DIABATIC HEATING AND CONVECTIVE ASYMMETRIES DURING RAPID INTENSITY CHANGES OF TROPICAL CYCLONES OVER NORTH INDIAN OCEAN

作者：B.GEETHA,S.BALACHRAN

摘要：Rapid changes in Tropical Cyclone(TC)structure and intensity are the most diffi cult aspects of TC forecasting.The intensity and structural changes associated with rapid intensifi cation(RI)and rapid weakening(RW)instances of TCs of North Indian Ocean(NIO)are analysed based on 5 cases each for RI and RW.The vertical profi les of heat(Q1)and moisture(Q2)based on heat and moisture budget equations are analysed to bring out the role of diabatic heating during the RI and RW processes.The associated structural changes are analysed based on the Fourier fi rst order wave number-1 asymmetry in the precipitation patterns associated with RI and RW instances.During RI process,there are 2 predominant Q1 maxima associated with latent heat release near the TC centre,one in the upper troposphere and the other in the lower troposphere.During RW process,there is a single dominant Q1 and Q2 maxima in the mid-troposphere.Regarding the structural changes,there is a pronounced front-back asymmetry in both RI and RW cases.The asymmetry amplitude in the inner core is lower in the case of RI events but,is quite high for RW events.Thus,RW events are characterised by large convective asymmetry.

发文机构：India Meteorological Department

关键词：tropicalcycloneRAPIDintensifiCATIONheatBUDGETmoistureBUDGETrainfallasymmetryFourieranalysis

分类号： P444[天文地球—大气科学及气象学]