Delayed impacts of the El Niño episodes in the central Pacific on the summertime climate anomalies of eastern China in 2003 and 2007
Delayed impacts of the El Niño episodes in the central Pacific on the summertime climate anomalies of eastern China in 2003 and 2007
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DOI：
10.1007/s00376-009-0553-7
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发表时间：
2009-05
影响因子：
5.8
通讯作者：
Ming Bao;Rongqing Han
中科院分区：
文献类型：
--
作者：
Ming Bao;Rongqing Han
在2003年和2007年的夏季，中国东部也遭受了类似的气候灾害，淮河流域发生了严重的洪水，长江三角洲南部和华南地区出现了热浪。利用NOAA的SST和OLR资料沿着NCEP/NCAR的再分析资料，分析了2002/03和2006/07年中太平洋厄尔尼诺事件及其对中国东部初夏气候异常的延迟影响。可能的物理过程表现为：两次中等厄尔尼诺事件都在初冬期间在赤道中太平洋成熟。赤道太平洋中西部海面附近的纬向风异常激发了向东传播的赤道Kelvin波，影响了厄尔尼诺事件的演变。从春季到初夏，赤道中太平洋异常东风与赤道西太平洋Kelvin上升波向东传播的结束同时出现，有利于西太平洋海温和次表层温度的赤道暖水。这些条件有利于2003年和2007年初夏赤道西太平洋的温暖状态。由于初夏赤道西太平洋对流活动活跃，加上春季至初夏热带西太平洋海温弱暖异常，西太平洋暖池对流活动呈现出强对流异常只出现在热带西太平洋暖池南部地区的格局，影响夏季西太平洋副热带高压的纬向移动。从热带西太平洋暖池热对流特殊型的关键作用和西北太平洋异常反气旋的响应，解释了赤道中太平洋厄尔尼诺事件延迟影响及其衰减演变对中国东部气候异常的物理过程。
In the summers of 2003 and 2007, eastern China suffered similar climate disasters with severe flooding in the Huaihe River valley and heat waves in the southern Yangtze River delta and South China. Using SST data and outgoing longwave radiation (OLR) data from NOAA along with reanalysis data from NCEP/NCAR, the 2002/03 and 2006/07 El Niño episodes in the central Pacific and their delayed impacts on the following early summertime climate anomalies of eastern China were analyzed. The possible physical progresses behaved as follows: Both of the moderate El Niño episodes matured in the central equatorial Pacific during the early winter. The zonal wind anomalies near the sea surface of the west-central equatorial Pacific excited equatorial Kelvin waves propagating eastward and affected the evolution of the El Niño episodes. From spring to early summer, the concurring anomalous easterly winds in the central equatorial Pacific and the end of upwelling Kelvin waves propagating eastward in the western equatorial Pacific, favored the equatorial warm water both of the SST and the subsurface temperature in the western Pacific. These conditions favored the warm state of the western equatorial Pacific in the early summer for both cases of 2003 and 2007. Due to the active convection in the western equatorial Pacific in the early summer and the weak warm SST anomalies in the tropical western Pacific from spring to early summer, the convective activities in the western Pacific warm pool showed the pattern in which the anomalous strong convection only appeared over the southern regions of the tropical western Pacific warm pool, which effects the meridional shift of the western Pacific subtropical high in the summer. The physical progress of the delayed impacts of the El Niño episodes in the central equatorial Pacific and their decaying evolution on the climate anomalies in eastern China were interpreted through the key role of special pattern for the heat convection in the tropical western Pacific warm pool and the response of the western North Pacific anomalous anticyclone.