两种再分析资料中夏季地表气温与中国测站资料的差异

Differences in 1958-2001 Summertime Surface Air Temperatures between Two Reanalysis Data and Observations in China

采用中国194站气温观测资料(OT)、NCEP/NCAR(NT)和ERA-40(ET)再分析月平均2m温度资料,使用线性分析、方差分析、小波分析、EOF等方法,对三种温度资料周期、方差以及年际和年代际变化进行对比分析。结果发现:(1)ET与OT数值、距平及变化趋势非常接近;NT低于OT,1965年以前其数值及距平与OT、ET差异较大;ET与OT的相似性优于NT,对地面温度变化进行周期分析时,使用ET资料较好。在使用NT的原始资料时需慎重,距平值在1965年之后有一定的可信度。(2)ET与OT线性趋势以及空间模态类似,NT变化趋势远大于OT与ET,ET对我国温度长期变化趋势的再现能力优于NT,在研究我国温度长期变化时NT具有不确定性。(3)ET与NT均能反映我国温度的时空分布和变化特征,但ET更加准确;研究我国北方(30°N以北)温度年代际变化时,ET较好;研究我国温度年际变化时两种资料能力相当。(4)三种温度资料均显示1976年前后我国地表气温有明显差异。ET与OT在1976年前后的变化及空间分布十分一致,NT与OT不完全一致。此外,1965年之前的NCEP/NCAR温度资料存在类似于"PSFC"的问题,使用时应慎重。

This article simulated a weather developing process in the agro-pastoral transitional zone of Inner Mongolia from 1800 UTC 23 July to 1800 UTC 27 July,2001 with mesoscale atmospheric numerical model ARPS（Advanced Regional Prediction System）.To understand the change of mesoscale numerical model＇s ability in atmospheric multi-scale movement simulation,especially for smaller space-time scale motion at different model resolutions,the authors analyzed simulation results of u,v,w,θ,p for different model resolutions.The rank sum test and Analysis of variance（ANOVA） show that the model resolution improvement can affect the five variables＇ simulation to different extents.The impact on p,θ and w is the greatest,the impact on u and v takes second place.The lower troposphere and the boundary layer are the most sensitive to the resolution,followed by the upper troposphere.The spectrum analysis and wavelet analysis show that enhancing resolution can improve the model＇s ability in the atmospheric multi-scale characteristics simulation and the improvement is different for different atmospheric layers and meteorological elements.In general,the simulation effect in upper layers is better than in lower layers,and the simulation effect of variables with strong cycle signals is better than that with weak cycle signals.