Circulation dynamics of Mediterranean precipitation variability 1948-98
Circulation dynamics of Mediterranean precipitation variability 1948-98
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DOI：
10.1002/joc.973
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发表时间：
2003-12-01
期刊：
影响因子：
--
通讯作者：
Jacobeit, J
中科院分区：
文献类型：
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作者：
Dünkeloh, A;Jacobeit, J
典型相关分析被用来确定主要的耦合环流-降雨模式，并将地中海降水的近期变化和趋势与大尺度环流动力学联系起来。分析的基础是北大西洋-欧洲地区的位势高度（500和1000百帕水平）（国家环境预测中心-国家大气研究中心再分析）和1948- 1998年期间为地中海地区选择的高分辨率（0.5度x 0.5度）月降雨网格（气候研究单位，诺里奇）。将月度分析与季节性样本的相似特征相结合，产生冬季（12月至3月），春季（4月至5月）和夏季（6月至9月）类型的耦合变率;整个地中海的特定秋季类型不会发生在月度时间尺度上。与一个或两个季节特别相关的耦合模式包括夏季的东大西洋急流（EA-Jet）相关模式和冬季和春季的地中海纬向环流（MMC）模式。最重要的模式，在整个一年的动力调整，反映了地中海振荡（MO）的季节性周期，这是连接（与季节依赖性）的北极涛动（AO）和北大西洋涛动（NAO）的北方半球遥相关模式。近几十年来，地中海地区的冬季降雨趋势普遍减少，而东南部的情况相反，这与几种相关环流模式随时间的变化有关。因此，不同的区域降雨量的变化被集成到一个整体之间的相互关系，地中海降雨模式和大尺度大气环流动力学。版权所有（C）2003皇家气象学会。
Canonical correlation analysis is used to identify main coupled circulation-rainfall patterns and to relate recent variability and trends of Mediterranean precipitation to large-scale circulation dynamics. Analyses are based on geopotential heights (500 and 1000 hPa levels) for the North Atlantic-European area (National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis) and on highly resolved (0.5degrees x 0.5degrees) monthly rainfall grids (Climatic Research Unit, Norwich) selected for the Mediterranean area during the 1948-98 period. Combining monthly analyses with similar characteristics to seasonal samples yields winter (October-March), spring (April-May) and summer (June-September) types of coupled variability; a particular autumn type for the whole Mediterranean does not occur on the monthly time scale. Coupled patterns specifically linked to one or two seasons include an east Atlantic jet (EA-Jet) related pattern for summer and a Mediterranean meridional circulation (MMC) pattern for winter and spring. The most important pattern recurring with dynamical adjustments throughout the whole year reflects the seasonal cycle of the Mediterranean oscillation (MO), which is linked (with seasonal dependence) to the Northern Hemisphere teleconnection modes of the Arctic oscillation (AO) and North Atlantic oscillation (NAO). Winter rainfall trends of the recent decades marked by widespread decreases in the Mediterranean area and by opposite conditions in the southeastern part are linked to particular changes over time in several of the associated circulation patterns. Thus, different regional rainfall changes are integrated into an overall interrelation between Mediterranean rainfall patterns and large-scale atmospheric circulation dynamics. Copyright (C) 2003 Royal Meteorological Society.