Abstract: The Red Sea is located in the heart of the "dust belt" area between North Africa and the Arabian Peninsula, the largest sources of dust in the world. Satellite retrievals show very high aerosol optical depth in the region. In the summer unique atmospheric conditions cause the "dust trapping" effect over the southern Red Sea and produce the world's largest aerosols radiative effect. This effect from dust is expected to have a profound thermal and dynamic impact on the Red Sea, but it has not been studied or evaluated previously. Due to the strong dust radiative effect at the sea surface, uncoupled ocean modeling approaches with prescribed atmospheric boundary conditions result in an unrealistic ocean response. Therefore, to study the impact of dust on the regional climate of the Middle East and the Red Sea, we employed the Regional Ocean Modeling System fully coupled with the Weather Research and Forecasting model. We modified the atmospheric model to account for the radiative effect of dust. The simulations show that, in the equilibrium response, dust cools the Red Sea, reduces the surface wind speed, and weakens both the exchange at the Bab-el-Mandeb strait and the overturning circulation. The salinity distribution, freshwater, and heat budgets are significantly altered. Validation of the simulations against observations and satellite retrievals indicates that accounting for radiative effect from dust almost completely removes the bias and reduces errors in the top of the atmosphere fluxes and sea surface temperature. Our results suggest that dust plays an important role in the energy balance, thermal, and circulation regimes in the Red Sea.
Bio: Dr. Sergey Osipov got his bachelor and master degrees from Moscow Institute of Physics and Technology in Russia, in 2009 and 2011, respectively. He then joined the Atmospheric and Climate Modeling group at KAUST, where he got Ph.D. in 2017. He is currently working as a postdoctoral fellow at Max Planck Institute for Chemistry (MPIC) in Mainz, Germany. His research interests comprise climate modeling at regional and global scales and, in particular, the role of the volcanic eruptions. His recent work spans atmospheric and ocean dynamics and large-scale circulation, radiative transfer in the atmosphere, aerosols (including dust, volcanic sulfate, and brown carbon) microphysical and optical properties, radiative forcing of aerosols and trace gases, their effect on photolysis and photochemistry.