在NCEP和ERA 40再分析中北半球中纬度大气变率的Hayashi谱
Hayashi Spectra of the Northern Hemisphere Mid-latitude Atmospheric Variability in the NCEP and ERA 40 Reanalyses
摘要：
我们比较了45年的再分析NCEP-NCAR和ECMWF的中纬度冬季大气变率的重叠时间框架1957-2002年的代表性。我们采用经典的方法计算500 hPa高度场的Hayashi谱。特别是在前15年的记录中，高频-高波数传播波和低频-低波数驻波中发现了差异。这意味着，在第一阶段，两个数据集有不同的斜压有效能量转换过程的代表。从1973年开始，飞机数据对欧洲-大西洋天气波的积极影响得到了强调。由于在第一阶段同化的数据是稀缺的，质量较低，比后来，他们提供了一个较弱的约束模式的动力。因此，再分析产品中产生的差异可能主要归因于模型行为的差异。
英文摘要：
We compare 45 years of the reanalyses of NCEP-NCAR and ECMWF in terms of their representation of the mid-latitude winter atmospheric variability for the overlapping time frame 1957-2002. We adopt the classical approach of computing the Hayashi spectra of the 500 hPa geopotential height fields. Discrepancies are found especially in the first 15 years of the records in the high-frequency-high wavenumber propagating waves and secondly on low frequency-low wavenumber standing waves. This implies that in the first period the two datasets have a different representation of the baroclinic available energy conversion processes. In the period starting from 1973 a positive impact of the aircraft data on the Euro-Atlantic synoptic waves has been highlighted. Since in the first period the assimilated data are scarcer and of lower quality than later on, they provide a weaker constraint to the model dynamics. Therefore, the resulting discrepancies in the reanalysis products may be mainly attributed to differences in the models' behavior.
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