Potential of representing the diurnal cycle of local-scale precipitation in northeastern Thailand using 5-km and 2-km grid regional climate models

Abstract

The diurnal cycle of precipitation over northeast Thai‐ land during the Southeast Asian summer monsoon season was examined using non-hydrostatic (5-km grid) and convection-permitting (2-km grid) regional climate models. The results indicate that these fine grid models exhibit a better performance in terms of representing the diurnal cycle of precipitation due to the realistic orographic repre‐ sentation. The models successfully simulated the local cir‐ culation corresponding to the intensification of precipita‐ tion and were consistent with the satellite-based observed diurnal cycle of precipitation. The model simulation indi‐ cated that the convergence area over the mountain on the south of the Khorat Plateau occurred in the afternoon in association with the occurrence of precipitation. The con‐ vergence area migrated northward and contributed to the precipitation peak over the plateau during the nighttime. A bias in terms of the amount of precipitation in the 5-km grid model was partially removed through the convectionpermitting 2-km grid model.