Climate driven variability of wind-waves in the Red Sea

Wind-wave variability in the Red Sea has been studied over a period of 32 years (1979-2010) by hindcasting the wind-waves using a third generation spectral wave model, WaveWatch III, forced with the Climate Forecast System Reanalysis (CFSR) winds. The wave model results have been validated against the satellite observations and available measurements in the Red Sea. The study reveals robust spatial and temporal variability of wind speed and significant wave height in the Red Sea. The role of climatic indices on the wind-wave variability has been assessed. The highest extreme wave heights (99th percentile) are centered at three regions; around 23 degrees N, 19 degrees N, and 15 degrees N latitudes, while the 90th percentile and mean significant wave heights are scattered in the deep waters of the Red Sea. Contrasting trends of the significant wave heights such as negative trends in the northern Red Sea during summer and positive trends in the southern Red Sea during winter are the highlights, where the trends are significant and comparable with the trends at few marginal seas around the globe. A clear distinction exists between the two parts of the Red Sea in response of the variability due to climatic indices. Among the climatic indices, the North Atlantic Oscillation (NAO) and the El Nino-Southern Oscillation (ENSO) show significant positive and negative correlations with the characteristic wave heights in the northern and southern Red Sea.