登陆热带气旋的维持条件和涡度收支

本文统计1960—1986年登陆或登陆后移入珠江三角洲范围内的44个热带气旋陆上维持时间等气候特征,结果指出热带气旋登陆后平均维持时间为31.7h。陆上平均维持时间与热带气旋登陆时的中心强度和范围成正比,并选取了比平均维持时间长和短的两个个例作涡度收支等计算,结果表明两者涡度收支的主要差别在垂直输送项和反映积云对流作用的余项上。

MAINTENANCE CONDITIONS AND VORTICITY BUDGET OF THE TROPICAL CYCLONE AFTER LANDING

In this paper,the climatology features of maintenances for 44 tropical cyclones are investigated, which landed or entered the Delta area of the Pearl River in 1960-1986. It is found that the mean maintenance time overland is in direct proportion to the intensity and size of the cyclones when landing. In addition, a comparison between two cyclone cases, of which one remained for only about 29 hours after landing and the other over 100 hours, is made.The result shows that the difference of vorticity budget is very significant. The most pronounced difference is found in the vertical transfer term and the residual term which is supposed to be a reflection of cumulus effects. This contrast reflects their different intensity in large-scale vertical motion and cumulus convection. Similar conclusion is obtained in a comparison of apparent heat source and apparent moisture sink.