近40年来青藏高原非绝热加热变化特征

Variation Characteristics of Diabatic Heating over Tibetan Plateau in Recent 40 Years

利用青藏高原站点观测资料与ERA5、NCEP II、JRA55和MERRA2再分析资料,对比分析了4种再分析资料在青藏高原非绝热加热描述偏差的时空特征。结果表明:(1)4种再分析资料在青藏高原模拟的误差存在较大的空间差异性。ERA5的模拟结果与观测的最为接近,其中,ERA5再分析资料对感热的模拟比对潜热的模拟更准确。(2)ERA5再分析资料在描述青藏高原各区域感、潜热及净短、长波辐射的日变化趋势与观测的较一致,各要素全天峰值出现在12:00-15:00,但在量级上有较大差异。(3)基于青藏高原地区适用性较好的ERA5资料,近40年青藏高原感热呈西北、西南、东北部感热减小、潜热增大的总体空间变化趋势,高原净辐射年代际变化总体呈增大趋势。各季节感热和潜热平均值在空间上均呈现出从西向东减小的分布特征,而净长波辐射和净短波辐射平均值则呈现出从西向东增大的分布特征。

Based on the observation data of Tibetan Plateau(TP)and the ERA5,NCEP II,JRA55 and MERRA2 reanalysis data,the spatio-temporal characteristics of the description deviation of the diabatic heating over TP from four reanalysis data are compared and analyzed.The results show that:(1)There are great spatial differences in the simulation errors of the four reanalysis data on the TP.The simulation result of ERA5 is the closest to the observation,of which the simulation of sensible heat by reanalysis data of ERA5 is more accurate than that of latent heat.(2)ERA5 reanalysis data are more consistent with observation.in describing the diurnal variation trends of sensible heat,latent heat,net short-wave radiation and long-wave radiation over TP,and the peaks of these elements basically appear between 12:00 and 15:00,but there exist large differences in their magnitudes.(3)Based on the suitability of ERA5 reanalysis over TP,the sensible heat over TP in recent 40 years shows an overall spatial variation trend of decreasing sensible heat and increasing latent heat in the northwest,southwest and northeast,and an overall trend of increasing interannual variation of net radiation.The spatial mean values of sensible heat and latent heat in all seasons show a decreasing distribution from west to east over TP,while the mean values of net long-wave radiation and net short-wave radiation show an increasing distribution from west to east over TP.