Forecasting tropical cyclones in Bangladesh: a Markov renewal approach

Bangladesh frequently suffers from tropical cyclones possibly due to its unique location. The funnel-shaped northern part of the Bay of Bengal causes tidal bores when cyclones make landfall. These tropical cyclones can be very devastating and can severely affect the coastline of Bangladesh. In this study we analyzed 135 tropical cyclones occurred in Bangladesh during 1877–2009 considering the physical characteristics of the storm surge process. For analyzing the storm surge process, a Markov renewal model that takes into account both the sojourn times and the transitions between different types of cyclones simultaneously was considered. Exponential distribution for the sojourn times was assumed to derive the probabilities of occurrence of different types of cyclones for various lengths of time intervals. Given the type of the last cyclone occurred probabilities of occurrence of the next cyclone are reported using the fitted Markov renewal model. The mean recurrence times of different type of cyclones were also calculated assuming ergodicity of the Markov renewal process.