卑尔根气候模式中亚洲—太平洋涛动和影响西北太平洋热带气旋频数的环流背景的关系

Linkage between Asian-Pacific Oscillation and the Large-Scale Atmospheric Circulations Related to the Tropical Cyclone Frequency over the Western North Pacific in Bergen Climate Model

利用挪威卑尔根的全球大气-海洋-海冰耦合模式的300年气候态数值积分结果,结合观测资料,分析了夏季亚洲-太平洋涛动(APO)的年际变化对与西北太平洋热带气旋生成频数相关联的大尺度环流背景的影响。模式结果表明,当夏季APO异常偏强(弱)时,西太平洋副热带高压位置偏东(西)偏北(南),南亚高压位置偏北(南),西北太平洋低层大气异常辐合(辐散),高层大气异常辐散(辐合),对流活动加强(减弱)。这种环流背景条件有(不)利于西北太平洋热带气旋的发生发展,西北太平洋热带气旋频数因而偏多(少)。

The linkage between Asian-Pacific oscillation （APO） and the large-scale atmospheric circulations related to the tropical cyclone frequency over the western North Pacific is examined using a 300-year integration of an atmosphere-ocean-sea ice coupled model and observational data. The result shows that when the summer APO is stronger （weaker） than normal, the western Pacific subtropical high moves eastward （westward） and northward （southward）, and the south Asian high shifts northward （southward）, concurrent with the anomalous low-level convergence （divergence） and high-level divergence （convergence） as well as the strengthened （weakened） convections over the western North Pacific. These circulation backgrounds favor （disfavor） the genesis of tropical cyclones, and thus more （less） tropical cyclones tend to appear over the western North Pacific.