Equatorial Mid‐Tropospheric Easterly Jet over the eastern Pacific: Comparison from the ECMWF and NCEP‐NCAR reanalyses
Equatorial Mid‐Tropospheric Easterly Jet over the eastern Pacific: Comparison from the ECMWF and NCEP‐NCAR reanalyses
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东太平洋赤道中对流层东急流：ECMWF 和 NCEP-NCAR 再分析的比较
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
D. Polzin
中科院分区：
文献类型：
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作者：
S. Hastenrath;D. Polzin
[1]欧洲中期天气预报中心（ECM）1979-93年再分析的高空数据集进行了评估，比较国家环境预报中心，国家大气研究中心（NCP）再分析同期。注意力集中在赤道中对流层东风急流（EMTEJ）在东太平洋，首先注意到从一个短系列的rawin探测在加拉帕戈斯，然后证实其广泛的空间背景下，从NCP 40年再分析。目前的后续研究有助于从两个来源与不同的模式同化的证据进行比较。EMTEJ的主要特征得到了证实，尽管来自ECM的风总体上比加拉帕戈斯上空的测量值慢，而来自NCP的风总体上比测量值快。在ECM和NCP中，沿赤道沿着的东风速度最大值在东太平洋上空，位于600-700毫巴附近，并在逐渐降低的高度上进一步向西移动。发散在速度最大的范围内普遍存在，主要是由高空的下沉引起的。ECM证据与NCP的不同之处在于东风速度最大值的位置更靠向西，气流总体较弱。
[1] The upper-air data set of the European Centre for Medium-Range Weather Forecasts (ECM) 1979–93 Reanalysis is evaluated in comparison to the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCP) Reanalysis for the same period. Attention is focused on the Equatorial Mid-Tropospheric Easterly Jet (EMTEJ) over the eastern Pacific, first noted from a short series of rawin soundings at Galapagos, and then corroborated in its broad spatial context from the NCP 40-year Reanalysis. The present follow-up study contributes a comparison of evidence from the two sources with different model assimilations. The major characteristics of the EMTEJ are confirmed, although the winds from ECM are overall slower and those from NCP faster than the measurements over Galapagos. In both ECM and NCP the easterly speed maximum along the equator is over the eastern Pacific located around 600–700 mb and further westward at progressively lower elevations. Divergence prevails in the realm of the speed maximum and is primarily fed by subsidence from aloft. The ECM evidence differs from NCP by a more westward location of the easterly speed maximum and overall weaker flow.