Application of Fuzzy Clustering Technique for Analysis of North Indian Ocean Tropical Cyclone Tracks

ABSTRACT A fuzzy, c-means (FCM) clustering technique is explored to investigate the track of tropical cyclones over the North Indian Ocean (NIO) for the period (1976-2014). A total of five clusters is objectively identified based on partition index, partition coefficient, Dunn Index and separation index. The results obtained during analysis emphasized that each cluster has the unique features in terms of their genesis location, landfall, travel duration, trajectory, seasonality, accumulated cyclone energy and Intensity. Analysis of large scale environmental parameters, constructed preceding day of genesis show some of these parameters to be potential precursors to TC formation for almost all the clusters, most prominently, mid-tropospheric humidity, zonal wind, vorticity and outgoing long wave radiation of the main developing regions. The individual clusters have the several distinct features in their seasonal cycles. The cluster C5 shows distinct bimodal distributions where as other clusters are formed throughout the year. ENSO influenced the cyclone frequency in two of the five clusters. The MJO is found to play an important role in the genesis of the cyclone. The post monsoon season cyclone frequency is more in MJO phase 2, 3 and 4. The technique (FCM) can be used as a guideline in terms of the probable affected zone of TC Tracks by the operational forecasters.