青藏高原与同纬度其他地区热带对流层顶气压变化特征的比较

基于1979—2014年ERA-Interim逐日再分析温度资料,依据温度递减率插值法计算出青藏高原及同纬度其他地区热带对流层顶气压数据,比较了高原和同纬度其他地区热带对流层顶气压季节变化和长期变化趋势,讨论了热带对流层顶气压与高空温度的关系。结果表明:1)在季节变化上,除12月和1月外,青藏高原热带对流层顶气压全年低于同纬度其他地区;青藏高原热带对流层顶气压、对流层中上层以及平流层下部平均温度均表现出比同纬度其他地区更明显的单峰型特征。2)热带对流层顶气压与高空温度变化关系密切,对流层中上层(平流层下部)平均温度升高(降低),有利于热带对流层顶气压降低;相对于同纬度其他地区,青藏高原对流层顶气压与对流层中上层平均温度的关系更密切。3)1979—2014年青藏高原和同纬度其他地区各季节的热带对流层顶气压均呈现出不同程度的下降趋势,冬春季下降趋势更加显著;青藏高原各季节对流层中上层增温和平流层下部降温的幅度均超过同纬度其他地区,导致其热带对流层顶气压的下降趋势比同纬度其他地区更加明显。

Comparison on variation features of the tropical tropopause pressure over the Tibetan Plateau and the other regions in the same latitudes

In this study,based on the daily temperature dataset from ERA-Interim analysis during 1979-2014,and according to the temperature lapse rate interpolation method,the tropopause pressure over the Tibetan Plateau and other regions in the same latitudes are calculated.First,the seasonal variation and long-term trends of the tropical tropopause pressure over the Tibetan Plateau,in comparison to those over other regions in the same latitudes,are discussed.Next,the relationships between the tropical tropopause pressure and upper air temperature are preliminary addressed.The results of the study are as follows:1)In terms of seasonal change,with the exceptions of December and January,the tropical tropopause pressure over the Tibetan Plateau is lower than that over other regions in the same latitudes in each month.In addition,compared with other regions in the same latitudes,the single structure of the tropical tropopause pressure,mean temperature in the upper troposphere,and mean temperature in the lower stratosphere over the Tibetan Plateau are shown to be more distinct.2)The tropical tropopause pressure the Tibetan Plateau and other regions in the same latitudes display a close relation with the upper air temperature,i.e.when the mean temperature in the upper troposphere (in the lower stratosphere) increases (decreases),the tropical tropopause pressure decreases.Furthermore,the tropical tropopause pressure the Tibetan Plateau is more closely linked with the mean temperature in the upper troposphere than that over other regions in the same latitudes.3)From 1979 to 2014,both the tropical tropopause pressure of the Tibetan Plateau and non-plateau regions decreased with time during each month,especially in spring and winter.Meanwhile,compared with the other regions in the same latitudes,the upward (downward) trends of the mean temperature in the upper (lower) troposphere of the Tibetan Plateau were faster all year round,which led to a more rapid tropical tropopause pressure decline on the Tibetan Plateau.