THE RELATIONSHIP BETWEEN THE MOVEMENT OF THE MEIYU/BAIU RAIN BELT AND THE PERIODIC NORTHWESTWARD PROPAGATION OF THE CONVECTIVE ACTIVITY FROM TROPICAL WEST PACIFIC

摘要

In order to investigate the effect of the factors in lower latitudes on Meiyu/Baiu front, a diagnostic analysis for the two cases during June to July of 1985 and 1986 was examined. We found that (1) when the tropical convective activity moves westward to 10. 5-15.5°N/140°E from east side of 10. 5-15. 5°N/160°E, the northward shifts of the Meiyu/Baiu rain belt occurs; (2) the main factor which results in the northward and southward shifts of Meiyu/Baiu rain belt is thought as the 8, 18 and 30 day oscillations of the tropical convective activity around West Pacific.Meanwhile, the wave train propagating from Lake Baikal via Okhotsk Sea to the tropics could sometimes shift Baiu rain belt southward: (3) the onsets of Meiyu in China of both cases tend to take place just when the convective activity around lower latitudes moves westward through about 140°E with the 8, 18 and 30 day oscillation periods firstly coming to June.