摘要：India Meteorological Department (IMD) introduced cone of uncertainty (COU) in cyclonic disturbances (CDs) alongwith the 72 hr track forecast over the north India Ocean (NIO) in 2009. The track forecast for CDs is issued for 6, 12, 18, 24, 36, 48, 60 and 72 hrs time period from the stage of deep depression onwards. An attempt is made to evaluate COU forecast issued by IMD during 2009-2011(3 years). The size of the cone is deduced from climatological track forecast errors. The accuracy of COU forecast has been analysed with respect to basin of formation, season of formation, intensity and type of track (climatological/straight moving and recurving/looping type) of CDs by calculating percentage of total number of forecasts in each category lying within COU.
关键词：Tropical cyclone ; North Indian Ocean ; Cone of uncertainty ; Track
