The Role of Soil Temperature Feedbacks for Summer Air Temperature Variability Under Climate Change Over East Asia

The ongoing climate change has posed severe threat to the natural system and human society. However, how soil temperature feedbacks matter for climate change projections is not yet well explored. In this study, we assess the role of soil temperature feedbacks for summer air temperature variability over East Asia under global warming. Regional climate model simulations with and without soil temperature-atmosphere interactions were performed to isolate the role of soil temperature feedbacks under historical (1976-2005) and future (2071-2100) warming conditions. Results indicate that soil temperature feedbacks can largely enhance interannual variability of summer daily mean and minimum surface air temperatures over East Asia, with strongest impacts over Mongolia and many areas of northern Tibetan Plateau and northern China, in the historical period. The soil temperature feedback strength below 925-hPa mainly depends on changes in longwave radiation, surface heat flux partitioning, and temperature advections, while it is largely determined by the diabatic heating processes in the lower troposphere. The spatial distribution of soil temperature feedbacks is projected to change notably over East Asia under future warming condition. In particular, the impacts of soil temperature feedbacks on summer temperature are shown to be stronger in the lower troposphere under future condition. These results imply the important role of soil temperature feedbacks on air temperature variability for regional climate modeling especially in the context of climate change.