Numerical experiments on the impact of spring north pacific SSTA on NPO and unusually cool summers in Northeast China
Numerical experiments on the impact of spring north pacific SSTA on NPO and unusually cool summers in Northeast China
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DOI：
10.1007/s00376-014-3247-8
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发表时间：
2014-09
影响因子：
5.8
通讯作者：
Y. Lian;Bin Zhao;Baizhu Shen;Shangfeng Li;Gang Liu
中科院分区：
文献类型：
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作者：
Y. Lian;Bin Zhao;Baizhu Shen;Shangfeng Li;Gang Liu
一组春季海洋强迫的数值试验表明，在Niño 4区的冷（暖）El Niño（La Niña）位相和西风漂流区的海表温度异常（SSTA）的共同强迫下，初夏东北冷涡（NECV）活动异常增强。在春季，赤道中太平洋厄尔尼诺位相和西风漂移SSTA强迫将导致非绝热波的撤退，引起热带气流的椭圆低频异常。这将增强从热带向热带外进而向中高纬传播的异常气旋-反气旋-气旋-反气旋低频波列，构成副热带和北太平洋中高纬初夏环流异常的主要物理机制。春季中赤道太平洋的拉尼娜强迫一方面会诱发初夏鄂霍次克海至日本海高压的遥相关异常，另一方面也会间接触发对流层低层的正低频东亚-太平洋遥相关（EAP）波列。
A set of numerical experiments designed to analyze the oceanic forcing in spring show that the combined forcing of cold (warm) El Niño (La Niña) phases in the Niño4 region and sea surface temperature anomalies (SSTA) in the westerly drifts region would result in abnormally enhanced NorthEast Cold Vortex (NECV) activities in early summer. In spring, the central equatorial Pacific El Niño phase and westerly drift SSTA forcing would lead to the retreat of non-adiabatic waves, inducing elliptic low-frequency anomalies of tropical air flows. This would enhance the anomalous cyclone-anticyclone-cyclone-anticyclone low-frequency wave train that propagates from the tropics to the extratropics and further to the mid-high latitudes, constituting a major physical mechanism that contributes to the early summer circulation anomalies in the subtropics and in the North Pacific mid-high latitudes. The central equatorial Pacific La Niña forcing in the spring would, on the one hand, induce teleconnection anomalies of high pressure from the Sea of Okhotsk to the Sea of Japan in early summer, and on the other hand indirectly trigger a positive low-frequency East Asia-Pacific teleconnection (EAP) wave train in the lower troposphere.