MECHANISM OF LOCALLY-INDUCED CONVECTION DEVELOPMENT AND ITS EFFECTS ON VAPOR TRANSPORTATION OVER TONLE SAP LAKE AREA

Abstract

Mechanisms of the development of local circulation and convective updraft around Tonle Sap Lake were examined by using a non-hydrostatic model (ARPS) coupled with a land surface scheme (SiB2) . Two atmospherically calm periods with little influence of the monsoon were selected as this research targets: one was in April with around the minimum lake area and the other in October with the almost maximum. The results of the numerical simulation show clear local circulations induced by the lake-land contrast and the mountain topography. Convective updraft was formed during daytime at the lakeshore due to the lake breeze both in April and October. During nighttime, a lined up convective system was formed only in October when the difference of air-mass density between over land and lake was larger. These convective activities are considered to correspond to the rainfall events in the southwest region in the evening in October and on the lake during nighttime in April.