Interdecadal changes in the Asian winter monsoon variability and its relationship with ENSO and AO
Interdecadal changes in the Asian winter monsoon variability and its relationship with ENSO and AO
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DOI：
10.1007/s13143-014-0042-5
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发表时间：
2014-08
影响因子：
2.3
通讯作者：
K. Yun;Y. Seo;K. Ha;June‐Yi Lee;Y. Kajikawa
中科院分区：
文献类型：
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作者：
K. Yun;Y. Seo;K. Ha;June‐Yi Lee;Y. Kajikawa
利用1958-2012年美国国家环境预报中心-国家大气研究中心再分析1（NCEP）的3个地面气温资料，（2）来自欧洲中期天气预报中心（ECMWF）40年再分析和中期数据（ERA）的组合数据集;（3）日本55年再分析（JRA）。特别注意已支付给前四个经验正交函数（ESTA）模式的AWM温度变化，共同占64%的总方差，并已被确定为可预测的模式。这4种模态的特征如下：第一模态为印度-西太平洋南部增温，并伴随着整个海盆增温趋势的逐渐增强;第二模态为北方增温，1980年代后期后出现年代际变化;第三和第四模态为南北三重型，并在1970年代后期出现阶段性变化。这三个再分析在产生前三个模态时彼此吻合得很好，但在捕获第四模态的空间和时间特征时显示出很大的差异。因此认为前三阶模态比其余高阶模态更可靠。年代际变化主要集中在前两个模态。第一种模态的年际变化呈逐渐减小的趋势，而第二种模态的年际变化在近10年中则较大。另外，在20世纪70年代后期以后，第一模态与厄尔尼诺-南方涛动（ENSO）的联系减弱，而第二模态与北极涛动（AO）的联系增强。这表明AO对AWM变率的作用越来越大，而ENSO对AWM变率的作用越来越小。更好地了解主导模态的年代际变化将有助于推进季节预报和AWM变率的可预报性。
Interdecadal changes in the Asian winter monsoon (AWM) variability are investigated using three surface air temperature datasets for the 55-year period of 1958–2012 from (1) the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis 1 (NCEP), (2) combined datasets from the European Centre for Medium-range Weather Forecasts (ECMWF) 40-yr reanalysis and interim data (ERA), and (3) Japanese 55-year reanalysis (JRA). Particular attention has been paid to the first four empirical orthogonal function (EOF) modes of the AWM temperature variability that together account for 64% of the total variance and have been previously identified as predictable modes. The four modes are characterized as follows: the first mode by a southern warming over the Indo-western Pacific Ocean associated with a gradually increasing basin-wide warming trend; the second mode by northern warming with the interdecadal change after the late 1980s; the third and fourth modes by north-south triple pattern, which reveal a phase shift after the late 1970s. The three reanalyses agree well with each other when producing the first three modes, but show large discrepancy in capturing both spatial and temporal characteristics of the fourth mode. It is therefore considered that the first three leading modes are more reliable than the rest higher modes. Considerable interdecadal changes are found mainly in the first two modes. While the first mode shows gradually decreasing variance, the second mode exhibits larger interannual variance during the recent decade. In addition, after the late 1970s, the first mode has a weakening relationship with the El Niño-Southern Oscillation (ENSO) whereas the second mode has strengthening association with the Artic Oscillation (AO). This indicates an increasing role of AO but decreasing role of ENSO on the AWM variability. A better understanding of the interdecadal change in the dominant modes would contribute toward advancing in seasonal prediction and the predictability of the AWM variability.