UNIVERSITI PUTRA MALAYSIA

SEASONAL PATTERN OF WATER MASSES IN THE SOUTH CHINA SEA

ABD MUHAIMIN BIN AMIRUDDIN

FPAS 2011 7

© COPYRIG

HT UPM

SEASONAL PATTERN OF WATER MASSES IN THE SOUTH CHINA SEA

By:

ABD MUHAIMIN BIN AMIRUDDIN

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfillment of the Requirement for the Degree of

Master of Science

October 2011

© COPYRIG

HT UPM

ii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfillment of the requirement for the degree of Master of Science

SEASONAL PATTERN OF WATER MASSES IN THE SOUTH CHINA SEA

By

ABD MUHAIMIN BIN AMIRUDDIN

October 2011

Chairman : Assoc. Prof. Dr. Zelina Zaiton Ibrahim, PhD Faculty : Faculty of Environmental Studies The purpose of this study is to investigate the seasonal pattern and movement of

water masses and their relation to the currents and circulations in the South China

Sea (SCS). Prior studies of water masses, currents and circulations mainly focus only

on the winter and summer seasons and on the deep basin of the SCS. This study is

carried out over the whole SCS region for the four seasons of winter, spring, summer

and fall. The hydrographic dataset from World Ocean Database 2009 is used. The

dataset is processed, analyzed and visualized using the software Ocean Data View.

The quality control procedure carried out comprised removal of duplicate stations,

visual inspection and standard deviation checks. The data quality controlled dataset

is analyzed using descriptive statistics, seasonal water mass visualization plots,

seasonal variation and water mass analyses. The results indicate that seasonal

variation of water mass mainly occurred in the surface layer. The sea surface

temperature is generally lowest in winter and highest in summer. The sea surface

salinity is highest in spring and lowest in fall. In winter, the water mass is cold and

salty in the northern SCS. The cold Taiwan Strait water and salty, surface Luzon

© COPYRIG

HT UPM

iii

Strait water flow into the northern SCS. The Northeast Monsoon induced the

intrusion of these waters into the SCS. In spring, the water mass generally becomes

warmer and saltier. The inflow of surface Luzon Strait water into the SCS remains.

The warm water from southern SCS propagates into the central SCS. In spring and

summer, the saline SCS water intrudes into the Gulf of Thailand. During summer,

the water mass is generally warmer and fresher. The warm and fresher Karimata

Strait waters flow into the southern SCS. The Southwest Monsoon induced the flow

of Karimata Strait water into the SCS and the flow of SCS waters into the Gulf of

Thailand. In fall, the water mass cools and freshens. The Taiwan Strait water starts to

intrude into northern SCS. In general, the circulation is cyclonic over the SCS basin

in winter. In spring, the cyclonic circulation occupies the north and south of SCS

whereas anticyclonic circulation emerged in the central SCS. During summer and

fall, the circulation is cyclonic in the northern SCS whereas anticyclonic circulation

occurs in the southern SCS. In conclusion, the water mass pattern in the SCS changes

over the seasons in relation to the monsoon system. The surface water masses of the

SCS are generally colder in winter, saltiest in spring, warmest in summer and fresher

in fall. As a result of analyzing the seasonal changes over the whole year instead of

only in winter and summer; it was found that in spring, there is propagation of water

from the southern SCS into the central SCS. In addition, the anticyclonic circulation

emerged in the central of SCS. During fall, there is start of water intrusion from

Taiwan Strait into northern SCS and the retreat of Karimata Current in the southern

SCS. These addition seasonal changes of water mass, currents and circulations plots

can contribute to ocean climate research, marine resources management and

submarine operations in the SCS.

© COPYRIG

HT UPM

iv

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

SEASONAL PATTERN OF WATER MASSES IN THE SOUTH CHINA SEA

Oleh

ABD MUHAIMIN BIN AMIRUDDIN

Oktober 2011

Chairman : Assoc. Prof. Dr. Zelina Zaiton Ibrahim, PhD Faculty : Faculty of Environmental Studies Kajian ini bertujuan untuk mengetahui pola bermusim dan pergerakan jasad air dan

hubungannya dengan arus dan peredaran di Laut China Selatan (SCS). Kajian

terdahulu berkenaan jasad air, arus dan peredaran hanya tertumpu kepada musim

sejuk dan musim panas dan di kawasan laut dalam SCS. Kajian ini dilakukan di

seluruh kawasan SCS untuk empat musim iaitu musim sejuk, musim bunga, musim

panas dan gugur. Data hidrografi dari ‘World Ocean Database 2009’ digunakan.

Dataset diolah, dianalisis dan divisualisasikan dengan menggunakan software ‘Ocean

Data View’. Prosedur kawalan kualiti yang dilakukan terdiri daripada pembuangan

stesen yang duplikasi, pemeriksaan visual dan pemeriksaan sisihan piawai. Data

yang telah dikawal kualitinya dianalisis dengan menggunakan statistik deskriptif,

plot visualisasi jasad air bermusim, variasi mengikut musim dan analisa jasad air.

Keputusan analisis menunjukkan bahawa variasi jasad air mengikut musim berlaku

terutamanya pada lapisan permukaan. Suhu permukaan laut di musim sejuk pada

amnya adalah yang terendah dan di musim panas adalah yang tertinggi. Kemasinan

paras laut tertinggi di musim bunga namun yang terendah di musim gugur. Di musim

© COPYRIG

HT UPM

v

sejuk, jasad air adalah sejuk dan masin di utara SCS. Air sejuk dari Selat Taiwan dan

air masin pada permukaan dari Selat Luzon mengalir masuk ke utara SCS. Angin

monsun Timur Laut menyebabkan pengaliran masuk air tersebut ke dalam SCS. Pada

musim bunga, jasad air menjadi panas dan masin. Kemasukan air permukaan dari

Selat Luzon ke SCS kekal. Air memanas dari selatan SCS bergerak ke tengah SCS.

Pada musim bunga dan musim panas, air masin dari SCS mengalir ke kawasan Teluk

Thailand. Di musim panas, jasad air pada amnya lebih panas dan kemasinan

berkurang. Air memanas dan lebih tawar dari Selat Karimata mengalir ke selatan

SCS. Angin Barat Laut mempengaruhi aliran air Selat Karimata ke kawasan SCS dan

aliran air SCS ke Teluk Thailand. Pada musim gugur, jasad air menjadi lebih dingin

dan kemasinan semakin berkurangan. Air dari Selat Taiwan mulai mengalir masuk

ke utara SCS. Pada amnya, peredaran laut adalah siklon di musim sejuk di SCS. Pada

musim bunga, peredaran siklon menempati di kawasan utara dan selatan SCS

manakala peredaran antisiklon muncul di tengah SCS. Semasa musim panas dan

gugur, peredaran adalah siklon di utara SCS manakala peredaran antisiklon berlaku

di selatan SCS. Sebagai kesimpulan,pola jasad air di SCS berubah mengikut musim

berdasarkan sistem monsun. Jasad air permukaan di SCS amnya menjadi lebih sejuk

di musim sejuk, sangat masin di musim bunga, menjadi lebih panas di musim panas

dan menjadi lebih tawar di musim gugur. Hasil analisis perubahan bermusim

sepanjang tahun, dibandingkan dengan yang tertumpu pada musim sejuk dan musim

panas sahaja, adalah didapati bahawa pada musim bunga, terdapat pergerakan air dari

selatan SCS ke tengah SCS. Selain itu, peredaran antisiklon muncul di tengah SCS.

Di musim gugur, air dari Selat Taiwan mula mengalir masuk ke utara SCS dan aliran

keluar arus Selat Karimata di selatan SCS. Pertambahan maklumat berkenaan

© COPYRIG

HT UPM

vi

perubahan jasad air mengikut musim, arus dan peredaran ini boleh menyumbang

kepada kajian iklim laut, pengurusan sumber laut dan operasi kapal selam di SCS.

© COPYRIG

HT UPM

vii

ACKNOWLEDGEMENTS

Alhamdulillah, thanks to the Allah, Al-Mighty, for giving me all His blessing,

‘mehnah’, ‘ibrah’, courage and strength to finish my study.

I would like to put across my utmost gratitude to my project supervisor, Assoc. Prof.

Dr. Zelina Zaiton Ibrahim for all her supervision, guidance, and dedication. Her

constructive criticism, endless ideas and useful comments has been very precious. I

would like to thank my co-supervisor, First Admiral (R) Assoc. Prof. Dr. Sutarji

Kasmin for his positive comments and helpful suggestions.

I am grateful to Mr. Nabeel Gazzaz for his guidance in thesis writing. Thanks to Dr.

Tingting Zu, for providing me some literatures from China. Appreciation also goes to

Assoc. Prof. Dr. Latifah Ibrahim, Head of Department of Environmental

Management for her constant support and encouragement. Thanks are also extended

to all my colleagues, especially Mr. Syazwan Aizat, Mrs. Fershteh Jaderi, Mr. Milad

Bagheri and Ms. Khairiyah Rahim for valuable discussions and meaningful

assistance.

Finally, special appreciations to my parents, Mr. Amiruddin Fakih and Mrs. Fatimah

Kamaludin and my loving wife, Ms. Rashidah Ismail, for their patience,

understanding and support.

© COPYRIG

HT UPM

viii

I certify that an Examination Committee has met on 6 October 2011 to conduct the final examination of Abd Muhaimin Bin Amiruddin on his thesis entitled “Seasonal Pattern of Water Masses in the South China Sea” in accordance with the Universities and University College Act 1971 and the Constitution of the Universiti Putra Malaysia [P.U.(A) 106] 15 March 1998. The committee recommends that the students be awarded the Master of Science. Members of the Examination Committee were as follows: Mohd Bakri Ishak, Ph.D Associate Professor Faculty of Environmental Studies Universiti Putra Malaysia (Chairman) Mohamad Ibrahim Mohamed, Ph.D Professor Faculty of Environmental Studies Universiti Putra Malaysia (Internal Examiner) Wan Nor Azmin Sulaiman, Ph.D Associate Professor Faculty of Environmental Studies Universiti Putra Malaysia (Internal Examiner) Tetsuo Yanagi, Ph.D Professor Research Institute for Applied Mechanics Kyushu University (External Examiner)

_______________________________ SEOW HENG FONG, PhD Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia

Date: 20 December 2011

© COPYRIG

HT UPM

ix

This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfillment of the requirement for the degree of Master of Science Environmental Systems and Processes. The members of the Supervisory Committee were as follows: Zelina Zaiton Ibrahim, Ph.D Associate Professor Faculty of Environmental Studies Universiti Putra Malaysia (Chairman) First Admiral (R) Sutarji Kasmin, Ph.D Associate Professor Faculty of Environmental Studies Universiti Putra Malaysia (Member)

________________________________ BUJANG BIN KIM HUAT, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia

Date:

© COPYRIG

HT UPM

x

DECLARATION

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

_________________________________

ABD MUHAIMIN BIN AMIRUDDIN

Date: 6 October 2011

© COPYRIG

HT UPM

xi

TABLE OF CONTENTS Page

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

ii iv vii viii x

xiii xv

xviii CHAPTER 1 INTRODUCTION 1 2 LITERATURE REVIEW

2.1 Introduction 2.2 Patterns of Water Masses in the SCS 2.2.1 Temperature 2.2.2 Salinity 2.2.3 Water Masses in the SCS 2.2.4 Factor Affecting Water Mass 2.3 Currents and Circulations of the SCS 2.4 Approaches to Study Patterns of Water Masses 2.4.1 Methods 2.4.2 Data Sources 2.4.3 Research Tools 2.4.4 Data Analysis Technique 2.5 Selected Research Approach 2.6 Summary

8 8 9

15 18 20 29 33 33 34 36 38 39 41

3 METHODOLOGY

3.1 Introduction 3.2 Research Framework 3.3 Study Area 3.4 Research Tool 3.5 Data Gathering 3.5.1 Data Processing and Method 3.5.2 Quality Control Procedure 3.6 Data Analysis and Method 3.6.1 Introduction

42 42 44 47 47 47 51 58 58

© COPYRIG

HT UPM

xii

3.6.2 Descriptive Statistics of General Water Mass Condition 3.6.3 Seasonal Visualization of Spatial and Seasonal Changes 3.6.4 Seasonal Variation 3.6.5 Water Mass Analyses for Characterization of Water Masses 3.7 Summary

59 60 68 69

70 4 RESULTS AND DISCUSSION

4.1 Introduction 4.2 General Mean Water Mass Conditions 4.3 Variation in Spatial and Seasonal Properties 4.3.1 Temperature 4.3.2 Salinity 4.3.3 Density 4.4 Discussion on Currents and Circulations 4.5 Water Mass Characterizations 4.6 Effect of Monsoon Winds on Water Mass Distribution

72 72 77 78 95

112 120 124 131

5 SUMMARY, CONCLUSION AND

RECOMMENDATIONS 134

REFERENCES/ BIBLIOGRAPHY 143 BIODATA OF STUDENT 151 LIST OF PUBLICATIONS 152