10:15 〜 10:30
[AAS03-06] Seasonal Diurnal Variations of Deep Convective Clouds Over the Philippine Climate Regions
キーワード：deep convective clouds, diurnal, the Philippines
This study characterizes the seasonal diurnal variations of deep convective cloud (DCC) over the Philippine climate regions based on the Modified Corona Classification. DCCs during non-tropical cyclone days were identified using infrared brightness temperature threshold of 208 K. Hourly DCC temperature, percentage, and frequency distributions were obtained from 2016 to 2018 during the northeast monsoon season or Amihan (December to February), warm-dry season (March to May), southwest monsoon season or Habagat (June to August), and transition season (September to November). The temperature and percentage distributions of DCC follow a general diurnal pattern in all climate regions and seasons except Type II and during Amihan. Coldest and maximum percentage of DCC occurs in the afternoon (1500-1800 LST), whereas warmest and minimum percentage of DCC happens in the late morning (0900-1200 LST). Although both temperature and percentage display a general pattern, spatiotemporal maps reveal that coldest DCC (<199 K) does not coincide and are not collocated with areas of high DCC frequency. Reanalysis data were used to further examine the environmental conditions associated with the development of DCC. Warm surface temperature and moisture convergence shows a significant influence on the diurnal development of DCC, while low inhibition, large-scale upward wind, and unstable boundary conditions control the existence and development of deep convective clouds. The findings from this study can improve the understanding of deep convective activity in the Philippines, facilitating more effective disaster risk management associated with deep convective systems.