Role of the atmosphere in seasonal phase locking of El Niño
Role of the atmosphere in seasonal phase locking of El Niño
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DOI：
10.1029/2004gl021619
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发表时间：
2004-12
影响因子：
5.2
通讯作者：
H. Spencer
中科院分区：
文献类型：
--
作者：
H. Spencer
利用大气 GCM、HadAM3 研究了热带东部太平洋大气对持续海温异常的响应随季节周期的变化。赤道风响应在一月和二月最弱，此时最温暖的海温位于赤道以南；而在四月最温暖的海温位于赤道上时，赤道风响应最强。这可能会对厄尔尼诺现象发生和终止的季节性产生影响。此前曾观察到，与厄尔尼诺现象相关的热带太平洋西风异常在北半球冬季向赤道以南移动，并在赤道减弱。有人认为，这可能有助于厄尔尼诺现象在春季结束。这些实验表明，这种转变只能响应厄尔尼诺期间的平均季节周期而出现，不需要海温异常的变化。
The variations with the seasonal cycle of the atmospheric response to constant SST anomalies in the eastern tropical Pacific are investigated with the atmospheric GCM, HadAM3. The equatorial wind response is weakest in January and February when the warmest SSTs are south of the Equator and strongest in April when the warmest SSTs are on the Equator. This may have consequences for the seasonality of the onset and termination of El Niño. Westerly wind anomalies in the tropical Pacific associated with El Niño have previously been observed to shift south of the Equator, weakening on the Equator, during the northern winter. It has been suggested that this may contribute to the termination of El Niño in spring. These experiments demonstrate that such a shift can arise solely in response to the mean seasonal cycle during El Niño and does not require changes in SST anomalies.