여름철 낙뢰 발생 시 정지궤도 위성의 휘도온도 특성

Abstract

The characteristics of brightness temperature (BT) of infrared and water vapor channels from MTSAT-1R have been investigated using 12 persistent and frequent lightning cases selected from the summer lightnings of 2006-2008. The infrared (IR1, 10.3-11.3 ) and water vapor (WV, 6.5-7.0 ) channels from the MTSAT-1R and the lightning observation data from Korea Meteorological Administration are used. When there is no lightning, the BTs of the IR1 and WV channels show the largest frequency at around 290-295K and 245K, respectively. On the other hand, the BTs of two channels show the largest frequency at 215K caused by strong convection when there is lightning. As a result, the WV-IR1 difference (BTDWI) sharply increases from -50K to 0K. Although it depends on the evolution stage of thunderstorms, the lightning mainly occurs at the core of circular convection in the mesoscale convective complex (MCC), whereas the lightning occurs by concentrated line-shape in the squall line. A strong positive correlation exists between the lightning frequency and the BT in the MCC regardless of the BT, but only at the very cold BT in the squall line. In general, the characteristics of BT are well defined for the lightning occurring in the concentrated line, but they are not well defined in the MCC, especially during the decaying stage of MCC. When they are defined well, the lightning occurs when the BTs of IR1 and WV are lower than 215K, BTDWI is near -3 to 1K, and local standard deviation of IR1 decreases to around 1K.