UNIVERSITI PUTRA MALAYSIA

DEVELOPING OF A MODEL FOR MEASURING AND EXTRACTING

OCEAN SURFACE CURRENT PATTERNS FROM RADARSAT-1 SAR AND ALTIMETER DATA

MOHAMED AHMED MAIYAS

FK 2007 28

DEVELOPING OF A MODEL FOR MEASURING AND EXTRACTING OCEAN SURFACE CURRENT PATTERNS FROM RADARSAT-1 SAR AND

ALTIMETER DATA

By

MOHAMED AHMED MAIYAS

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia in Fulfilment of the Requirements for the Degree of Doctor of Philosophy

MAY 2007

ii

DEDICATION

To the soul of my father

Who started dreaming of me to be a human rather than an educated person

and wished me to be a man of wisdom and positive thinking.

Today what I am is just because of his direction and affections

&

To the rest of my extended families

mother, brothers, sisters, wife and kids

your encouragement has seen me through this long journey

iii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in

fulfilment of the requirement for the degree of Doctor of Philosophy

DEVELOPING OF A MODEL FOR MEASURING AND EXTRACTING OCEAN SURFACE CURRENT PATTERNS FROM RADARSAT-1 SAR AND

ALTIMETER DATA

By

MOHAMED AHMED MAIYAS

May 2007

Chairman: Professor Shattri bin Mansor, PhD

Faculty: Engineering

Remote sensing technology can be used to collect large scale data on ocean areas

and provide precise information on ocean surface dynamics and atmospheric

interactions. Many other ocean surface features can be detected by utilizing this

technology. In this study, a robust model was developed based on Doppler

frequency that utilizes RADARSAT-1 SAR imageries in measuring and

extracting ocean surface current patterns such as velocity and direction. The

SAR data used in the study were acquired during the period 20-31 March 2005

and supported with altimeter data of GEOSAT-2 and TOPEX/POSEIDON also

collected at the same period. The study area is located between the longitudes

102°50'00'' to 103°40'00'' East and latitudes 5°25'00'' to 5°40'00'' North, at the east

coast of Kuala Terengganu. The area was divided into four main parts

iv

comprising the onshore, fieldwork area, midshore, and offshore area witch is

about 98 km. off the coast. The model was applied on the SAR image at three

different modes (Wide- 3, High extended- 6 and Standard-2) with the objectives

of 1) comparing between the modes and identifying the appropriate mode for

coastal current modeling, 2) modeling the spectral intensity of the SAR data in

the study area covering the onshore, midshore, offshore and the fieldwork area,

3) examining the impacts of tide and wind speed and direction on surface

current movements on the coastal water of Kuala Terengganu, Malaysia and 4)

investigating the impact of the Doppler frequency shift and incidence angle on

the sea surface current detection. The results of the study were validated using

TOPEX/POSEIDON satellite altimeter data for the same period and in situ data

measurements taken with AWAC instrument during the fieldwork. The study

did not only find that the incidence angle in SAR had an effect on the surface

current patterns but also that, there is a strong relation between the image

backscatter and Doppler frequency. It was again discovered that the velocity

and direction of the current changed through the period of the study according

to the changing of Doppler frequency shift used in the model to extract the sea

surface current velocity and direction from the three SAR images. At the

onshore area, the velocity of current extracted based on the Wide-3 mode

varied between 0.22 m/s to 0.25 m/s with the average of 0.24 m/s, while based

on the Standard-2 mode it varied between 0.52 m/s to 0.65 m/s with an

v

average velocity of 0.56 m/s. The analysis of the spectral intensity of the SAR

data in different modes showed variation among the four areas. The spectral

intensity values were low in the onshore as against the high values recorded in

the offshore. Regression analysis was used to establish the coefficient of

determination between the velocities extracted from SAR data and the AWAC

in situ measurements. The analysis showed a fairly high correlation between

them of R² of 0.753 with the highest velocity under 0.27 m/s, R² of 0.726 with the

highest velocity under 0.32 m/s and R² of 0.863 with the highest velocity under

0.75 m/s. These results were obtained from the regression between the AWAC

data and the RADARSAT-1 SAR in Wide-3, Extended High-6 and Standard-2

modes respectively. It can be said that the investigation between different radar

systems should be used as geomantic tool to investigate water current

movement.

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Abstrak tesis yang dikemukakan kepada Senat Unversiti Putra Malaysia sebagai

memenuhi keperluan untuk ijazah Doktor Falsafah

PEMODELAN CORAK ARUS PERMUKAAN LAUT DARI RADARSAT-1 SAR

DAN ALTIMETER DATA

Oleh

MOHAMED AHMED MAIYAS

Mei 2007

Pengerusi: Profesor Shattri bin Mansor, PhD

Fakulti: Kejuruteraan

Teknologi Penderiaan Jarak Jauh boleh digunakan untuk mengumpul data

berkenaan kawasan laut yang berskala besar dan dapat memberikan maklumat

terperinci dinamik permukaan lautan dan interaksi atmosfera. Ciri-ciri lain

permukaan laut juga boleh dikenalpasti dengan menggunakan teknologi ini.

Untuk penyelidikan ini, satu model tahan lasak dibina yang menggunakan imej-

imej RADARSAT-1 SAR dalam pengukuran dan pengasingan corak arus

permukaan laut seperti kelajuan dan arah. Data SAR yang digunakan dalam

penyelidikan ini diperolehi dalam tempoh 20-31 March 2005 dengan disokong

oleh data altimeter GEOSAT-2 dan TOPEX/POSEIDON yang turut dikumpul

dalam tempoh yang sama. Kawasan penyelidikan terletak di antara longitud

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102o50’00” hingga 103 o40’00” Timur dan latitud 52 o5’00” hingga 5 o40’00” Utara,

di timur perairan Kuala Terengganu. Kawasan tersebut terbahagi kepada empat

bahagian yang merangkumi persisiran dalam, kawasan lapangan kerja,

persisiran tengah dan persisiran luar iaitu lebih kurang 98 km daripada

persisiran pantai. Model tersebut digunakan ke atas imej SAR pada tiga mod

yang berlainan (Wide- 3, High extended- 6 dan Standard- 2) berdasarkan objektif

berikut 1) membandingkan antara mod dan mengenal pasti mod yang

bersesuaian untuk model arus perairan, 2) memodelkan intensiti spektral data

SAR dalam kawasan penyelidikan yang merangkumi persisiran dalam,

kawasan lapangan kerja, persisiran tengah dan persisiran luar, 3) mengkaji

impak kelajuan ombak dan angin dan arah ke atas pergerakan arus permukaan

perairan Kuala Terengganu, Malaysia dan 4) mengenalpasti impak anjakan

frekuensi Doppler dan sudut insiden ke atas pengenalpastian arus permukaan

lautan. Keputusan penyelidikan disahkan menggunakan data altimeter satelit

TOPEX/POSEIDON untuk tempoh masa yang sama dan data pengukuran in

situ diambil menggunakan alatan AWAC semasa kerja lapangan. Penyelidikan

ini tidak hanya menemui sudut insiden dalam SAR mempunyai kesan ke atas

corak arus permukaan tetapi juga terdapat kaitan yang kuat antara imej

serakan-belakang anjakan frekuensi Doppler yang digunakan dalam model

untuk mengasingkan kelajuan arus permukaan laut dan arah daripada tiga imej

SAR tersebut. Di kawasan persisiran dalam, kelajuan arus yang didapati

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berdasarkan kepada mod Wide-3 berubah antara 0.22 m/s hingga 0.25 m/s

dengan purata 0.24 m/s, manakala berdasarkan mod Standard-2 ia berubah

antara 0.52 m/s hingga 0.65 m/s dengan purata kelajuan 0.56 m/s. Analisis

intensiti spektral data SAR dalam pelbagai mod menunjukkan variasi antara ke

empat-empat kawasan. Nilai intensiti spektral adalah rendah di persisiran

dalam berbanding nilai yang tinggi di kawasan persisiran luar. Analisis regresi

digunakan untuk mendapatkan pekali penentuan antara kelajuan yang

diperolehi daripada data SAR dan pengukuran in situ AWAC. Analisis

menunjukkan korelasi yang agak tinggi antara data tersebut di mana R2 = 0.753

dengan kelajuan tertinggi pada 0.27 m/s, R2 = 0.726 dengan kelajuan tertinggi

pada 0.32 m/s dan R2 = 0.863 dengan kelajuan tertinggi pada 0.75 m/s.

Keputusan yang diperolehi adalah daripada regresi antara data AWAC dengan

mod-mod RADARSAT-1 SAR pada Wide-3, Extended High-6 dan Standard-2.

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ACKNOWLEDGEMENTS

All praises and thanks go to (ALLAH) SWT, the supreme ruler of the universe

for the spiritual and gift bestowed upon me in the performance of my routines.

It is not easy to thank enough in so few words everyone who is one way or

another have enabled me to successfully complete my PhD program. I wish to

acknowledge the following individuals with gratitude appreciation for their

contribution that made this thesis what it is.

I express my hearty gratitude to my advisory committee, Prof. Hj. Dr. Shattri bin

Mansor, the Head of the Spatial and Numerical Modeling Laboratory, Institute

of Advance Technology, Universiti Putra Malaysia, and Dr. Helmi Zulhaidi Bin

Mohd Shafri, Faculty of Engineering, Universiti Putra Malaysia for their

encouragement, keen interest, guidance, valuable suggestions, kind cooperation,

and supervision to this thesis work. Dr. Maged Mahmoud Marghny, Faculty of

Geoinformation Science and Engineering, Universiti Teknologi Malaysia who

taught me his radar knowledge, Doppler calculation and also for his guidance

and corporation.

My appreciation and thank also goes to members of research team of the GIS

and Geomatic Engineering Unit, include Assoc. Prof. Dr. Abdul Rashid bin

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Mohd Shariff, Assoc. Prof. Dr. Ahmad Rodzi Mahmud, and Prof. Hj. Dr.

Noordin Ahmad, without their valuable advice and encouragement this study

wouldn’t have reached this fruitful end.

I will never forget to thank my brother Mr. Ali Ahmed Maiyas, Lecturer of

networks and IT, University of Al-Sharjah, United Arab Emirates for his finance

help and encouragement without which this study wouldn’t have been possible.

Mr. Al-khirbash, Mr. Al-Ezzani, and Mr. Al-Akhbari, my study colleagues,

technical officers of SNML specially Mr. Hermi and officers of ITMA, in-situ

measurement team from KUSTEM and not forgetting the faculty of engineering

particularly the GIS who were helpful and supportive. My appreciation also

goes to the government of the Republic of Yemen who gives me the opportunity

to continue my study in Malaysia.

I would like to extend my thanks to the following organizations in Malaysia:

Malaysian Center for Remote Sensing (MACRES)

National Hydraulic Research Institute of Malaysia (NAHRIM)

Department of Surveying and Mapping Malaysia (JUPEM)

Last but not least I will never forget to thank my wife for her patience and

encouragements and my lovely children.

xi

I certify that and Examination Committee has met on date of viva to conduct the final examination of Mohamed Ahmed Maiyas on his PhD thesis entitled “Modeling the Ocean Surface Current Patterns from RADARSAT-1 SAR and Altimeter Data” in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The Committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committee are as follows: Chairman, PhD Professor Faculty of Graduate Studies Universiti Putra Malaysia (Chairman) Examiner 1, PhD Professor Faculty of Graduate Studies Universiti Putra Malaysia (Internal Examiner) Examiner 2, PhD Professor Faculty of Graduate Studies Universiti Putra Malaysia (Internal Examiner) External Examiner, PhD Professor Faculty of Graduate Studies Universiti Putra Malaysia (External Examiner)

HASANAH MOHD GHAZALI, PhD Professor/Deputy Dean School of Graduate Studies Universiti Putra Malaysia Date:

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This thesis submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Doctor of Philosophy. The members of the Supervisory Committee are as follows: Shattri bin Mansor, PhD Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) Maged Mahmoud Marghany, PhD Lecturer Faculty of Geoinformation Science and Engineering Universiti Teknologi Malaysia (Member) Helmi Zulhaidi bin Mohd Shafri, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Member)

AINI IDERIS, PhD Professor/ Dean School of Graduate Studies Universiti Putra Malaysia

Date: 9 August 2007

xiii

DECLARATION I hereby declare that the thesis is based on my original work except for quotations and citations, which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions.

MOHAMED AHMED MAIYAS

Date: 9 July 2007

xiv

TABLE OF CONTENTS

Page

DEDICATION ABSTRACT ABSTRAK ACKNOWLEDGEMENTS APPROVAL DECLARATION LIST OF TABLES LIST OF FIGURES LIST OF ABBREVIATIONS

ii iii vi

ix xi xiii

xvii xviii xxii

CHAPTER

1 INTRODUCTION 1.1 Introduction 1.2 Problem Statement 1.3 Hypothesis 1.4 Objectives 1.5 Scope of the Study 1.6 Significant of the Study

1.7 Thesis Organization

1.1 1.1 1.5 1.7 1.7 1.8 1.9 1.11

2 LITERATURE REVIEW

2.1 Introduction 2.2 Radar Characteristics 2.2.1 Wavelength 2.2.2 Polarization 2.2.3 Incident Angle 2.2.4 Backscatter Coefficient 2.3 SAR Imagine Mechanism Theory

2.3.1 RADARSAT-1 SAR Imaging Modes 2.3.2 Applications of RADARSAT-1 Data to Oceanography

2.4 Satellite Radar Altimeter

2.4.1 Comparison between SAR and Altimeter 2.5 Sea Surface Current SAR Algorithms 2.5.1 Bragg Scattering 2.5.2 Doppler Frequency Shift

2.1 2.1 2.1 2.2 2.5 2.5 2.6 2.7 2.10

2.13 2.15

2.17 2.18 2.19 2.22

xv

2.5.3 ATI Interferometeric SAR Techniques 2.5.4 HF Ocean Radar 2.6 Sea Surface Currents Theory 2.6.1 Forces Causing the Surface Current 2.6.2 Acoustic Wave and Current 2.7 Current Properties in Kuala Terengganu Waters 2.8 Summary

2.35 2.40 2.42 2.44 2.46 2.49 2.51

3 MATERIALS AND METHODS

3.1 Study Area. 3.2 Data Collection

3.3 In-situ Measurement 3.3.1 AWAC Deploying on March 21, 2005 3.3.2 AWAC Deploying on March 25, 2005 3.3.3 AWAC Deploying on March 31, 2005 3.3.4 In-situ Data Analysis

3.4 Processing 3.4.1 Geometric Correction

3.4.2 Kernel Window Size 3.4.3 Model Formulation 3.4.4 Doppler Spectral Intensity 3.4.5 Sea Surface Current Direction

Extracted from RADARSAT-1 SAR Images

3.5 Method of Least Square 3.6 Geostrophic Current from Satellite Altimetry 3.7 3D Bathymetry Visualization

3.1 3.1 3.5 3.7 3.9 3.9 3.10 3.14 3.14 3.17 3.18 3.18 3.24

3.28 3.30 3.31 3.33

4 RESULTS AND DISCUSSION 4.1 Introduction

4.2 In –situ Measurement Results 4.2.1 Current Velocity

4.2.2 Current Direction 4.2.3 Result of the Tide

4.3 Sea Surface Current Velocities Simulated from RADARSAT-1 SAR Images

4.3.1 Onshore RADARSAT-1 SAR Surface Current Velocity

4.3.2 Fieldwork RADARSAT-1 SAR Surface

4.1 4.1 4.1 4.1 4.5 4.9

4.11

4.11

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Current Velocity 4.3.3 Midshore RADARSAT-1 SAR Surface Current Velocity 4.3.4 Offshore RADARSAT-1 SAR Surface Current Velocity Offshore 4.4 Sea Surface Current Velocities Versus RADARSAT-1 SAR SAR Physical Properties and Bathymetry

4.4.1 Physical Properties of RADARSAT-1 SAR Wide-3 Mode 4.4.2 Physical Properties of RADARSAT-1 Extended High-6 Mode

4.4.3 Pysyical Properties of RADARSAT-1 Standard-2 mode

4.5 Image spectral intensity 4.5.1 Image spectral intensity from

RADARSAT-1 Wide-3 4.5.2 Image spectral intensity from RADARSAT-1 Extended High-6

4.5.3 Spectral Intensity from RADARSAT-1 SAR Standard-2 Discussion

4.6 Sea Surface Current Direction 4.6.1 Sea Surface Current Direction on March 21, 2005 4.6.2 Sea Surface Current Direction on March 25, 2005 4.6.3 Sea Surface Current Direction on March 31, 2005 4.7 Validation of the Relationship between the velocities extracted from RADARSAT-1 SAR images and in-situ measurements

4.12

4.12

4.13

4.17

4.17

4.20

4.21 4.27

4.27

4.28

4.29

4.33 4.54

4.54

4.56

4.58

4.69

5 CONCLUSION 5.1 Conclusion 5.2 Recommendations

5.1 5.1 5.5

REFERENCES APPENDICES BIODATA OF THE AUTHOR

R.1 A.1 B.1

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LIST OF TABLES

Table Page

2.1 Standard Wavelength/Frequency Bands Nomenclature of Radar Systems 2.4

2.2 Characteristics of Earth Orbital SAR Systems 2.11

2.3 RADARSAT-1 SAR Characteristics and Orbit Characteristic 2.12

2.4 RADARSAT-1 SAR Imaging Modes 2.13

2.5 Summary of the of Sea Surface Current Patterns Extraction from SAR Images

3.1 Summary of Seasonal Conditions on East Coast Peninsular Malaysia 3.4

3.2 RADARSAT-1 SAR Image Description 3.5

3.3 The Ancillary Data 3.6

3.4 Schedule of the AWAC Deployment 3.10

3.5 AWAC Deploying Parameters Unites Used in the Measurement 3.13

4.1 Table 4.1: Summaries the Result of the Sea Surface Current Velocities and Directions during the in-situ Measurement 4.36

4.2 Table 4.2: average sea surface current velocities simulated from RADARSAT-1 SAR Wide-3, Extended High-6, and Standard-3 modes 4.40

xviii

LIST OF FIGURES

Figure Page

2.1 Electromagnetic Spectrum in the Visible, Near, Middle and Thermal Infrared and the Microwave Regions 2.3

2.2 Schematic Diagrams of System and Local Incident Angle 2.6

2.3 RADARSAT-1 SAR Imaging Modes Acquisition 2.12

2.4 Satellite Altimetry Operation Comparing to SAR Swath 2.17

2.5 Illustration of Bragg Scattering 2.20

2.6 The Observation Geometry in the Velocity Vector and Target Pan 2.26

2.7 Schematic Geometry of the ATI-SAR 2.36

2.8 The Orientation of the Three Slanted Transducers used by the AWAC 2.48

3.1 Study Area Location 3.3

3.2 Deploying the AWAC in the Fieldwork Area 3.11

3.3 A Sketch of AWAC Deploying in the Fieldwork Area 3.12

3.4 Standard-2 Mode Image Shows the Study Area Locations Containing Onshore, Fieldwork, Midshore, and Offshore Areas 3.15

3.5 Flowchart of the Model Analysis 3.16

3.6 The Centeroid Doppler Shift Frequency Process Applied on the Subset Images of the Study Area 3.17

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4.1 Sea Surface Current Polar on March 21, 24, and 31, 2005 4.3

4.2 Current Velocity Extracted from AWAC through the Deploying measurement on March 21, 25, and 31, 2005 4.6

4.3 Current Direction Extracted from AWAC through the Deploying measurement on March 21, 25, and 31, 2005 4.8

4.4 The Tide Information on March 21, 25, and 31, 2005 4.10

4.5 Sea surface Current Velocity Simulated from RADARSAT-1 SAR Wide-3, Extended High-6, and Standard-2 Modes in the Onshore Area 4.13

4.6 Sea Surface Current Velocity Simulated from RADARSAT-1 SAR Wide-3, Extended High-6, and Standard-2 Modes in the Fieldwork Area 4.14

4.7 Sea Surface Current Velocity Simulated from RADARSAT-1 SAR Wide-3 and Standard-2 Modes in the Midshore 4.15

4.8 Sea Surface Current Velocity Simulated from RADARSAT-1 SAR Wide-3 and Standard-2 Modes in the Offshore Area

4.16

4.9 Comparison between Physical Properties of RADARSAT-1 SAR Wide-3 Mode and the Bathymetry along the Study Area

4.24

4.10 Comparison between Physical Properties of RADARSAT-1 SAR Extend High-6 Mode and the Bathymetry in the Onshore and Offshore.

4.25

4.11 Comparison between Physical Properties of RADARSAT-1 SAR Standard-2 Mode and the Bathymetry along the Study Area. 4.26

4.12 Doppler Spectral Intensity from Subset Image 512×512 (Wide-3 Mode) in the Onshore 4.30

4.13 Doppler Spectral Intensity from Subset Image 512×512 (Wide-3 Mode) in the Fieldwork 4.30

4.14 Doppler Spectral Intensity from Subset Image 512×512 (Wide-3 Mode) in the Midshore 4.30

xx

4.15 Doppler Spectral Intensity from Subset Image 512×512 (Wide-3 Mode) in the Offshore 4.30

4.16 Doppler Spectral Intensity from Subset Image 512×512 Extended High-6 Mode) in the Onshore 4.31

4.17 Doppler Spectral Intensity from Subset Image 512×512 Extended High-6 Mode) in the Fieldwork Area 4.31

4.18 Doppler Spectral Intensity from Subset Image 512×512 Standard-2 Mode) in the Onshore 4.32

4.19 Doppler Spectral Intensity from Subset Image 512×512 Standard-

2 Mode) in the Fieldwork Area 4.32

4.20 Doppler Spectral Intensity from Subset Image 512×512 Standard-2 Mode) in the Midshore 4.32

4.21 Doppler Spectral Intensity from Subset Image 512×512 Standard-2 Mode) in the Offshore 4.32

4.22 3D visualization of the bathymetry of the study area 4.34

4.23 RADARSAT-1 SAR Wide-3 Mode Cross Section in the Onshore 4.41

4.24 RADARSAT-1 SAR Wide-3 Mode Cross Section in the Offshore 4.41

4.25 RADARSAT-1 SAR Extended High-6 Mode Cross Section in the Onshore 4.42

4.26 RADARSAT-1 SAR Standard-2 Mode Cross Section in the Onshore 4.43

4.27 RADARSAT-1 SAR Standard-2 Mode Cross Section in the Offhore 4.43

4.28 Affection of Physical Properties of RADARSAT-1 SAR Standard-2 mode Backscatter on the Sea Surface Current Patterns 4.44

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4.29 Spectra Intensity of the Study Area Extracted from RADARSAT-1 SAR Wide-3, Extended High-6, and Standard-2 4.48

4.30 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 SAR Wide-3 (Onshore) 4.49

4.31 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 SAR Wide-3 (Insitu measurement) 4.49

4.32 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 SAR Wide-3 (Midshore) 4.50

4.33 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 SAR Wide-3 (Offshore) 4.50

4.34

Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 SAR Extended High-6 (Onshore)

4.51

4.35 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 Extended High-6 (Insitu measurement) 4.51

4.36 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 Standard-2 (Onshore) 4.52

4.37 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 Standard-2 (Insitu measurement) 4.52

4.38 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 Standard-2 (Midshore) 4.53

4.39 Spectral Magnitude of the Doppler Frequency Shift Extracted from the RADARSAT-1 Standard-2 (Offshore) measurement) 4.53

4.40 Sea Surface Current Direction Extracted from RADARSAT-1 SAR Image on 21/3/2005 at 6:48 AM 4.61

xxii

4.41 The Grid Map of the Geostrophic Current in the Study East Coast of Kuala Terengganu Collected by TOPEX/POSEIDON Merged Satellite Altimetry on March 21, 2005 4.62

4.42 Wind Direction on March 21, 2005 at 6 AM 4.63

4.43 Average of Wind Speed on March 19 to 22

2005 Extracted from GEOSAT-2 Altimeter 4.63

4.44 Sea Surface Current Direction Extracted from RADARSAT-1 SAR Image on March 25, 2005 at 7:39 AM 4.64

4.45 The Grid Map of the Geostrophic Current in the Study East Coast of Kuala Terengganu Collected by TOPEX/POSEIDON Merged Satellite Altimetry on March 25, 2005 4.65

4.46 Wind Direction on March 25, 2005 at 6 AM 4.66

4.47

Average of Wind Speed on March 23 to 28 2005 Extracted from GEOSAT-2 Altimeter

4.66

4.48 Sea Surface Current Direction Extracted from RADARSAT-1 SAR Image on March 31, 2005 at 6:57 AM 4.67

4.49 The Grid Map of the Geostrophic Current in the Study East Coast of Kuala Terengganu Collected by TOPEX/POSEIDON Merged Satellite Altimetry on March 25 2005 4.68

4.50 Wind Direction on March 31, 2005 4.69

4.51 Average of Wind Speed on March 28, 2005 to April 1 2005 Extracted From GEOSAT-2 Altimeter 4.70

4.52 Correlation between RADARSAT-1 Wide-3 Mode and In-situ Measurement on March 21, 2005 4.75

4.53 Residual Plots for RADARSAT-1 Wide-3 mode 4.76

4.54 Correlation between RADARSAT-1 Extended High-6 Mode 4.76

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and In-situ Measurement on March 25, 2005

4.55 Residual Plots for RADARSAT-1 Extended High-6 mode 4.76

4.56 Correlation between RADARSAT-1 Standard-2 Mode and In-situ Measurement on March 31, 2005 4.77

4.57 Residual Plots for RADARSAT-1 Standard-2 mode 4.77

xxiv

LIST OF ABBREVIATIONS

b the chirp rate = Rkv /2 2

bT Received signal azimuthal bandwidth

c velocity of light = 3 × 108

ƒ frequency of an electromagnetic wave

maxf Doppler peak frequency shift

xf spatial domain function

DF the change in the received frequency using AWAC

sF frequency of transmitted sound using AWAC

uF frequency domain function

k Radar wave number

1M First target direction

2M Second target direction

R Radar slant range

t Amplitude of the coherent in the image

T Coherent integration time

sT Gaussian function with width

u spatial frequency

V satellite velocity = 6212 m/s

cV horizontal ocean current

rv Radial velocity of a target

0x location of a point target in the SAR image

delay time

Wavelength

Incident angle

Local modification of the incident angle