Distribution Characteristics Of Tropopause Over The Tibetan Plateau And The Differences From The Same Latitude Regions

Based on daily temperature dataset from ERA-Interim analysis during 1979-2014 and according to the temperature lapse rate interpolation method, the tropopause in the North Hemisphere are calculated;The credibility of the tropopause calculated is verifiedby using radiosonde data of 9 stations over the Tibet Plateau(plateau) and the 16 stations over the same latitude plain area; On this basis,the spatio-temporal evolution characteristics of two types of tropopause (polar tropopause and tropical tropopause) frequency and tropical tropopause pressure over the plateau are compared with those over the same latitude regions, and the relationships between differences of tropopause and upper air temperature over the two regions are preliminary discussed. The results are as follows:(1)The seasonal variations of the tropical (polar) tropopause frequency are unapparent (apparent) with more (less) frequency in warm season than those in cold season;Compared with the same latitude regions, the tropical (polar) tropopause frequency over the plateau is more (less) from April to November, less (more) during other months and the differences of the two types of tropopause frequency over the plateau in cold and warm season are larger.(2) The seasonal and interannual variations of tropical (polar) tropopause frequency display positive (negative) linkage with the mean temperature in the upper troposphere, negative (positive) linkage with the mean temperature in the lower stratosphere; Under the background of global warming, both the tropical (polar)tropopause frequency over the plateau and the same latitude regions increase(decrease) with time goes from 1979-2014.The upward (downward) trend of the tropical (polar) tropopause frequency over the plateau is faster compared with those over the same latitude regions.(3) The seasonal variations of tropical tropopause pressure over the plateau display single structure with the pressure lower in Spring and Summer, higher in Autumn and Winter;Except December and January, the tropical tropopause pressure over the plateau is lower than that over the same latitude regions in each month. And compared with the same latitude regions,the single structure of the tropical tropopause pressure over the plateau is more distinct.(4) The seasonal and interannual variations of tropical tropopause pressure display positive (negative) linkage with the mean temperature in the upper troposphere (in the lower stratosphere); Under the background of global warming,both the tropical tropopause pressure over the plateau and the same latitude regions decrease with time goes in each month from 1979-2014; The downward trends of the tropical tropopause pressure over the plateau are faster compared with that over the same latitude regions.