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Sea Level Rise Estimation and Interpretation in Malaysian Region Using Multi-Sensor Techniques

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Sea Level Rise Estimation and Interpretation in Malaysian Region Using Multi-Sensor Techniques SEA LEVEL RISE ESTIMATION AND INTERPRETATION IN MALAYSIAN REGION USING MULTI-SENSOR TECHNIQUES AMI HASSAN MD DIN UNIVERSITI TEKNOLOGI MALAYSIA SEA LEVEL RISE ESTIMATION AND INTERPRETATION IN MALAYSIAN REGION USING MULTI-SENSOR TECHNIQUES AMI HASSAN MD DIN A thesis submitted in fulfilment of the requirements for the award of the degree of Doctor of Philosophy (Geomatic Engineering) Faculty of Geoinformation and Real Estate Universiti Teknologi Malaysia SEPTEMBER 2014 iii DEDICATION I dedicate this work to my beloved Mother, Wife, Children and in memory of my late Father iv ACKNOWLEDGEMENT All praises to Allah, the Lord of the Universe. May the peace and blessings of Allah be upon Prophet Muhammad s.a.w, His last messenger. Special thanks goes to my mentors, Prof. Dr. Sahrum Ses and Assoc. Prof. Kamaludin Mohd Omar for their tireless advice, constructive comments, great support and friendship during this long journey in completing my study. Working with them has improved my skills enormously. This work was possible through the financial aid from the Skim Latihan Akademik Bumiputera (SLAB), UTM. I would also like to extend my gratitude to Assistant Prof. Marc Naeije (Delft University of Technology) for guiding me in the altimeter field and willing to spend his precious time answering even trivial questions posed by me. Thanks also to Prof. Dr. Andy Hooper and Dr. Miguel Caro Cuenca (Delft University of Technology) for introducing me to PS InSAR, particularly to the concept, algorithm and software. I also very much appreciate Mr Soeb Nordin (DSMM Staff), Dr Mohd Effendi Daud (UTHM) and Mr Jhonny for their valuable discussions, recommendations and support in understanding Bernese processing during the early stages of my study. I am deeply indebted to Mr Jespal Singh Gill for his assistance in proof reading this thesis. I am also grateful to my colleagues, especially Mr Mohamad Asrul Mustafar (UiTM), Mr Mohd Faiz Pa’suya, Mr Wan Aminullah Abdul Aziz and all friends in GNSS and Geodynamics Research Group, UTM who have provided assistance in various occassions. Unfortunately, it is not possible to list all of them in this limited space. I would like to express my sincerest gratitude to My Late Father, Mother, Brothers and Sisters for their love, prayers and constant support. I also express my deepest appreciation for my family-in-law. As for the utmost appreciation and gratitude, I would like to thank my lovely wife, Nadia Hartini Mohd Adzmi for her understanding, support and love during the past few years. To my daughter, Arina and my sons, Ahnaf and Afifi, with all their love they make me very happy. They are a major driving force and a great source of inspiration for completing my study. I am utterly grateful to them. v ABSTRACT Rise in sea level is one of the disastrous effects of climate change. A relatively small increase in sea level could affect the natural coastal system. This study presents an approach to estimate before interpreting the precise sea level trend based on a combination of multi-sensor techniques in the Malaysian region over a period of 19 years. In the study, six altimeter missions were used to derive the absolute sea levels which were processed in the Radar Altimeter Database System. Next, 21 tide gauge stations along the coastlines of Malaysia were utilised to derive the rate of relative sea levels that took into account sea level changes and vertical land motions. To obtain absolute sea level at tide gauge, vertical land motions at these stations were removed by employing three techniques, namely GPS, Persistent Scatterers Interferometric Synthetic Aperture Radar and altimeter minus tide gauge. Bernese software with double difference strategy was employed to process data from 87 local and 30 international GPS stations. Using Persistent Scatterers Interferometric Synthetic Aperture Radar, the Stanford Method for Persistent Scatterer software processed 111 images. Besides that, the satellite altimeter and tide gauges were used to retrieve the differential rates estimated by altimetry and tidal data to obtain the rate of vertical land motion. Following that, absolute sea level rates from the tide gauge stations and multi-satellite altimeter missions were combined. This combination produced the regional sea level trend of the Malaysian seas. The findings from the multi-sensor techniques showed that the regional sea level trend has been rising at a rate of 2.65 ± 0.86 mm/yr to 6.03 ± 0.79 mm/yr for the chosen sub-areas, with an overall mean of 4.47 ± 0.71 mm/yr. Upon completion of the study, a Sea Level Information System for the Malaysian seas was developed to facilitate users in analysing, manipulating and interpreting sea level and vertical land motion data. This system is expected to be valuable for a wide variety of climatic applications to study environmental issues related to flood and global warming in Malaysia vi ABSTRAK Kenaikan paras laut adalah salah satu kesan buruk perubahan iklim. Peningkatan kecil dalam paras laut boleh menjejaskan sistem semula jadi pantai. Kajian ini membentangkan satu pendekatan untuk menganggarkan sebelum mentafsir trend paras laut tepat berdasarkan kombinasi teknik multi-sensor di rantau Malaysia dalam tempoh 19 tahun. Dalam kajian, enam misi altimeter telah digunakan untuk memperolehi paras laut mutlak yang telah diproses dalam Sistem Pangkalan Data Altimeter Radar. Seterusnya, 21 stesen tolok pasang surut di sepanjang garis pantai Malaysia telah digunakan untuk mendapatkan kadar paras laut relatif yang mengambil kira perubahan paras laut dan pergerakan tanah menegak. Untuk mendapatkan paras laut mutlak pada tolok pasang surut, pergerakan tanah menegak di stesen-stesen ini telah dikeluarkan dengan menggunakan tiga teknik, iaitu GPS, Radar Aperture Sintetik Interferometri Sebaran Berterusan dan altimeter tolak tolok pasang surut. Perisian Bernese dengan strategi perbezaan ganda dua telah digunakan untuk memproses data daripada 87 stesen tempatan dan 30 stesen GPS antarabangsa. Menggunakan Radar Aperture Sintetik Interferometri Sebaran Berterusan, perisian Kaedah Stanford untuk Sebaran Berterusan telah memproses 111 imej. Di samping itu, altimeter satelit dan tolok pasang surut telah digunakan untuk memperolehi kadar perbezaan anggaran dengan data altimeter dan tolok pasang surut untuk mendapatkan kadar pergerakan tanah menegak. Berikutan itu, kadar paras laut mutlak dari stesen tolok pasang surut dan misi altimeter multi-satelit telah digabungkan. Gabungan ini telah menghasilkan trend paras laut serantau di laut Malaysia. Penemuan daripada teknik multi-sensor menunjukkan trend paras laut serantau telah meningkat pada kadar 2.65 ± 0.86 mm/tahun kepada 6.03 ± 0.79 mm/tahun untuk sub-kawasan yang dipilih, dengan min keseluruhan 4.47 ± 0.71 mm/tahun. Dalam menyelesaikan kajian, Sistem Maklumat Paras Laut untuk laut Malaysia telah dibangunkan bagi membolehkan pengguna menganalisis, memanipulasi dan mentafsirkan data paras laut dan pergerakan tanah menegak. Sistem ini dijangka berharga untuk pelbagai aplikasi iklim untuk mengkaji isu-isu alam sekitar yang berkaitan dengan banjir dan pemanasan global di Malaysia. vii TABLE OF CONTENTS CHAPTER TITLE PAGE NUMBER DECLARATION ii DEDICATION iii ACKNOWLEDGEMENTS iv ABSTRACT v ABSTRAK vi TABLE OF CONTENTS vii LIST OF TABLES xiv LIST OF FIGURES xvii LIST OF SYMBOLS xxviii LIST OF ABBREVIATIONS xxxi LIST OF APPENDICES xxxv 1 INTRODUCTION 1 1.1 Research Background 1 1.2 Problem Statement 3 1.3 Research Objectives 6 1.4 Research Scope 6 1.5 Contribution of the Research 11 1.6 Research Methodology 12 1.7 Outline of the Thesis 17 2 SEA LEVEL CHANGES 19 2.1 Introduction 19 viii 2.2 Sea Level Changes Associated with Climate Change 19 2.3 Processes Contributing to Sea Level Changes 21 2.4 The Scientific Evidence of Holocene Sea Level Rise: Present and Future Projection 22 2.4.1 Holocene Sea Level Rise 23 2.4.2 Present and Future Projection of Sea Level Rise 25 2.5 Sea Level Rise Studies in Malaysia and its Neighbouring Countries 27 2.6 Measuring Sea Level Changes from Multi-sensors 30 2.6.1 Vertical Datum References 33 2.7 Summary 34 3 SEA LEVEL QUANTIFICATION FROM SATELLITE ALTIMETER AND TIDE GAUGE 36 3.1 Introduction 36 3.2 Satellite Altimeter 37 3.2.1 Principle of Satellite Altimeter 39 3.2.2 Orbit Determination 43 3.2.2.1 Satellite Laser Ranging (SLR) 44 3.2.2.2 Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) 45 3.2.2.3 The Precise Range and Range-Rate Equipment (PRARE) 46 3.2.2.4 Global Positioning System (GPS) 47 3.2.2.5 Altimeter 47 3.2.3 Multi-mission Satellite Altimeter 47 3.2.4 Crossover Adjustment for Multi-mission Altimeter 49 3.3 Radar Altimeter Database System (RADS) Framework 51 ix 3.4 RADS Processing Strategy for Determination of Sea Level Anomaly 54 3.5 Range and Geophysical Corrections: Best for Malaysian Case 59 3.5.1 Dry Troposphere Correction 60 3.5.2 Wet Troposphere Correction 63 3.5.3 Ionosphere Correction 64 3.5.4 Sea-state Bias Correction 70 3.5.5 Ocean Tides Correction 74 3.5.6 Dynamic Atmosphere Correction 76 3.5.7 Mean Sea Surface 78 3.6 Tide Gauge 80 3.6.1 Sea Level Anomaly Determination from Tidal Data 83 3.7 Long-term Time Series Analysis of Sea Level and Vertical Land Motion using Robust Fit Technique 86 3.8 Data Verification: Altimeter versus Tide Gauge 87 3.9 Summary 96 4 VERTICAL LAND DISPLACEMENT QUANTIFICATION FROM GLOBAL POSITIONING SYSTEM (GPS) 98 4.1 Introduction 98 4.2 The Global Positioning System (GPS) 98 4.2.1 Reference Systems 99 4.2.1.1 The International Terrestrial
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