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Title:	The viability of using precipitable water vapor variations in detecting the El Nino-Southern oscillation at the maritime continent
Authors:	Farah Hani Abdul Rahim (P36297)
Supervisor:	Mohd. Alauddin Mohd. Ali, Prof. Dr.
Keywords:	Precipitable water Water vapor Atmospheric Global positioning system Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	24-Jul-2012
Description:	The occurrences of extreme weather events have increased and are being linked to the rise in average global surface temperature with a projected increase of 1.1 to 6.4°C by the end of the 21st century. An increase in the atmospheric moisture content due to this rise is inevitable and will result in varying effects in the weather system on a global and regional scale. The regional weather is expected to intensify with more frequent thunderstorms, tornadoes and hurricanes from the increased humidity. Such events bring dire effects to communities. Thus, mitigation and adaptation are necessary where and when prevention is not possible. However, the materialization of the steps in mitigating and adapting must begin with an understanding of its root cause, which is the water vapor. In this research, the characterization of atmospheric precipitable water vapor (PWV) was performed to investigate the behavior and viability of PWV for monitoring and detecting El Niño-Southern Oscillation (ENSO) events. In order to do this, four ground-based Global Positioning System (GPS) satellite data at the Borneo Island were employed to derive the PWV from 2003 to 2007 for comparison with ENSO events. The PWV and sea surface temperature (SST) anomalies at Niño regions were used in testing the viability of PWV in detecting ENSO events through the introductions of the Differential Anomalistic Determination (DAD) and the Minor Shift in Standard Deviation (MISS) methods. Finally, a physical mechanism of the water vapor transport during ENSO is also proposed. This study finds mean annual cycle of PWV ranging within 36 to 42 mm with instrumentation bias comparison ranging from a median of 10.2 to 23.2 mm. The PWV annual cycle at Borneo Island resembles those of the Southern Hemisphere albeit with a 1-month lag. Prevailing seasonal variations were exhibited in all stations with March-April-May as the most humid season and December-January-February as the least humid season. Intraseasonal oscillations with a periodicity of 20 to 60 days were seen across all stations. However, a dominant cycle of ~40 days were only seen at Kota Kinabalu, Labuan and Miri. A further analysis of ENSO effects on PWV showed PWV dropping during the onset of El Niño 2006 up to a threshold between SST anomalies of 0.4 and 0.5°C. This onset was detectable a few months before the peak of the event using the coupled DAD and MISS method. However, the method only works for El Niño and requires further analysis before it can be incorporated into mitigation applications in Borneo Island. A hypothesis to explain the physical mechanism of water vapor transport during El Niño and La Niña based on the observed findings is presented. The increased warming during El Niño promotes water vapor formation. However, the persistent warming causes dissipation of water vapor thereby minimizing the development of rain-bearing clouds. During La Niña, parallel increases in cooling and air density promote cloud formation. The clouds have lower water-carrying capacity due to the cooling thereby increasing the occurrences of rainfall.,Certification of Master's / Doctoral Thesis" is not available
Pages:	127
Call Number:	TA595.5.F347 2012 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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