The Land-Sea Breeze of the Red Sea: Observations, Simulations, and Relationships to Regional Moisture Transport

Unique in situ observations of atmospheric conditions over the Red Sea and the coastal Arabian Peninsula are examined to study the dynamics and regional impacts of the local land-sea breeze cycle (LSBC). During a 26-month data record spanning 2008-2011, observed LSBC events occurred year-round, frequently exhibiting cross-shore wind velocities in excess of 8 m/s. Observed onshore and offshore features of both the land- and sea-breeze phases of the cycle are presented, and their seasonal modulation is considered. Weather Research and Forecasting climate downscaling simulations and satellite measurements are used to extend the analysis. In the model, the amplitude of the LSBC is significantly larger in the vicinity of the steeper terrain elements encircling the basin, suggesting an enhancement by the associated slope winds. Observed and simulated conditions also reflected distinct gravity-current characteristics of the intrinsic moist marine air mass during both phases of the LSBC. Specifically, the advance and retreat of marine air mass was directly tied to the development of internal boundary layers onshore and offshore throughout the period of study. Convergence in the lateral moisture flux resulting from this air mass ascending the coastal topography (sea-breeze phase) as well as colliding with air masses from the opposing coastline (land-breeze phase) further resulted in cumulous cloud formation and precipitation.