Statistics on the Modulation of Madden-Julian Oscillation onTropical Cyclone Activity in the Western North Pacific

Using the Madden-Julian oscillation (MJO) index provided by Climate Prediction Center, NOAA, and the tropical cyclone (TC) best track dataset over the western North Pacific (WNP) provided by Shanghai Institute of Typhoon of CMA, the quantified statistics of the modulation of MJO on tropical cyclone activity are performed. The results show that the genesis, intensity, landfall, and path of TCs are all modulated by MJO significantly. When the upper-air convergent center locates in 120°E-160°E (MJO phases 3-5), there are less TCs form and the genesis position locates more north in the WNP; While the upper-air convergent center locates in 10°W-70°E(MJO phases 8-10), more TCs form and the genesis position locates more southward. When the upper-air convergent center locates at 70°E, i.e., MJO phase 10, the intensity of TCs is significantly modulated; during phases 1-4 and 10, the vigorous TCs occur in the east of the Philippines of WNP, indicating the dominant northwestward and northward paths, possibly making landfall on the East and North China; while during the phases 5-8, the TCs occur frequently in the vicinity of the Philippines to the South China Sea, suggesting the dominant westward tracks and possible TC landfall on the south China. These statistical facts could be useful in the prediction of TC intraseasonal activity.