In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region...In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region E), are defined with frequency of TC's occurrence at each grid for a 45-year period(1965–2009), where the frequency of occurrence(FO) of TCs is triple the mean value of the whole western North Pacific. Over the region S, there are decreasing trends in the FO of TCs, the number of TCs' tracks going though this region and the number of TCs' genesis in this region. Over the region P, the FO and tracks demonstrate decadal variation with periods of 10–12 year, while over the region E, a significant 4–5 years' oscillation appears in both FO and tracks. It is demonstrated that the differences of TCs' variation in these three different regions are mainly caused by the variation of the Western Pacific Subtropical High(WPSH) at different time scales. The westward shift of WPSH is responsible for the northwesterly anomaly over the region S which inhibits westward TC movement into the region S. On the decadal timescale, the WPSH stretches northwestward because of the anomalous anticyclone over the northwestern part of the region P, and steers more TCs reaching the region P in the greater FO years of the region P. The retreating of the WPSH on the interannual time scale is the main reason for the FO's oscillation over the region E.展开更多
By analyzing the features of cold and warm summer of the northeast China during 1961-2002,the results showed the time from 1960s to late 1970s was the phase of cold summer took place,and the time from 1980s to early 1...By analyzing the features of cold and warm summer of the northeast China during 1961-2002,the results showed the time from 1960s to late 1970s was the phase of cold summer took place,and the time from 1980s to early 1990s was the phase of cold and warm summer alternately took place.After the middle and late period of 1990s,it was the concentrated occurrence period of warm summer.The cool and warm summer had the continuity and cluster occurrence characteristics.The frequency of the cool summer was more than the warm summer,and the abnormal degree of warm summer was stronger than the cool summer,and the influence scope was wide.The cool summer had 4 frequent occurrence centers,and the warm summer had 2 frequent occurrence centers,located at the mountain zone and the hills zone.Not only the cool summer was easy to appear,but also the warm summer was easy to happen in the west and the east of Heilongjiang province.Comparatively speaking,the cool summer was easier to appear in the Changbai Mountain area.展开更多
基金supported by the National Natural Science Foundation of China(Nos. 41106018, 40975038)Program 973 (Nos. 2012CB417402, 2010CB950402, 2012CB955604)
文摘In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region E), are defined with frequency of TC's occurrence at each grid for a 45-year period(1965–2009), where the frequency of occurrence(FO) of TCs is triple the mean value of the whole western North Pacific. Over the region S, there are decreasing trends in the FO of TCs, the number of TCs' tracks going though this region and the number of TCs' genesis in this region. Over the region P, the FO and tracks demonstrate decadal variation with periods of 10–12 year, while over the region E, a significant 4–5 years' oscillation appears in both FO and tracks. It is demonstrated that the differences of TCs' variation in these three different regions are mainly caused by the variation of the Western Pacific Subtropical High(WPSH) at different time scales. The westward shift of WPSH is responsible for the northwesterly anomaly over the region S which inhibits westward TC movement into the region S. On the decadal timescale, the WPSH stretches northwestward because of the anomalous anticyclone over the northwestern part of the region P, and steers more TCs reaching the region P in the greater FO years of the region P. The retreating of the WPSH on the interannual time scale is the main reason for the FO's oscillation over the region E.
文摘By analyzing the features of cold and warm summer of the northeast China during 1961-2002,the results showed the time from 1960s to late 1970s was the phase of cold summer took place,and the time from 1980s to early 1990s was the phase of cold and warm summer alternately took place.After the middle and late period of 1990s,it was the concentrated occurrence period of warm summer.The cool and warm summer had the continuity and cluster occurrence characteristics.The frequency of the cool summer was more than the warm summer,and the abnormal degree of warm summer was stronger than the cool summer,and the influence scope was wide.The cool summer had 4 frequent occurrence centers,and the warm summer had 2 frequent occurrence centers,located at the mountain zone and the hills zone.Not only the cool summer was easy to appear,but also the warm summer was easy to happen in the west and the east of Heilongjiang province.Comparatively speaking,the cool summer was easier to appear in the Changbai Mountain area.
