Hydrodynamic and Thermohaline Effects on the Gulf due to Super Cyclone Gonu of 2007

Super Cyclone Gonu in 2007 traversed an extremely rare path (Figure 1), traveling much closer to the Arabian/Persian Gulf (simply, the Gulf) than other previous tropical cyclones in the Arabian Sea. It caused tremendous damage to the coasts of Oman, Iran and United Arab Emirates (UAE). In addition, a high peak rainfall about 900 mm was recorded during Gonu and led to flash floods and massive beach erosion (Fritz et al. 2010). Both hydrodynamic and coupled hydrodynamic and wave models, configured through the Delft3D modeling suite and forced by winds from Cyclone Gonu, are used to test and develop hydrodynamic and wave predictions of extreme weather event for the Gulf region. Significant wave height of about 3.2-3.8 m at the coastal areas were estimated and both models show the spatial and temporal variations of local changes in salinity (±2 ppt, more) and temperature (±4 ℃, more), due to the enormous inflows of fresher water from the Arabian Sea driven by Gonu. Representative results are shown in Figure 2. In addition, a sensitivity analysis is performed to investigate the model response to different cyclone conditions, anticipating potential future cyclones and the characterization of their impacts. This study will provide a basis for future depiction of possible surge and flooding risk for coastal regions in the Gulf, and also estimate the potential effect on the variations to the salinity and temperature characteristics of the Gulf due to cyclone forcing. Keywords: Cyclone Gonu, Significant Wave Height, Salinity, Temperature