青藏高原不同海拔地表感热的年际和年代际变化特征及其成因分析  

The Interannual and Decadal Variation Characteristics of the Surface Sensible Heating at Different Elevations over the Qinghai-Tibetan Plateau and Attribution Analysis

作　　者：于威 刘屹岷[2,3] 杨修群 吴国雄[2,3] YU Wei;LIU Yimin;YANG Xiuqun;WU Guoxiong(China Meteorological Administration-Nanjing University（CMA-NJU）Joint Laboratory for Climate Prediction Studies,School of Atmospheric Sciences,Nanjing University,Nanjing 210023,Jiangsu,China;State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]南京大学大气科学学院/中国气象局-南京大学气候预测研究联合实验室,江苏南京210023 [2]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029 [3]中国科学院大学,北京100049

出　　处：《高原气象》2018年第5期1161-1176,共16页Plateau Meteorology

基　　金：国家自然科学基金项目(91437219;91637312;41730963);中国科学院前沿科学重点研究项目(QYZDY-SSW-DQC018);NSFC-广东联合基金(第二期)超级计算科学应用研究专项和国家超级计算广州中心(U1501501)

摘　　要：利用1961-2014年中国气象观测站逐日常规资料,分析了在不同季节和不同海拔上,青藏高原地表感热的气候态特征以及热量拖曳系数和密度对地表感热计算的影响,并研究了高原地表感热在年际、年代际以及趋势变化上的时空分布特征;最后定量研究了表面风速与地气温差在年际和年代际时间尺度上对地表感热变化的相对贡献。结果表明,使用实际密度和常热量拖曳系数的总体动力学公式计算的地表感热最为合理;总体来说高原地表感热随着高度上升而增加,春季最大,秋季与冬季最小;空间分布上,春季高原东南部大北部小,夏季南部小北部大。春季年际、年代际地表感热经验正交函数分解第一模态空间型分别具有高原南北反向分布和高原主体与其东北反向分布的特征,夏季与之相似。高原整体而言,20世纪60-70年代末(春季)或70年代初(夏季),地表感热增加,其后至21世纪00年代初地表感热下降,之后又上升。在显著下降的1979-2003年间,春夏两季地表感热变化趋势分布均呈一致性的减弱,其中南部减弱最为显著。平均而言,在年际时间尺度上,表面风速对地表感热的贡献与地气温差对地表感热的贡献大小相当;而在年代际时间尺度上,表面风速对地表感热的贡献大于地气温差对地表感热的贡献。Based on the daily regular meteorological observations in the period of 1961-2014 provided by the China Meteorological Administration,the climatological characteristics of the surface sensible heating（SH） over the Qinghai-Tibetan Plateau（QTP） in different seasons and at different elevations have been studied.The impact of the drag coefficient for heat and air density on SH has also been analyzed.Besides,the temporal and spatial distributions of SH over the QTP on different time scales were investigated.Furthermore,the contributions of surface wind speed and ground-air temperature difference to the variation of SH on interannual and decadal time scales were revealed.The results showthat the SH calculated by using real density and constant drag coefficient for heat is most reasonable.The SH increases with increasing elevation of the QTP,and the maximum SH scores in spring with the minimum occurs in autumn and winter.The spatial distribution of SH over the QTP is that the southeast（south） part is large（small） while the north part is small（large） in spring（summer）.The first leading mode of empirical orthogonal function analyses for spring and summer SH shows an out of phase distribution between south and north on interannual time scale,and between the main body and northeast part on the decadal time scale.Furthermore,SH increases from 1961 to the late（early） 1970 s in spring（summer）,and then decreases until early 2000 s,after that it increases.Besides,the trend of spring and summer SH shows uniform decreasing in the whole QTP with particularly pronounced decreasing in the south part during 1979-2003.The surface wind speed and ground-air temperature difference contribute nearly equal to the variation of SH on the interannual time scale,however the former is larger than the latter on the decadal time scale.

关 键 词：青藏高原 地表感热 年际 年代际 变化趋势 

分 类 号：P468.0[天文地球—大气科学及气象学]