The Relationship Between Springtime Surface Sensible Heat Enhancement over the Qinghai-Xizang Plateau and Spring Rainfall in Southern China

Based on daily surface sensible heat flux (SH) data from 73 meteorological stations across the central-eastern Qinghai-Xizang Plateau, daily precipitation data from 402 stations in southern China, and ERA5 reanalysis data, this study investigates the springtime enhancement characteristics of SH over the central-eastern Qinghai-Xizang Plateau, its influence on spring rainfall in southern China, and the associated physical mechanisms.The results indicate that: (1) The springtime surface sensible heat peak time (T) and enhancement intensity (Q) over the central-eastern Qinghai-Xizang Plateau exhibit significant interannual and decadal variability, with a strong positive correlation between them.Specifically, a later occurrence of the peak sensible heat in spring is associated with a stronger enhancement intensity.(2) Both T and Q exhibit significant positive correlations with spring rainfall in southern China.To evaluate their combined effects, a composite index termed the Surface Sensible Heat Enhancement Index (ISH) is introduced.This index demonstrates a strong positive correlation with spring rainfall in southern China (correlation coefficient = 0.60, p