Effects of Orography on the Tail-End Effects of Typhoon Ketsana

摘要

The study of tail-end effects of typhoon on orography is new to Malaysia. The current study used FY-2Dsatellite data to investigate the variation of selected parameters of the Typhoon Ketsana system. In situ data, obtained viathe radiosonde technique, were used to verify the atmospheric conditions, whereas the Advanced Spaceborne ThermalEmission and Reflection Radiometer Global Digital Elevation Model was applied to determine the structure of themountains in East Malaysia (EM). This study aimed to identify typhoon-terrain effects, in terms of wind, cloud, and rainof the tail-end effects of typhoon in a regional environment. The tail-end effects of Typhoon Ketsana were altered by theorography in EM such that a slow movement with higher rate of rainfall was distributed along the mountainous westernregion, and cloud classification distribution patterns were different before, during, and after the tail-end effects of thetyphoon. The wind intensity increased with altitude and affected the larger atmosphere region over EM. Additionally, thelocation of the Sabah region puts it at a higher risk to the impact of the tail-end effect of typhoons compared with theSarawak region due to its distance from the typhoon. This study concluded that the impacts of the tail-end effects of atyphoon can also be varied and enhanced by the orography.