THE STUDY OF THE SUDDEN NORTHWARD JUMP OF THE SUBTROPICAL HIGH OVER THE WESTERN PACIFIC

Based on the wind data at 200, 500 and 850 hPa levels from the ECMWF data sets and TBB data of Japan (JMA) Geostationary Meteorological Satellite (GMS) during 1980-1989, it is discussed that the characteristics of convection and westerly wind at low latitude vary and its relation to two jumps northward of the ridge line of the subtropical high over Western Pacific during summer. It is found that the outburst of low-level equatorial westerly wind and equatorial convection intensity over western pacific in the 2nd pentad of June caused the first northward jump of the subtropical high, and the low-level equatorial wester1y wind and equatorial convection moved northward to tropic in the 4th pentad of July caused the second northward jump of the subtropical high. Analysis results based on TBB show that the tropical convection strengthens (weakens) and the ridge line of the Western Pacific Subtropical high lies to the north (south) of normal state during summer.