5月青藏高原5套地表感热通量资料的对比分析

Comparative analysis of five sets of surface sensible heat flux data over the Tibetan Plateau in May

基于1979—2017年5月青藏高原地区149个站点观测资料计算的地表感热通量(OBCH)和4套再分析资料提供的地表感热通量,对比分析了青藏高原地表感热通量的时空变化特征。结果表明:5月各地表感热再分析资料在高原主体部分(3000 m以上部分)的气候平均值均为正值,说明高原主体5月为同一热源,且均呈高原西部(90°E为界)感热通量偏大,东部偏小的特征。5月高原主体各套平均地表感热通量均呈减弱趋势,除ERA感热表现为增强外,其余3套再分析资料在高原西部均表现为减弱,减弱趋势显著;5套资料在高原东部均表现为减弱趋势,除OBCH资料外,均表现为显著减弱。EOF分析发现,除了ERA-Interim资料,其余4套资料在高原主体第一模态主要表现为一致性变化,第二模态空间分布呈明显差异。从各套资料与OBCH资料的时间相关来看,ERA-Interim资料与OBCH资料相关系数可达0.70,说明二者在5月具有较好的年际变化一致性特征,而NCEP2资料与OBCH资料相关系数仅为0.33,说明二者具有较大的年际变化差异。

Based on the surface sensible heat flux calculated by 149 observed stations(OBCH)and four reanalysis data from 1979 to 2017,the temporal and spatial characteristics of SH over the Tibetan Plateau(TP)were analyzed.The results show that the climatic averages of the SH for the main TP(terrain height over 3000 m)are positive,indicating that the main body of the TP is a heat source in May,and also show the SH in western part of the TP(divided by 90°E)is larger than ones in the eastern part of the TP.The SH in the main part of the TP in May shows a weakening trend,except for the ERA-Interim,the SH of other three reanalysis data show a weakening trend in western plateau,the NCEP1,NCEP2,and JRA data are especially notable.The five sets of data show a weakening trend in eastern plateau,except for the OBCH data,which show a notably weakening trend.The EOF analysis finds that the other four sets of data in the first mode mainly showing consistency changes in the TP,except for the ERA-Interim data,and the spatial distribution of the second mode shows notable differences.According to the correlation analysis,the correlation shows that the ERA-Interim data is well related to the OBCH data in annual variations with a correlation coefficient of 0.70,but the NCEP2 data has significant differences from the OBCH data in annual variations with a correlation coefficient of 0.33.