1
CHAPTER
1.1
1.2
1.3
1.4
TABLE OF CONTENTS
TITLE
TITLE PAGE
DECLARATION
DEDICATIONS
ACKNOWLEDGEMENTS
ABSTRACT
ABSTRAK
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
LIST OF SYMBOLS
LIST OF ABBREVIATIONS
LIST OF APPENDICES
INTRODUCTION
Overview
Problem Statement
Objectives
Scope of Study xvii xviii
1
2
4
1
4
PAGE i ii iii iv v vi vii xi xiii xv

2
3
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
1.5 Outline of Thesis
Methodology
Introduction
Radar Data
Disadvantages of Radar Measurement
Radar Measurement Principle
Z-R Relationship
Selection of radar Data
Rain Gauge Data
Attenuation Measurements Using Microwave
Links
RAIN ATTENUATION, RAIN MODELS,
3.1
AND REDUCTION FACTORS
Background
3.2
3.3
3.4
3.5
Attenuation by Rain
Rainfall Rate, Rain Cell Size, and Rain Height
Rainfall Rate for 0.01 % of the time or R
0.01
Rain Prediction Models
3.5.1 Crane’s Global Model
3.5.2 ITU-R Model
3.6 Reduction Factor
3.6.1 Lin Model
3.6.2 Moupfouma Model
3.6.3 CETUC Model
3.6.4 Improved CETUC Model viii
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7
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7
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5
4
3.6.5 Goddard and Thurai Model
3.6.6 ITU-R Model
3.6.7 Singapore Model
3.6.8 DAH Model
3.7
3.6.9 Comments on reduction Factor Models
Rain in Malaysia
3.8 Determination of Rain Cell Size
RAIN GAUGE AND RADAR DATA
4.1 Introduction
4.2 Rain Gauge and Rain Gauge Networks
4.2.1 Casella Rain Gauge
4.3 Radar Data Collection
4.3.1 Kluang Radar Data Format
DATA ANALYSIS AND RESULTS
5.0
5.1
Introduction
Rain Gauge Data Analysis
5.1.1 Preliminary Data Analysis
5.1.2 Selection of Rain Gauge Network
(RGN-UTM 1) Data
5.1.3 RGN-UTM 1 Data Analysis
5.1.4 Cell Size and Intensity Distribution
5.1.5 Rain Distribution Inside a Rain Cell
5.2 Radar Data Analysis
5.2.1 Rejection of Permanent Echo
5.2.2 Preliminary Results ix
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6 x
6.1
6.2
5.2.3 Distribution of Rain Rate from Radar Data
5.2.4 Determination of Rain Cell Size from Radar
Data
5.3
5.2.5 Rain Attenuation Measurements in UTM
Deducing the Reduction Factor from Radar
Data
CONCLUSION AND FUTURE STUDIES
Conclusion
Future Studies
REFERENCES
APPENDICES
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116
128
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85

LIST OF FIGURES
TITLE FIGURE
2.1
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
Examples of virtual links
Rain formation through cold and warm air fronts
Rain cell diameter versus rainfall rate
Height of melting layer
Rain height
The global rain rate regions
Rain rate distribution curves for various regions
Rainfall climatic zones
Rainfall rate contours for 0.01% of the time for Asia
Revised rainfall rate contours for 0.01% of the time
4.1
4.2
4.3
RGN-UTM 1 Rain gauge network stations
RGN-UTM 2 Rain gauge network stations
Casella Tipping Bucket Rain Gauge with Integral
Logger
Tipping buckets of a Casella Rain Gauge
Merged PPI scan
4.4
4.5
4.6
4.7
4.8
4.9
A Kluang radar station PPI scan
A Kluang radar station RHI scan
A MATLAB radar plot
Top view of typical composite image
4.10 A cross-section of a typical composite image
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54
55
56
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29
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5.1
5.2
5.3
5.4
5.5
Graph of Rainfall Rate Recordings at all Rain Gauge
Stations
Rain Rate Distribution for 120 mm/hr at Civil Station
Rain Rate Distribution for 90 mm/hr at Civil Station
Rain Rate Distribution for 60 mm/hr at Civil Station
Rain Rate Distribution for 30 mm/hr at Civil Station
5.6 Averaged Rain Rate Distributions for RGN-UTM 1
54.7 Averaged Rain Rate Distribution for all stations
5.8
5.9
Rain rate distributions for RGN-UTM 2
Rain distributions assuming that TV Station is the center of the rain cell
5.10 Rain distribution assuming the IVAT Station to be the center of the rain cell
5.11 Averaged rain cell size
5.12 RGN-UTM 2 Rainfall rate distribution
5.13 Rain rate distribution
5.14 The plots of original data and the curve-fit line
5.15 Rain Cell Size Distribution
5.16 The best-fit curve for 1-km path links attenuation distribution
5.17 Attenuation for 0.01% of the time at 7, 10, and 15
GHz
5.18 Reduction factor (r) plots for 1 to 10-km path lengths at frequencies of 7, 10, and 15 GHz for 0.01% of the time
5.19 Best fit line for coefficient a
5.20 Best fit line for coefficient b
5.21 Plots of all the reduction factor models at 7 GHz
5.22 Plots of all the reduction factor models at 10 GHz
5.23 Plots of all the reduction factor models at 15 GHz
6.1
6.2
Proposed reduction factor r
Predicted attenuation due to rain for 0.01 % of the time
97
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100
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102
111
111
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63 xii
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LIST OF TABLES
TITLE TABLE
3.1 Point Rain Rate (R
P
) Distribution Values (mm/h)
Versus Percent of Year Rain Rate is exceeded
3.2 Rainfall rates in the climatic zones
4.1 dBZ-R values for Kluang radar
4.2 Radar Scan Elevation Angles
4.3 Number of matrices in each data folders
4.4 The corresponding actual rain rate values in mm/hr to the rain rate level
5.1 Rain events recorded at all rain gauges locations
5.2 Correlations for no. of readings at all stations
5.3 Equal Rainfall Rate At All Three Stations
5.4 The Rainfall Rates and their durations for all Rain
Gauge Stations RGN-UTM 1
5.5 The Rainfall Rate Percentages and the Averaged
Rainfall Rate Percentage for all Rain Gauge Stations
5.6 Simultaneous rain rate readings at all stations when
IVAT and TV Studio stations register 120 mm/hr rain rate
5.7 Distribution of rainfall rate of RGN-UTM 2
5.8 R
0.01
Values for RGN-UTM 2 Stations
5.9 Rainfall Intensity for averaged 1-km path
PAGE
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62
63
65
70
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52
57
59
60
71
76
78
79
81

5.10 Rain rate distribution for range-bin size of 1-km from radar data
5.11 Rain Cell Size Distributions
5.12 Specifications for Binariang system links
5.13 Specifications for Digi system links
5.14 Distribution of attenuation for 1-km links operating at 7
GHz
5.15 Attenuation (dB) for 0.01% of the time; at 7, 10, and 15
GHz for path lengths of 1 to 10-km
5.16 Reduction factor (r) values for 1 to 10-km path lengths at frequencies of 7, 10, and 15 GHz for 0.01% of the time
5.17 a & b values for best fit lines of reduction factors at 7,
10, and 15 GHz
5.18 a and b values at 7, 10, and 15 GHz
5.19 The reduction factor (r) for the proposed Malaysia model
5.20 Comparison of r from various models at 7 GHz
5.21 Comparison of r from various models at 10 GHz
5.22 Comparison of r from various models at 15 GHz
5.23 Comparison of predicted attenuations (dB), with measurements
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95 xiv
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91

α
β
s
A a
A r b c
D d dB e dBZ
F k
L m n(r) p
Q t
(r) r
R
R
0.01
LIST OF SYMBOLS regression exponential for specific attenuation exponential in Moupfouma’s model. specific attenuation due to rain (dB/km) attenuation of radiowave propagating through free-space (dB) excess attenuation due to water vapor attenuation of radiowave due to rain (dB) excess attenuation due to mist and fog; regression exponential for radar reflectivity excess attenuation due to oxygen diameter of rain cell (km) absorption losses due to other gasses decibels excess attenuation due to rainfall radar reflectivity factor in dB
Frequency (GHz) regression coefficient for specific attenuation path length (km) exponential in Moupfouma’s model. number of raindrops per unit volume per radius interval (m
-3 mm
-1
) time percentage, percentage total extinction cross-section (cm
2
) radius (cm), reduction factor rainfall rate (mm/hr) rainfall rate (mm/hr) for 0.01 % of the time

R t
Z threshold values of a specific rain rate radar reflectivity factor (dBZ or mm
6
/m
3
) xvi

xvii
LIST OF ABBREVIATIONS
3D-RAPIC 3 dimensional software to process and handle weather radar data
CETUC Center for Telecommunication Studies of the Catholic University of
CMOS
DAH
DSD, dsd
Rio de Janeiro
Complementary metal-oxide semiconductor
Dissanayake, Allnutt, Haidara drop size distribution
EPROM
ITU
ITU-R
LOS
PPI
Erasable programmable read-only memory
International Telecommunication Union
International Telecommunication Union-Radio communication
Section
Line-of-sight
Pulse-Position Indicator
PPI r
Pulse-position-indicator
Reduction factor
RGN-UTM 1 Rain Gauge Network in UTM no. 1
RGN-UTM 2 Rain Gauge Network in UTM no. 2
RHI Rain Height Indicator
RHI
STC
UTC
UTM
Rain height indicator
Sensitivity Time Control
Universal Time Constant
Universiti Teknologi Malaysia

xviii
LIST OF APPENDICES
TITLE APPENDIX
3.4
3.5
3.6
3.7
4.1
4.2
4.3
4.4
4.5
1.1
3.1
3.2
3.3
Earth’s Climate and Raindrops
Specifications of the Casella Rain Gauge
Data Sample from RGN-UTM 1
Radar Measurement Theory
Radar Calibration Checklist
Kluang Radar Station Specifications
An Example of a Radar Data
Radar Data Encoding Format
MATLAB programs
Radar Rain Rate Distribution
Rain Cell Diameter from Radar Data
1 to 10-km path attenuations at 7, 10, and 15 GHz
Rec. ITU-R P.838-1
PAGE
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148
149
153
157
162
173
174
222
128
137
138
139