Anomalous winter climate conditions in the Pacific rim during recent El Niño Modoki and El Niño events
Anomalous winter climate conditions in the Pacific rim during recent El Niño Modoki and El Niño events
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DOI：
10.1007/s00382-008-0394-6
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发表时间：
2009-04
期刊：
影响因子：
4.6
通讯作者：
H. Weng;S. Behera;T. Yamagata
中科院分区：
文献类型：
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作者：
H. Weng;S. Behera;T. Yamagata
目前的工作比较了厄尔尼诺现象、莫多基现象和厄尔尼诺现象对1979-2005年寒冬期间环太平洋异常气候的影响。厄尔尼诺现象与热带太平洋海面温度、降水和高层辐散风异常中的三极(偶极)模式有关，这与太平洋海洋-大气条件的多个“回旋镖”有关。这些“回旋镖”的纬向和经向范围反映了它们的独立影响，从西部的低纬度到东部的高纬度。在中太平洋，更多的水汽在厄尔尼诺·莫多基期间从热带地区输送到更高纬度，这是因为湿润的“回旋镖”手臂向东移动。外部“回旋镖”臂的不连续显示了热带和亚热带/温带系统之间的强烈相互作用。这两种现象以截然不同的方式改变了早期研究中发现的太平洋/北美模式和北美相关的气候异常。厄尔尼诺-莫多基期间，美国西部北部干燥、南部潮湿的跷跷板更有可能出现，而厄尔尼诺-莫多基期间美国西部大部分地区是潮湿的。厄尔尼诺-莫多基期间美国西南部的水汽是从北移的ITCZ输送到美国西南部的，而在厄尔尼诺-莫多基期间，它是由沿极锋急流南移的风暴输送的。与厄尔尼诺-莫多基期间相比，与之相比，与厄尔尼诺-莫多基期间在菲律宾海上空相比，与厄尔尼诺-莫多基期间相比，与厄尔尼诺-莫多基期间相比，与之相关的东亚冬季季风反气旋出现在中国南海上空，导致东亚南部降水异常。
Present work compares impacts of El Niño Modoki and El Niño on anomalous climate in the Pacific rim during boreal winters of 1979–2005. El Niño Modoki (El Niño) is associated with tripole (dipole) patterns in anomalies of sea-surface temperature, precipitation, and upper-level divergent wind in the tropical Pacific, which are related to multiple “boomerangs” of ocean-atmosphere conditions in the Pacific. Zonal and meridional extents of those “boomerangs” reflect their independent influences, which are seen from lower latitudes in the west to higher latitudes in the east. In the central Pacific, more moisture is transported from the tropics to higher latitudes during El Niño Modoki owing to displacement of the wet “boomerang” arms more poleward toward east. Discontinuities at outer “boomerang” arms manifest intense interactions between tropical and subtropical/extratropical systems. The Pacific/North American pattern and related climate anomalies in North America found in earlier studies are modified in very different ways by the two phenomena. The seesaw with the dry north and the wet south in the western USA is more likely to occur during El Niño Modoki, while much of the western USA is wet during El Niño. The moisture to the southwestern USA is transported from the northward shifted ITCZ during El Niño Modoki, while it is carried by the storms traveling along the southerly shifted polar front jet during El Niño. The East Asian winter monsoon related anticyclone is over the South China Sea during El Niño Modoki as compared to its position over the Philippine Sea during El Niño, causing opposite precipitation anomalies in the southern East Asia between the two phenomena.