Mixed layer depth variability in the Red Sea

Cheriyeri P Abdulla,Alaa M Albarakati,Mohammed A Alsaafani,Turki M Alraddadi

doi:10.5194/os-14-563-2018

Cheriyeri P Abdulla, Alaa M Albarakati + Show 2 more

Open Access

https://doi.org/10.5194/os-14-563-2018

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Journal: Ocean Science	Publication Date: Jul 2, 2018
Citations: 12	License type: CC BY 4.0

Affiliation: King Abdulaziz University, Sana'a University

Abstract

Abstract. For the first time, a monthly climatology of mixed layer depth (MLD) in the Red Sea has been derived based on temperature profiles. The general pattern of MLD variability is clearly visible in the Red Sea, with deep MLDs during winter and shallow MLDs during summer. Transitional MLDs have been found during the spring and fall. The northern end of the Red Sea experienced deeper mixing and a higher MLD associated with the winter cooling of the high-saline surface waters. Further, the region north of 19° N experienced deep mixed layers, regardless of the season. Wind stress plays a major role in the MLD variability of the southern Red Sea, while net heat flux and evaporation are the dominating factors in the central and northern Red Sea regions. Ocean eddies and Tokar Gap winds significantly alter the MLD structure in the Red Sea. The dynamics associated with the Tokar Gap winds leads to a difference of more than 20 m in the average MLD between the north and south of the Tokar axis.

Highlights

The surface mixed layer is a striking and universal feature of the open ocean where the turbulence associated with various physical processes leads to the formation of a quasihomogeneous layer with nearly uniform properties
The thickness of this layer, often called the mixed layer depth (MLD), is one of the most important oceanographic parameters, as this layer directly communicates and exchanges energy with the atmosphere and has a strong impact on the distribution of heat (Chen et al, 1994), ocean biology (Polovina et al, 1995), and near-surface acoustic propagation (Sutton et al, 2014)
The maximum value of climatological mean MLD is observed in February in the northern Red Sea, while the minimum occurs at various instances, especially during summer months

Summary

Introduction

The surface mixed layer is a striking and universal feature of the open ocean where the turbulence associated with various physical processes leads to the formation of a quasihomogeneous layer with nearly uniform properties. The thickness of this layer, often called the mixed layer depth (MLD), is one of the most important oceanographic parameters, as this layer directly communicates and exchanges energy with the atmosphere and has a strong impact on the distribution of heat (Chen et al, 1994), ocean biology (Polovina et al, 1995), and near-surface acoustic propagation (Sutton et al, 2014). The stirring associated with turbulent eddies predominantly changes the mixing process, mainly along the isopycnal surfaces where stirring may occur with minimum energy (de Boyer Montegut et al, 2004; Hausmann et al, 2017; Kara et al, 2003)

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