A Study on Low-Frequency Variability in Current and Sea Level in the Lombok Strait and Adjacent Region
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Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1992 A Study on Low-Frequency Variability in Current and Sea Level in the Lombok Strait and Adjacent Region. Dharma Arief Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Arief, Dharma, "A Study on Low-Frequency Variability in Current and Sea Level in the Lombok Strait and Adjacent Region." (1992). LSU Historical Dissertations and Theses. 5289. https://digitalcommons.lsu.edu/gradschool_disstheses/5289 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. 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Ann Arbor, MI 48106 A STUDY ON LOW FREQUENCY VARIABILITY IN CURRENT AND SEA-LEVEL IN THE LOMBOK STRAIT AND ADJACENT REGION A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College In partial fulfillment of the requirements for the degree of Doctor of Philosophy In Department of Oceanography and Coastal Sciences by Dharma Arief B.S., Bandung Institute of Technology, 1977 M.S., Louisiana State University 1988 May 1992 ACKNOWLEDGEMENTS I would like to thank to Dr.Stephen P. Murray, Coastal Studies Institute, Louisiana State University, for his guidance in conducting this research and during the writing of this manu script. Appreciations are extended to Dr. William J.Wiseman Jr., Dr. Masamichi Inoue, Dr. Harry H.Roberts, and Dr. S.A.Hsu for their valuable suggestions and advice. I also thank to Dr. Nan van Heerden, and all personnel of Coastal Studies Institute for their assistance during this research. Special acknowledgement is due to my parents, my wife Lya, and my children Ayusta and Riana for their support and understanding. ii TABLE OF CONTENTS ACKNOWLEDGEMENTS .............................................................................................................. ii TABLE OF CONTENTS ................................................................................................................. iii LIST OF TABLES............................................................................................................................ vi LIST OF FIGURES.......................................................................................................................... vii ABSTRACT....................................................................................................................................... X I. INTRODUCTION .......................................................................................................................... 1 II. BACKGROUND KNOWLEDGE .............................................................................................. 8 A. THE INDONESIAN SEAS .................................................................................................... 8 1. Topographic setting .......................................................................................................... 8 2. Circulation ........................................................................................................................... 9 3. Water m asses ..................................................................................................................... 10 B. THE SOUTH COAST OF JAVA - LOMBOK REGION ................................................. 11 1. Topographic s e ttin g .......................................................................................................... 11 2. Circulation ............... 11 C. THE LOMBOK STRAIT ....................................................................................................... 12 1. Topographic s e ttin g ................................................................................................... 12 2. Oceanographic measurements: ..................................................................................... 13 3. Water m asses ..................................................................................................................... 14 4. Circulation: .......................................................................................................................... 14 D. REGIONAL METEOROLOGICAL CONDITIONS......................................................... 15 1. S easonal P eriod ................................................................................................................. 15 2. Intraseasonal period .......................................................................................................... 16 3. Cyclones .............................................................................................................................. 17 4. Westerly Wind B urst .......................................................................................................... 18 E. CHAPTER SUMMARY......................................................................................................... 19 III. MATERIALS AND METHODS............................................................................................... 20 A. DATA......................................................................................................................................... 20 1. Current .................................................................................................................................. 20 2. Sea Level / Pressure G auge ............................................................................................ 22 3. Wind and Atmospheric Pressure .................................................................................... 22 B. M ETHODS.............................................................................................................................. 24 1. Interpolation for missing d a t a ........................................................................................ 24 i i i 2. Coordinate rotation ......................................................................................................... 27 3. Data Filtering .................................................................................................................... 27 4. Time domain analysis ..................................................................................................... 28 5. Spectral A nalysis.................................... 29 IV. DESCRIPTION OF PHYSICAL PROCESSES IN THE LOMBOK STRAIT................ 31 A. CURRENTS IN THE LOMBOK STRAIT........................................................................ 31 1. Directional and Vertical Properties .............................................................................. 31 2. Monthly C urrents ............................................................................................................ 36 3. Spectral Characteristics of AE25 C urrents................................................................. 39 4. Sub-tidal Currents at A E 25 ........................................................................................... 43 B. SEA LEVEL IN THE LOMBOK STRAIT ........................................................................ 46 1. S ea Level Characteristics ............................................................................................. 46 2. Spectral Characteristics ................................................................................................. 46 V. CURRENT AND SEA-LEVEL SLOPE RELATION IN THE LOMBOK STRAIT 51 A. CURRENTS - SEA-LEVEL SLOPES RELATIONSHIP .............................................