Impact of Stratospheric Sudden Warming on East Asian Winter Monsoons
Impact of Stratospheric Sudden Warming on East Asian Winter Monsoons
复制标题
平流层突然变暖对东亚冬季风的影响
DOI：
10.1155/2015/640912
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发表时间：
2015
影响因子：
2.9
通讯作者：
Cai Hongke
中科院分区：
文献类型：
--
作者：
Chen Quanliang;Xu Luyang;Cai Hongke
利用欧洲中期天气预报中心40年再分析资料，分析了1957 ~ 2002年发生的52次平流层突然变暖事件。将能下降到对流层的风场合成，研究其对东亚冬季风的影响。结果表明，当SSW发生时，北极涛动（AO）和北太平洋涛动（NPO）均处于负位相，对流层环流呈波浪状。西伯利亚高压和阿留申低压都得到加强，导致亚洲大陆和北太平洋之间的梯度增大。因此，一个强大的EAWM观察到广泛的冷却内陆和沿海东亚。相反，在SSW的峰值之后，对流层环流是相当纬向对称的AO和NPO的负相位。对流层中层东亚大槽加深东移。这种结构有利于东亚内陆地区的变暖和以日本为中心的东亚沿海地区的变冷。分析了SSW生命周期中行星波的活动。行星波的异常传播和伴随的振幅变化可以很好地解释观测到的环流和EAWM。
Fifty-two Stratospheric sudden warming (SSW) events that occurred from 1957 to 2002 were analyzed based on the 40-year European Centre for Medium-Range Weather Forecasts Reanalysis dataset. Those that could descent to the troposphere were composited to investigate their impacts on the East Asian winter monsoon (EAWM). It reveals that when the SSW occurs, the Arctic Oscillation (AO) and the North Pacific Oscillation (NPO) are both in the negative phase and that the tropospheric circulation is quite wave-like. The Siberian high and the Aleutian low are both strengthened, leading to an increased gradient between the Asian continent and the North Pacific. Hence, a strong EAWM is observed with widespread cooling over inland and coastal East Asia. After the peak of the SSW, in contrast, the tropospheric circulation is quite zonally symmetric with negative phases of AO and NPO. The mid-tropospheric East Asian trough deepens and shifts eastward. This configuration facilitates warming over the East Asian inland and cooling over the coastal East Asia centered over Japan. The activities of planetary waves during the lifecycle of the SSW were analyzed. The anomalous propagation and the attendant altered amplitude of the planetary waves can well explain the observed circulation and the EAWM.