Interdecadal Changes in the Relationship between ENSO, EAWM, and the Wintertime Precipitation over China at the End of the Twentieth Century
Interdecadal Changes in the Relationship between ENSO, EAWM, and the Wintertime Precipitation over China at the End of the Twentieth Century
复制标题
ENSO、东亚冬季风与20世纪末中国冬季降水关系的年代际变化
DOI：
10.1175/jcli-d-16-0422.1
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发表时间：
2017-03-01
影响因子：
4.9
通讯作者：
Ge, Jingwen
中科院分区：
文献类型：
--
作者：
Jia, Xiaojing;Ge, Jingwen
本文研究了世纪末中国东南部冬季降水异常与厄尔尼诺-南方涛动（ENSO）和东亚冬季风（EAWM）关系的年代际变化。1998/99年以后，中国东南部冬季降水与ENSO和EAWM的关系明显减弱。通过将数据划分为两个子周期[1980-98（P1）和1999-2015（P2）]，对这种关系的年代际变化的可能机制进行了研究。结果表明，在没有EAWM线性贡献的情况下，ENSO对中国东南部冬季降水的影响是有限的。相反，在P1，对应于一个独立于ENSO弱于正常的EAWM，异常南风沿着中国东南沿海与西北太平洋上的反气旋输送水汽到中国。而在P2阶段，由于东亚冬季风的体制转换，东亚冬季风对中国东南部冬季降水的影响减弱。与东亚夏季风相关的北太平洋SLP正异常在P2时东移，导致相应的异常南风沿着其西翼东移，对中国东南部冬季降水正异常的贡献不大。
The current study investigates the interdecadal changes in the relationship between the winter precipitation anomalies in southeastern China, El Nino-Southern Oscillation (ENSO), and the East Asian winter monsoon (EAWM) at the end of the twentieth century. It appears that the relationships between the interannual variability of the southeastern China winter precipitation and ENSO as well as EAWM are obviously weakened after 1998/99. The possible mechanisms accounting for this interdecadal change in the relationship have been examined by dividing the data into two subperiods [1980-98 (P1) and 1999-2015 (P2)]. The results indicate that, without the linear contribution of EAWM, ENSO only play a limited role in the variability of winter precipitation in southeastern China in both subperiods. In contrast, in P1, corresponding to an ENSO-independent weaker-than-normal EAWM, anomalous southerlies along coastal southeastern China associated with an anticyclone over the northwestern Pacific transport water vapor to China. However, in P2 the impact of EAWM on winter precipitation in southeastern China is weakened because of the regime shift of EAWM. The EAWM-related positive SLP anomalies over the North Pacific move eastward in P2, causing an eastward migration of the associated anomalous southerlies along its western flank and therefore cannot significantly contribute to the positive winter precipitation anomalies in southeastern China.