Variability in wintertime position and strength of the North Pacific jet stream as represented by re-analysis data
Variability in wintertime position and strength of the North Pacific jet stream as represented by re-analysis data
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DOI：
10.1002/joc.1750
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发表时间：
2009-05-01
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影响因子：
--
通讯作者：
Ellis, Andrew W.
中科院分区：
文献类型：
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作者：
Barton, Neil P.;Ellis, Andrew W.
流行的国家环境预测中心（NCEP）/国家大气研究中心（NCAR）再分析数据库被用来创建一个平均冬季季节性急流数据库的北方太平洋地区1948-1949年至2004-2005年。平均季节性300 hPa标量风的网格被用来确定的纬向位置的主要中纬度急流的纵向分辨率为2.5度，从亚洲东部到北美西部。该地区急流的位置和强度是北美主要和西部地区下游冬季降水变化的关键决定因素。结果表明，急流的纬向位置在北方太平洋东半部的变化较大，而季节性急流的速度变化最大的区域在北方太平洋中部。世纪后半叶，北方太平洋中部地区的平均季节急流速度有显著的增加。一个空间上一致的，但统计学上不显著的趋势，朝着更偏南的位置的射流在研究期间被掩盖。这些结果并没有证实目前关于中纬度急流与最近和未来气候变化相关的一般向极移动的理论，这表明这种观测到的或理论上的半球移动在特定区域内可能不一定很明显，或者过去50年的任何移动都小于NCEP/NCAR数据集的2.5度分辨率。急流数据支持急流与太平洋-北美大气遥相关型之间的联系，以及急流与被称为太平洋年代际振荡的北方太平洋海表温度异常振荡之间的联系。版权所有（c）2008皇家气象学会
The popular National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) re-analysis database was used to create a mean winter seasonal jet stream database for the northern Pacific Ocean region for the period 1948-1949 through 2004-2005. Grids of mean seasonal 300 hPa scalar wind were used to determine the latitudinal position of the primary mid-latitude jet on a longitudinal resolution of 2.5 degrees from eastern Asia to western North America. The position and strength of the jet stream across this region are key determinants of winter precipitation variability downstream across the predominantly and western region of North America. Results show that the latitudinal position of the jet exhibits greater variance over the eastern half of the northern Pacific Ocean, while the greatest variance in the speed of the seasonal jet Occurs across the central northern Pacific Ocean. A statistically significant increase in the speed of the mean seasonal jet occurred over the central area of the northern Pacific Ocean during the last half of the 20th century. A spatially consistent but statistically insignificant trend toward a more southerly position of the jet Occurred during the study period. The results do not confirm current theories of a general pole-ward shift in mid-latitude jet streams in association with recent and future climate change, suggesting that such an observed or theoretical hemispheric shift may not necessarily be evident within a particular region or that any shift over the last 50 years has been less than the 2.5 degrees resolution of the NCEP/NCAR dataset. The jet stream data Support the connection between the jet and the Pacific-North American atmospheric teleconnection pattern and between the jet and the oscillation of sea surface temperature anomalies in the northern Pacific Ocean known as the Pacific Decadal Oscillation. Copyright (c) 2008 Royal Meteorological Society