摘要
Based on an analysis of 51-year (1965 2015) data, the influence of El Ni o Southern Oscillation (ENSO) events on tropical cyclone (TC) activity is examined over the western North Pacific (WNP). The total number of TCs formed in the entire WNP reduces by about 3.4 TCs per year in La Ni a years, whereas TCs have an equivalent genesis number between El Ni o years and climatology. During El Ni o years, the frequency of TC formation increases remarkably in the southeast quadrant (140 E 180 , 0 17 N) and decreases in the northwest quadrant (120 140 E, 17 30 N). During La Ni a years, TCs tend to form in the northwest and southwest quadrants (120 140 E, 0 17 N) quadrants. TCs tend to become long-lived in the peak season (from July to Septem- ber) of El Ni o years and during strong El Ni o events. TC genesis shows a southeastward positive shift in terms of lifetime and intensity during El Ni o years, thus more super TCs (winds ≥ 58.64 m s 1) are formed in the southeast quadrant. Further analysis using the genesis potential index (GPI) indicates that the interannual variations in the TC genesis and track are significantly influenced by a combination of large-scale dynamic and thermodynamic conditions.
Based on an analysis of 51-year(1965–2015) data, the influence of El Ni?o–Southern Oscillation(ENSO) events on tropical cyclone(TC) activity is examined over the western North Pacific(WNP). The total number of TCs formed in the entire WNP reduces by about 3.4 TCs per year in La Ni?a years, whereas TCs have an equivalent genesis number between El Ni?o years and climatology. During El Ni?o years, the frequency of TC formation increases remarkably in the southeast quadrant(140?E–180?, 0?–17?N) and decreases in the northwest quadrant(120?–140?E, 17?–30?N). During La Ni?a years, TCs tend to form in the northwest and southwest quadrants(120?–140?E, 0?–17?N) quadrants. TCs tend to become long-lived in the peak season(from July to September) of El Ni?o years and during strong El Ni?o events. TC genesis shows a southeastward positive shift in terms of lifetime and intensity during El Ni?o years, thus more super TCs(winds ≥ 58.64 m s-1) are formed in the southeast quadrant. Further analysis using the genesis potential index(GPI) indicates that the interannual variations in the TC genesis and track are significantly influenced by a combination of large-scale dynamic and thermodynamic conditions.
基金
supported by grants from the National Natural Science Foundation of China (Nos. 41621064 and 41606003)
