Contrast patterns and trends of lapse rates calculated from near-surface air and land surface temperatures in China...

The near-surface lapse rate reflects the atmospheric stability above the surface. Lapse rates calculated from land surface temperature (γ_Ts) and near-surface air temperature (γ_Ta) have been widely used. However, γ_Ts and γ_Ta have different sensitivity to local surface energy balance and large-scale energy transport and therefore they may have diverse spatial and temporal variability, which has not been clearly illustrated in existing studies. In this study, we calculated and compared γ_Ta and γ_Ts at ~ 2200 stations over China from 1961 to 2014. This study finds that γ_Ta and γ_Ts have a similar multiyear national average (0.53 °C/100 m) and seasonal cycle. Nevertheless, γ_Ts shows steeper multiyear average than γ_Ta at high latitudes, and γ_Ts in summer is steeper than γ_Ta, especially in Northwest China. The North China shows the shallowest γ_Ta and γ_Ts, then inhibiting the vertical diffusion of air pollutants and further reducing the lapse rates due to accumulation of pollutants. Moreover, the long-term trend signs for γ_Ta and γ_Ts are opposite in northern China. However, the trends in γ_Ta and γ_Ts are both negative in Southwest China and positive in Southeast China. Surface incident solar radiation, surface downward longwave radiation and precipitant frequency jointly can account for 80% and 75% of the long-term trends in γ_Ta and γ_Ts in China, respectively, which provides an explanation of trends of γ_Ta and γ_Ts from perspective of surface energy balance.