Surface energy distribution over the Tibetan Plateau and Southern Plain: Impact on convection development in dual coupling regime classification

Abstract

This study aims to comprehend the impact of surface states on precipitation and convection, with a focus on the Tibetan Plateau. The study examines the effects of energy distribution on the plateau and southern lowlands, comparing differences between the two regions through WRF simulations. The results reveal that changes in surface energy distribution can trigger both direct and indirect feedback on convective precipitation, and that the surface energy distribution controls how the total surface energy contributes to precipitation. This is reflected not only in effects on the spatial distribution, magnitude, and type of precipitation, but also on the timing and height of cloud formation. The study also examines the role of specific microphysical processes to the generation and dissipation of rainfall. The microphysical processes related to cold cloud rainfall are more significantly affected by surface energy distribution and exhibit negative feedback. The higher the proportion of cold cloud processes, the more significant the negative feedback. This coupling state characteristics are not limited by regions and can be generalized. Finally, this study investigated the boundary layer variables and microphysical variables in the entrainment layer and found that the existence of negative feedback in the dry coupling regime mainly depends on the stronger collision and aggregation effects brought about by the larger particles and stronger vertical motion.