Extreme Intensity of Tropical Cyclone (TC) Making Landfall and Influence on Climate Change
Dr. Porpattama Hammachukiattikul
邀请人 ： 包庆 研究员
This presents study on the variation in the frequency and intensity of tropical cyclones (TCs) making rainfall during the period 1949-2020. Domain as latitude 0o-20oN and longitude 100o-120oE. The season of tropical cyclone landfall on domain study is usually from May to November and peaks from June to November, representing 95% of the annual number of landfalls. The focus of this study is June to November. A total of 247 TCs made landfall during the period of study. The large-scale environment uses the monthly dataset from NCEP reanalysis (1993-2020), and the horizontal resolution is 2.5o latitude x 2.5o longitude. It is a dynamic TC development and intensification factor, such as vertical wind shear (VWS) and relative humidity 850hPa. The VWS is calculated from the magnitude of the difference between 200 and 859 hPa. The monthly mean oceanic temperature (1993-2020) dataset from Global Ocean Ensemble Physic and resolution is 1o x 1o. and 75 vertical layers. It is used to estimate the TC potential (TCHP), which measures the ocean heat content of water warner over 26oC. The time series of TCHP using the Regime shift index (RSI) by Rodinov (2004) was shown. It identifies a significant change in the sequential running mean with a certain cut-off length (8 years in this study) based on the student’s t-test and a certain confidence level (95%). The result indicated the timing of shift show in 2010. 2010, the characteristic pattern showed a high TCHP area, and Thailand got considerable flooding. Also, the ocean heat content in the domain study provides a higher value, which is relative to global warming. Then why Thailand had droughts in 2015 after a big flood in 2010-2011？The two factors that contributed to drought in Thailand in 2015 are the impact of ENSO characteristics on monsoon and tropical cyclones decreasing. The Ocean Nino index shows that 2015-2016 is very strong El Niño and 2010-2011 is very strong La- Niña. El Niño 2015 strongly impacted upper Thailand by producing dry signals during the JJAS monsoon season. Also, the number of tropical in the domain study was 42 (El Niño years) and 92 (La- Niña years), and the number of landfalls was 14 (El Niño years) and 42(La- Niña years).
Porpattama Hammachukiattikul，泰国普吉皇家大学副教授、博士。分别于2003、2005和2010年在泰国King Mongkut‘s University of Technology Thonburi大学数学系获得学士、硕士和博士学位。主要研究方向为numerical modeling, small-scale physical processes, climate change, tropical cyclone, control theory 和 chaos。发表关于泰国气象及中南半岛气候数值模拟的期刊和会议论文多篇。