| dc.description.abstract | In the present study we define a Shamal event as a WNW-N wind with an hourly average speed ≥ 9.85 m/s blowing during at least 3 hours/day. These events have a significant impact on surface heat fluxes (shortwave, longwave, sensible and latent), momentum fluxes, and as a result on vertical water column stratification, currents, and mixing intensities. We examined mixing processes and volume transport in response to Shamal events using observational data (time-series of temperature, dissolved oxygen, light intensity, and currents as well as surface meteorological data) collected over two periods (mid-January to mid-April 2013 and mid-October to mid-January 2014) in the vicinity of Qarooh Island, Kuwait. We further estimated turbulence parameters (Reynolds stresses, eddy diffusivities, TKE, and its dissipation rates) and compared them to two equation turbulence model simulations (k-kl and k-ϵ) during three Shamal events. The comparison of the measured and simulated turbulence parameters demonstrated satisfactory agreement between the two. Mixing in the bottom boundary layer was mainly controlled by two main forcings. The first forcing was the increase in mixing resulting from the current shear frequency generated by tides. The second was by the Shamal induced convection.
Using time-series of the observational current structure, we show that winds parallel to the coast generated a subsurface volume transport that was perpendicular to the coast causing upwelling / downwelling. The extent of the upwelling / downwelling region was found to be confined in the region near the coast and did not extend to Qarooh Island (24 nm offshore). The thermal structure at Qarooh was mainly influenced by a warm tongue that extended across the Gulf from the SE. | en |
