What primarily regulates the evolution of convection in Hainan Island?

Abstract

The evolution characteristics of convection in Hainan Island and their key regulators are still not fully recognized. Using years of high-resolution radar and reanalysis data, this study investigated the statistical characteristics of the evolution of convection in Hainan Island and discussed the key regulators leading to these characteristics. Results show that environmental winds significantly promote near-surface high potential temperature center and its induced convergence center to shift to the leeward side. The leeward-side convergence center is further enhanced due to the dynamical effects caused by the environmental winds bypassing or crossing the mountains, favoring convection to mostly occur on the leeward side in the late morning or at noon. After convection is triggered, it tends to develop northward in the afternoon due to northward migrations of the high potential temperature center and convergence center on the leeward side, and concentrate northward under southwesterly winds or contract southward under other environmental winds in the evening due to the decay of solar radiation heating and resultant divergence tendency. The findings can help to provide a basic prediction of the evolution of convection in Hainan Island.