Standard Operation Procedure for Tropical Cyclone Vital Parameters over North Indian Ocean

Abstract

There is a growing need for improvement in tropical cyclone (TC) vital parameters (Knaff 2011) in view of the requirements of numerical weather prediction (NWP) models and various stake holders. As the damage due to a TC is directly proportional to the square of the maximum sustained wind (MSW) and loss due to a TC is proportional to cube of MSW, the surface wind structure associated with a TC serves insurance agencies to assess the damage due to a TC. The disaster managers who prepare for the impact of a landfalling TC may use the wind field information as guidance as to where the most severe wind or surge damage may occur. The TC Vital parameters also serve as input to NWP models and storm surge models that are run prior to landfalling events to create synthetic vortex (Chourasia et al. 2013), as most of the NWP models fail to simulate accurately the location and intensity of the TC. The creation of synthetic vortex helps in improving the track and intensity forecast of the model. In the parametric storm surge prediction models, the surface wind structure in the quadrant base form alongwith the radius of maximum wind (RMW) and pressure drop (ΔP) at the centre are utilised to create the wind stress and hence predict the storm surge (Dube et al. 2013). In post-event cases, these wind structure data are utilised for diagnosis of TC and to better plan for future TC forecasts. Engineers and planners rely on historical TC information to determine long-term risks to facilities and infrastructure and to ensure the resilience of communities to potential disasters. Another most important use of this product is the determination of ship avoidance area over the sea due to a TC.