CHARACTERISTICS OF TROPICAL CYCLONES ACTIVITIES VARYING WITH ENVIRONMENTAL FIELDS OF MID-AND LOWER-LATITUDES

Using historical data from 1951 to 1996, this paper makes statistical study and elaborate comparisons of tropical cyclone (TC) activity in middle and low latitudes. Some useful results have been achieved. For example, about 65% (90% in May) of the low-latitude tropical cyclones can move north into middle latitudes; TCs in middle latitudes move by about 60 more to the east and 10 km/h faster than in low latitudes; about 60% of the TCs dissipate in middle latitudes; the mean intensity is the maximum near the line dividing the middle and low latitude systems. The work paves the way for more work on revealing characteristics of interactions between middle and low latitude circulation systems.