Numerical assessment of climatological trends for annual and seasonal wave characteristics during recent 41 years

Analysis of wind generated waves due to the prevailing climate change induced by global warming is vital for benefit to the coastal community. In the present paper, the hindcasting of decadal variation namely (i) 1979-1992, (ii) 1993-2006, and (iii) 2007-2019 of wind-wave climate over seasonal and annual scale through 41 years starting from 1979 is carried out using ERA5 reanalysis wind-forcing with a daily temporal and 0.5 degrees x 0.5 degrees spatial resolution. The numerical simulations are executed over the computational domains (i) Global-Indian Ocean and (ii) Regional-south Gujarat to north Goa for evaluating the variability analysis of annual and seasonal mean significant wave heights. The evaluation framework is validated over three in-situ measurement locations with good correlation as compared to the simulated results. The results indicate that at this site the wind and wave activity is noted to increase during transition from 1979-1992 to 1993-2006, then a declination of mean significant wave height is noted during the span 2007-2019. Further, along with the spatial variation estimation, 27 locations along 15 m bathymetric contour at 25 km interval are selected for trend line study. All the 27 locations exhibits a similar kind of trend by variation of decreasing trend from 1979-2019 with variations 0.07-0.22 cm/year. This study highlights the significance in simulating the prevailing wind-wave changes at a regional level considering the impact of the climatology and seasonality changes for effective coastal management, environmental impact assessments and sustainable development.

Automated summary

This study examines the wind-wave climate data over a span of 41 years to analyze the characteristics and trends of wind-generated waves. The results indicate significant changes in wave activity at specific locations during different time periods, highlighting the importance of understanding and simulating wind-wave changes for effective coastal management, environmental impact assessments, and sustainable development.