International audienceThe objective of this study is to document and shed light on the circulation around the Delagoa Bight region in the southern Mozambique Channel using a realistic modelling approach. A simulation including mesoscale forcings at the boundaries of our regional configuration succeeds in reproducing the general circulation in the region as well as the existence of a semi-permanent cyclonic eddy, whose existence is attested by in situ measurements in the Bight. Characterised by a persistent local minimum in SSH located around 26°S—34°E, this cyclonic eddy termed herein the Delagoa Bight lee eddy occurs about 25% of the time with no clear seasonal preference. Poleward moving cyclones, mostly generated further north, occur another 25% of the time in the Bight area. A tracking method applied to eddies generated in Delagoa Bight using model outputs as well as AVISO data confirms the model realism and provides additional statistics. The diameter of the eddy core varies between 61 and 147 km and the average life time exceeds 20 days. Additional model analyses reveal the systematic presence of negative vorticity in the Bight that can organise and form a Delagoa Bight lee eddy depending on the intensity of an intermittent southward flow along the shore and the spatial distribution of surrounding mesoscale features. In addition, the model solution shows other cyclonic eddies generated near Inhambane and eventually travelling through the Bight. Their generation and pathways appears to be linked with large Mozambique Channel rings

Understanding the dynamics of the coastal oceans is important for managing coastal ecosystems, and hence for protecting lives and planning sustainable development. Among other countries in the southwest Indian Ocean, Mozambique has a greater number of environmental problems to solve. These problems include the landing of tropical cyclones 1 along the coast and associated heavy rain and flooding events which cause loss of life, infrastructural damage, coastal erosion, incident droughts, water pollution, overexploitation of marine and coastal resources, and weather and climate change and extremes. 2,3 Many of these problems can be monitored, so that remedial action can be taken, by conducting sustainable institutional collective research. 4 Therefore Mozambican institutions should attain adequate capacity of human resources in strategic research areas (e.g. weather and climate extremes, mitigating harmful effects of climate change, and conservation and sustainable management of marine and coastal resources). 5 It was because of the aforementioned problems that, for the first time, an initiative developed by a Mozambican research group to focus on oceanic and atmospheric dynamics was established.

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