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Abstract：
The near-surface lapse rate reflects the atmospheric stability above the surface. Lapse rates calculated from land surface temperature (γTs) and near-surface air temperature (γTa) have been widely used. However, γTs and γTa 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 γTa and γTs at ~ 2200 stations over China from 1961 to 2014. This study finds that γTa and γTs have a similar multiyear national average (0.53 °C/100 m) and seasonal cycle. Nevertheless, γTs shows steeper multiyear average than γTa at high latitudes, and γTs in summer is steeper than γTa, especially in Northwest China. The North China shows the shallowest γTa and γTs, 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 γTa and γTs are opposite in northern China. However, the trends in γTa and γTs 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 γTa and γTs in China, respectively, which provides an explanation of trends of γTa and γTs from perspective of surface energy balance.
摘要：
近地表流失率反映了地表以上的大气稳定性。根据地表温度（γTs）和近地表空气温度（γTa）计算的飞行速度已被广泛使用。然而,γTs和γTa对局部表面能量平衡和大规模能量传输具有不同的敏感性，因此它们可能具有不同的时空变异性。这在现有研究中没有得到明确说明。在这项研究中,我们计算并比较了1961年至2014年中国~2200个站点的γTa和γTs。这项研究发现，γTa和γTs具有相似的多年全国平均水平（0.53°C/100m）和季节周期。然而，γTs在高纬度地区显示出比γTa更陡的多年平均值，夏季的γTs比γTa陡，尤其是在中国西北地区。华北地区的γTa和γTs最浅，然后抑制空气污染物的垂直扩散，并进一步降低由于污染物积累而导致的流失率。此外，在中国北方，γTa和γTs的长期趋势信号相反。然而,中国西南地区γTa和γTs的趋势均为负，中国东南部为正。表面入射太阳辐射，地表向下的长波辐射和沉淀频率共同可以占中国γTa和γTs长期趋势的80%和75%，分别,从表面能平衡的角度解释了γTa和γTs的变化趋势。
