Abstract:Based on the ERA-Interim NCEP/NCAP reanalysis data and CPC soil moisture data during 1979-2015,this paper investigated the temporal and spatial distribution characteristics of land surface heat in mid-latitude of East Asia in summer and the linkage between soil moisture anomalies in early spring and anomalous land surface warming in mid-latitude of East Asia,and discussed the possible mechanisms of the influence of soil moisture in early spring on the land surface heat warming in mid-latitude of East Asia in summer.Results show that there is a significant warming trend of summer land surface in mid-latitude of East Asia with the most rapid and strongest warming happened in the Lake Baikal and its south.Meanwhile,there is an evident interdecadal transition from cold to warm around the middle of 1990s.Further analysis suggests that there are close relationships between spring and summer soil moisture anomalies over regions from the West Siberia to the north of the Lake Baikal and summer soil surface temperature in the Lake Baikal and its south at both interdecadal and interannual scales.Increased spring and summer soil moisture over regions from the West Siberia to the north of the Lake Baikal is usually related to summer land surface warming in the Lake Baikal and its south.The anomalous soil moisture can alter the general circulation anomalies in summer,thus affect the land surface thermal anomalies in mid-latitude of East Asia in summer.Increased spring and summer soil moisture tends to induce positive geopotential height anomalies and anticyclonic anomalous circulation in the Lake Baikal and its south,which can further reduce summer cloud amount over the region and result in significant land surface warming in mid-latitude of East Asia.On the contrary,decreased spring and summer soil moisture usually produces cyclonic anomalous circulation and increases summer cloud amount,which is not conducive to land surface warming over the region.