Unraveling the South–North Dipole in August Precipitation–Surface Air Temperature Relationship Over the Tibetan Plateau

Abstract

The Tibetan Plateau (TP) exerts strong summer thermal forcing that plays a critical role in regulating regional and even global climate anomalies. However, how radiative feedback associated with precipitation modulates surface thermal conditions over the TP remains incompletely understood. Using the high-resolution CMFD 2.0 dataset by integrating multisource observational data, this study investigates the relationship between precipitation and surface air temperature (SAT) during the peak rainy month (August) over the TP for the period 1980–2023. The results show a pronounced south–north dipole pattern in the precipitation–SAT relationship, characterized by negative correlations over the southern TP and positive correlations over the northern TP. Further analysis indicates that, in the southern TP, increased precipitation leads to a reduction in surface shortwave radiation downward (SSRD), thereby weakening surface heating and cooling the SAT. In contrast, in the northern TP, increased precipitation enhances surface longwave radiation downward (SLRD), strengthening atmospheric heating and raising SAT. These responses are consistent with the respective responses of SAT to SSRD and SLRD in the southern and northern TP, respectively. Therefore, this study provides a novel perspective on how precipitation over the TP modulates surface thermal anomalies through distinct shortwave and longwave radiative feedback processes.