Characteristics of Diurnal Variations in Convection and Precipitation over the Southern Tibetan Plateau during Summer

Abstract

This study investigated diurnal cycles in convection and precipitation over the complex mountain-valley terrain of the southern Tibetan Plateau (TP) during the mature phase of the summer monsoon. Cloud-cover frequency (CCF) for high cloud increased after 13 LST (07 UTC) over the mountain ranges along 28.5 degrees N and 30.2 degrees N, reaching a maximum near 18 LST (12 UTC). Areas of high CCF subsequently moved towards the valley area along 29.3 degrees N; relatively high CCF persisted there until early morning. Tropical Rainfall Measuring Mission (TRMM) PR data show a nearly identical variation in rainfall frequency. Formation and development of convective-type clouds and phase differences in the diurnal cycle were strongly affected by TP topography. Possible mechanisms for convective enhancement over the southern TP are also discussed.