Cover Letter
Manuscript Title: Estimation of various tidal parameters along southeast coast of Pakistan
for harnessing tidal energy
Corresponding Author: Ambreen Insaf, Department of Applied Physics, University of
Karachi, Karachi, Pakistan, 75270. Email: ainsaf@uok.edu.pk. Cell no.: +923452847046
Co-Author 1: Dr. Zeeshan Alam Nayyar, Department of Applied Physics, University of
Karachi, Karachi, Pakistan.
Co-Author 2: Mirza Salman Baig, Department of Applied Physics, University of Karachi,
Karachi, Pakistan.
Co-Author 3: Taufeeque Rauf, Hydrographic Department, Pakistan Navy.
Co-Author 4: Dr. Nayyer Alam Zaigham, GeoEnvoTech Services, Karachi, Pakistan.
This manuscript has neither been, nor will be sent elsewhere for publication.
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Estimation of various tidal parameters along southeast coast of Pakistan
for harnessing tidal energy
Ambreen Insaf1 , Zeeshan Alam Nayyar1, Mirza Salman Baig1, Taufeeque Rauf2 and Nayyer
Alam Zaigham3
1
Department of Applied Physics, University of Karachi, Karachi, Pakistan.
2
Hydrographic Department, Pakistan Navy.
3
GeoEnvoTech Services, Karachi, Pakistan.
ABSTRACT
The understanding of sea tides and related phenomena are essential for estimating
numerous general oceanography parameters any coast like tidal range, spring-neap tides,
tide induced currents, to calculate and plan the harnessing of tidal energy for electricity
generation. Energy consumption and demand in Pakistan, especially in the coastal city of
Karachi has increased drastically over past decade and this power situation particularly
become worst in summer, where installed energy generation capacity has not much
improved. This lead to a situation of increase in unit price of electricity for domestic and
commercial users. One of the solutions to this energy crisis in the coastal city Karachi is
to explore sustainable and renewable means like tidal energy for electricity generation.
For harnessing tidal energy, propagation of tides have been studied along the Karachi
coast (24o 48’N 66o 58’E) located on the southeastern coastline of Pakistan for the period
of three months during summer of 2014. In this research study an attempt has been made
to estimate various essential tidal energy harnessing factors including harmonic constant,
tide type, range, spring-neap variation of tides, and tidal and non-tidal variations along the
coast of Karachi, especially in presence of Tropical cyclone Nanauk which occurred
during June 10, 2014 to June 13, 2014 in Arabic sea.
Key words: Tidal energy, Tidal parameters, type of tides, spring tide, neap tide, Pakistan.
1
Department of Applied Physics, University of Karachi, Karachi 75270, Pakistan
Email: ainsaf@uok.edu.pk
2
1. Introduction
Tides play a very important role in the formation of global climate as well as the ecosystems
for ocean habitants. At the same time, tides are substantial potential source of clean
renewable energy for future human generations (Gorlov, 2001). The analysis of tidal behavior
has been developed by many notable mathematicians and applied physicists, including
Newton, Airy, Laplace, George Darwin and Kelvin (Twidell and Weir, 2006).
Tidal power, sometimes called tidal energy, is the energy dissipated by tidal movements
which directly derives from the interaction of the gravitational forces between the seas and
the primary astronomical bodies of our system (Owen and Trevor, 2008). This is generated
from the combination of gravity among the earth, the sun, and the moon. Newton’s law of
gravitation can be mathematically expressed as:
where,
FG = Tide Generating Force
G = universal gravitational constant
m1, m2 = respective masses of the object (earth, sun, or moon)
r = distance between the center of the objects
Tide is affected by near shore hydrography, bottom friction, Coriolis acceleration, and
resonant effect (Sorensen, 2005).Tidal range is influenced by the relative distance and
position of the earth, the sun, and the moon. There are many factors that influenced the tide
and each of these variables can be represented mathematically by one or more sine wave
function and are called harmonic constituents of the tides. Another factor that influenced the
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tide is called surge, caused by meteorological effects including wind, atmosphere pressure
changes etc.
1.1. Pakistan and Tidal Renewable Energy
Energy crisis seems to be a global problem and every country is now looking for alternative
and sustainable way to generate electricity to meet its ever growing energy demand and to
minimize the environmental hazards. Similar dramatic situation arises in case of Pakistan,
where energy crises threating the country socio-economically, as the power demand has
drastically increased during past decades than its supply. The energy demand versus supply
scenario in the country become worse during summer season (Nayyar et al., 2014). This lead
to a situation of increase in electricity cost for domestic and commercial/industrial users.
Solution to this energy crisis in Pakistan is to explore and exploit sustainable rather
renewable sources for electricity generation. Potential for generating electricity from almost
all type of renewable energy sources exist in Pakistan comprising of solar, wind, geothermal
and tidal/oceanic energies (Nayyar et al., 2014).
Energy sources in Pakistan’s current energy mix include hydel, thermal (coal, natural gas and
furnace oil), and nuclear for electricity generation and gasoline, diesel and compressed
natural gas (CNG) for transport sector. In addition, electricity generation using renewable
energy resources has just started in the country, as reported by Pakistan Energy CrisisRecommended Solutions, prepared by Pakistan Academy of Sciences (PAS, 2013). Pakistan
has about 1000 km long coast line, but as there is no adequate data collection and rational
thinking to utilize the available tidal energy (Zaigham and Nayyar, 2005), therefore tidal
energy is supposed to be one of the best candidates for the approaching revolution of
renewable energy in the country.
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1.2. Study Area
Tide propagations were studied at Karachi (24o 48’N 66o 58’E), located on the coast of
Pakistan and contains two major ports of the country, namely Kemari and Port Qasim as
shown in Figure 1. It is located in the province of Sindh and is surrounded by islands, namely
Manora, Churna and Bundal. The Karachi coast constitutes a coastal belt of about 100 km
situated between the Indus Delta on the southeast and Hub River on the west. Area of
Karachi city is approximately 3527 km2 holding 9.856318 million people, making it the
largest cosmopolitan city of Pakistan (PBS, 2014).
2. Data Processing and Collection
The tidal data pertaining to this research study were collected from June 2014 to August
2014. The automatic tide gauges and tide poles were used to collect tidal observations on sea
level with a resolution of one minute. These permanent automatic tide gauges were
maintained by Hydrographic department, Pakistan NAVY. Detailed analyses were made on
the observed sea level to understand tidal and non-tidal variations.
Harmonic analysis of observed sea level provides the basis for predictions of tides (Thomson
and Emery, 2014). The harmonic tidal constituents which enable us to recognize
characteristic features of tides at our study area include main lunar diurnal constituent (O1);
Luni-solar constituent (K1); main lunar semidiurnal constituent (M2) and main solar
semidiurnal constituent (S2) (Pawlowicz et al., 2002). Four major constituents and relative
strength compare to M2 for Karachi city have been determined and listed in Table 1. Each
constituent combines in different ways at specific location to produce the local tide.
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The classification of different types of tide is presented in table 2. The relative importance of
diurnal and semi-diurnal harmonics can be determined from following ratio (∂):
∂=
The ratio ∂ between (O1 + K1) and (M2 and S2) have been calculated as 0.540 for the study
area declaring the tide type as mixed with semidiurnal predominantly. Close examination of
the predicted tidal patterns at study area in Figure 2 also shows that semidiurnal tides are
dominant.
Observed hourly tidal data were extracted from tidal data per minute to compare it with the
predicted model. Daily high and low water were also extracted from observed tidal data per
minute for three months to calculate different tidal parameters as shown in Figure 2.
3. Results and Discussion
In this section we describe the observed sea-level variations at Karachi for three months and
relate it to the astronomy and other affects. The regular and predicted pattern of tides is
modified by irregular factors, the principle ones being the atmospheric pressure and the winds
acting on the sea surface (Pugh, 1987). Figure 3 shows how the predicted pattern of sea level
at Karachi was modified by the meteorological affects in June 2014, July 2014 and August
2014.Under normal meteorological conditions it was observed that predicted sea level
variations are well matched with observed sea level and differences up to 0.35 meter were
observed due to seasonal variation but significant differences up to 0.8 meters were observed
for the period of June 10, 2014 to June 13, 2014.
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Significant difference in the predicted and observed sea level during June are caused by
meteorological affect are called surges and these irregularities are shown in Figure 4. These
variations observed in the sea level for the month of June are comparatively high due to the
tropical cyclone Nanauk in June 2014.
Tropical cyclone Nanauk formed west of India on June 10, 2014 and since then had been
moving toward the northwest over the open waters of the Arabian Sea, shown in Figure 5
(Adonai, 2014). Nanauk contained powerful storms dropping rain at a rate of over 247.3 mm
or 9.7 inches per hour when viewed on June 11, 2014. On June 13, 2014 the storm's last
official position was at 21.3 north latitude and 64.3 east longitude, about 285 nautical miles
(328 miles/528 km) southwest of Karachi, Pakistan. At that time the dissipating storm was
moving to the north at 9 knot (Gutro, 2014).
As a result of this cyclone, Figure 4 clearly shows extremely total high level caused by the
coincidence of a spring tide and increase in sea level due to storm occurred during 10-13 June
2014.
Large surges, causing flood occur during the tropical storm Nanauk. These dramatic rises and
resulting coastal flooding are rare events in Karachi. Beach huts in Hawk’s Bay, Sand’s Pit
and Paradise Point areas have effected by the rise in sea level. The water reached the roads in
these area and villagers living along the Karachi coastline had to flee their homes (Dawn,
2014).
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Tidal parameters that are important for harnessing tidal energy from sea tides are calculated
by extracting daily high and low tides from observed tidal data per minute for the months of
June to August 2014 for the Karachi city and are mentioned in Table 3:
By analyzing height of the tide at study area for given duration, it is found that height of tides
varies from 2.0m to 3.5m which is comparable to that of The Kislaya Guba Power Plant,
Russia (Bernshtein, 1969) and BaiShakou Power Station, China (Twidell and Weir, 2006).
All the tidal parameters presented in Table 3 shows good indication for harnessing tidal
energy especially during spring tide, where significant tidal range was found, but during neap
tide it was low. The overall tidal variations observed for three months at the coast of Karachi
are comparable to the above two mentioned tidal power plants for harnessing renewable
green energy.
4. Conclusion
In this study an effort have been made to acquire the available tidal data from hydrographic
department of Pakistan Navy and process it to extract and calculate some useful information
that are important for harnessing tidal energy at study area including tide type, difference in
predicted and observed tides, storm surges, spring-neap variations, tides heights and range.
After analyzing all the available data and calculating results, a view is establish that may
leads in future a complete system of power generation through tidal energy at study area. It is
concluded that type of the tide found at study area are mixed with semidiurnal predominantly
means there are two high and two low tides per day for a duration of 6 hours 14 minutes each.
Predicted sea level variations were compared with the observed sea level variations for three
months and as a consequence predicted sea level variations well matched with the observed
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sea level variations except for the month of June 2014 because if the occurrence of tropical
cyclone Nanauk. During spring tide, significant tidal range was observed for the given three
months as compared to neap tide. After examination of different tidal parameters at study
area and comparing it with the other tidal power plants, it is also concluded that coastal belt
of Pakistan has significant potential to harness tidal energy to overcome the energy crisis of
the country and improve the socio-economic and environmental conditions.
5. Acknowledgment
The authors are thankful to Hydrographic Department, Pakistan Navy for providing valuable
support for this research study.
References
Adonai, 2014. Tropical Cyclone "Nanauk" intensifies in Arabian Sea. The Watchers.
Bernshtein, L., 1969. Problem of the utilization of tidal energy and the experimental Kislaya
Guba tidal powder plant. Power Technology and Engineering (formerly Hydrotechnical
Construction) 3, 12-18.
Dawn, 2014. High tides force fishermen to flee homes, DAWN. DAWN.com, Pakistan.
Gorlov, A., 2001. Tidal energy. Academic, London.
Gutro, R., 2014. Nanauk (was 02A - Northern Indian Ocean/Arabian Ocean), NASA Sees
Tropical Storm Nanauk's Soaking Swan Song. NASA.
Nayyar, Z.A., Zaigham, N.A., Qadeer, A., 2014. Assessment of present conventional and
non-conventional energy scenario of Pakistan. Renewable and Sustainable Energy Reviews
31, 543-553.
Owen, A., Trevor, M., 2008. Tidal current energy: origins and challenges. Future energy.
Oxford: Elsevier, 111-128.
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Pawlowicz, R., Beardsley, B., Lentz, S., 2002. Classical tidal harmonic analysis including
error estimates in MATLAB using T_TIDE. Computers & Geosciences 28, 929-937.
PBS, 2014. AREA & POPULATION OF ADMINISTRATIVE UNITS
RURAL/URBAN: 1951-1998 CENSUSES, in: Statistics, P.B.o. (Ed.), Islamabad.
BY
Pugh, D., 1987. Tides, surges and mean sea-level: a handbook for engineers and scientists,
472 pp. John Wiley, Hoboken, NJ.
Sorensen, R.M., 2005. Basic coastal engineering. Springer Science & Business Media.
Thomson, R.E., Emery, W.J., 2014. Data analysis methods in physical oceanography.
Newnes.
Twidell, J., Weir, A.D., 2006. Renewable energy resources. Taylor & Francis.
Zaigham, N.A., Nayyar, Z., 2005. Prospects of renewable energy sources in Pakistan.
Renewable-Energy Technologies and Sustainable Development. Islamabad: COMSATS, 6586.
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Tables
Table 1 Tidal Constituent and relative strength parameters at Karachi coast.
Symbol
Relative strength
M2
100.00
S2
37.80
K1
50.00
O1
24.39
Table 2 Types of tides.
Ratio
Tide Type
0.0 to 0.25
Semidiurnal
0.25 to 1.5
Mixed (predominantly semidiurnal)
1.5 to 3.0
Mixed (predominantly diurnal)
> 3.0
Diurnal
Table 3 Tidal parameters for June 2014, July 2014 and August 2014 at Karachi coast.
Tidal Parameters
June 2014
July 2014
August 2014
Highest tide
3.416 m
3.366 m
3.542 m
Lowest tide
0.596 m
-0.18 m
0.118 m
Largest Tidal Range
2.652 m
3.083 m
3.074 m
Spring tide
2.819 m
3.446 m
3.424 m
Neap tide
0.26 m
0.617 m
0.474 m
Mean spring tidal range
1.8 m
2.203 m
2.367 m
Mean neap tidal range
0.987 m
1.49 m
1.385 m
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Figure Captions
Figure 1
A map of study area [Figure Source: Google maps]
Figure 2
Predicted Sea Level, Karachi coast, June 2014, July 2014 and August 2014
Figure 3
Predicted and observed variations in sea level, Karachi coast, June 2014, July
2014 and August 2014
Figure 4
Meteorological irregularities in observed sea level, Karachi, June 2014, July
2014 and August 2014
Figure 5
Tropical cyclone Nanauk forecasted track.
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Figure 2
A map of study area [Figure Source: Google maps]
Figure 2
Predicted Sea Level, Karachi coast, June 2014, July 2014 and August 2014
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Figure 3
Predicted and observed variations in sea level, Karachi coast, June 2014, July
2014 and August 2014
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Figure 4
Meteorological irregularities in observed sea level, Karachi, June 2014, July
2014 and August 2014
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Figure 5
Tropical cyclone Nanauk forecasted track.
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