Life Period of Cyclonic Disturbances Over the North Indian Ocean During Recent Years

Abstract

Tropical cyclones (TCs) are one of the most devastating disastrous weather events worldwide and especially over the North Indian Ocean (NIO). About 75 % of all TCs which killed 5000 or more human population had developed over this basin during the past 300 years (Dube et al., Mausam 64:193–202, 2013). Considering this, there is always a need to strengthen monitoring, prediction and warning services for the TCs apart from preparedness and planning. The preparedness and planning for TC mitigation needs climatological information about the TCs to assess the hazard potential. Mohapatra et al. (Nat Hazards 63:1601–1620, 2012a; 2015) have analysed TC hazard proneness of various coastal districts of India in terms of frequency, intensity and associated adverse weather like heavy rain, gale winds and storm surge etc., However, the damage potential and the lead time available for management of the TC disaster depend crucially on the life period of the TCs, especially its period of stay over oceanic region before the landfall as the track and landfall forecast can be provided accurately to the disaster managers after the genesis of the TC only. The TCs over the NIO show large-scale spatio-temporal variations in terms of genesis, track, intensity and landfall (Mohapatra et al., Construction and quality of best tracks parameters for study of climate change impact on tropical cyclones over the North Indian Ocean during satellite era. In: Mohanty UC, Mohapatra M, Singh OP, Bandyopadhyay BK, Rathore LS (eds.) Monitoring and prediction of tropical cyclones over the Indian Ocean and climate change. Springers and Capital publishers, New Delhi, pp 3–17, 2014; Tyagi et al., Inter-annual variation of frequency of cyclonic disturbances landfalling over WMO/ESCAP Panel Member Countries, WMO/TD-No. 1541 on Ist WMO international conference on Indian Ocean tropical cyclones and climate change, Muscat, Sultanate of Oman, 8–11 March 2009, WWRP-2010/2, pp 1–7, 2010; IMD, Tracks of cyclones and depressions (1891–2007). Electronic Version 1.0/2008, Published by IMD, Chennai, 2008; Cyclone warning in India; Standard operational procedure. IMD, New Delhi, 2013). Therefore, there is a need to find out the average life period of the cyclonic disturbances (CDs) with different intensities in different seasons and year as a whole over different ocean basins, namely, Bay of Bengal (BOB), Arabian Sea (AS) and the North Indian Ocean (NIO) as a whole. There are many studies over the Northwest Pacific and North Atlantic Ocean on the above climatological aspects. However, studies are limited over the NIO.

Annexure I

Table 6 Duration (h) of cyclonic disturbances in different stages over the NIO from 1990 to 2013 in winter

Table 7 Duration (h) of cyclonic disturbances in different stages over the NIO from 1990 to 2013 in pre-monsoon

Table 8 Duration (h) of cyclonic disturbances in different stages over the NIO from 1990 to 2013 in monsoon

Table 9 Duration (h) of cyclonic disturbances in different stages over the NIO from 1990 to 2013 in post-monsoon

Table 10 Duration (h) of cyclonic disturbances in different stages over the NIO from 1990 to 2013 during year as a whole