Impact of the Subtropical High on the Extratropical Transition of Tropical Cyclones over the Western North Pacific  

作　　者：宋金杰 伍荣生 权婉晴 杨程 

机构地区：[1]Key Laboratory of Mesoscale Severe Weather/Ministry of Education, and School of Atmospheric Sciences, Nanjing University

出　　处：《Acta meteorologica Sinica》2013年第4期476-485,共10页

基　　金：Supported by the National Natural Science Foundation of China (41105036, 41105035, 40730948, 40830958, and 40921160382)

摘　　要：Recent publications have investigated the interactions between the extratropical transitions （ETs） of tropical cyclones （TCs） and midlatitude circulations; however, studies of ET events have rarely considered the relationship between the storm and the nearby subtropical high. The TC best-track data provided by the Regional Specialized Meteorological Center-Tokyo Typhoon Center of the Japan Meteorology Agency are used in conjunction with the NCEP/NCAR reanalysis data to discuss the potential effects of the subtropical high on ETs over the western North Pacific basin. When the western Pacific subtropical high （WPSH） is weakened and withdrawn toward the east, more TCs follow recurving paths and the midlatitude trough activity is intensified. These changes lead to enhanced ET activity. By contrast, when the WPSH strengthens and extends westward, the number of TCs that follow direct westward paths increases and the midlatitude trough is relatively inactive. These conditions lead to reduced occurrences of ET cases. Abnormal activity of the WPSH should be considered as an important factor in determining ET activity.Recent publications have investigated the interactions between the extratropical transitions （ETs） of tropical cyclones （TCs） and midlatitude circulations; however, studies of ET events have rarely considered the relationship between the storm and the nearby subtropical high. The TC best-track data provided by the Regional Specialized Meteorological Center-Tokyo Typhoon Center of the Japan Meteorology Agency are used in conjunction with the NCEP/NCAR reanalysis data to discuss the potential effects of the subtropical high on ETs over the western North Pacific basin. When the western Pacific subtropical high （WPSH） is weakened and withdrawn toward the east, more TCs follow recurving paths and the midlatitude trough activity is intensified. These changes lead to enhanced ET activity. By contrast, when the WPSH strengthens and extends westward, the number of TCs that follow direct westward paths increases and the midlatitude trough is relatively inactive. These conditions lead to reduced occurrences of ET cases. Abnormal activity of the WPSH should be considered as an important factor in determining ET activity.

关 键 词：tropical cyclone extratropical transition western Pacific subtropical high 

分 类 号：P444[天文地球—大气科学及气象学]