SST Anomalies in the Mozambique Channel Using Remote Sensing and Numerical Modeling Data

Yu Liu,Guoqing Han,Qingyue Wang,Changming Dong,Joel Sommeria,Junde Li,Jingsong Yang

doi:10.3390/rs11091112

Abstract

Based on both satellite remote sensing sea surface temperature (SST) data and numerical model results, SST warming differences in the Mozambique Channel (MC) west of the Madagascar Island (MI) were found with respect to the SST east of the MI along the same latitude. The mean SST west of the MI is up to about 3.0 °C warmer than that east of the MI. The SST differences exist all year round and the maximum value appears in October. The area of the highest SST is located in the northern part of the MC. Potential factors causing the SST anomalies could be sea surface wind, heat flux and oceanic flow advection. The presence of the MI results in weakening wind in the MC and in turn causes weakening of the mixing in the upper oceans, thus the surface mixed layer depth becomes shallower. There is more precipitation on the east of the MI than that inside the MC because of the orographic effects. Different precipitation patterns and types of clouds result in different solar radiant heat fluxes across both sides of the MI. Warm water advected from the equatorial area also contribute to the SST warm anomalies.

Highlights

The existence of islands has significant impacts on the local hydrological environment, especially influencing the physical processes in the lee of islands [1,2,3,4,5,6,7,8,9,10]
For the first type, when the wind blows across an island, the intensity of the wind behind the island is drastically reduced because the roughness of the island surface is much larger than that of the sea surface and mountains over the island have a blocking effect
Weakening wind intensity weakens the mixing of the upper oceans and the surface mixed layer depth becomes shallow

Summary

Introduction

The existence of islands has significant impacts on the local hydrological environment, especially influencing the physical processes in the lee of islands [1,2,3,4,5,6,7,8,9,10]. These processes can be categorized into two types: (i) oceanic response to wind wakes; and (ii) variation in oceanic current when it passes an island (hereafter referred to as oceanic current wakes).

Reynolds’ SST Data

TMI Cloud Data

AVISO Geostrophic Current Data

AVHRR SST Data

NCEP CFSR Reanalysis Data

Model Configuration

Phenomena

Mechanisms

Heat Flux

Conclusions