On the sporadic nature of meridional heat transport by transient eddies
On the sporadic nature of meridional heat transport by transient eddies
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DOI：
10.1002/qj.2011
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发表时间：
2013-04-01
影响因子：
8.9
通讯作者：
Czaja, A.
中科院分区：
文献类型：
--
作者：
Messori, G.;Czaja, A.
本研究分析了欧洲中期天气预报中心ERA中期再分析中由于瞬变涡旋引起的纬向大气热输送。每天使用850毫巴气压水平的0.7度纬度和经度分辨率数据。概率密度函数（PDF）的纬向瞬变涡热输送显示一个接近零的最有可能的值和一个非常大的偏度，这突出了极端事件所发挥的主导作用。当考虑纬向截面时，在北方和南半球，前五个半球的事件通常贡献了一半以上的净向极输送。由于这种对极端情况的敏感性，在给定的位置和季节，瞬态涡旋的大部分热量输送是通过随机间隔的爆发（每个季节几次）实现的，而不是通过连续的事件。极端事件的优势可以用纬向速度与湿静力能时间异常之间的良好位相关系来解释。这和事件的时空特征与Eady型生长系统是兼容的。版权所有（c）2012皇家气象学会
The present study analyses meridional atmospheric heat transport, due to transient eddies, in the European Centre for Medium-Range Weather Forecasts ERA-Interim reanalysis. Daily, 0.7 degrees latitude and longitude resolution data at the 850 mb pressure level are used. Probability density functions (PDFs) of meridional transient-eddy heat transport display a near-zero most likely value and a very large skewness, which highlights the dominant role played by extreme events. When considering zonal sections, in both the Northern and Southern Hemispheres, events in the top five percentiles typically contribute to over half of the net poleward transport. As a result of this sensitivity to extremes, a large fraction of the heat transport by transient eddies, at a given location and season, is realised through randomly spaced bursts (a few per season), rather than through a continuum of events. The predominance of extreme events can be explained by the favourable phase relationship between meridional velocity and moist static energy temporal anomalies. This and the spatiotemporal characteristics of the events are compatible with Eady-type growing systems. Copyright (c) 2012 Royal Meteorological Society