Trend Analysis of Extreme Wind and Wave Height at Key Port Locations along the Indian Coastline

Abstract

Abstract Long-term trends of wind speed (WS) and significant wave height (SWH) in the Arabian Sea (AS) and Bay of Bengal (BoB) are of great interest to scientists, engineers, climate modelers, and policymakers. It is associated with global climate change and efficient offshore and near-shore socio-economic activity management. In this study, the climatology and variability of mean and extreme SWH and WS is determined during the monsoon (JJA) and post-monsoon (SON) seasons along the Indian coastline during 1979--2021 using ERA5 reanalysis datasets. The generalized extreme value (GEV) distribution is utilized to determine the extreme values of SWH and WS. Further, linear trend analysis is also carried out at six key port locations (Paradip, Visakhapatnam, Chennai, Mumbai, Mangalore, and Kochi) along the Indian coastline. The outcome reveals that mean SWH displays an increasing trend (Paradip, Visakhapatnam, Chennai, Mumbai, Mangalore, and Kochi) during JJA and SON seasons while mean WS shows a decreasing trend in JJA season and an increasing trend in SON season. The maximum rate of increase in extreme SWH is observed at Kochi (r=0.78 cm yr-1) and Paradip port (1.32 cm yr-1) during JJA and SON seasons, respectively. In SON season, extreme WS exhibits an increasing trend at all six locations, and the rate of increase is maximum at Visakhapatnam (3.46 cm s-1 yr-1), followed by Paradip (3.39 cm s-1 yr-1) and minimum at Mumbai (1.84 cm s-1 yr-1). Kochi and Paradip ports experienced a significant increase in extreme SWH and WS during JJA and SON seasons, respectively.