Spatial and temporal variation of surface waves in shallow waters along the eastern Arabian Sea.

We studied the spatial and temporal variation of surface waves along the eastern Arabian Sea during 2011 and 2012. Measured directional wave data at two shallow water locations and re-analysis datasets (ERA-Interim) at 0.75° intervals at four locations were used for the study. The study region covers 270km along the west coast of India and lies between Karwar and Ratnagiri. The temporal variations of wave parameters were less than 10% at both locations for temporal intervals up to 12h except during the monsoon/storm period. During the storm period, the variation in significant wave height within 3h was around 13% and was up to 26% inside 12h. Comparatively low (<10%) spatial variation was found for wave height during the monsoon season and higher variation (>20%) was observed during the non-monsoon season. The pattern of spatial variation of wave parameters was similar during both the years for the measured and re-analysis datasets. The study shows that during the monsoon period, the wave characteristics were similar for the 270km long stretch since the waves along this part were predominantly (~72%) swells.