Modelling cyclonic eddies in the Delagoa Bight region
| Type | Article | ||||||||||||
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| Date | 2016-05 | ||||||||||||
| Language | English | ||||||||||||
| Author(s) | Cossa O.1, 4, Pous Stephane1, 2, Penven P.1, 3, Capet X2, Reason C. J. C.1 | ||||||||||||
| Affiliation(s) | 1 : Univ Cape Town, Dept Oceanog, ZA-7700 Rondebosch, South Africa. 2 : Univ Paris 06, Univ Paris 04, LOCEAN Lab, CNRS IRD MNHN, Paris, France. 3 : UBO, IFREMER, IRD, LMI ICEMASA,Lab Phys Oceans,CNRS,UMR 6523, Plouzane, France. 4 : Inst Nacl Hidrografia & Navegacao, Maputo, Mozambique. |
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| Source | Continental Shelf Research (0278-4343) (Pergamon-elsevier Science Ltd), 2016-05 , Vol. 119 , P. 14-29 | ||||||||||||
| DOI | 10.1016/j.csr.2016.03.006 | ||||||||||||
| WOS© Times Cited | 8 | ||||||||||||
| Keyword(s) | Delagoa Bight, Cyclonic lee eddy, Coastal countercurrent, Numerical model, Mozambique Channel, Shelf processes | ||||||||||||
| Abstract | The 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. | ||||||||||||
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