____________________
_________
Name of External Examiner
_________
Signature
Date_________________
iii
DEDICATION
This work is dedicated to my father Ato Tufa Amessa and my wife Belaynesh Gerasu
whose love and support has made these all possible.
iv
STATEMENT OF THE AUTHOR
First, I declare that this project is my own work that all sources of materials used for this
graduate project have been duly acknowledged. This project has been submitted in partial
fulfillment of the requirement of M.Sc. degree at Haramaya University and is deposited at
the University Library to be made available to borrowers under rules of the Library. All
scholarly matter that is included in the paper has been given recognition through citation
that I have cited and referenced all sources used in this paper. I solemnly declare that this
Graduate project is not submitted to any other institution anywhere for the award of any
academic degree, diploma, or certificate.
Brief quotations from this project may be used without any special permission provided
that accurate and complete acknowledgement of the source is made. Request for
permission for extended quotation from or reproduction of this project in whole or part
may be granted by the head of the school or department or the dean of the school of
graduate studies when in his or her judgment the proposed use of the material is in the
interest of scholarship. In all other instances, however, permission must be from the
author of the project.
Name Lemma Tufa
Signature________________
School/Department: Physics
Date of submission_________________
v
BIBLIOGRAPHICAL SKETCH
The author was born on July 24, 1979 in Kachise town, Gindeberet Woreda, West Shoa
Zone, Oromia Regional State. He pursued his elementary and secondary school
educations at Kachise primary and Gindeberet high schools, respectively. In 2000 he
joined Jimma teachers college obtained diploma in physics in 2002. He joined summer
in-service program at Haramaya University and graduated with BEd in physics in 2007.
Finally in 2010 he joined the School of Graduate Studies of Haramaya University in 2010
in-summer program to pursue MSc in Physics (Environmental physics).
vi
ACKNOWLEDGMENTS
Primarily, I would like to give glory to almighty God, who made me a person of I am
today.
Next, I would like to express my deepest gratitude to my advisor Dr Gelana Amente for
his expert guidance, constructive comments, suggestions, and encouragement throughout
my study period.
I am also grateful to all my friends who supported me by giving comments and
suggestions during preparation of this paper.
I would like to extend my appreciation to Gindeberet Preparatory school teachers and
principals for their positive supports during my study
Last but not least, I would like to thank my wife Belaynesh Gerasu who stood by my side
all the time.
vii
ACRONYMS
IR
Infrared Region
IRSR
Interim Reference Sunshine Recorder
KWh
Kilowatt hour
L A.T
Local Apparent Time
PRT
Platinum Resistance Thermometer
PV
Photovoltaic
Qrat
Downward radiation from the atmosphere
Tmax
Maximum air temperature
Tmin
Minimum air temperature
Tave
Average air temperature
UV
Ultraviolet
viii
TABLE OF CONTENTS
STATEMENT OF THE AUTHOR
V
BIBLIOGRAPHICAL SKETCH
VI
ACKNOWLEDGMENT
VII
ACRONYMS
VIII
LIST OF TABLES
XI
LIST OF FIGURES
XII
LIST OF TABLES IN APPENDICES
XIII
ABSTRACT
XIV
1. INTRODUCTION
1
2. REVIEW LITRATURE
4
2.1. Global Solar Radiation
4
2.1.1. Geometry of the earth and the sun
4
2.1.2. Declination angle
5
2. 1.3. Solar radiation on the earth’s surface
6
2. 1.4. The hour angle
8
2.2. Sunshine Duration
9
2.3. Solar Photovoltaic System
10
2.4. Temperature
13
3. MATERIALS AND METHODS
14
3.1. Site Description
14
3.2. Data Collection
14
3.3. Data Analysis
15
4. RESULTS AND DISSCUSSION
19
4.1. Air Temperature and Solar Radiation in Dry Season
19
4.1.1. Correlation between daily solar radiation and maximum air temperature
19
4.1. 2. Correlation between daily solar radiation and average air temperature
22
4.1.3. Correlation between air Temperature (Tmax-Tmin) and daily solar Radiation
24
4.2. Solar Radiation and Air Temperature in Wet Season
26
4.2.1. Correlation between daily solar radiation and maximum air temperature
26
4.2.2. Correlation between daily solar radiation and average air temperature
28
4.2.3. Correlation between air Temperature (Tmax-Tmin) and Solar Radiation
30
ix
Table of contents (Continued...)
4.3. Correlation between Air Temperature and Estimated Hourly Solar Intensity in April
8-22/2014
34
4.4. Comparison between Actually Measured Intensity and Estimated Hourly Solar
Radiation
36
5. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS
39
5.1. Summary
39
5.2. Conclusion
39
5.3. Recommendations
40
6. REFERENCES
41
7. APPENDICES
45
x
LIST OF TABLES
Table
Page
1. Correlation coefficients of daily solar radiation and maximum air temperature
33
2. The estimated hourly solar radiation and measured solar radiation i (w/m2)
36
xi
LIST OF FIGURES
Figure
Page
1. Geometry of solar collector and location of sun relative to earth
5
2. Campbell-Stokes-Heliograph (Scharmer and Grief, 2000).
10
3. photovoltaic effect in a cell (Tamirat Bemrew, 2007).
12
4. circuit diagram for the module connected with a100  resistor and a voltmeter
14
5. solar module set for measuring PV voltage using multimeter
15
6. Solar radiation vs maximum air temperature in dry season 2010 and 2011
20
7. Solar radiation vs maximum air temperature in dry season 2012 and 2013
21
8. Solar radiation versus average air temperature in dry season 2010 and 2011
22
9. Solar radiation vs average air temperature in dry season 2012 and 2011
23
10. solar radiation versus air temperature (Tmax-Tmin) in dry season 2010 and 2011
24
11. Solar radiation versus temperature (Tmax-Tmin) in dry season 2012 and 2013
25
12. Solar radiation vs maximum air temperature in wet season 2010 and 2011
26
13. Solar radiation vs maximum air temperature in wet season 2012 and 2013
27
14. Solar radiation versus average air temperature inwet season 2010 and 2011
28
15. Solar radiation vs average air temperature in wet season 2012 and 2013
29
16. Solar radiation versus air temperature (Tmax-Tmin) in wet season 2010 and 2011
30
17. Solar radiation versus air temperature (Tmax-Tmin) in wet season 2011 and 2013
31
18. Air temperature vs solar radiation by average of the four years
32
19. Estimated hourly solar radiation versus air temperature April 8-22/2014)
34
20. Measured solar radiation versus air temperature (April 8-22/2014)
35
21. Estimated and measured solar intensity vs Date
37
xii
LIST OF TABLES IN APPENDICES
Table
Page
1. Air temperature in (oc) and daily solar radiation H in (KWh/m2) dry season
46
2. Air temperature in (oc) and daily solar radiation H in (KWh/m2) wet season
62
3a. Measured intensity I(W/m2) and corresponding air temperature in (oc)
70
3b. Estimated daily mean solar radiation of April (8-22/ 2014) H (kwh/m2)
71
xiii
ABSTRACT
The effect of air temperature on solar radiation was studied at Kachise meteorological
station of West Shoa zone Gindeberet Woreda. The study was carried out by estimating
global solar radiation on horizontal surface using sunshine hour’s data as input to
Angstrom-Prescott model and Hourly solar radiation using Collares-Pereira and Rabl in
order to correlate with Tave , Tmax
and
Tmax-Tmin. The daily global solar radiation of the
four years (2010-2013) showed best correlation with maximum air temperature (Tmax) by
coefficient of determination R2 about 0.80 and the hourly solar radiation correlated with
corresponding air temperature by coefficient of determination R2 =0.64 This indicates
that there is an effect of air temperature on solar radiation. Photovoltaic voltage and air
temperature was measured for two weeks in April. 2014 three times per day at 9:00,
12:00, and 15:00 using a 14cm by 14cm and 12V solar module, also showed good
correlation by R2=0.75 that shows the effect of air temperature on PV system The hourly
solar radiation of April, 8-22/2014 was also estimated and correlated with PV power
intensity. The result of correlation between estimated and measured values obtained
revealed good correlation with Pearson’s correlation r = 0.93 and the error was 8.2%.
Since it is less than 10% the measurement is valiade and coefficient of determination
R2=0.75 indicates positive relationship between airtemperature and measured solar
intensity.
Keywords: Intensities, Photovoltaic Power, Pyrometers
xiv
1. INTRODUCTION
The sun is the largest energy source of our planet. It is the ultimate source of all energy
except tidal and geothermal power. Even the energy from the fossil fuels indirectly comes
from the sun. It radiates 174 trillion KWh of energy to the earth per hour. In other words,
the earth receives 1.74x1017 watts of power from the sun (Gelma Boneya, 2011)
Solar radiation in the form of electromagnetic wave emanates from the 𝑠𝑢𝑛, s surface and
propagates spherically in to the space. Some part of the radiation reaches the earth surface
after atmospheric effect (reflection, refraction, absorption, scattering etc). Such radiation is
called diffused radiation and some part of radiation that reaches the earth surface without
atmospheric effect is called direct radiation (Duffie and Beckman; 1991; Patil, 1999; Aldo,
2005).
Sunshine duration during a given periods is defined as the sum of those sub-periods for
which the direct solar irradiance exceeds 120 Wm-2..That means the daily Sunshine hours is
the integration of the hourly values of Sunshine durations from sun rise to sun set. Before
installing a solar energy system, it is necessary to predict both the demand and the likely
solar energy available, together with their variability. Knowing this and the projected
pattern of energy usage from the device, it is possible to calculate the size of collector and
storage. Ideally, the data required to predict the solar input are several years of
measurements of irradiance on the proposed collector plane. These are very rarely available,
so the required measures have to be statistically estimated from meteorological data
available either (i) from the site, or (ii) (more likely) from some ‘nearby’ site having similar
irradiance, or (iii) (most likely) from an official solar atlas or database. All such data have
systematic error and uncertainty, and natural climatic variability (Twidel and Wier, 2006)
.
Air temperature is a parameter that may positively or negatively affect either both or one
of sunshine duration and solar cell performance. It is measured in thermometer unit ℃,
Kelvin (K) and sometimes ℉. In traditional and modern automatic weather stations the air
temperature is measured inside shelters Stocouples mounted in the shelter. Thermometers
record the minimum and maximum air temperature over a 24-hour period.
2
There are two convectional types of solar panels: Crystalline silicon and thin film. The most
common solar cell material is crystalline silicon. But the newer materials making solar cells
include thin film materials such as amorphous silicon. When solar panels are combined in
series and combined with other components they become a solar electric system or solar
array. PV cells work with direct and diffused light and generate electricity even during
cloudy days, though with reduced production and conversion efficiency. Electricity
production is roughly proportional to the solar irradiance, while efficiency is reduced only
slowly as solar irradiance declines.Since energy is needed to produce electron excitation
and to activate the PV process. We can also use this rated output to estimate the number of
panels we need to meet some or all of our electricity needs.
A photovoltaic panel is a flat plate, composed of photovoltaic cells that have the property of
converting the energy from the sun into direct current electrical energy. When the
temperature of a photovoltaic module is increased, the efficiency drops. This can typically
result in an efficiency drop off of 0.5% per °C increase in the cell operating temperature. It
means it is already known that there is a negative correlation between temperatures,
photovoltaic power. The operating temperature is increased because a large part of the solar
radiation is not converted to electricity but is absorbed by the panel as heat (Tamirat
Bimrew, 2007). Ethiopia receives 4.55 to 6.5KWh/m2/day (annual averages) of solar
intensity (Drake and Yacob Mulugeta, 1996 Breyer et al., 2009). This varies significantly
during the year, ranging from a minimum of 4.55KWh/m2 in July to a maximum of
6.55KWh/m2 in February and March.
In this study the correlation between solar radiation, photovoltaic power, and air
temperature was determined based on meteorological data obtained from West Shoa Zone,
Gindeberet Woreda, Kachise meteorological station
General objective
General objective of the project was to determine correlation between air temperature and
solar radiation based on data of Kachise meteorological station and to verify the calculated
result with actually measured values
3
Specific objectives
(a) To study the effect of sunshine duration on air temperature.
(b) To assess which of the air temperature parameters (average, maximum or T max-Tmin) is
best correlated with sunshine duration.
(c) To evaluate the correlation between estimated hourly solar radiation and measured
photovoltaic power intensity.
Rationale for the project
Now day’s meteorological station may be found at some areas. However, it is not enough to
estimate accurate solar radiation about that area since estimation instruments are not
regularly maintained and its accuracy is not checked especially in remote areas. So there
may be overestimation or underestimation of solar radiation. However, any measurement
cannot be without errors, the project evaluated the correlatioin between air temperature with
solar radiation and photovoltaic power.
4
2. REVIEW OF LITERATURE
2.1. Global Solar Radiation
Solar energy is a form of electromagnetic waves, traveling with speed of light, c, which is
related to its frequency, υ, and wavelength, λ, through the relation c =vλ. The solar
spectrum lies almost wholly within the wavelength range 0.2 < λ < 4.0μm, with a peak at
about 0.475μm. Compared to the total electromagnetic spectrum with a wavelength range
10
-14
< λ < 1016μm, it is clear that the solar radiation spectrum is only a very small
component of electromagnetic waves. The visible range is even smaller, it has a wavelength
range of about 0.4 < λ < 0.7μm. (Sharew Anteneh, 2007)
The utilization of solar energy, like any other natural resources, requires detailed
information on availability. The study of solar radiation should incorporate solar radiation
level with weather condition. The global solar radiation potential will be milestone for
designing and predicting the performance of solar energy equipment and solar energy
potential. It is known that the higher the altitude the greater the solar radiation under the
clear and intermediate sky conditions, but under the overcast days the solar radiation is very
low in comparison with sunny days (Ammann, 2005)
The solar radiation reaching the earth’s surface consists of two components: direct and
diffuse solar radiation.The direct component of solar radiation is the part of the direct solar
beam which reaches the earth surface directly from the sun without being scattered,
reflected or dispersed in any form. The diffused component is that the part of the solar
radiation which reaches the earth’s surface as a result of scattering, reflection, and
dispersion of the solar beam. The sum of the direct and diffuse components of solar
radiation gives the total (global) solar radiation (Al-Salaymeh, A. 2006)
2.1.1. Geometry of the earth and the sun
As the earth rotates once in 24 hours about its own axis, it defines the point of north (N) and
south (S) poles. The axis of the poles is normal to the earth’s equatorial plane. The earth’s
surface is defined by its latitude and longitude. Latitude is defined positive for points north
of the equator and negative for south of the equator so the solar radiation on a point of earth
5
surface can be determined by the daily insolation energy, H, is the total energy per unit area
received in one day from the sun and can be expressed using equation (2.1)
𝑡=24ℎ
H=∫𝑡=0
𝐺𝑑𝑡
(2.1)
Where, G is the insolation energy per hour per unit area and dt is time derivative.
The daily insolation varies with latitude and season. The seasonal variation at high latitudes
is most significant. Its seasonal variation arises from three main factors: variation in the
length of the day that is the number of hours between sunrise and sunset, orientation of the
receiving surface and variation in atmospheric absorption (Twidell and weir, 2006).
For any solar based system design, the most important factors are the position of
the sun in the sky, the slope and orientation of a collecting surface, and obstruction
and reflection properties of neighboring structures. Figure 1, shows the geometry
describing orientation of a collector and position of the sun in the sky. The angle
between the collector surface and the horizontal is called slope, 𝛽 (with 0 0 <𝛽<90 0
for a surface facing towards the equator; 90 0 <𝛽<180 0 for a surface facing away
from the equator). Surface azimuth angle, 𝛾 is the angle between the normal to the
surface and the local longitude meridian, projected on the horizontal plane. In
either hemisphere, 𝛾 equals 0 0 for a surface facing due south, 180 0 due north, 0 0 to
180 0 forsurface facing westward, and 0 0 to - 180 0 eastward. For a horizontal
surface, 𝛾 is always 0 0 (Twidell and weir, 2006).
.
Figure 1: Geometry of solar collector and location of sun relative to earth
2.1.2. Declination angle
6
The key calculation input for generating the solar geometry is the declination angle. The
declination angle (δ) is the angle between the Equatorial Plane and the line joining the
center of the Earth's sphere to the center of the solar disk. The axis of rotation of the Earth
about the poles is set at an angle to the so called Plane of the Ecliptic. The angle of
inclination is 23o 27'. The maximum declination angle of 23o27' in the Northern Hemisphere
occurs at the Summer Solstice, on June 21st. The minimum declination angle of -23o 27' in
the Northern Hemisphere occurs at the Winter Solstice on December 22nd. The declination
of the sun is a continuously varying function of time, but the rate of change within a
specific day is small enough to allow the use of a constant value for any Julian day. One
parameter, the Julian day number, enables the solar declination to be established for any
point in time with acceptable practical accuracy. For very high accuracy the Year Number,
the Longitude of the site and the precise time of day have to be introduced into the
methodology but this refinement is not usually necessary in most practical studies. Latitude
enters in the subsequent geometric calculations (Scharmer and Greif, 2000).
2. 1.3. Solar radiation on the earth’s surface
Solar radiation has to pass through the atmosphere before reaching the earth’s surface. The
amount of radiation falling on the earth’s surface depends on several factors, the most
important ones being the following: Earth-Sun distance, tilt of the Earth’s axis, the Earth’s
atmosphere, and the ratio of reflected irradiance to incoming irradiance (surface albedo). The
solar beam traverses the earth’s atmosphere. The earth receives less energy due to
atmospheric constituents or atmospheric path. The average distance between the sun and the
earth is about 1.5 × 108 km. The earth’s axis is tilted at 23.50 with respect to its orbit around
the sun. This tilted position together with the earth’s daily rotation accounts for the
distribution of solar radiation over the earth’s surface, the change in the length of day and
night and the change of seasons. Only twice a year is the sun truly overhead. The radiation
falling on a given location on the earth’s surface also depends on the sun’s angle, which is a
function of the time of the day. The sun becomes truly overhead to the surface of the earth
during summer and winter solstices (Almorox, and Almorox, 2000).
The earth is surrounded by an atmosphere which contains various gaseous constituents,
suspended dust, and other minute solid and liquid particles. The attenuation processes
7
involving such atmospheric matter are absorption, refraction, reflection, diffraction, and
scattering. In the case of a clear atmosphere, attenuation of solar radiation occurs
simultaneously by three distinct physical processes, namely:(1) selective absorption by
water vapor, molecular oxygen, ozone and carbon dioxide; (2) Rayleigh scattering by
particles of sizes smaller than or equal to 0.1λ where λ is the wavelength of radiation being
scattered; and (3) Mie scattering by particles of size greater than or between 5λ and 25λ.
For an atmosphere with particles of size between 0.1λ and 5λ attenuation also takes place by
diffraction (Sharew Anteneh, 2007). One major consequence of Rayleigh scattering is that
one half of the scattered radiation is sent back to space. The other half is forward scattered.
The back scattering removes almost all the unabsorbed ultra-violet (UV) radiation and
hence reducing greatly the dangerous effects of this radiation on the earth. Because the
Rayleigh scattering coefficient varies with
1
𝜆4,
shorter wavelengths are scattered more than
the longer wavelengths.
For the case of Mie scattering, depletion in solar radiation occurs by true scattering, as well
as by absorption by particles. Absorption in the UV region is mainly due to ozone, while
water vapor absorbs strongly in the infrared (IR) region. Generally little absorption takes
place in the visible region. In both the UV and IR absorption, the energy can be re-emitted
at different wavelengths. As the size of particles become larger than 25λ, the process of
reflection and diffraction become dominant in attenuation, and the laws of geometrical
optics apply. Rain drops and clouds belong to this category of particles. Clouds reflect
much of the radiation falling on them, while rain drops refract. Aerosol absorption results
in higher attenuation of solar beam than scattering. The principle of the absorption process
can be expressed as:
I = I0exp(-αz)
(2.2)
Where Io = a beam of light with some original intensity, I = the incoming intensity of light
that reaches the earth surface, α is the absorption coefficient and z is the length of the path
traversed. Notice that absorption occurs all along the path of travel (Sharew Anteneh,
2007). The amount of absorption (or scattering) that occurs to the solar beam as it traverses
the earth’s atmosphere depends on the atmospheric constituents, and on the solar altitude.
The solar altitude determines the length of the path of the beam that has to travel before
8
reaching the earth’s surface. If the sun is along the zenith, (i.e. vertically above) it is
overhead and the path length is shortest. On the other hand, if the sun is in a direction
making an angle 𝜃 with the zenith direction, the path length is longer. The path length of the
solar beam in any direction is expressed as a ratio of actual path to that of the shortest path
in the zenith direction, a quantity termed the ”air-mass”, m, and defined as:
m = actual path length traversed in the direction of 𝜃 per path length in the zenith direction
By definition, m = 0 outside the atmosphere.In a cloudy atmosphere considerable depletion
of the solar beam takes place. A major part of the solar radiation is reflected back to space,
and other part is absorbed, while the rest of the radiation is transmitted downwards to the
earth as diffuse radiation (Sharew Anteneh, 2007).
2. 1.4. The hour angle
The time system used for computing the geometric position of the sun is based on the use of
the Julian day, j, to describe the position of the day in the annual sequence of days and the
use of the hour angle, ω, to describe the time of day as an angle measured from solar noon.
The hour angle at solar noon is set as zero. The Earth rotates about its axis once in 24 hours,
so the passage of one hour represents a 15 degree rotation. The hour angle is set as positive
after solar noon and negative before solar noon. 09:00 Local Apparent Time( L.A.T.)
yields an hour angle of -45oand 15:00 L.A.T. an hour angle of +45
2.1.5. Extraterrestrial radiation from the sun
The mean irradiance normal to the solar beam outside the atmosphere of the Earth at mean
solar distance is 1367 W/m2. This value is known as the Solar Constant, Io. However, since
the earth revolves around the sun in an elliptical orbit, the earth is slightly closer to the sun
in the Northern Hemisphere winter and slightly further away during the Northern
Hemisphere summer. The time of closest approach is known as the Perihelion and occurs
around January 2nd. The point of greatest distance is known as Aphelion. The distance
between the earth and sun varies by + 1.7%. Following the inverse square law, the range of
the irradiance varies + 3.3%. In addition, the value of Io varies within a period of 11.2 years
by about 1 W/m2. This is caused by cyclical variations of solar activity (Scharmer and
Greif, 2000).
9
2.2. Sunshine Duration
The duration of solar radiation and its energy that reaches the ground are becoming
important spatial data. The physical quantity of sunshine duration (n) is routinely observed
at most weather stations. For climatologically purposes derived terms such as daily sunshine
hours are used, as well as percentage quantities, such as relative daily sunshine duration,
n/N, where N is astronomical daylength, may be related to the extraterrestrial or to the
maximum sunshine duration. A sunshine recorder is used to indicate the amount of sunshine
at a given location. According to World Meteorological Organization (WMO, 2003),
sunshine duration during a given period is defined as the sum of those sub-periods for
which the direct solar irradiance exceeds 120 W m-2. In order to homogenize the data of the
worldwide network for sunshine duration, a special design of the Campbell-Stokes
Sunshine Recorder, the so-called Interim Reference Sunshine Recorder (IRSR), was
recommended as the reference (Adam, 2012).
The requirements of sunshine recorders vary, depending on site and season, according to the
dominant cloud formation. The latter can be mainly described by three ranges of relative
daily sunshine duration n/N such as “cloudy sky” (0 ≤ n/N < 0.30), “scattered clouds” (0.30
≤ n/N < 0.70) and “fair weather” (0.70 ≤ n/N ≤ 1.0) (WMO, 2006; Adam, 2012). The results
are used to help provide information on the climate of an area, agriculture, and tourism.
There are four main types of errors in sunshine duration registration with this type of
instruments. (1) The over-burning of the registration paper during intermittent sunshine,
which results in over estimation of sunshine duration, (2) The threshold sensitivity of the
Campbell-Stokes Recorder of 120 W/m2, which results in under estimation of sunshine
duration, (3) The analysis of the registration paper made by hand that may cause additional
errors in either direction, and finally, (4) Deteriorations of the performance of the glass
sphere caused by weather phenomena like rain or hoar frost and by insufficient maintenance
which results in under estimation of sunshine duration (Scharmer and Grief, 2000).
10
Figure 2: Campbell-Stokes-Heliograph (Scharmer and Grief, 2000).
Among the instruments measuring solar radiation quantities the pyrheliometer is used for
recording direct solar radiation. The registration method is again based on temperature
differences caused by heating of absorbing planes, but the instrument itself is constructed in
a different way. It has to be oriented exactly in direction of the sun´s disk. To satisfy these
condition new types of pyrheliometer mounted on automatic tracking supports must be used
and this inflates the cost of the instrument. Figure 2 shows an example for a roof installed
solar tracker. Unfortunately pyrheliometers are generally not used within routine
observations because direct solar radiation can be easily derived from the difference
between global and diffuse radiation. The routine measuring of all three radiation quantities
would make the detection of errors within one quantity easier (Scharmer and Greif, 2000).
The very first equation was given by Angstrom in 1924; and Angstrom’s regression
coefficients ‘a’ and ‘b’ have important physical interpretations with respect to the total
11
insolation reaching the earth’s surface at any place. The coefficient ‘a’ is supposed to be
related to the percentage of extra terrestrial insolation reaching the earth’s surface on a
completely cloud covered day that is the diffuse radiation while ‘b’ is related to the
percentage of extra terrestrial insolation absorbed by the clouds on such a day. The estimated
daily global solar radiation( H ) is obtained for any station, therefore, depends on the
accuracy with which these coefficients are determined which is neither a very accurate nor a
very convenient way to calculate mean daily solar radiation and the exact evaluation of daily
global radiation with a cloud free atmosphere is difficult. This obstacle is removed by
Prescott (1940) by means of amending the equation and replacing daily global radiation with
a cloud free atmosphere with daily total extra terrestrial solar radiation on a horizontal
surface. Prescott (1940) replaced Ho (monthly average daily extraterrestrial solar radiation)
with the daily total extra terrestrial solar radiation on a horizontal surface (Ho). The new
regression had the form expressed by equation (3.5). ‘a’ and ‘b’ were the new regression
parameters, established empirically for each location (Sharma, 2013)
2.3. Solar Photovoltaic System
The photovoltaic effect converts solar energy directly into electricity. When sunlight strikes
a photovoltaic cell, electrons in a semiconductor material are free from their atomic orbits
and flow in a single direction. This creates direct current electricity, which can be used
immediately converted to alternating current or stored in a battery. Whenever sunlight
arrives at its surface, the cell generates electricity. PV cells normally have a lifespan of at
least 20-25 years. They usually last longer if frequent overheating temperatures in excess of
70ºC (158ºF) is prevented (Robertson and Athienitis, 2007).
To understand the operation of a PV cell, both the nature of the material and the nature of
sunlight need to be considered. Solar cells (see Fig 3) consist of two types of materials,
often p-type silicon, and n-type silicon. Light of certain wavelength is able to ionize the
atoms in the silicon and the internal field produced by the junction separates some of the
positive charge (“holes”) from the negative charge (electrons) within the photovoltaic
device. The holes are swept into the positive or p-layer and the electron are swept into the
negative or n-layer. Although these opposite charges are attracted to each other, most of
them can only recombined by passing through an external circuit outside the material
because of the internal potential energy barrier. An advantage of photovoltaic panels is that
12
they are able to collect both direct and diffuse radiations, so the technology can work even
on cloudy days. Approximately 25 percent of the incident radiation is captured when the
sun is high in the sky, depending on the amount of dust and haze in the atmosphere
(Yinghao, 2011).
Power can be produced from the cell under illumination, since the free electrons have to
pass through the load to recombine with the positive holes. The amount of power available
from a PV device is determined by; the type and area of the PV material, the intensity of the
sunlight and the wavelength of the sun light (Tamirat Bemrew, 2007).
Figure3: photovoltaic effect in a cell (Tamirat Bemrew, 2007).
13
2.4. Temperature
A platinum resistance thermometer (PRT) is used for the measurement of air temperature at
all synoptic stations and all supplementary stations that employ an automatic system
(NMLAF, 2010). Cloud cover acts to suppress differences in surface and free air
temperature by reducing otherwise enhanced surface heating during day and enhanced
surface cooling during night. Thus day-time positive values of ∆T (Ts> Ta) (Ta = free air
temperature and Ts = surface temperature) and ∆T is the difference between Ta and Ts, are
reduced under increased cloudiness, while night-time negative values are minimized. Low
clouds are more influential than high clouds at night since low clouds are warmer and
consequently emit more thermal radiation toward the surface. Moisture, in the form of
specific humidity, controls latent heat transfer. In a dry atmosphere where evaporation is
limited, free air temperatures are likely to be relatively cold in comparison with the
mountain surface. Where ∆T = the difference between surface temperature and free air
temperature this means, ∆T will be negative (Ta> Ts) for warm advection and positive for
cold advecion (Ta< Ts). Advection is closely related to the direction of the large-scale wind
and is of particular importance in mid latitudes where air mass contrasts are great. The
systematic investigation of this phenomenon has not been fully studied (Pepin, 2005).
The atmosphere emittance is a complex function of air temperature and moisture content. A
simple relationship, which ignores the vapor pressure of the atmosphere, could be used to
estimate the apparent sky-temperature (Wong and Chow, 2001).The correlation between
solar radiation and temperature in winter season is strong positive and truly opposite with
the summer season. There are several manifestations of inconsistency between variables at
an individual station. Significant trends in maximum and minimum temperature with
opposite sign and simultaneous significant increases in the numbers both of cold and hot
days. The basic manifestation of consistency among several variables can be deduced from
a tendency for all temperature variables and sunshine duration to attain one sign, and for
relative humidity and cloudiness to attain the opposite sign. A more detailed insight can be
gained from correlation matrices the variables can be considered as mutually consistent if
their trends are correlated with each other or appear in the same trend complex (Pokorna
and Radan, 2005).
14
3. MATERIALS AND METHODS
3.1. Site Description
The study focuses on West Shoa Zone Gindeberet Woreda, Kachise meteorological station,
which is located at 192 km west of Addis Ababa, Ethiopia, at an altitude of 2558 meters
with latitude of between 9° 20′ 51" 𝑎𝑛𝑑 9° 56′ 4"°N and longitude of 37°51′ °E. The place
has a mean maximum temperature of 21. 4 ℃ and mean minimum temperature of 10.3 ℃. It
is a temperate area with average annual rainfall of about 845 mm (meteorological
document).
3.2. Data Collection
Photovoltaic power intensities were obtained by installing a solar module of 14cm x 14cm
Optimum voltage 12V to measure voltage for two weeks, three times per day on days April
8 to 22/2014. Materials used were: 100ῼ resistor, multimeter, and thermometer.
Sun
V
R=100 
Figure 4: circuit diagram for the module connected with a1 00  resistor and a
voltmeter
15
Figure5: solar module set for measuring PV voltage using multimeter
3.3. Data Analysis
The location latitude (  ), time of the year, and time of the day (hour angle, ω), Solar
declination angle (δ) is the angle between the earth’s equatorial plane and the earth sun line.
Solar hour angle, ω, is the angle earth has rotated since solar noon. The relations between
these angles are given below (Duffie and Beckman, 1991)
δ=23.45sin(360
284+𝑛𝑑
365
)
(3.1)
Where δ=solar declination angle
𝑛𝑑 =day number of the year starting from January 1st as 1
ω= (12-𝑡𝐿 )150 it is hour angle (°)
(3.2)
Where 𝑡𝐿 =local solar time in hours
sin 𝛼𝑠 =sin( 𝜙) sin( 𝛿) + cos(𝛿 )cos( 𝜙) cos(𝜔)
𝛼𝑠 = Solar altitude (°)
 = latitude (°)
(3.3)
16
By integrating the soar constant over the day-length gives us the daily solar radiation on the
horizontal surface (Medugu and Yakubu, 2011)
Ho =
24×3600×𝐼𝑠𝑐
П
(1+0.033× cos(
2П𝑛𝑑
365
𝜔
) × (cos 𝜙 cos 𝛿 sin 𝜔𝑠+ П 180𝑠 sin 𝜙 sin 𝛿) (3.4)
The daily mean global solar radiation values have been estimated using Angstrom model,
and months were taken of dry seasons and rainy seasons of four years. In order to find the
solar radiation intensity obtained every hours of the day, the mean daily global solar
radiation (H) were evaluated using Angstrom model equation (3.5). Oncethe solar radiations
of all hours of the day were computed, thus the estimated hourly power intensity (Ip )of
solar radiation can be calculated as (Collares-Pereira and Rabl, 1979):
𝑛
H=Ho (a+b𝑁)
(3.5)
Where: H= daily average radiation on horizontal surface (KWh/m2), Ho=average daily
extraterrestrial radiation on a horizontal surface (KWh /m2), n= average daily number of
hours of bright sunshine, a and b are coefficients given as (Medugu and Yakubu, 2011):
𝑛
a=-0.110+0.235cos(𝜙) +0.323(𝑁)
𝑛
b=1.449-0.553cos( 𝜙)-0.694𝑁
(3.6)
(3.7)
The maximum possible daily sunshine hours in a day time from Sun rise to Sun set is given
by an equation:
2
N = 15 𝜔𝑠
(3.8)
𝜔s= cos−1 ( −tan( 𝛿) tan(  ))
(3.9)
The daily mean global solar radiation values have been estimated using Angstrom model,
and months were taken from dry seasons and rainy seasons of four years. The hourly solar
radiation intensities were correlated with their corresponding air temperatures using mat lab
General linear curve fitting.
17
Graphical correlation between air temperature values, daily mean solar radiation, and hourly
solar intensity, tables of analyzed data and coefficient values that are used to test the effect
air temperature on solar radiation based on meteorological data of four years were taken
from Kachise meteorological station. The daily mean solar radiation was estimated from
sunshine hour using Angstrom-Prescott model for each year (2010-2013) to be correlated
with daily extremes of air temperature
From daily mean solar radiation the hourly power intensity (Ip ) have been calculated to be
correlated with corresponding air temperature values on April 8-22/2014 in order to
compare with measured solar radiation at Kachise meteorological station. The estimated
half hourly power intensity (Ip,est ) of solar radiation can be calculated as (Collares-Pereira
and Rabl, 1979):
Ip=rtxH
(3.10)
Where: rt is the ratio of hourly total to daily total global radiation and is expressed as
rt =
π
cosω − cosωs
(x + y ∗ cos ω)
π
24
sinωs − 180 ∗ ωs ∗ cosωs
(3.11)
π
x = 0.409 + 0.5016sin (ωs − )
3
(3.12)
π
y = 0.6609 − 0.4767sin (ωs − )
3
(3.13)
Where x and y are site dependent constants (Scharmer and Grief, 2000).
The rt for all half hours gives approximately one. Hence, multiplying rt for a specific time
with estimated mean daily global solar radiation (H) gives estimated hourly intensity of
solar radiation. The estimated hourly intensities of solar radiation of specific hours of a day
9:00, 12:00, and 3:00 were correlated with the air temperature of corresponding hours of the
day. The hourly solar radiation intensities were correlated graphically with their
corresponding air temperature. Similarly the solar power intensities were estimated from the
measured voltages as:-
18
V2
P=
R
measured intensity =
P
A
(3.14)
(3.15)
Where: P, V, R and A are power of solar radiation, voltage of solar radiation, resistor and
area of the solar module respectively. These measured values were then compared with the
corresponding values of the estimated hourly power intensity of solar radiation and the error
calculated using the following equation:
% Error =
(Estimated value−measured value) x 100
measured value
(3.16)
19
4. RESULTS AND DISCUSSION
.
In Ethiopia there are two common known seasons:-The months of wet season are: June,
July, August and September and months of dry season:- October, November, December,
January, February, March, April, and May. Solar radiation of each year was correlated with
air temperature seasonally in this project work. The effect of air temperature on hourly solar
radiation and on PV system also has been tested.
4.1. Air Temperature and Solar Radiation in Dry Season
4.1.1. Correlation between daily solar radiation and maximum air temperature
In absence of direct measurements, solar radiation is usually estimated by means of
different methodologies. Thus Sunshine duration, maximum and minimum air temperature,
and relative humidity may be used however; sunshine duration is widely used and
recognized (Michele, 2014). In this project the daily solar radiation was estimated using
Angstrom-Prescott model since the aim of this study was to determine the effect of air
temperature on solar radiation using meteorological data. The solar module which was used
to measure the solar radiation at any time rather than predicting the solar radiation in a
given time using sunshine duration the hourly or half hourly solar radiation is estimated by
applying Collares-Pereira and Rabl’s model..
20
Daily solar radiation vs Tmax in dry season 2010
7
y = 0.58*x - 8.6
R2=0.80
2
Daily solar radiation (KWh/m)
6
5
4
3
2
1
16
18
20
22
24
Daily Tmax in degree celsius
26
(a)
Daily solar radiation vs Tmax in dry season 2011
7
y = 0.4*x - 3.8
2
R =0.72
2
Daily solar radiation (KWh/m)
6
5
4
3
2
16
18
20
22
Daily Tmax in degree celsius
24
26
(b)
Figure 6: Solar radiation vs maximum air temperature in dry season 2010 and 2011
The graphical correlation between maximum air temperature and daily mean solar radiation
for dry season of the year 2010 shown in figure 6(a) that indicated strong correlation with
coefficient of determination R2 = 0.80 is observed. Figure 6(b) shows the result obtained
was good correlation with coefficient of determination R2 = 0.72 for dry season in 2011.
21
Daily solar radiation vs Tmax in dry season 2012
7
y = 0.29*x - 0.74
R2=0.69
2
Daily solar radiation (KWh/m)
6
5
4
3
2
17
18
19
20
:
21
22
23
24
Daily Tmax in degree c elsius
25
26
(a)
Daily solar radiation vs Tmax in dry season 2013
7
2
Daily solar radiation (KWh/m)
6
5
4
y = 0.32*x - 1.4
2
R =0.61
3
2
16
18
20
22
24
Daily Tmax in degree celsius
26
(b)
Figure 7: Solar radiation vs maximum air temperature indry season 2012 and 2013
The relationship between daily solar radiation and maximum air temperature in dry season
has also been tested for the years 2012 and 2013. The results obtained showed positive
correlation between the estimated daily solar radiation and daily maximum air temperature
that coefficients of determination R2 =0.69 and 0.61 respectively as figure 7(a) and 7(b)
showed.
22
4.1. 2. Correlation between daily solar radiation and average air temperature
Temperature is high during the day and is considerably reduced at night causing the daily
range of temperature to be large. But in the case of monthly averages, variation is minimal
and the annual range of temperature is small. This holds true in both the highlands and
lowlands. Slight seasonal variations in the angle of the sun's rays and the length of the day
are primary controls on temperature, resulting in a yearly temperature range is less than the
daily range that we consider the daily average to be more significant (Nata Tadesse, 2006).
Daily solar radiation vs Tave in dry season 2010
7
2
Daily solar radiation (KWh/m)
6
5
4
y = 0.39*x - 0.84
2
R =0.26
3
2
11
12
13
14
15
16
17
Daily Tave in degree c elsius
18
19
(a)
Daily solar radiation vs Tave in dry season 2011
7
2
Daily solar radiation (KWh/m)
6
5
4
y = 0.23*x + 2.1
R2=0.26
3
2
11
12
13
14
15
16
17
Daily Tave in degree c elsius
18
19
20
(b)
Figure 8: Solar radiation vs average air temperature in dry season 2010 and 2011
23
The average of daily maximum air temperatures and daily minimum air temperatures of dry
sesons in the four years was calculated to be correlated with daily mean solar radiation for
dry season of the selected years. The results obtained in figure 8(a) and (b) are the
correlation results of 2010 and 2011 their relationship said to be positive considering R2
value 0.26 for both years.
Effect of average air temperature on daily solar radiation was investigated. The results show
that average air temperature has a positive correlation with solar radiation that the
coefficient of determination (R2) is averagely 0.40 for both 2012 and 2013 as figure 9 (a)
and (b) indicated. The correlation is not strong due to the fact that in clear sky day time, the
average air temperature dominates at about 9am to 12am and beyond up to 3Pm, yet the
maximum solar radiation intensity occurs at noon.
Daily solar radiation vs Tave in dry season 2012
7
2
Daily solar radiation (KWh/m)
6
5
4
y = 0.29*x + 1.2
2
R =0.44
3
2
11
12
13
14
15
16
17
Daily Tave in degree c elsius
18
19
20
(a)
Daily solar radiation vs Tave in dry season 2013
7
2
Daily solar radiation (KWh/m)
6
5
4
y = 0.32*x + 0.52
R2=0.41
3
2
13
14
15
16
17
18
Daily Tave in degree c elsius
19
20
(b)
Figure 9: Solar radiation vs average air temperature in dry season 2012 and 2013
24
4.1.3. Correlation between air Temperature (Tmax-Tmin) and daily solar Radiation
As solar radiation versus air temperature of the suggested season shows as air temperature
increases intensity of solar radiation also increases during day time however, air
temperature slightly decreases but, solar radiation intensity extremely decreases to zero to
night (at sunset) the graphical value below revealed (Tmax-Tmin) air temperature shows
correlation with daily solar radiation.
Daily solar radiation vs Tmax-Tmin in dry season 2010
7
y = 0.22*x + 2
2
R =0.31
2
Daily solar radiation (KWh/m)
6
5
4
3
2
8
10
12
14
16
18
Daily Tmax-Tmin in degree c elsius
20
22
(a)
Daily solar radiation vs Tmax-Tmin in dry season 2011
7
y = 0.065*x + 4.9
R2=0.10
2
Daily solar radiation (KWh/m)
6
5
4
3
2
-5
0
5
10
15
Daily Tmax-Tmin in degree c elsius
20
25
(b)
Figure 10:Solar radiation vs temperature (T max -T min ) in dry season 2010 and 2011
25
The difference of the two air temperature extremes maximum and minimum air temperature
effect also tested. Unlike the correlation between daily solar radiation and daily maximum
air temperature the result obtained by correlating daily solar radiation with Tmax-Tmin shows
weak correlation for the years 2010 and 2011 that correlation coefficient used to determine
degree of correlation are R2 =0.3 and 0.1 respectively that figure 10(a) and (b) expressed by
linear regression. This is becouse of there is no relatioship between solar radiation of the
day time and minimum air temperature of the night time.
Daily solar radiation vs Tmax-Tmin in dry season 2012
2
Daily solar radiation (KWh/m)
7
6
5
y = 0.17*x + 3.9
R2=0.30
4
3
2
4
6
8
10
12
14
16
Daily Tmax-Tmin in degree c elsius
18
20
(a)
Daily solar radiation vs Tmax-Tmin in dry season 2013
7
2
Daily solar radiation (KWh/m)
6
5
4
y = 0.16*x + 4
R2=0.22
3
2
4
6
8
10
12
14
Daily Tmax-Tmin in degree c elsius
16
18
(b)
Figure 11: Solar radiation vs temperature in dry season (T max -T min ) 2012 and 2013
26
The results obtained from correlation of air temperature and daily solar radiation in
figure 11 shows relatively weak correlation between estimated daily solar radiation
and the difference of extreme air temperature values with average R 2 =0.25 as
figure 11(a) and (b) above shows for the years 2012 and 2013 respe ctively
4.2. Solar Radiation and Air Temperature in Wet Season
4.2.1. Correlation between daily solar radiation and maximum air temperature
Regarding air temperature, Ethiopia has a cold summer and mild winter. Fog is infrequent
and usually confined in summer in early mornings, but there are long periods in the
mountainous areas. Visibility is generally very good; however, during the summer season the
sky is not much clear. The low irradiance values are in the rain season is associated with least
sunshine hours. (Sharew Anteneh, 2007).
:
Daily solar radiation vs Tmax in wet season 2010
7
y = 0.73* x - 11
R2=0.62
2
Daily solar radiation (KWh/m)
6
5
4
3
2
1
17
18
19
20
Daily Tmax.
21
22
23
in degree c elsius
24
25
(a)
:
Daily solar radiation vs Tmax in wet season 2011
7
y = 0.74* x - 10
R2=0.58
2
Daily solar radiation (KWh/m)
6
5
4
3
2
1
15
16
17
18
19
20
Daily Tmax in degree celsius
21
22
23
(b)
Figure 12: Solar radiation vs maximum air temperature in wet season 2010 and
2011
27
The wet season is rainy and cloudy sky that low irradiance and also low air temperature
values have been recorded as it is observed from the meteorological data of the area. The
correlation was tested between daily maximum air temperature and daily mean solar
radiation for wet season of 2010 and 2011 and the results of correlation for these years
showed positive relationship that R2 is about 0.60 for both years expressed on figure 12(a)
and (b) above.
Daily solar radiation vs Tmax in wet season 2012
6.5
2
Daily solar radiation (KWh/m)
6
5.5
5
4.5
4
y = 0.27*x - 0.61
3.5
2
R =0.14
3
2.5
2
1.5
15
16
17
18
19
20
21
22
Daily Tmax in degree celsius
23
24
(a)
Daily solar radiation vs Tmax in wet season 2013
7
y = 0.41* x - 3.5
R2=0.50
2
Daily solar radiation (KWh/m)
6
5
4
3
2
14
16
18
20
22
Daily Tmax in degree celsius
24
26
(b)
Figure 13: Solar radiation vs maximum air temperature in wet season2012 and
2013
In the figure 13(a) and (b) above significantly there was positive correlation between
maximum air temperature and daily mean solar radiation since the correlation coefficient
R2 is 0.50 for 2013 but R2 is 0.14 for 2012 indicates positive relationship between air
28
temperature and solar radiation for the year but this doesnot weak correlation. However, the
values of correlation coefficient in case of correlation using linear correlation
4.2.2. Correlation between daily solar radiation and average air temperature
The estimated daily solar radiation values indicated relatively strong correlation in wet
season with the average air temperature.The values were expressed graphically by linear
regrresion well as determination coefficient R2 indicate the relationship between average air
temperature an daily solar radiation.
Daily solar r adiation vs Tave in dr y season 2010
6.5
2
Daily solar radiation (KWh/m)
6
y = 1* x - 12
R2=0.45
5.5
5
4.5
4
3.5
3
2.5
2
1.5
13
13.5
14
14.5
15
15.5
16
Daily Tave in degr ee c elsius
16.5
17
17.5
(a)
Daily solar radiation vs Tave in wet season 2011
9
2
Daily solar radiation (KWh/m)
8
y = 0.91* x - 9.6
R2=0.38
7
6
5
4
3
2
13
14
15
16
17
18
Daily Tave in degree celsius
19
20
(b)
Figure 14: Daily solar radiation versus average air temperature in wet season 2010
and 2011
In case of both wet and dry season’s average air temperature correlated positively next to
maximum air temperature. Figure 14(a) and (b) showed relatively positive correlation for
29
2010 and 2011 that the degree of fitness can be determined by R2 =0.45 and 0.38
respectively.
Daily solar radiation vs Tave in wet season 2012
6.5
2
Daily solar radiation (KWh/m)
6
5.5
5
4.5
4
y = 0.39*x - 1.1
2
R =0.10
3.5
3
2.5
2
1.5
13
14
15
16
Daily Tave in degree celsius
17
18
(a)
Daily solar radiation vs Tave in wet season 2013
6.5
y = 0.39*x - 0.72
6
2
Daily solar radiation (KWh/m)
2
R =0.51
5.5
5
4.5
4
3.5
3
2.5
2
1.5
8
10
12
14
16
Daily Tave in degree celsius
18
(b)
Figure 15: Daily solar radiation vs average air temperature in wet season 2012 and
2013
30
In the year 2012 any extreme values of air temperature correlated weakly with daily solar
radiation relative to the correlations have been done for the other years there may be
erroneous value recorded in the data of the year. While the result obtained for 2013 is good
correlation as in figure 15(b) indicated.
4.2.3. Correlation between air Temperature (Tmax-Tmin) and Solar Radiation
In this study months of wet seasons Jun, July August and September were considered.
Correlation between solar radiation and air temperature was done, and the determination
correlation coefficient shows positive relationship between daily solar radiation and (TmaxTmin) air temperature in (℃) and daily solar radiation in (Kwh/m2).
:
Daily solar radiation vs Tmax-Tmin in wet season 2010
6.5
y = 0.45*x - 1.3
R2=0.4
2
Daily solar radiation (KWh/m)
6
5.5
5
4.5
4
3.5
3
2.5
2
1.5
8
10
12
14
Daily Tmax-Tmin in degree c elsius
16
18
(a)
Daily solar radiation vs Tmax-Tmin in wet season 2011
2
Daily solar radiation (KWh/m)
6
y = 0.6* x - 0.96
R2=0.42
5
4
3
2
1
0
2
4
6
8
Daily Tmax-Tmin in degree c elsius
10
12
(b)
Figure16 : Solar radiation versus air temperature (T max -T min ) in wet season 2010
and 2011
31
The difference of maximum and minimum air temperature in wet season of 2010 and 22011
showed positive regression than dry season that for both years coefficient of determination
R2 is about 0.40 as showed in figure 16(a) and (b) above but it is not strong correlation.
Daily solar radiation vs Tmax-Tmin in wet season 2012
6.5
6
y = 0.26*x + 2.2
2
Daily solar radiation (KWh/m)
2
R =0.13
5.5
5
4.5
4
3.5
3
2.5
2
1.5
4
6
8
10
Daily Tmax-Tmin in degree celsius
12
14
(a)
Daily solar radiation vs Tmax-Tmin in wet season 2013
6.5
6
y = 0.35*x + 2
2
Daily solar radiation (KWh/m)
2
R =0.48
5.5
5
4.5
4
3.5
3
2.5
2
1.5
2
4
6
8
10
Daily Tmax-Tmin in degree c elsius
12
(b)
Figure17 : Solar radiation versus air temperature (T max -T min ) in wetseason 2012 and
2013
The results obtained in all the four years by correlating air temperatures Tmax , Tav and TmaxTmin with daily mean solar radiation all showed positive relationship. There are slight
differences between the values of correlation coefficient of determination in case of wet
32
season. Figure 17(a) showed good correlation by R2 = 0.50 in this year the difference of
maximum and minimum air temperature has positive relationship with daily solar radiation.
Air temperature (oc)
30
y = 1.9432x + 12.465
R² = 0.6456
25
20
y = 1.5259x + 7.7537
R² = 0.388
y = 0.6675x + 10.441
R² = 0.035
15
10
5
T(max) Av
0
(Tmax-Tmin) Av
0
1
2
3
4
5
6
7
8
(Tav) Av
Air temperature in( 0c)
Dry seasons solar radiation (KWh/m^2)
30.00
25.00
y = 1.3173x + 14.153
R² = 0.6414
y = 0.9535x + 10.369
R² = 0.5673
y = 1.3052x + 3.5804
R² = 0.5897
20.00
15.00
10.00
5.00
0.00
0.0000
2.0000
4.0000
6.0000
8.0000
(Tmax) AV
(Tmax-Tmin)Av
TAv. Av
Wet seasons solar radiation in ( KWh/m^2)
Figure 18: Air temperature vs solar radiation by average of the four years
Figure 18 shows that incase of both dry and wet seasons daily solar radiation correlated
more with maximum air temperature (Tmax) and less with (Tmax-Tmin) air temperature and
average of maximum and minimum in dry season but in wet season the coefficient of
determination values revealed that, there is very good correlation between the daily mean
solar radiation and all types of air temperature.
33
In 2010 and 2011 the correlation result of maximum air temperature with daily solar
radiation was strong for both dry and wet seasons that the coefficient of determination R2
are 0.80 and 0.72 for dry , and 0.60 and 0.58 for wet respectively. Similar results obtained
in dry season of 2012 and 2013 that maximum air temperature was correlated with daily
solar radiation by R2 0.69 and 0.61 respectively.
In this project work a linear model on matlab curve fitting equation has been used for the
four suggested years. The regression of the fitting equation is:Y=ax+b
The regression constants, a and b with correlation coefficient R2 of each season were used
to express degrees of correlations. The results demonstrated that most of estimated daily
solar radiation from Sunshine hour’s data has good correlation with the maximum air
temperature.
Table 1: Correlation coefficients of daily solar radiation and maximum air
temperature
Year
Wet season
Dry season
a
b
R2
a
b
R2
2010
0.730
-11.00
0.60
0.58
-8.6
0.8
2011
0.740
-10.00
0.58
0.4
-3.8
0.72
2012
0.270
-0.60
0.14
0.3
-0.7
0.69
2013
0.410
-3.60
0.50
0.3
1.4
0.61
Av
0.54
-6.30
0.46
0.40
-2.94
0.71
The coefficients of determination of correlation between estimated daily solar radiation and
maximum air temperature of the four years are summarized by classifing in to dry and wet
seasons in order to formulate the linear equation by which daily mean solar radiation
correlated with the maximum air temperature using average values expressed in Table 1.
The values are high for dry season than wet season
.
34
Daily solar radiation and maximum air temperature are correlated by regression equations
obtained from average values in table 1 with the corresponding correlation coefficient of
detrmination R2 for each season of the four years are:
Y=0.54x-6.3
R2 =0.46 for wet season
and
Y=0.4x-2.9
R2=0.71
for dry
season.
Where, Y represents estimated daily solar radiation and X represents values of daily
maximum air temperature. From the results above it can be inferred that the values of
correlation coefficient R2 indicates strong relationship between solar radiation and
maximum air temperature
4.3. Correlation between Air Temperature and Estimated Hourly Solar Intensity in
April 8-22/2014
Incident solar radiation per unit area on a surface found by integration of irradiance over a
specified time, usually an hour or a day. Insolation is a term applying specifically to solar
energy irradiation. The symbol H is used for insolation for a day. The symbol I is used for
insolation for an hour (or other period if specified) (Agarwal, 2012).
Estimmated solar intensity vs air temp. April 8-22/2014
y = 3.5*x - 24
2
Estimated solar intensity (W/m)
60
55
2
R =0.64
50
45
40
35
30
16
17
18
19
20
21
22
23
24
o
Air temperature (c )
Figure 19: Estimated hourly solar radiation versus air temperature April 8-22/2014)
35
Measured solar intensity versus c orresponding air temperature
y = 3.8*x - 35
2
R =0.75
2
Photovoltaic power intensity in (w/m)
55
50
45
40
35
30
16
17
18
19
20
21
22
23
24
o
Air temperature in (C )
Figure 20: Measured solar radiation versus air temperature (April 8 -22/2014)
Estimated hourly solar radiation of two weeks of April 2014 was correlated with air
temperature of corresponding time the regression of the values showed positive correlation
as it can be observed from figure 19 its correlation coefficient of determination R2 =0.64.
Correlation between measured solar power intensity and air temperature on April 8-22/2014
is also deduced from figure 20 that the power output performance of the photovoltaic
system and air temperature are correlated. The regression equations obtained with the
corresponding correlation coefficients are R2 is 0.75, r is 0.86, the sum of square error(SSE)
is 1216, and root mean square error(RMSE) is 5.318, that indicates positive relationship.
This project work results of correlation between extremes of air temperature :
maximum air temperature, difference of daily maximum and minimum air temperatures and
average of daily maximum and minimum air temperatures with daily mean solar radiation
the coefficient of determination R2 are lowest for daily average air temperature and for
Tmax-Tmin, which are 0.2, 0.3 0.7 respectively. Since there is air temperature bias difference
between maximum and minimum air temperature but highest values of correlation
coefficients obtained by correlating maximum air temperature with daily mean solar
radiation as dessicused above from table 1.
The air temperature and solar intensity that has been measured at the same time of hours at
9am, 12am and 3pm indicated strong correlation in figure 20 by R2 = 0.75. Whatever, there
will be slight difference between estimated and measured values of solar intensities. From
36
this one can generalize that there is positive relationship between air temperature, sunshine
hours, and photovoltaic system at the study area.
4.4. Comparison between Actually Measured Intensity and Estimated Hourly Solar
Radiation
The solar module was used to measure the solar radiation at any time rather than predicting
the solar radiation in a given time using sunshine duration. The result of this study indicated
a fairly good agreement between estimation of hourly solar radiation and measured solar
radiation at proposed time.
Table 2: The estimated hourly solar radiation and measured solar radiation I (w/m 2 )
Estimated
Measured
date
at 9 am
at 12am
at 3 pm
at 9am
at 12am
at 3pm
8
39.8
62.1
39.8
35.6
57.3
36.0
9
39.4
61.4
39.4
36.0
56.4
34.3
10
39.7
54.1
39.7
33.5
54.1
34.3
11
39.3
41.3
39.3
35.1
52.0
36.0
12
28.7
44.6
28.7
32.7
53.1
27.6
13
40.2
62.4
40.2
37.8
57.3
31.8
14
39.8
61.6
39.8
31.0
56.0
36.0
15
37.9
58.6
37.9
29.5
55.4
36.9
16
40
61.7
40
27.9
57.3
38.9
17
39.2
60.6
39.2
34.3
56.3
39.4
18
40.7
62.8
40.7
34.3
57.9
32.7
19
41.8
64.4
41.8
36.9
57.5
34.3
20
41.9
64.5
41.9
37.7
57.0
36.0
21
40.5
62.3
40.5
37.9
57.8
36.9
22
39.4
60.5
39.4
36.0
57.7
35.2
Ave.
39.22
58.86
39.22
34.4
56.2
35.1
37
Solar module temperature is in turn influenced by ambient temperature, cloud patterns,
and wind speed. When the wind blew with a high speed and when the sky was covered
with clouds as well as difference of incidence and air mass also affect solar module or an
array’s power and production (del-Cueto, 2007; Myers, 2009; King et al, 1997).a humid air
blew at the moment of recording the data. This showed the influences of the atmospheric
parameters on the performance of the solar module. PVs have inherent problem of not
accurately estimating solar radiation since they are temperature dependent and have also
low efficiency of only 10% (Rao and Parulekar, 2009) The result in table 2 showed that the
differences between the measured and estimated value is calculated by:
% Error =
(Estimated value−measured value) x 100
measured value
That is about 3.9 w/m2 while taking the voltage measurements the error calculated is
approximately 8.2% we conclude that sunshine duration can give good estimation of solar
intensity and actual solar radiation intensity measurement has been made with PV high
Solar radiation
in(w/m^2)
accuracy (> 90%) is obtained.
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
8 10 12 14 16 18 20 22 9 11 13 15 17 19 21 8 10 12 14 16 18 20 22
April (8-22) /2014
I estimated
I measured
80.0
60.0
40.0
20.0
Temperature
estimated intensity
measured intensity
0.0
Figure 21: Estimated and measured solar intensity vs Date (April 8-22/2014)
38
In general comparisons have been made between hourly power intensity of estimated and
measured value of solar radiation at Kachise meteorological station. The result obtained
shows that most of the measured values were consistent with the estimated ones throughout
the days as shown in the figure above.
In each result of correlation between extremes of air temperature with daily and hourly solar
radiation the coefficient of determination R2 are lowest for daily average air temperature
and for Tmax-Tmin, incase of both respectively. However, the maximum air temperature is
more related to daily solar radiation.The air temperature and solar intensity that has been
measured at the same time of hour in this project work indicated strong correlation for both
estimated and measured solar intensities that were expressed in figure 20 by R2 =0.64 for
estimated and R2 =0.75 for measured solar intensity. Whatever, there will be slight
difference between estimated and measured values of solar intensities.
39
5. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS
5.1. Summary
The daily mean global solar radiation was estimated using Angstrom-Prescott model. Since
the aim of this study was to determine the effect of air temperature on solar radiation using
meteorological data of Kachise station. Correlations have been made between estimated
daily solar radiation air temperature extremes Tave, Tmax, and (Tmax.-Tmin) for four years
(2010, 2011, 2012 and 2013.
High value of correlation coefficient R2 =0.8 obtained in dry season of 2010 that shows
strong relationship between maximum air temperature and lower correlation values in
general were observed in wet season with R2 about 0.5 regarding maximum temperature.
However, correlation with the other air temperature extremes showed positive result.
All results obtained by correlating extremes of air temperature with daily mean solar
radiation and hourly solar intensities showed that there is strong relationship between air
temperature and global solar radiation. The hourly solar radiation of April 8-22/2014 also
estimated and correlated with corresponding air temperature the result seen from the
correlation was positive that R2 is 0.64 and the correlation between air temperature and
measured solar intensity was more strong that R2 is 0.75 this indicates positive relationship
between PV system and air temperature about room temperature values.
The comparison between estimated hourly solar radiation and measured solar intensity
shows good relationship between the measured values and estimated hourly solar radiation
that the calculated error is 8.2%. The study done under this project would help us to
estimate the solar potential energy around Kachise meteorological station and to test effect
of air temperature on solar radiation day to day.
5.2. Conclusion
Effect of air temperature on daily mean solar radiation and hourly solar intensity was
investigated. The results show that there is a direct proportionality between the air
temperatures of the locality and solar radiation. Thus, the application of photovoltaic
40
technology in the conversion of solar energy to electricity is favorable during high air
temperature values.
The value of daily and hourly solar radiations is essential in assessing the climatologically
potential solar energy utilization for the region and in estimating the averages or expected
values of the output of solar collectors. The coefficient of determination of correlation
between solar radiation and air temperature is high. The result obtained in general indicated
that there is direct relationship between solar radiation and air temperature and also air
temperature affects performance of PV power intensity.
Sunshine duration data of the meteorological station give good estimation of solar intensity
compared with actual measurement of solar radiation intensity measurement made is high
accuracy (> 90%) that was obtained by this work.
5.3. Recommendations
This study is not enough to clarify the effect of air temperature on solar radiation in case of
time scale, namely hourly, daily, monthly, seasonal, and annual. Therefore, more
investigation is necessary based on Kachise meteorological data.
This project estimated the average solar potential of the study area. Hence it is possible to
recommend any concerned body that the area has great promise/potential for hot water
generation, application of solar cookers, and effectiveness of solar collector’s application at
that area due to the fact that solar energy is the most renewable energy that should be
harnessed.
Regarding to air temperature the utilization of solar energy may be harnessed more in the
areas of low altitude, where the air temperature is higher.
41
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45
7. APPENDICES
46
Appendex.Table 1: Air temperature in ( o c) and daily solar radiation H (KWh/m 2 )
January
Date TMAX TMIN
D/c
Av
2010 2010 2010 2010
1 24.1
9.0 15.1 16.6
2 24.3
6.5 17.8 15.4
3 24.8
4.0 20.8 14.4
4 24.0
7.6 16.4 15.8
5 24.0
7.2 16.8 15.6
6 24.9
7.2 17.7 16.1
7 24.0
5.0 19.0 14.5
8 24.3
7.0 17.3 15.7
9 24.0
2.6 21.4 13.3
10 24.4
2.9 21.5 13.7
11 24.5
6.0 18.5 15.3
12 24.3
7.0 17.3 15.7
13 24.4
7.7 16.7 16.1
14 24.5
6.5 18.0 15.5
15 24.3
7.5 16.8 15.9
16 24.0
5.8 18.2 14.9
17 24.2 10.0 14.2 17.1
18 24.5
8.0 16.5 16.3
19 24.7
9.0 15.7 16.9
20 24.6
8.5 16.1 16.6
21 24.4
3.2 21.2 13.8
22 22.0
4.2 17.8 13.1
23 25.0
2.5 22.5 13.8
24 25.3
4.0 21.3 14.7
25 25.4
5.0 20.4 15.2
26 17.4
4.5 12.9 11.0
27 25.8
4.0 21.8 14.9
28 26.0
6.0 20.0 16.0
29 26.1
6.5 19.6 16.3
30 26.0
7.8 18.2 16.9
H10
5.6
5.6
5.8
5.7
5.7
5.8
5.7
5.8
5.2
5.9
5.9
5.8
5.9
5.8
5.9
5.5
5.4
5.8
5.6
5.9
5.7
4.1
5.9
6.0
6.0
1.1
6.1
6.0
6.1
6.1
TMAX TMIN
2011 2011
20.7
3.0
20.0
3.2
18.5
3.4
19.5
2.8
22.3
2.0
22.5
3.2
22.4
2.6
23.6
3.4
23.8
3.5
23.4
3.1
22.5
3.6
23.5
3.2
23.0
2.5
23.8
1.5
23.7
4.4
24.7
3.5
24.8
2.0
24.3
2.2
24.7
3.4
20.1
1.1
24.0
2.6
24.9
4.0
24.8
1.6
24.4
2.6
25.0
4.0
24.8
4.2
24.5
5.2
25.0
3.5
24.8
1.0
24.7
2.5
d/c
2011
17.7
16.8
15.1
16.7
20.3
19.3
19.8
20.2
20.3
20.3
18.9
20.3
20.5
22.3
19.3
21.2
22.8
22.1
21.3
19.0
21.4
20.9
23.2
21.8
21.0
20.6
19.3
21.5
23.8
22.2
Av
2011
11.9
11.6
11.0
11.2
12.2
12.9
12.5
13.5
13.7
13.3
13.1
13.4
12.8
12.6
14.1
14.1
13.4
13.3
14.1
10.6
13.3
14.5
13.2
13.5
14.5
14.5
14.9
14.3
12.9
13.6
H11
3.5
3.3
2.8
3.6
4.7
4.4
5.1
4.9
5.2
5.1
5.0
5.0
4.9
5.1
5.8
5.9
5.9
5.9
5.6
2.8
5.7
6.0
6.0
5.9
6.0
6.1
6.1
6.1
6.1
6.1
47
JANUARY
Date
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
TMAX TMIN
2012 2012
22.0
9.2
24.0
9.9
24.6
9.6
24.0 10.4
24.5 10.0
23.5 11.7
22.8 11.6
22.7
9.9
22.6
9.8
22.8
9.5
24.2 10.6
23.0 10.7
24.4 10.5
24.0 11.0
24.3
9.2
23.0 10.0
24.5 10.5
24.5
9.4
24.2 10.9
24.5 10.9
23.9 10.3
23.5 11.0
23.5 10.5
23.8 10.2
24.2 11.2
24.2 10.4
24.0 10.6
24.6 11.5
24.2 10.2
25.2 10.5
d/c
Av
2012 2012
12.8 15.6
14.1 17.0
15.0 17.1
13.6 17.2
14.5 17.3
11.8 17.6
11.2 17.2
12.8 16.3
12.8 16.2
13.3 16.2
13.6 17.4
12.3 16.9
13.9 17.5
13.0 17.5
15.1 16.8
13.0 16.5
14.0 17.5
15.1 17.0
13.3 17.6
13.6 17.7
13.6 17.1
12.5 17.3
13.0 17.0
13.6 17.0
13.0 17.7
13.8 17.3
13.4 17.3
13.1 18.1
14.0 17.2
14.7 17.9
H12
5.8
5.8
5.8
5.8
5.8
5.8
5.8
5.8
5.8
5.8
5.9
5.9
5.9
5.9
5.9
5.7
5.9
5.9
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.1
6.1
6.1
6.1
TMAX TMIN
d/c
Av
2013 2013 2013 2013
19.6
9.2 10.4 14.4
22.5
9.5 13.0 16.0
23.4
7.7 15.7 15.6
22.5
8.0 14.5 15.3
22.5
8.8 13.7 15.7
23.6 11.5 12.1 17.6
19.4 11.7
7.7 15.6
19.6 11.5
8.1 15.6
19.9 10.5
9.4 15.2
22.4 10.7 11.7 16.6
21.6 10.3 11.3 16.0
22.0 11.0 11.0 16.5
23.9 10.0 13.9 17.0
22.8
9.7 13.1 16.3
22.9 11.0 11.9 17.0
23.5 12.7 10.8 18.1
23.2 10.4 12.8 16.8
23.8 10.9 12.9 17.4
24.0 10.6 13.4 17.3
24.0 11.0 13.0 17.5
23.5 10.2 13.3 16.9
24.0 11.5 12.5 17.8
22.5 10.5 12.0 16.5
23.5 10.5 13.0 17.0
23.5 11.2 12.3 17.4
24.5 12.4 12.1 18.5
25.0 11.6 13.4 18.3
25.0 12.2 12.8 18.6
25.0 10.6 14.4 17.8
24.0 10.6 13.4 17.3
H13
4.4
5.8
5.8
5.8
5.8
5.7
4.0
4.4
4.8
5.5
5.5
5.4
5.9
5.9
5.9
5.9
5.9
5.9
6.0
6.0
6.0
6.0
6.0
6.0
6.0
5.8
6.1
6.1
6.1
5.9
48
February
Date
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
TMAX
2010
25.9
25.5
25.8
25.7
25.4
19.5
25.0
22.0
20.0
17.2
17.0
24.0
23.0
25.0
26.0
26.0
20.1
24.5
21.7
25.2
25.6
24.0
25.0
24.2
24.1
19.0
22.6
19.5
TMIN
2010
10.0
9.0
10.7
10.0
11.0
11.0
9.0
11.0
10.0
10.3
8.6
9.2
8.5
9.2
8.2
8.5
9.0
7.2
7.5
10.6
12.0
11.2
10.0
12.2
9.5
11.0
9.8
9.0
D/c
2010
15.9
16.5
15.1
15.7
14.4
8.5
16.0
11.0
10.0
6.9
8.4
14.8
14.5
15.8
17.8
17.5
11.1
17.3
14.2
14.6
13.6
12.8
15.0
12.0
14.6
8.0
12.8
10.5
Av
2010
18.0
17.3
18.3
17.9
18.2
15.3
17.0
16.5
15.0
13.8
12.8
16.6
15.8
17.1
17.1
17.3
14.6
15.9
14.6
17.9
18.8
17.6
17.5
18.2
16.8
15.0
16.2
14.3
H10
6.0
6.2
6.2
6.2
6.2
3.0
5.5
3.9
3.3
1.5
1.6
5.4
4.9
5.9
6.3
6.1
2.0
5.1
3.6
6.2
6.5
5.7
6.5
5.6
6.2
2.6
4.5
2.5
TMAX
2011
24.8
24.9
25.2
25.2
24.9
25.2
26.0
24.9
25.3
25.4
25.0
25.4
24.2
24.5
25.6
24.6
24.5
25.4
24.7
25.0
25.5
25.0
25.5
25.6
26.0
26.8
25.5
25.4
TMIN
2011
1.5
1.7
2.6
4.1
4.5
3.9
3.1
3.8
2.5
2.0
2.9
3.0
4.0
4.2
3.8
3.9
4.9
4.1
5.0
4.0
3.5
5.8
4.4
4.2
3.6
3.8
3.5
3.6
d/c
Av
2011 2011
23.3 13.2
23.2 13.3
22.6 13.9
21.1 14.7
20.4 14.7
21.3 14.6
22.9 14.6
21.1 14.4
22.8 13.9
23.4 13.7
22.1 14.0
22.4 14.2
20.2 14.1
20.3 14.4
21.8 14.7
20.7 14.3
19.6 14.7
21.3 14.8
19.7 14.9
21.0 14.5
22.0 14.5
19.2 15.4
21.1 15.0
21.4 14.9
22.4 14.8
23.0 15.3
22.0 14.5
21.8 14.5
H11
6.1
6.0
6.2
6.2
6.2
6.2
6.2
6.3
6.3
6.3
6.3
6.3
6.3
6.4
6.4
6.4
6.4
6.4
6.4
6.5
6.5
6.5
6.5
6.5
6.5
6.6
6.6
6.5
49
February
Date TMAX
TMIN
d/c
2012 2012 2012
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
24.5
26.0
25.0
24.0
24.5
24.5
25.2
24.5
25.7
25.7
24.7
24.1
25.5
26.5
24.6
25.0
25.0
25.5
25.6
25.5
25.5
26.0
26.0
24.0
25.5
26.0
26.0
26.0
9.9
9.8
10.0
10.9
11.2
10.3
10.6
13.0
11.5
8.9
11.7
11.5
11.0
11.0
11.0
12.2
11.0
10.4
12.2
11.6
11.2
12.5
12.3
12.0
13.4
13.2
13.5
10.5
14.6
16.2
15.0
13.1
13.3
14.2
14.6
11.5
14.2
16.8
13.0
12.6
14.5
15.5
13.6
12.8
14.0
15.1
13.4
13.9
14.3
13.5
13.7
12.0
12.1
12.8
12.5
15.5
Av
2012
H12
17.2
17.9
17.5
17.5
17.9
17.4
17.9
18.8
18.6
17.3
18.2
17.8
18.3
18.8
17.8
18.6
18.0
18.0
18.9
18.6
18.4
19.3
19.2
18.0
19.5
19.6
19.8
18.3
6.1
6.1
6.1
6.2
6.2
6.2
6.2
6.2
6.3
6.3
6.3
6.3
6.3
6.3
6.3
6.4
6.4
6.4
6.4
6.0
6.4
6.5
6.5
6.5
6.5
6.5
6.6
6.6
TMAX TMIN
2013 2013
25.0
25.0
24.0
25.0
25.1
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.0
25.5
25.4
25.0
25.0
25.7
25.0
25.0
25.0
25.0
25.0
25.0
25.8
25.2
26.0
25.0
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
10.6
11.5
14.5
d/c
2013
14.4
14.4
13.4
14.4
14.5
14.4
14.4
14.4
14.4
14.4
14.4
14.4
14.4
14.9
14.8
14.4
14.4
15.1
14.4
14.4
14.4
14.4
14.4
14.4
15.2
14.6
14.5
10.5
Av
2013 H13
17.8
17.8
17.3
17.8
17.9
17.8
17.8
17.8
17.8
17.8
17.8
17.8
17.8
18.1
18.0
17.8
17.8
18.2
17.8
17.8
17.8
17.8
17.8
17.8
18.2
17.9
18.8
19.8
6.0
6.2
5.5
6.0
6.2
6.1
6.1
6.2
6.3
6.3
6.1
6.3
6.3
6.4
6.4
6.4
6.4
6.4
6.4
6.5
6.5
6.4
6.5
6.5
6.5
6.6
6.6
6.6
50
March
Date TMAX TMIN D/c
Av
TMAX TMIN d/c
Av
2010 2010 2010 2010 H10
2011 2011 2011 2011 H11
1
17.2
10.0
7.2 13.6
1.4
25.5
5.0 20.5 15.3
6.6
2
24.4
10.0 14.4 17.2
5.6
25.7
3.1 22.6 14.4
6.6
3
22.0
10.6 11.4 16.3
4.8
24.9
2.4 22.5 13.7
6.6
4
22.3
9.5 12.8 15.9
4.0
25.0
4.4 20.6 14.7
6.5
5
21.2
10.0 11.2 15.6
3.3
25.0
3.4 21.6 14.2
6.5
6
24.0
8.6 15.4 16.3
5.2
23.2
3.6 19.6 13.4
5.9
7
25.7
6.8 18.9 16.3
6.3
25.0
2.6 22.4 13.8
6.2
8
25.5
6.0 19.5 15.8
6.5
23.8
2.5 21.3 13.2
5.0
9
25.5
3.5 22.0 14.5
6.5
25.4
2.5 22.9 14.0
6.5
10
25.0
4.5 20.5 14.8
6.0
25.3
9.2 25.3 12.7
6.0
11
26.4
4.6 21.8 15.5
6.7
25.3
9.0 16.3 17.2
6.5
12
26.5
5.0 21.5 15.8
6.8
25.7
9.8 15.9 17.8
6.0
13
26.5
9.4 17.1 18.0
6.8
22.0
8.5 13.5 15.3
4.7
14
25.5
8.4 17.1 17.0
6.8
19.8
8.8 11.0 14.3
3.6
15
25.4
10.8 14.6 18.1
6.8
25.0 11.0 14.0 18.0
6.1
16
25.7
11.2 14.5 18.5
6.5
17.0 10.2
6.8 13.6
1.2
17
25.8
9.0 16.8 17.4
6.5
19.0
8.5 10.5 13.8
2.3
18
25.3
9.5 15.8 17.4
6.2
20.0 12.9
7.1 16.5
3.0
19
23.8
10.0 13.8 16.9
4.4
20.4 12.5
7.9 16.5
3.6
20
23.0
10.6 12.4 16.8
3.3
22.4 11.5 10.9 17.0
5.2
21
24.6
10.6 14.0 17.6
5.7
23.6 11.2 12.4 17.4
5.6
22
26.0
11.6 14.4 18.8
6.4
22.1 11.6 10.5 16.9
5.1
23
26.6
10.0 16.6 18.3
6.9
25.0 12.5 12.5 18.8
6.6
24
26.5
10.0 16.5 18.3
6.9
25.6 12.0 13.6 18.8
6.8
25
25.6
11.5 14.1 18.6
6.7
25.7 12.5 13.2 19.1
6.9
26
25.7
10.0 15.7 17.9
6.5
25.8 12.5 13.3 19.2
6.9
27
24.0
9.0 15.0 16.5
5.9
26.0 12.2 13.8 19.1
6.9
28
22.0
10.5 11.5 16.3
2.3
26.0 12.0 14.0 19.0
6.9
29
22.0
8.5 13.5 15.3
2.7
25.8 11.5 14.3 18.7
6.8
30
19.6
7.5 12.1 13.6
1.8
25.6 12.4 13.2 19.0
6.7
51
March
Date
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
TMAX TMIN d/c
Av
TMAX TMIN d/c
Av
2012 2012 2012 2012 H12
2013 2013
2013 2013 H13
26.0
10.0
16.0
18.0
6.6
26.0
13.8
12.2
19.9
6.6
26.0
13.0
13.0
19.5
6.6
27.0
12.8
14.2
19.9
6.6
25.4
10.6
14.8
18.0
6.4
27.0
13.3
13.7
20.2
6.1
25.2
10.8
14.4
18.0
6.2
24.0
13.5
10.5
18.8
6.5
24.0
10.2
13.8
17.1
5.9
24.0
14.0
10.0
19.0
6.6
25.5
10.0
15.5
17.8
6.4
23.6
14.5
9.1
19.1
6.6
25.8
11.8
14.0
18.8
6.6
22.5
11.4
11.1
17.0
6.7
26.2
11.4
14.8
18.8
6.7
23.0
11.2
11.8
17.1
6.4
25.0
12.0
13.0
18.5
6.7
23.3
12.3
11.0
17.8
5.7
26.0
12.5
13.5
19.3
6.6
24.2
11.3
12.9
17.8
5.9
25.7
11.3
14.4
18.5
6.7
24.0
11.7
12.3
17.9
6.2
26.5
12.0
14.5
19.3
6.7
25.8
11.3
14.5
18.6
5.0
26.0
12.4
13.6
19.2
6.7
25.0
12.2
12.8
18.6
5.5
26.6
14.0
12.6
20.3
6.8
25.0
12.0
13.0
18.5
5.9
26.0
13.6
12.4
19.8
6.8
25.5
12.6
12.9
19.1
6.8
26.0
13.5
12.5
19.8
6.8
25.5
12.1
13.4
18.8
6.8
26.0
11.1
14.9
18.6
6.8
25.5
12.0
13.5
18.8
6.7
25.8
10.2
15.6
18.0
6.8
24.0
12.2
11.8
18.1
6.2
25.9
10.4
15.5
18.2
6.8
24.4
12.3
12.1
18.4
6.5
24.8
11.0
13.8
17.9
6.8
25.5
13.5
12.0
19.5
6.8
24.7
9.2
15.5
17.0
6.7
25.5
12.2
13.3
18.9
6.8
25.0
12.2
12.8
18.6
6.7
25.5
12.4
13.1
19.0
6.8
25.4
13.5
11.9
19.5
6.6
20.5
11.9
8.6
16.2
4.3
23.9
13.5
10.4
18.7
5.8
21.0
11.6
9.4
16.3
5.4
25.5
10.5
15.0
18.0
6.1
25.4
12.0
13.4
18.7
6.9
25.0
11.0
14.0
18.0
5.0
25.3
12.0
13.3
18.7
6.8
25.0
10.4
14.6
17.7
6.6
25.1
12.5
12.6
18.8
6.9
25.0
10.5
14.5
17.8
6.9
25.6
12.4
13.2
19.0
6.9
24.8
11.2
13.6
18.0
6.3
25.7
11.0
14.7
18.4
6.9
25.0
11.4
13.6
18.2
6.1
25.5
11.1
14.4
18.3
6.9
21.0
11.2
9.8
16.1
5.3
26.2
12.5
13.7
19.4
6.9
52
April
TMAX TMIN d/c
Date TMAX TMIN D/c
Av
Av
2010 2010 2010 2010 H10 2011 2011 2011 2011 H11
1 25.8
7.5 18.3 16.7
4.7 25.8 13.2 12.6 19.5 6.9
2 22.5
8.0 14.5 15.3
3.6 25.7 12.3 13.4 19.0 6.9
3 23.7
9.5 14.2 16.6
4.9 24.5 11.4 13.1 18.0 6.9
4 25.5
8.5 17.0 17.0
6.7 25.0 10.7 14.3 17.9 6.9
5 26.5
8.0 18.5 17.3
6.5 24.2 10.8 13.4 17.5 6.7
6 26.5 10.0 16.5 18.3
6.4 26.5 13.8 12.7 20.2 6.3
7 26.0
8.8 17.2 17.4
6.7 26.5 12.9 13.6 19.7 6.6
8 26.0 11.5 14.5 18.8
6.9 24.8 13.1 11.7 19.0 5.9
9 24.0 10.8 13.2 17.4
6.9 25.2 12.6 12.6 18.9 6.0
10 26.3 10.0 16.3 18.2
7.0 26.0 12.5 13.5 19.3 7.0
11 26.1 10.4 15.7 18.3
6.9 26.0 13.3 12.7 19.7 7.0
12 24.8 11.0 13.8 17.9
6.8 25.7 12.5 13.2 19.1 6.9
13 23.0
8.6 14.4 15.8
4.2 17.5 12.4
5.1 15.0 1.3
14 24.5
9.5 15.0 17.0
4.7 25.5 12.3 13.2 18.9 6.0
15 23.2
9.6 13.6 16.4
5.8 25.7 12.9 12.8 19.3 6.9
16 22.0 10.5 11.5 16.3
2.0 22.2 11.2 11.0 16.7 5.8
17 25.5
9.0 16.5 17.3
5.6 25.0 11.6 13.4 18.3 6.3
18 25.5 10.6 14.9 18.1
6.5 25.0 11.2 13.8 18.1 6.4
19 24.5 11.5 13.0 18.0
4.3 25.8
9.8 16.0 17.8 7.0
20 25.0 11.2 13.8 18.1
6.3 23.0 11.0 12.0 17.0 5.4
21 24.0 10.5 13.5 17.3
6.2 25.7 13.0 12.7 19.4 7.0
22 23.0 11.5 11.5 17.3
5.1 23.7 11.7 12.0 17.7 4.6
23 24.5 12.4 12.1 18.5
5.4 25.0 13.4 11.6 19.2 4.7
24 25.7 12.8 12.9 19.3
4.7 26.0 14.0 12.0 20.0 7.0
25 24.2 12.2 12.0 18.2
4.2 26.0 12.8 13.2 19.4 7.0
26 27.0
9.0 18.0 18.0
6.6 25.8 11.8 14.0 18.8 7.0
27 25.7
9.5 16.2 17.6
3.9 26.0 13.0 13.0 19.5 7.0
28 24.0
8.8 15.2 16.4
4.9 26.0 11.5 14.5 18.8 6.8
29 24.3 10.2 14.1 17.3
5.7 25.3 12.1 13.2 18.7 6.6
30 23.0 10.5 12.5 16.8
2.7 24.0 11.8 12.2 17.9 5.6
53
April
TMAX TMIN d/c
Date TMAX TMIN d/c
Av
Av
2012 2012 2012 2012 H12
2013 2013 2013 2013 H13
1 19.0
11.6
7.4
15.3
5.0 26.4
13.0 13.4 19.7
6.9
2 20.0
11.2
8.8
15.6
5.6 25.5
14.0 11.5 19.8
6.9
3 25.0
11.4 13.6
18.2
6.7 26.0
11.9 14.1 19.0
7.0
4 25.0
12.5 12.5
18.8
6.9 26.0
12.5 13.5 19.3
7.0
5 25.2
13.5 11.7
19.4
6.9 26.0
12.6 13.4 19.3
7.0
6 26.0
13.5 12.5
19.8
7.0 26.0
13.0 13.0 19.5
7.0
7 24.0
13.0 11.0
18.5
5.9 26.0
12.5 13.5 19.3
6.9
8 24.5
14.2 10.3
19.4
6.7 25.7
12.5 13.2 19.1
6.9
9 25.0
12.8 12.2
18.9
6.9 25.5
11.5 14.0 18.5
6.8
10 26.0
11.6 14.4
18.8
7.0 26.0
12.0 14.0 19.0
7.0
11 25.5
13.2 12.3
19.4
7.0 25.5
13.8 11.7 19.7
7.0
12 25.5
12.0 13.5
18.8
6.3 26.0
12.5 13.5 19.3
7.0
13 25.6
13.8 11.8
19.7
6.7 26.3
14.4 11.9 20.4
6.9
14 26.1
12.2 13.9
19.2
6.8 25.0
14.0 11.0 19.5
6.6
15 26.4
14.3 12.1
20.4
6.3 24.5
13.2 11.3 18.9
6.2
16 25.7
11.5 14.2
18.6
6.9 25.5
11.2 14.3 18.4
6.4
17 25.8
11.7 14.1
18.8
6.8 26.5
12.0 14.5 19.3
7.0
18 26.0
11.0 15.0
18.5
7.0 25.6
13.8 11.8 19.7
7.0
19 25.5
10.9 14.6
18.2
7.0 24.5
12.1 12.4 18.3
5.9
20 25.5
9.3 16.2
17.4
7.0 24.0
10.8 13.2 17.4
6.7
21 25.0
13.0 12.0
19.0
7.0 26.0
12.0 14.0 19.0
6.4
22 24.0
11.5 12.5
17.8
6.9 26.0
14.0 12.0 20.0
6.7
23 19.0
10.5
8.5
14.8
4.9 26.0
12.5 13.5 19.3
6.9
24 24.0
11.6 12.4
17.8
6.3 26.0
10.9 15.1 18.5
7.0
25 24.0
13.4 10.6
18.7
6.9 26.0
14.2 11.8 20.1
6.8
26 25.8
13.2 12.6
19.5
7.0 26.0
13.4 12.6 19.7
5.0
27 25.0
14.4 10.6
19.7
6.9 26.0
12.5 13.5 19.3
7.0
28 25.7
14.8 10.9
20.3
6.7 24.6
14.0 10.6 19.3
6.6
29 26.0
12.5 13.5
19.3
6.4 25.5
12.0 13.5 18.8
7.0
30 25.2
12.6 12.6
18.9
6.8 24.5
12.5 12.0 18.5
6.3
54
May
TMAX TMIN d/c
Date TMAX TMIN D/c
Av
Av
2010 2010 2010 2010 H10
2011 2011 2011 2011 H11
1 25.3
9.4 15.9 17.4
6.4 24.7 12.9 11.8 18.8
6.6
2 25.3
9.0 16.3 17.2
6.5 25.1 14.0 11.1 19.6
5.9
3 26.4 11.8 14.6 19.1
6.9 25.2 13.6 11.6 19.4
6.5
4 25.0 11.0 14.0 18.0
6.1 25.7 12.9 12.8 19.3
6.9
5 21.6
7.5 14.1 14.6
4.0 25.5 12.7 12.8 19.1
6.9
6 25.4
8.0 17.4 16.7
6.3 25.8 13.2 12.6 19.5
6.7
7 25.3
9.5 15.8 17.4
6.3 25.8 12.0 13.8 18.9
6.5
8 21.0 10.8 10.2 15.9
4.0 25.9 13.6 12.3 19.8
6.8
9 22.0 10.0 12.0 16.0
4.4 25.0 13.2 11.8 19.1
6.0
10 21.0 11.0 10.0 16.0
3.1 25.4 12.2 13.2 18.8
6.4
11 24.0
7.5 16.5 15.8
5.1 25.4 13.0 12.4 19.2
5.9
12 22.0 11.0 11.0 16.5
3.9 24.0 12.0 12.0 18.0
6.7
13 24.8 10.5 14.3 17.7
5.7 25.8 10.0 15.8 17.9
6.9
14 21.0 11.4
9.6 16.2
3.3 25.7 11.0 14.7 18.4
6.9
15 21.2 12.5
8.7 16.9
3.4 25.0 11.0 14.0 18.0
6.8
16 26.0 11.0 15.0 18.5
6.3 25.4 10.9 14.5 18.2
6.9
17 23.7
9.0 14.7 16.4
4.6 25.7 11.0 14.7 18.4
6.3
18 25.2
9.5 15.7 17.4
5.8 25.7 12.5 13.2 19.1
6.3
19 25.0 10.5 14.5 17.8
6.9 20.0 10.4
9.6 15.2
4.5
20 24.0
9.2 14.8 16.6
5.4 26.0 10.4 15.6 18.2
6.0
21 25.8 10.6 15.2 18.2
6.0 25.8 11.0 14.8 18.4
6.6
22 26.0
9.5 16.5 17.8
6.8 26.0 11.0 15.0 18.5
6.9
23 26.5
9.0 17.5 17.8
6.5 20.6 11.5
9.1 16.1
3.9
24 24.5
9.6 14.9 17.1
5.2 20.5 10.5 10.0 15.5
4.9
25 23.0
8.7 14.3 15.9
4.5 20.2 10.0 10.2 15.1
4.8
26 23.0 10.5 12.5 16.8
4.4 20.5 11.5
9.0 16.0
4.4
27 24.5 10.0 14.5 17.3
5.3 15.5 21.8
-6.3 18.7
4.3
28 25.7 10.0 15.7 17.9
6.6 25.0 11.4 13.6 18.2
6.2
29 25.8
8.0 17.8 16.9
6.8 25.1 11.2 13.9 18.2
5.9
30 24.8
6.5 18.3 15.7
5.6 21.0 10.6 10.4 15.8
4.0
31 23.5 11.0 12.5 17.3
4.6 21.0 12.2
8.8 16.6
5.5
55
May
TMAX TMIN d/c
Date TMAX TMIN d/c
Av
Av
2012 2012 2012 2012 H12 2013 2013 2013 2013 H13
1
24.9 12.4 12.5 18.7
6.1 25.0 10.0 15.0 17.5 6.8
2
24.8 12.4 12.4 18.6
6.7 25.5 11.8 13.7 18.7 7.0
3
25.2 11.0 14.2 18.1
6.9 24.5 11.4 13.1 18.0 6.8
4
25.0 11.0 14.0 18.0
7.0 21.0 11.4
9.6 16.2 5.2
5
24.0 11.3 12.7 17.7
6.9 22.0 12.5
9.5 17.3 5.3
6
24.8 12.2 12.6 18.5
6.9 21.0 14.0
7.0 17.5 5.0
7
24.0 11.6 12.4 17.8
6.3 23.0 13.9
9.1 18.5 6.0
8
24.2 10.0 14.2 17.1
6.6 23.5 12.2 11.3 17.9 6.4
9
17.0 13.5
3.5 15.3
2.2 25.0 11.8 13.2 18.4 6.9
10
20.0 12.5
7.5 16.3
5.0 23.2 12.1 11.1 17.7 6.0
11
17.0 12.7
4.3 14.9
1.3 22.0 11.6 10.4 16.8 5.3
12
23.7 13.0 10.7 18.4
6.7 25.0 10.9 14.1 18.0 6.8
13
25.5 11.7 13.8 18.6
6.5 23.0 10.9 12.1 17.0 6.1
14
25.0 13.6 11.4 19.3
6.9 24.0 12.0 12.0 18.0 6.8
15
20.0 13.2
6.8 16.6
5.3 23.0 12.5 10.5 17.8 6.1
16
25.6 12.2 13.4 18.9
6.9 24.0 13.0 11.0 18.5 6.5
17
23.5 13.3 10.2 18.4
5.8 25.0 11.0 14.0 18.0 6.9
18
26.0 14.6 11.4 20.3
6.8 25.0 11.0 14.0 18.0 6.9
19
20.0 12.8
7.2 16.4
4.8 24.5 11.0 13.5 17.8 6.8
20
25.9 12.5 13.4 19.2
6.8 24.0 11.7 12.3 17.9 6.8
21
25.0 13.4 11.6 19.2
6.7 25.0 11.8 13.2 18.4 6.9
22
25.0 12.2 12.8 18.6
6.5 24.3 11.5 12.8 17.9 6.7
23
26.2 11.5 14.7 18.9
6.9 24.5 10.4 14.1 17.5 6.9
24
25.0 11.2 13.8 18.1
6.8 23.0 11.0 12.0 17.0 6.7
25
25.0 11.8 13.2 18.4
6.9 23.4 11.0 12.4 17.2 6.6
26
25.5 12.0 13.5 18.8
6.5 21.5 12.1
9.4 16.8 5.3
27
20.0 10.0 10.0 15.0
5.4 19.0 12.9
6.1 16.0 4.1
28
26.0
9.2 16.8 17.6
6.6 24.0 11.6 12.4 17.8 6.8
29
25.0
9.7 15.3 17.4
6.7 25.0 10.0 15.0 17.5 6.8
30
25.8 11.5 14.3 18.7
6.8 24.5
9.5 15.0 17.0 6.8
31
25.7 10.3 15.4 18.0
6.8 23.4 10.0 13.4 16.7 6.8
\
56
October
TMAX TMIN d/c
Date TMAX TMIN D/c
Av
Av
2010 2010 2010 2010 H10
2011 2011 2011 2011 H11
1
24.5 11.0 13.5
17.8
5.6 25.8 11.3 14.5 18.6
6.3
2
24.5
9.5 15.0
17.0
5.5 25.7 13.0 12.7 19.4
6.7
3
25.3
6.0 19.3
15.7
6.6 25.0 10.0 15.0 17.5
6.6
4
25.2
6.0 19.2
15.6
6.5 25.4 11.5 13.9 18.5
6.6
5
24.5 10.0 14.5
17.3
5.5 25.3 10.0 15.3 17.7
6.7
6
24.5
9.0 15.5
16.8
4.5 25.4
9.7 15.7 17.6
6.2
7
25.8 12.5 13.3
19.2
6.6 25.4 10.0 15.4 17.7
6.3
8
25.7
9.8 15.9
17.8
6.6 24.9 10.8 14.1 17.9
6.2
9
25.8 12.0 13.8
18.9
6.6 23.9 10.0 13.9 17.0
6.5
10
25.7 10.6 15.1
18.2
6.6 25.7 11.3 14.4 18.5
6.6
11
25.7 13.4 12.3
19.6
6.6 25.3
9.4 15.9 17.4
6.3
12
25.6 11.0 14.6
18.3
6.6 25.3 10.4 14.9 17.9
6.4
13
24.2
8.2 16.0
16.2
5.2 25.6
9.5 16.1 17.6
6.5
14
25.0
5.8 19.2
15.4
4.7 25.7 10.0 15.7 17.9
6.5
15
25.3
7.0 18.3
16.2
6.0 25.6 10.5 15.1 18.1
6.5
16
24.2
9.5 14.7
16.9
5.4 25.0
9.0 16.0 17.0
6.5
17
25.0 11.4 13.6
18.2
6.3 21.5 10.0 11.5 15.8
6.5
18
25.4 11.0 14.4
18.2
6.5 22.6 10.2 12.4 16.4
6.5
19
25.4 11.5 13.9
18.5
6.4 25.0
9.6 15.4 17.3
6.5
20
25.3
8.0 17.3
16.7
6.4 25.3
9.2 16.1 17.3
6.4
21
25.2 12.0 13.2
18.6
6.3 25.7
9.5 16.2 17.6
6.4
22
25.0
7.8 17.2
16.4
6.4 25.8
8.5 17.3 17.2
6.4
23
22.2
7.6 14.6
14.9
4.4 25.4
9.8 15.6 17.6
6.4
24
22.6
9.8 12.8
16.2
4.9 25.3 11.0 14.3 18.2
6.4
25
23.7
5.8 17.9
14.8
5.1 25.4
9.8 15.6 17.6
6.4
26
24.6
9.0 15.6
16.8
6.3 25.1
9.4 15.7 17.3
6.3
27
24.7
9.0 15.7
16.9
6.3 25.8
9.6 16.2 17.7
6.3
28
24.5
8.5 16.0
16.5
6.2 25.5 10.5 15.0 18.0
6.3
29
23.8
5.0 18.8
14.4
5.6 25.1 10.2 14.9 17.7
6.2
30
23.6
4.0 19.6
13.8
5.5 25.4 11.0 14.4 18.2
6.3
31
24.7
9.0 15.7
16.9
6.0 25.2 10.8 14.4 18.0
6.2
57
October
TMAX TMIN d/c
Date TMAX TMIN d/c
Av
Av
2012 2012 2012 2012 H12
2013 2013 2013 2013 H13
1
25.0
10.6
14.4 17.8
6.7 23.8 10.9 12.9 17.4
6.8
2
24.9
10.6
14.3 17.8
6.7 17.7
9.8
7.9 13.8
1.3
3
20.0
10.4
9.6 15.2
5.0 24.0 10.0 14.0 17.0
6.0
4
25.7
10.5
15.2 18.1
6.7 20.0
9.7 10.3 14.9
6.3
5
25.4
10.2
15.2 17.8
6.7 19.3 10.0
9.3 14.7
4.8
6
24.9
10.2
14.7 17.6
6.6 18.0 11.0
7.0 14.5
3.3
7
24.8
11.0
13.8 17.9
6.6 16.0 12.3
3.7 14.2
1.6
8
24.7
9.3
15.4 17.0
6.6 18.8 12.4
6.4 15.6
2.6
9
24.7
9.4
15.3 17.1
6.5 20.2 10.8
9.4 15.5
5.3
10
24.8
9.0
15.8 16.9
6.6 20.5 10.5 10.0 15.5
4.9
11
24.8
9.0
15.8 16.9
6.6 19.0
9.8
9.2 14.4
5.1
12
25.0
9.2
15.8 17.1
6.5 20.6 12.3
8.3 16.5
5.9
13
24.1
8.0
16.1 16.1
6.6 22.0 11.3 10.7 16.7
6.4
14
24.7
8.9
15.8 16.8
6.6 19.5 10.3
9.2 14.9
5.5
15
25.0
9.4
15.6 17.2
6.5 22.5 10.5 12.0 16.5
6.4
16
24.5
9.0
15.5 16.8
6.5 23.5 11.3 12.2 17.4
6.3
17
24.5
10.6
13.9 17.6
6.5 24.8 10.5 14.3 17.7
6.5
18
24.0
10.2
13.8 17.1
6.5 24.7 11.0 13.7 17.9
6.5
19
24.0
9.9
14.1 17.0
6.5 20.0
9.7 10.3 14.9
6.5
20
24.6
9.5
15.1 17.1
6.5 24.0 11.0 13.0 17.5
6.4
21
24.3
9.5
14.8 16.9
6.4 24.5 11.0 13.5 17.8
6.3
22
24.5
9.3
15.2 16.9
6.4 24.6 10.7 13.9 17.7
6.4
23
24.3
10.6
13.7 17.5
6.4 23.8
9.3 14.5 16.6
6.4
24
24.5
10.9
13.6 17.7
6.4 23.7
9.3 14.4 16.5
6.2
25
24.5
10.9
13.6 17.7
6.4 23.6
8.6 15.0 16.1
6.3
26
24.0
9.5
14.5 16.8
6.4 23.8
9.0 14.8 16.4
6.3
27
24.5
8.3
16.2 16.4
6.4 24.4
8.9 15.5 16.7
6.3
28
23.8
8.0
15.8 15.9
6.3 22.0
9.5 12.5 15.8
6.3
29
23.7
10.6
13.1 17.2
6.3 22.0 10.1 11.9 16.1
6.3
30
24.0
10.8
13.2 17.4
6.1 23.0
9.9 13.1 16.5
6.3
31
18.0
11.2
6.8 14.6
4.5 22.5 10.5 12.0 16.5
6.2
58
November
TMAX
Date TMAX TMIN D/c
Av
TMIN d/c
Av
2010 2010 2010 2010 H10
2011 2011 2011 2011 H11
1
24.5
9.4 15.1 17.0
6.2
25.0 10.4 14.6 17.7 6.1
2
24.6
8.0 16.6 16.3
6.2
20.8 10.2 10.6 15.5 4.9
3
24.6
5.5 19.1 15.1
6.2
21.7 10.0 11.7 15.9 5.7
4
24.5
7.0 17.5 15.8
6.2
18.0 10.0
8.0 14.0 4.2
5
24.6
9.5 15.1 17.1
6.2
19.5 10.5
9.0 15.0 5.3
6
24.7
6.0 18.7 15.4
6.2
19.5 11.0
8.5 15.3 5.3
7
24.8
4.5 20.3 14.7
6.1
19.0 11.0
8.0 15.0 5.0
8
24.5
4.5 20.0 14.5
6.0
25.0 10.2 14.8 17.6 6.0
9
24.0
6.0 18.0 15.0
6.1
21.0 10.4 10.6 15.7 5.3
10
23.4
7.0 16.4 15.2
4.8
21.0 10.0 11.0 15.5 5.4
11
24.0
5.4 18.6 14.7
5.5
22.0
9.9 12.1 16.0 5.1
12
24.1
6.0 18.1 15.1
5.8
18.0
9.7
8.3 13.9 3.0
13
23.5
7.6 15.9 15.6
5.5
25.0
9.4 15.6 17.2 6.1
14
23.6
6.0 17.6 14.8
4.8
25.4 10.0 15.4 17.7 6.0
15
23.5
3.0 20.5 13.3
4.9
25.3
9.8 15.5 17.6 6.0
16
25.9
3.5 22.4 14.7
6.0
25.4 10.2 15.2 17.8 6.0
17
24.6
3.5 21.1 14.1
5.8
25.3
9.9 15.4 17.6 6.0
18
25.0 10.5 14.5 17.8
6.0
25.6
9.5 16.1 17.6 6.0
19
25.0
6.0 19.0 15.5
6.0
25.6
9.7 15.9 17.7 6.0
20
24.0
8.0 16.0 16.0
5.9
24.9 10.8 14.1 17.9 6.0
21
25.0
7.6 17.4 16.3
6.0
25.4 10.6 14.8 18.0 6.0
22
24.1
9.5 14.6 16.8
5.9
24.0
9.0 15.0 16.5 5.9
23
23.4
5.5 17.9 14.5
5.6
24.0
9.2 14.8 16.6 5.9
24
23.3
3.0 20.3 13.2
5.4
23.8
9.7 14.1 16.8 5.8
25
20.0
2.4 17.6 11.2
3.2
23.4
8.8 14.6 16.1 5.5
26
16.0
6.0 10.0 11.0
2.7
17.0
9.8
7.2 13.4 4.8
27
22.0
2.5 19.5 12.3
4.0
23.4
9.4 14.0 16.4 5.8
28
24.7
3.5 21.2 14.1
5.9
23.5
9.0 14.5 16.3 5.9
29
24.7
3.0 21.7 13.9
5.9
23.4
9.0 14.4 16.2 5.8
30
24.4
6.0 18.4 15.2
5.8
24.0
9.4 14.6 16.7 5.9
59
November
TMAX TMIN d/c
Date TMAX TMIN d/c
Av
Av
2012 2012 2012 2012 H12
2013 2013 2013 2013 H13
1
21.0
9.8 11.2 15.4
5.6 22.0 11.5 10.5
16.8
6.2
2
20.0
9.3 10.7 14.7
5.1 23.2 10.0 13.2
16.6
6.2
3
23.8
9.6 14.2 16.7
6.2 23.7 11.9 11.8
17.8
6.1
4
23.7
9.3 14.4 16.5
6.2 23.8 10.7 13.1
17.3
6.1
5
23.5
9.4 14.1 16.5
6.1 21.8 11.3 10.5
16.6
5.8
6
23.8
9.0 14.8 16.4
6.2 21.3 12.0
9.3
16.7
5.8
7
18.0 10.4
7.6 14.2
4.5 24.3 10.5 13.8
17.4
6.1
8
21.0 10.3 10.7 15.7
5.5 24.0 10.3 13.7
17.2
6.1
9
23.4 10.9 12.5 17.2
6.1 24.0 11.3 12.7
17.7
6.1
10
23.7 10.5 13.2 17.1
6.1 21.0 12.0
9.0
16.5
5.2
11
23.0 10.0 13.0 16.5
6.0 19.8 10.5
9.3
15.2
6.1
12
23.4 10.5 12.9 17.0
6.1 24.0 10.9 13.1
17.5
5.9
13
23.5 11.0 12.5 17.3
6.1 20.4 10.3 10.1
15.4
5.9
14
23.4 10.5 12.9 17.0
6.1 18.0 10.0
8.0
14.0
3.8
15
23.0 10.2 12.8 16.6
6.0 19.0 11.2
7.8
15.1
4.6
16
22.4 10.2 12.2 16.3
6.0 21.0
9.5 11.5
15.3
5.6
17
21.5 10.0 11.5 15.8
5.8 21.4
8.9 12.5
15.2
5.0
18
23.0
9.9 13.1 16.5
6.0 20.0
9.2 10.8
14.6
4.9
19
23.0 10.4 12.6 16.7
6.0 21.8
9.5 12.3
15.7
5.9
20
23.2 10.2 13.0 16.7
6.0 21.5
9.8 11.7
15.7
5.5
21
23.1 10.6 12.5 16.9
6.0 22.0 10.3 11.7
16.2
5.9
22
23.4 10.2 13.2 16.8
6.0 22.0
8.8 13.2
15.4
5.9
23
21.3
9.8 11.5 15.6
5.9 21.0
9.0 12.0
15.0
5.9
24
21.0
9.9 11.1 15.5
5.9 21.5 10.0 11.5
15.8
5.9
25
22.0 10.5 11.5 16.3
5.9 20.8
9.9 10.9
15.4
5.8
26
21.7 10.1 11.6 15.9
5.9 21.0
9.5 11.5
15.3
5.9
27
23.0
9.1 13.9 16.1
5.9 20.7
8.5 12.2
14.6
5.5
28
22.9
9.6 13.3 16.3
5.9 23.0
8.3 14.7
15.7
5.9
29
22.0
9.8 12.2 15.9
5.8 23.4
7.9 15.5
15.7
5.9
30
21.8
9.2 21.8 10.9
5.3 22.0
8.7 13.3
15.4
5.9
60
December
TMAX TMIN
Date TMAX TMIN D/c
Av
d/c
Av
2010 2010 2010 2010 H10 2011
2011 2011 2011 H11
1 24.5
4.5 20.0 14.5 5.8 23.0
8.8 14.2 15.9
5.8
2 24.7
4.4 20.3 14.6 5.8 23.1
10.3 12.8 16.7
5.8
3 24.7
6.6 18.1 15.7 5.8 23.0
9.5 13.5 16.3
5.8
4 24.7
7.0 17.7 15.9 5.8 23.8
9.4 14.4 16.6
5.8
5 24.8
4.8 20.0 14.8 5.8 23.0
8.0 15.0 15.5
5.8
6 24.7
5.0 19.7 14.9 5.8 23.4
9.6 13.8 16.5
5.8
7 24.5
5.5 19.0 15.0 5.8 23.6
8.9 14.7 16.3
5.8
8 24.8
7.5 17.3 16.2 5.7 23.4
10.0 13.4 16.7
5.8
9 24.8
6.0 18.8 15.4 5.8 23.4
9.5 13.9 16.5
5.8
10 24.6
6.0 18.6 15.3 5.8 23.7
8.5 15.2 16.1
5.8
11 24.4
7.5 16.9 16.0 5.8 23.8
10.3 13.5 17.1
5.8
12 22.7
7.5 15.2 15.1 4.7 23.4
10.5 12.9 17.0
5.8
13 20.4
7.2 13.2 13.8 3.2 23.8
9.6 14.2 16.7
5.8
14 23.8
3.0 20.8 13.4 5.1 23.6
9.5 14.1 16.6
5.8
15 24.0
1.0 23.0 12.5 5.7 23.4
10.5 12.9 17.0
5.8
16 24.6
5.4 19.2 15.0 5.8 23.1
9.0 14.1 16.1
5.8
17 24.5
6.0 18.5 15.3 5.8 23.4
9.5 13.9 16.5
5.8
18 24.6
5.0 19.6 14.8 5.8 23.5
10.0 13.5 16.8
5.7
19 24.6
2.0 22.6 13.3 5.8 23.6
10.7 12.9 17.2
5.8
20 24.8
7.2 17.6 16.0 5.8 23.0
11.0 12.0 17.0
5.7
21 24.8
5.5 19.3 15.2 5.8 23.0
10.6 12.4 16.8
5.7
22 24.6
8.6 16.0 16.6 5.8 23.0
10.0 13.0 16.5
5.7
23 24.6
7.2 17.4 15.9 5.7 23.1
9.6 13.5 16.4
5.8
24 24.6
6.5 18.1 15.6 5.7 23.1
8.5 14.6 15.8
5.8
25 24.5
9.5 15.0 17.0 5.7 23.4
8.9 14.5 16.2
5.8
26 24.5
9.8 14.7 17.2 5.7 23.3
11.5 11.8 17.4
5.8
27 24.6
9.0 15.6 16.8 5.8 23.2
8.0 15.2 15.6
5.8
28 24.2
8.0 16.2 16.1 5.2 23.6
7.5 16.1 15.6
5.8
29 19.0
7.0 12.0 13.0 2.7 23.1
7.0 16.1 15.1
5.8
30 24.2
8.0 16.2 16.1 5.3 23.4
8.0 15.4 15.7
5.8
31 16.5
7.0
9.5 11.8 1.9 23.2
10.0 13.2 16.6
5.8
61
December
TMAX TMIN d/c
Date TMAX TMIN d/c
Av
Av
2012 2012 2012 2012 H12
2013 2013 2013 2013 H13
1
22.0
9.5 12.5
15.8
5.8 22.2
9.2 13.0
15.7
5.7
2
21.4
9.2 12.2
15.3
5.8 23.0
8.0 15.0
15.5
5.8
3
21.5
8.9 12.6
15.2
5.8 22.8
7.8 15.0
15.3
5.8
4
21.0
8.8 12.2
14.9
5.8 23.0
9.3 13.7
16.2
5.8
5
21.0
8.9 12.1
15.0
5.8 23.5
7.6 15.9
15.6
5.8
6
22.5
9.1 13.4
15.8
5.8 22.8
5.7 17.1
14.3
5.8
7
21.5
8.7 12.8
15.1
5.6 22.5
5.0 17.5
13.8
5.8
8
22.0
8.8 13.2
15.4
5.8 22.0
5.0 17.0
13.5
5.8
9
21.0
8.8 12.2
14.9
5.7 22.5
5.9 16.6
14.2
5.8
10
22.0
8.6 13.4
15.3
5.8 22.0
3.8 18.2
12.9
5.8
11
22.5
8.4 14.1
15.5
5.8 23.0
8.5 14.5
15.8
5.7
12
22.6
7.9 14.7
15.3
5.8 22.8
6.5 16.3
14.7
5.8
13
22.6
7.7 14.9
15.2
5.8 23.0
6.8 16.2
14.9
5.7
14
22.7
7.6 15.1
15.2
5.8 24.0
6.0 18.0
15.0
5.8
15
22.5
8.1 14.4
15.3
5.8 23.5
7.5 16.0
15.5
5.8
16
21.1
8.3 12.8
14.7
5.7 22.0
6.9 15.1
14.5
5.4
17
21.0
8.5 12.5
14.8
5.7 22.0
6.5 15.5
14.3
5.4
18
22.5
8.5 14.0
15.5
5.8 23.4
7.0 16.4
15.2
5.8
19
21.0
8.4 12.6
14.7
5.6 22.5
7.0 15.5
14.8
5.8
20
20.9
8.6 12.3
14.8
5.6 23.8
6.9 16.9
15.4
5.8
21
22.5
8.4 14.1
15.5
5.8 22.0
7.5 14.5
14.8
5.7
22
23.0
8.1 14.9
15.6
5.8 22.1
6.3 15.8
14.2
5.7
23
22.4
7.8 14.6
15.1
5.8 23.3
7.1 16.2
15.2
5.7
24
22.0
7.9 14.1
15.0
5.7 23.8
7.4 16.4
15.6
5.8
25
22.0
7.7 14.3
14.9
5.7 23.5
7.2 16.3
15.4
5.8
26
22.1
7.9 14.2
15.0
5.7 24.0
7.8 16.2
15.9
5.8
27
22.0
8.5 13.5
15.3
5.7 24.2
7.2 17.0
15.7
5.8
28
22.8
8.7 14.1
15.8
5.8 23.5
7.0 16.5
15.3
5.7
29
22.5
8.0 14.5
15.3
5.7 24.5
8.0 16.5
16.3
5.8
30
22.0
8.5 13.5
15.3
5.7 23.8
8.1 15.7
16.0
5.4
31
21.5
8.2 13.3
14.9
5.6 24.3
7.8 16.5
16.1
5.7
62
Appendix. Table 2: Air temperature in ( o c) and daily solar radiation H (KWh/m 2 )
of wet season of the four years
June
TMAX TMIN d/ce
Date TMAX TMIN d/ce Av
Av
2010 2010 2010 2010 H10
2011 2011 2011 2011 H11
1 25.8
7.5 18.3
16.7
6.8
19.6
10.5
9.1 15.1
5.0
2 24.5
8.0 16.5
16.3
6.5
22.0
11.0
11.0 16.5
6.7
3 23.6
7.5 16.1
15.6
5.4
22.5
11.6
10.9 17.1
6.8
4 23.0
9.5 13.5
16.3
5.9
22.2
12.5
9.7 17.4
6.6
5 23.5
9.0 14.5
16.3
6.0
23.0
11.4
11.6 17.2
6.3
6 24.5
8.0 16.5
16.3
6.2
23.0
11.8
11.2 17.4
6.8
7 24.3
8.8 15.5
16.6
6.6
22.5
11.4
11.1 17.0
6.7
8 24.2
8.0 16.2
16.1
6.1
22.5
11.6
10.9 17.1
4.7
9 24.5
8.5 16.0
16.5
5.5
20.5
12.6
7.9 16.6
4.1
10 25.0
8.5 16.5
16.8
6.7
23.2
17.6
5.6 20.4
6.1
11 23.0
10.2 12.8
16.6
5.9
20.4
10.6
9.8 15.5
4.7
12 24.0
9.5 14.5
16.8
5.5
21.2
11.5
9.7 16.4
5.4
13 23.8
8.5 15.3
16.2
6.4
19.0
10.6
8.4 14.8
1.5
14 23.5
10.0 13.5
16.8
6.7
19.2
10.0
9.2 14.6
4.5
15 25.5
7.8 17.7
16.7
6.8
21.0
10.8
10.2 15.9
5.3
16 25.0
10.5 14.5
17.8
5.4
21.8
12.2
9.6 17.0
6.7
17 24.0
10.6 13.4
17.3
5.8
22.0
12.6
9.4 17.3
6.7
18 23.7
8.0 15.7
15.9
6.7
21.8
11.6
10.2 16.7
6.5
19 23.5
10.0 13.5
16.8
6.6
20.8
11.5
9.3 16.2
2.6
20 23.5
11.0 12.5
17.3
6.7
19.4
11.8
7.6 15.6
1.9
21 23.0
10.5 12.5
16.8
5.8
20.6
10.3
10.3 15.5
4.4
22 24.5
9.5 15.0
17.0
6.7
20.8
10.7
10.1 15.8
6.2
23 20.2
9.2 11.0
14.7
2.8
22.5
11.0
11.5 16.8
5.0
24 22.0
9.8 12.2
15.9
4.0
20.0
10.2
9.8 15.1
2.9
25 20.0
10.5
9.5
15.3
2.6
20.4
11.0
9.4 15.7
6.3
26 22.5
8.0 14.5
15.3
5.3
21.4
9.4
12.0 15.4
6.3
27 20.5
8.5 12.0
14.5
2.5
20.3
10.5
9.8 15.4
3.2
28 20.0
8.0 12.0
14.0
2.2
19.5
11.2
8.3 15.4
2.1
29 21.5
8.2 13.3
14.9
6.5
19.4
9.8
9.6 14.6
5.4
30 20.2
10.5
9.7
15.4
3.3
18.0
10.6
7.4 14.3
1.3
63
June
TMAX TMIN d/ce Av
Date TMAX TMIN
d/ce
Av
26
2012 2012 2012 H12
2013 2013 2013 2013 H13
1
24.8
12.0
12.8 18.4
6.8 25.9
15.0 10.9 18.4
6.4
2
23.2
12.2
11.0 17.7
6.0 24.5
14.3 10.2 17.4
6.8
3
22.5
11.4
11.1 17.0
5.3 22.1
13.0
9.1 15.6
6.8
4
23.5
10.7
12.8 17.1
5.4 24.5
12.3 12.2 18.4
6.8
5
22.5
10.7
11.8 16.6
6.8 23.4
11.5 11.9 17.7
6.1
6
21.0
11.2
9.8 16.1
5.6 24.5
12.3 12.2 18.4
5.8
7
23.0
11.3
11.7 17.2
4.3 25.0
13.0 12.0 18.5
6.1
8
23.2
11.0
12.2 17.1
5.4 25.5
12.8 12.7 19.1
6.7
9
22.2
10.5
11.7 16.4
6.5 24.2
13.3 10.9 17.6
6.2
10
21.0
12.8
8.2 16.9
5.6 24.6
12.7 11.9 18.3
5.8
11
23.2
10.3
12.9 16.8
5.6 24.7
12.0 12.7 18.7
6.0
12
23.0
10.4
12.6 16.7
6.7 23.2
12.3 10.9 17.1
4.5
13
23.0
11.3
11.7 17.2
6.4 23.0
13.3
9.7 16.4
4.8
14
22.2
12.4
9.8 17.3
6.6 24.5
12.3 12.2 18.4
6.5
15
22.2
11.5
10.7 16.9
6.4 21.8
11.5 10.3 16.1
4.8
16
21.4
10.8
10.6 16.1
5.2 22.2
12.3
9.9 16.1
6.7
17
21.9
11.5
10.4 16.7
4.5 21.0
10.9 10.1 15.6
6.6
18
21.0
11.5
9.5 16.3
6.0 21.2
11.5
9.7 15.5
6.4
19
18.0
10.8
7.2 14.4
4.5 22.5
10.0 12.5 17.5
2.8
20
18.2
10.5
7.7 14.4
2.6 22.6
10.7 11.9 17.3
5.2
21
18.0
10.5
7.5 14.3
3.9 23.7
12.6 11.1 17.4
6.0
22
18.4
9.5
8.9 14.0
4.4 24.1
12.9 11.2 17.7
6.3
23
20.0
8.4
11.6 14.2
5.1 23.4
13.4 10.0 16.7
4.2
24
20.5
7.5
13.0 14.0
5.8 21.5
12.5
9.0 15.3
3.5
25
17.0
9.6
7.4 13.3
6.1 21.5
11.7
9.8 15.7
2.6
26
18.4
7.5
10.9 13.0
2.2 21.4
10.4 11.0 16.2
5.0
27
18.4
9.8
8.6 14.1
3.8 21.1
11.5
9.6 15.4
5.9
28
18.5
9.9
8.6 14.2
5.1 19.9
8.8 11.1 15.5
6.6
29
17.0
10.0
7.0 13.5
4.2 17.5
10.0
7.5 12.5
6.1
30
18.0
9.0
9.0 13.5
2.2 17.5
10.6
6.9 12.2
5.4
64
July
TMAX TMIN d/ce Av
Date TMAX TMIN
d/ce Av
2010
2010 2010 2010 H10
2011 2011 2011 2011 H11
1
22.0
10.5 11.5
16.3
3.7 19.8 10.8
9.0 15.3 4.5
2
23.8
11.0 12.8
17.4
5.2 20.5 11.6
8.9 16.1 4.3
3
22.5
8.5 14.0
15.5
6.1 20.1 11.4
8.7 15.8 6.2
4
24.0
8.2 15.8
16.1
6.2 20.4 10.0 10.4 15.2 5.8
5
22.0
9.0 13.0
15.5
6.6 18.6 11.5
7.1 15.1 3.9
6
21.0
9.5 11.5
15.3
4.9 20.0 10.4
9.6 15.2 5.2
7
23.0
10.0 13.0
16.5
6.4 17.8 10.2
7.6 14.0 3.1
8
21.0
10.5 10.5
15.8
5.1 21.0 10.2 10.8 15.6 6.0
9
21.0
10.5 10.5
15.8
4.5 20.8 11.5
9.3 16.2 5.2
10
25.5
9.6 15.9
17.6
5.1 21.6 10.6 11.0 16.1 6.4
11
23.0
9.0 14.0
16.0
5.9 20.7
9.7 11.0 15.2 5.6
12
21.0
10.2 10.8
15.6
2.8 19.0 11.5
7.5 15.3 2.4
13
24.5
10.6 13.9
17.6
6.5 14.5 10.4
4.1 12.5 3.1
14
22.5
11.0 11.5
16.8
3.7 15.0 10.5
4.5 12.8 1.2
15
23.5
11.0 12.5
17.3
6.3 17.6
9.2
8.4 13.4 3.5
16
23.3
7.0 16.3
15.2
6.3 20.6 10.4 10.2 15.5 5.9
17
23.6
9.2 14.4
16.4
5.4 18.5
9.8
8.7 14.2 2.2
18
18.4
10.0
8.4
14.2
1.3 17.2
9.8
7.4 13.5 1.3
19
21.0
6.1 14.9
13.6
6.1 18.7
9.5
9.2 14.1 1.8
20
18.5
10.5
8.0
14.5
1.3 19.4 11.0
8.4 15.2 5.9
21
18.0
9.0
9.0
13.5
1.3 18.2 10.0
8.2 14.1 4.2
22
20.0
8.0 12.0
14.0
5.3 19.5 11.0
8.5 15.3 2.8
23
21.0
9.5 11.5
15.3
4.7 17.8 10.6
7.2 14.2 2.7
24
20.0
9.0 11.0
14.5
2.4 16.4 10.6
5.8 13.5 2.2
25
17.4
9.0
8.4
13.2
1.3 17.3 10.0
7.3 13.7 3.1
26
20.0
7.4 12.6
13.7
3.7 20.0
9.9 10.1 15.0 4.2
27
20.0
9.2 10.8
14.6
3.7 20.5 10.3 10.2 15.4 4.2
28
17.0
9.5
7.5
13.3
1.3 20.5 10.5 10.0 15.5 6.3
29
21.5
8.5 13.0
15.0
5.0 19.1 11.2
7.9 15.2 2.2
30
21.5
10.5 11.0
16.0
3.7 15.2 10.8
4.4 13.0 1.3
31
22.6
9.0 13.6
15.8
4.5 15.8 15.4
0.4 15.6 1.4
65
July
TMAX
Date TMAX
TMIN d/ce Av
TMIN d/ce Av
2012 2012 2012 2012 H12
2013 2013 2013 2013 H13
1
17.0
8.8
8.2
12.9
4.0
18.5 11.5
7.0 12.8
3.1
2
16.8
9.4
7.4
13.1
1.7
18.7 11.3
7.4 13.1
5.8
3
15.9
9.0
6.9
12.5
5.1
18.2 11.9
6.3 12.3
4.3
4
17.2 10.0
7.2
13.6
1.9
18.2 11.0
7.2 12.7
4.6
5
17.5 10.4
7.1
14.0
3.0
17.1 10.7
6.4 11.8
2.4
6
18.4
8.9
9.5
13.7
3.1
18.2 10.8
7.4 12.8
2.4
7
18.5
9.5
9.0
14.0
2.6
18.7 10.6
8.1 13.4
3.5
8
19.5
9.0 10.5
14.3
5.0
16.0 12.5
3.5
9.8
5.4
9
19.5 10.0
9.5
14.8
5.9
16.4 11.5
4.9 10.7
1.2
10
21.3 10.6 10.7
16.0
3.5
17.8 12.0
5.8 11.8
4.2
11
20.3
9.9 10.4
15.1
6.4
19.5 12.2
7.3 13.4
6.5
12
19.5 11.4
8.1
15.5
5.5
16.8 12.5
4.3 10.6
6.1
13
20.0 10.4
9.6
15.2
5.3
17.5
9.8
7.7 12.6
3.2
14
18.0 10.9
7.1
14.5
5.2
17.8
9.7
8.1 13.0
4.4
15
18.0 10.2
7.8
14.1
4.5
16.8 12.5
4.3 10.6
4.7
16
19.5 10.7
8.8
15.1
3.7
17.4 12.0
5.4 11.4
3.6
17
18.0 10.0
8.0
14.0
3.9
15.8 11.6
4.2 10.0
1.3
18
16.5 10.3
6.2
13.4
2.8
15.7 12.5
3.2
9.5
1.3
19
18.5 10.2
8.3
14.4
3.9
18.6 13.0
5.6 12.1
4.3
20
18.4 10.5
7.9
14.5
3.3
18.4 12.0
6.4 12.4
4.7
21
16.3
9.7
6.6
13.0
4.2
15.1 13.5
1.6
8.4
1.3
22
16.6 11.0
5.6
13.8
3.1
15.2 12.5
2.7
9.0
1.3
23
18.4 11.5
6.9
15.0
3.6
19.5 12.8
6.7 13.1
4.2
24
16.2 10.0
6.2
13.1
4.1
18.5 12.3
6.2 12.4
6.0
25
15.0 11.6
3.4
13.3
1.9
15.5 13.5
2.0
8.8
5.3
26
18.8 10.7
8.1
14.8
2.7
14.5 12.5
2.0
8.3
1.8
27
16.0 10.9
5.1
13.5
3.4
17.5 10.1
7.4 12.5
2.4
28
20.1 11.7
8.4
15.9
1.9
14.7 11.8
2.9
8.8
2.8
29
16.0
9.9
6.1
13.0
5.1
18.5 12.3
6.2 12.4
2.7
30
22.2 11.0 11.2
16.6
2.0
17.3 11.3
6.0 11.7
3.9
31
17.5 10.0
7.5
13.8
6.8
15.4 11.1
4.3
9.9
2.1
66
August
TMAX
Date TMAX TMIN d/ce
Av
TMIN d/ce
Av
2010 2010 2010 2010 H10
2011 2011 2011 2011 H11
1 21.6
9.0
12.6 15.3
3.9
19.5 10.0
9.5 14.8
6.2
2 21.0
9.4
11.6 15.2
3.9
18.7 11.5
7.2 15.1
4.1
3 22.8
7.5
15.3 15.2
6.1
17.7 10.0
7.7 13.9
4.6
4 22.5 10.5
12.0 16.5
5.6
16.5 11.0
5.5 13.8
1.3
5 19.6 12.5
7.1 16.1
2.0
18.0 10.7
7.3 14.4
2.4
6 21.7
9.0
12.7 15.4
5.4
18.4 10.5
7.9 14.5
5.6
7 21.6
9.0
12.6 15.3
4.0
16.0 10.6
5.4 13.3
1.3
8 21.8
9.0
12.8 15.4
5.8
16.7 11.0
5.7 13.9
1.3
9 21.5
9.0
12.5 15.3
4.8
15.0 10.7
4.3 12.9
2.0
10 20.0
9.5
10.5 14.8
4.8
18.5
9.0
9.5 13.8
1.9
11 22.5
7.5
15.0 15.0
6.5
17.5 11.4
6.1 14.5
2.2
12 22.5
9.5
13.0 16.0
5.5
19.5 10.0
9.5 14.8
4.5
13 18.5 10.0
8.5 14.3
2.0
19.0 10.4
8.6 14.7
5.1
14 21.0
9.0
12.0 15.0
4.3
19.8 11.4
8.4 15.6
3.6
15 23.3
8.0
15.3 15.7
6.0
20.0 11.0
9.0 15.5
3.5
16 21.5 10.5
11.0 16.0
3.7
19.0 11.0
8.0 15.0
5.6
17 23.4
8.0
15.4 15.7
5.7
17.7 10.0
7.7 13.9
4.2
18 23.0 11.0
12.0 17.0
6.7
18.3 11.3
7.0 14.8
4.4
19 23.0 10.0
13.0 16.5
6.8
19.1
9.8
9.3 14.5
3.2
20 23.0
9.0
14.0 16.0
6.5
20.2 10.2
10.0 15.2
5.8
21 21.0
8.9
12.1 15.0
5.7
16.2 10.2
6.0 13.2
1.5
22 22.0 10.0
12.0 16.0
6.0
20.5
9.0
11.5 14.8
5.5
23 21.5
9.5
12.0 15.5
4.4
21.0 10.5
10.5 15.8
6.0
24 23.0 10.6
12.4 16.8
6.9
21.3 10.3
11.0 15.8
5.3
25 19.5 10.6
8.9 15.1
1.3
19.4 10.0
9.4 14.7
2.5
26 22.7
9.4
13.3 16.1
4.9
18.5 10.0
8.5 14.3
2.1
27 20.4 10.4
10.0 15.4
4.0
18.8 10.2
8.6 14.5
3.6
28 22.0
9.7
12.3 15.9
4.7
18.8 11.8
7.0 15.3
2.4
29 21.0 10.4
10.6 15.7
4.1
17.1 10.7
6.4 13.9
1.8
30 19.5 10.0
9.5 14.8
3.0
19.5 10.8
8.7 15.2
4.2
31 24.8
7.8
17.0 16.3
6.4
19.0 16.0
3.0 17.5
3.3
67
August
Date
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
TMAX TMIN
d/ce Av
2012
2012 2012 2012
18.7
12.0
6.7 15.4
15.2
11.3
3.9 13.3
18.9
9.4
9.5 14.2
22.4
9.5 12.9 16.0
22.1
11.5 10.6 16.8
17.5
10.3
7.2 13.9
18.2
10.8
7.4 14.5
19.6
9.0 10.6 14.3
16.9
9.2
7.7 13.1
18.3
11.0
7.3 14.7
18.8
10.7
8.1 14.8
19.0
9.7
9.3 14.4
18.9
10.0
8.9 14.5
19.0
10.6
8.4 14.8
17.9
8.5
9.4 13.2
16.5
9.5
7.0 13.0
16.2
10.0
6.2 13.1
19.4
9.2 10.2 14.3
16.8
10.0
6.8 13.4
19.2
10.0
9.2 14.6
18.6
9.4
9.2 14.0
18.4
10.2
8.2 14.3
19.6
8.4 11.2 14.0
17.6
9.2
8.4 13.4
16.2
10.8
5.4 13.5
18.6
10.6
8.0 14.6
17.8
9.8
8.0 13.8
19.4
10.5
8.9 15.0
20.5
9.5 11.0 15.0
17.9
11.4
6.5 14.7
21.8
10.5 11.3 16.2
TMAX
H12
2.9
3.2
1.3
4.4
6.8
6.5
2.2
3.5
5.5
1.3
3.7
2.6
4.8
4.8
3.1
5.3
3.7
1.8
5.2
2.0
5.5
5.2
5.5
5.9
4.9
1.3
4.5
3.7
4.8
6.0
2.5
2013
16.4
16.4
15.8
13.5
15.4
15.3
16.3
18.5
16.0
15.2
16.7
17.6
16.8
16.2
16.6
16.6
17.4
18.5
16.3
15.8
24.3
15.3
15.2
19.2
16.1
17.4
18.0
18.1
16.5
19.8
15.8
TMIN d/ce
Av
2013 2013 2013
13.0
3.4
9.9
13.0
3.4
9.9
12.8
3.0
9.4
13.2
0.3
6.9
13.6
1.8
8.6
13.5
1.8
8.6
13.6
2.7
9.5
12.7
5.8 12.2
15.0
1.0
8.5
14.2
1.0
8.1
13.8
2.9
9.8
13.5
4.1 10.9
13.7
3.1 10.0
14.0
2.2
9.2
14.0
2.6
9.6
14.5
2.1
9.4
13.8
3.6 10.5
14.2
4.3 11.4
13.9
2.4
9.4
14.5
1.3
8.6
13.6
10.7 17.5
14.4
0.9
8.1
13.8
1.4
8.3
13.5
5.7 12.5
13.2
2.9
9.5
12.7
4.7 11.1
13.0
5.0 11.5
12.8
5.3 11.7
14.0
2.5
9.5
13.9
5.9 12.9
11.9
3.9
9.9
H13
1.4
1.4
1.9
2.2
1.4
3.0
1.8
6.9
3.1
1.4
5.1
2.7
2.4
1.9
1.3
1.5
3.2
4.0
5.7
1.7
6.9
2.9
2.9
5.1
5.9
2.9
4.3
2.8
3.8
2.8
1.6
68
September
TMIN
d/ce
Av
Date TMAX
2010 2010 2010 2010 H10
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
20.6
20.0
20.5
21.5
23.2
22.0
21.0
22.5
19.3
19.2
21.5
21.0
21.0
21.0
21.8
19.0
21.0
21.1
21.0
21.0
20.7
21.5
21.5
22.8
20.0
18.8
22.5
23.3
22.8
22.2
9.0
9.5
7.0
9.5
8.5
10.0
10.0
7.6
8.5
9.0
8.0
9.5
8.5
9.0
9.5
8.5
7.0
9.5
7.0
7.5
6.5
6.0
9.5
6.6
8.0
6.5
6.5
6.2
6.6
10.9
11.6
10.5
13.5
12.0
14.7
12.0
11.0
14.9
10.8
10.2
13.5
11.5
12.5
12.0
12.3
10.5
14.0
11.6
14.0
13.5
14.2
15.5
12.0
16.2
12.0
12.3
16.0
17.1
16.2
11.3
14.8
14.8
13.8
15.5
15.9
16.0
15.5
15.1
13.9
14.1
14.8
15.3
14.8
15.0
15.7
13.8
14.0
15.3
14.0
14.3
13.6
13.8
15.5
14.7
14.0
12.7
14.5
14.8
14.7
16.6
3.3
2.5
2.9
2.8
3.5
2.7
2.2
3.6
2.5
2.5
3.8
3.3
3.1
3.0
4.1
3.6
2.5
2.9
3.1
2.0
2.7
3.5
3.2
2.6
2.0
1.9
4.1
3.5
2.4
2.9
TMAX TMIN d/ce Av
2011 2011 2011 2011 H11
19.1
19.5
16.8
19.4
19.9
19.6
19.5
17.8
19.6
19.4
20.2
20.5
19.5
20.0
19.0
19.5
19.6
20.0
20.0
20.0
20.6
21.0
19.3
20.2
19.4
18.5
18.8
21.0
21.0
22.0
10.5
11.3
9.8
9.6
10.0
10.5
11.5
10.5
10.1
10.5
11.4
10.2
9.2
10.5
10.5
11.0
10.5
10.2
10.5
10.0
12.0
11.5
11.2
10.2
10.6
10.0
10.0
9.4
12.0
13.2
8.6
8.2
7.0
9.8
9.9
9.1
8.0
7.3
9.5
8.9
8.8
10.3
10.3
9.5
8.5
8.5
9.1
9.8
9.5
10.0
8.6
9.5
8.1
10.0
8.8
8.5
8.8
11.6
9.0
8.8
14.8
15.4
13.3
14.5
15.0
15.1
15.5
14.2
14.9
15.0
15.8
15.4
14.4
15.3
14.8
15.3
15.1
15.1
15.3
15.0
16.3
16.3
15.3
15.2
15.0
14.3
14.4
15.2
16.5
17.6
1.9
3.5
3.3
3.9
5.5
4.2
2.5
1.4
3.5
5.1
5.0
5.5
5.5
4.7
4.7
5.8
4.7
5.1
6.1
6.3
5.6
6.1
2.8
4.8
4.9
1.2
4.6
6.7
6.7
6.7
69
September
TMAX TMIN
Date TMAX TMIN d/ce
Av
d/ce Av
22012 2012
2012 2012 H12 2013
2013 2013 2013 H13
1
18.2
8.8
9.4 13.5
6.5 18.0
12.6
5.4 11.7
5.4
2
18.2
9.5
8.7 13.9
3.3 18.4
12.4
6.0 12.2
4.3
3
19.4
9.9
9.5 14.7
3.2 17.5
13.1
4.4 11.0
2.5
4
18.0 10.3
7.7 14.2
5.4 21.6
11.7
9.9 15.8
6.1
5
17.5
9.0
8.5 13.3
3.7 18.4
12.8
5.6 12.0
4.3
6
18.8 10.1
8.7 14.5
3.6 16.6
13.6
3.0
9.8
2.7
7
18.2
9.0
9.2 13.6
5.8 19.0
12.4
6.6 12.8
5.4
8
22.2
8.2
14.0 15.2
4.2 21.2
13.4
7.8 14.5
6.0
9
19.5
9.8
9.7 14.7
6.4 18.8
12.7
6.1 12.5
3.9
10
19.0 11.5
7.5 15.3
4.8 19.5
13.2
6.3 12.9
3.7
11
18.0 10.1
7.9 14.1
3.2 21.6
13.5
8.1 14.9
6.4
12
20.1 10.6
9.5 15.4
2.8 16.8
13.1
3.7 10.3
4.7
13
18.9
9.5
9.4 14.2
6.0 15.5
12.9
2.6
9.1
3.2
14
23.1 10.0
13.1 16.6
5.8 17.6
13.8
3.8 10.7
4.3
15
17.8
9.0
8.8 13.4
6.6 16.4
13.7
2.7
9.6
4.0
16
18.0
9.6
8.4 13.8
5.5 14.5
12.9
1.6
8.1
1.4
17
23.1
9.5
13.6 16.3
5.7 20.6
13.7
6.9 13.8
5.9
18
19.5
9.2
10.3 14.4
6.6 22.2
13.8
8.4 15.3
5.1
19
19.7
9.8
9.9 14.8
6.3 19.9
11.0
8.9 14.4
3.9
20
18.9
9.8
9.1 14.4
5.3 18.8
11.9
6.9 12.9
6.0
21
21.2
8.9
12.3 15.1
4.6 20.0
11.0
9.0 14.5
6.7
22
21.5 10.0
11.5 15.8
6.5 20.8
11.8
9.0 14.9
6.7
23
20.1 11.2
8.9 15.7
6.6 20.5
12.1
8.4 14.5
6.4
24
21.2 10.0
11.2 15.6
6.1 17.2
10.8
6.4 11.8
4.4
25
21.2 10.0
11.2 15.6
6.5 23.8
11.3 12.5 18.2
6.7
26
21.8
9.7
12.1 15.8
6.4 21.5
11.6
9.9 15.7
6.2
27
20.5 10.0
10.5 15.3
6.7 22.0
10.3 11.7 16.9
5.6
28
20.2 10.0
10.2 15.1
6.1 24.2
11.0 13.2 18.7
6.6
29
17.5
9.8
7.7 13.7
6.2 24.5
12.5 12.0 18.3
6.7
30
17.5
9.0
8.5 13.3
4.9 24.4
12.3 12.1 18.3
6.2
70
Appendix. Table 3a:
temperature in ( o c)
Measured
Tat
intensity
I(W/m 2 )
and
corresponding
Imeas
Tat
date
9am
Iest
at 9am
12am
Iest
Imeas
Tat
15pm
Iest
Imeas
8
17.0
39.8
35.6
17.7
62.1
57.3
18.8
39.8
36
9
18.2
39.4
36.0
23.7
61.4
56.4
18.5
39.4
34.3
10
16.0
39.7
33.5
23.1
54.1
54.1
18.2
39.7
34.3
11
18.0
39.3
35.1
22.4
41.3
52
19.4
39.3
36
12
16.8
28.7
32.7
22.6
44.6
53.1
16.2
28.7
27.6
13
19.6
40.2
37.8
22.8
62.4
57.3
18.9
40.2
31.8
14
17.5
39.8
31.0
24.1
61.6
56
19.4
39.8
36
15
17.4
37.9
29.5
21.9
58.6
55.4
19.6
37.9
36.9
16
17.0
40
27.9
21.4
61.7
57.3
19.8
40
38.9
17
17.2
39.2
34.3
22.8
60.6
56.3
21.4
39.2
39.4
18
17.1
40.7
34.3
21.4
62.8
57.9
19.5
40.7
32.7
19
18.2
41.8
36.9
22.8
64.4
57.5
22.6
41.8
34.3
20
18.2
41.9
37.7
22.8
64.5
57
20.5
41.9
36
21
18.5
40.5
37.9
22.5
62.3
57.8
21.5
40.5
36.9
22
18.5
39.4
36.0
23.2
60.5
57.7
20.0
39.4
35.2
air
71
Appendix. Table 3b: Estimated daily mean solar radiation of april (8 -22/ 2014) H
(KWh/m 2 )
Date
nd
δ
8
98
6.76
9
99
10
Ws
N
Ho
n
a
b
H
1.59
91.14
12.15
10.51
9.90
0.38
0.34
6.94
7.14
1.59
91.21
12.16
10.51
9.10
0.36
0.38
6.84
100
7.53
1.59
91.27
12.17
10.52
9.30
0.37
0.37
6.88
11
101
7.91
1.59
91.34
12.18
10.52
8.70
0.35
0.41
6.77
12
102
8.29
1.60
91.40
12.19
10.52
4.30
0.24
0.66
4.93
13
103
8.66
1.60
91.47
12.20
10.52
9.30
0.37
0.37
6.88
14
104
9.04
1.60
91.53
12.20
10.53
8.70
0.35
0.41
6.77
15
105
9.41
1.60
91.59
12.21
10.53
7.40
0.32
0.48
6.42
16
106
9.78
1.60
91.66
12.22
10.53
8.60
0.35
0.42
6.75
17
107
10.14
1.60
91.72
12.23
10.53
8.00
0.33
0.45
6.60
18
108
10.50
1.60
91.78
12.24
10.53
9.00
0.36
0.39
6.83
19
109
10.86
1.60
91.85
12.25
10.53
10.60
0.40
0.30
6.98
20
110
11.22
1.60
91.91
12.25
10.52
10.40
0.40
0.31
6.98
21
111
11.57
1.61
91.97
12.26
10.52
8.50
0.35
0.42
6.72
22
112
11.92
1.61
92.03
12.27
10.52
7.70
0.32
0.47
6.50
72
Measured air temperature and PV voltage on April 8-22/2014
date
Tat 9am
Tat 12am
Tat 3pm
V9
V12
V3
8
17.0
17.7
18.8
8.4
10.6
8.5
9
18.2
23.7
18.5
8.4
10.5
8.4
10
16.0
23.1
18.2
8.1
10.3
8.3
11
18.0
22.4
19.4
8.3
10.1
8.4
12
16.8
22.6
16.2
8.0
10.2
7.4
13
19.6
22.8
18.9
8.6
10.6
8.6
14
17.5
24.1
19.4
8.2
10.5
8.4
15
17.4
21.9
19.6
7.9
10.4
8.5
16
17.0
21.4
19.8
7.8
10.6
8.7
17
17.2
22.8
21.4
8.2
10.5
8.8
18
17.1
21.4
19.5
8.2
10.7
8.0
19
18.2
22.8
22.6
8.5
10.6
8.2
20
18.2
22.8
20.5
8.6
10.6
8.4
21
18.5
22.5
21.5
8.6
10.6
8.5
22
18.5
23.2
20.0
8.4
10.6
8.3
73