The Asymmetric Effects of El Niño and La Niña on East Asian Winter Monsoon and their simulations by CMIP5 Atmospheric
The Asymmetric Effects of El Niño and La Niña on East Asian Winter Monsoon and their simulations by CMIP5 Atmospheric
复制标题
厄尔尼诺和拉尼娜对东亚冬季风的不对称影响及其CMIP5大气模拟
DOI：
10.1007/s13351-017-6095-5
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
郭准
中科院分区：
文献类型：
--
作者：
郭准
厄尔尼诺-南方涛动（ENSO）事件对东亚冬季风（EAWM）的年际变化有重要影响。然而，拉尼娜事件对东亚冬季风的影响并不是厄尔尼诺事件的镜像。虽然在厄尔尼诺事件期间，东亚冬季风总体上减弱，而在拉尼娜事件期间增强，但在厄尔尼诺事件期间，中国东南部降水增加和沿着东亚海岸线的地面气温升高更为显著。这些不对称效应是由厄尔尼诺事件期间西北太平洋反气旋和拉尼娜事件期间西北太平洋气旋的不对称纵向位置造成的;具体而言，拉尼娜事件期间西北太平洋气旋的中心相对于其对应的厄尔尼诺事件西移。这种中心位置的移动是由于远程厄尔尼诺和拉尼娜异常加热的纵向移动，以及WNP上局部海表温度异常幅度的不对称性造成的。然而，这种不对称的影响ENSO的EAWM几乎没有再现的耦合模式相互比较项目（CMIP 5）的第5阶段的大气模式，虽然异常环流的空间格局是合理的再现。CMIP 5模式的主要局限性是高估了异常的WNP反气旋/气旋，这导致了更强的EAWM降水响应。南海和北方西北太平洋附近潜热通量异常的高估可能是造成这些异常环流的关键因素。
El Niño–Southern Oscillation (ENSO) events significantly affect the year-by-year variations of the East Asian winter monsoon (EAWM). However, the effect of La Niña events on the EAWM is not a mirror image of that of El Niño events. Although the EAWM becomes generally weaker during El Niño events and stronger during La Niña winters, the enhanced precipitation over the southeastern China and warmer surface air temperature along the East Asian coastline during El Niño years are more significant. These asymmetric effects are caused by the asymmetric longitudinal positions of the western North Pacific (WNP) anticyclone during El Niño events and the WNP cyclone during La Niña events; specifically, the center of the WNP cyclone during La Niña events is westward-shifted relative to its El Niño counterpart. This central-position shift results from the longitudinal shift of remote El Niño and La Niña anomalous heating, and asymmetry in the amplitude of local sea surface temperature anomalies over the WNP. However, such asymmetric effects of ENSO on the EAWM are barely reproduced by the atmospheric models of Phase 5 of the Coupled Model Intercomparison Project (CMIP5), although the spatial patterns of anomalous circulations are reasonably reproduced. The major limitation of the CMIP5 models is an overestimation of the anomalous WNP anticyclone/cyclone, which leads to stronger EAWM rainfall responses. The overestimated latent heat flux anomalies near the South China Sea and the northern WNP might be a key factor behind the overestimated anomalous circulations.