The relationship between the Asian-Pacific oscillation (APO) and the tropical cyclone frequency over the western North Pacific (WNP) in summer is preliminarily investigated through an analysis of ob- served data. The ...The relationship between the Asian-Pacific oscillation (APO) and the tropical cyclone frequency over the western North Pacific (WNP) in summer is preliminarily investigated through an analysis of ob- served data. The result has shown clearly that APO is significantly and positively correlated to the tropical cyclone frequency in the WNP. If APO is above (below) the normal in summer, more (less) tropical cyclones will tend to appear in the WNP. The present study also addresses the large-scale at- mospheric general circulation changes underlying the linkage between APO and the WNP tropical cy- clone frequency. It follows that a positive phase of summer APO is concurrent with weakened as well as northward and eastward located western Pacific subtropical high (WPSH), low-level convergence and high-level divergence, and reduced vertical zonal wind shear in the WNP, providing favorable envi- ronment for the tropical cyclone genesis, and thus more tropical cyclones will come into being, and vice versa.展开更多
Using a statistical model for simulating tropical cyclone （TC） formation and a trajectory model for simulating TC tracks, the influence of the El Nino-Southern Oscillation （ENSO） on the peak-season （July-Septembe...Using a statistical model for simulating tropical cyclone （TC） formation and a trajectory model for simulating TC tracks, the influence of the El Nino-Southern Oscillation （ENSO） on the peak-season （July-September） TC prevailing tracks in the western North Pacific basin is assessed based on 14 selected El Nino and 14 selected La Nina years during the period 1950-2007. It is found that the combination of statistical formation model and a trajectory model can simulate well the primary features of TC prevailing tracks on the interannual timescale. In the El Nino years, the significant enhancement of TC activity primarily occurs south of 20°N, especially east of 130°E. TCs that take the northwestward prevailing track and affect East Asia, including Taiwan Island, the Chinese mainland, Korea, and Japan, tend to move more westward in the El Nino years, while taking a more northward track in the La Nina years. Numerical simulations confirm that the ENSO-related changes in large-scale steering flows and TC formation locations can have a considerable influence on TC prevailing tracks.展开更多
基金the National Natural Science Foundation of China (Grant Nos. 40631005, 40625014 and 40620130113)
文摘The relationship between the Asian-Pacific oscillation (APO) and the tropical cyclone frequency over the western North Pacific (WNP) in summer is preliminarily investigated through an analysis of ob- served data. The result has shown clearly that APO is significantly and positively correlated to the tropical cyclone frequency in the WNP. If APO is above (below) the normal in summer, more (less) tropical cyclones will tend to appear in the WNP. The present study also addresses the large-scale at- mospheric general circulation changes underlying the linkage between APO and the WNP tropical cy- clone frequency. It follows that a positive phase of summer APO is concurrent with weakened as well as northward and eastward located western Pacific subtropical high (WPSH), low-level convergence and high-level divergence, and reduced vertical zonal wind shear in the WNP, providing favorable envi- ronment for the tropical cyclone genesis, and thus more tropical cyclones will come into being, and vice versa.
基金supported by the Typhoon Research Project (2009CB421503) of the National Basic Research Program (the 973 Program) of Chinathe National Natural Science Foundation of China (NSFCGrant No. 408750387)+2 种基金the Social Commonwealth Research Program of the Ministry of Science and Technology of the People’s Republic of China (GYHY200806009)The research project was funded by the Colleges and Universities in Jiangsu Province Graduate Study Innovation Plan (CX09B 224Z)ZHOU Weican was supported by the Jiangsu Key Laboratory of Meteorological Disaster Pro-gram (KLME 060206)
文摘Using a statistical model for simulating tropical cyclone （TC） formation and a trajectory model for simulating TC tracks, the influence of the El Nino-Southern Oscillation （ENSO） on the peak-season （July-September） TC prevailing tracks in the western North Pacific basin is assessed based on 14 selected El Nino and 14 selected La Nina years during the period 1950-2007. It is found that the combination of statistical formation model and a trajectory model can simulate well the primary features of TC prevailing tracks on the interannual timescale. In the El Nino years, the significant enhancement of TC activity primarily occurs south of 20°N, especially east of 130°E. TCs that take the northwestward prevailing track and affect East Asia, including Taiwan Island, the Chinese mainland, Korea, and Japan, tend to move more westward in the El Nino years, while taking a more northward track in the La Nina years. Numerical simulations confirm that the ENSO-related changes in large-scale steering flows and TC formation locations can have a considerable influence on TC prevailing tracks.
