Joint observation–model mixed-layer heat and salt budgets in the eastern tropical Atlantic
Type | Article | ||||||||||||
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Date | 2023-05 | ||||||||||||
Language | English | ||||||||||||
Author(s) | Ngakala Roy Dorgeless1, 2, Alory Gaël3, Da-Allada Casimir Yélognissè1, 4, 5, Kom Olivia Estelle1, Jouanno Julien3, Rath Willi6, Baloïtcha Ezinvi1 | ||||||||||||
Affiliation(s) | 1 : Department of Oceanography and Applications, International Chair in Mathematical Physics and Applications, University of Abomey-Calavi, Cotonou, Benin 2 : Department of Oceanography and Environment, Institut National de Recherche en Sciences Exactes et Naturelles, Pointe-Noire, Congo 3 : Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, University of Toulouse, Toulouse, France 4 : Laboratoire de Géosciences, de l’Environnement et Applications, Université Nationale des Sciences Technologies, Ingénierie et Mathématiques, Abomey, Benin 5 : Laboratoire d’Hydrologie Marine et Côtière, Institut de Recherches Halieutiques et Océanologiques du Bénin, Cotonou, Benin 6 : GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Kiel, Germany |
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Source | Ocean Science (1812-0784) (Copernicus GmbH), 2023-05 , Vol. 19 , N. 3 , P. 535-558 | ||||||||||||
DOI | 10.5194/os-19-535-2023 | ||||||||||||
Abstract | In this study, we use a joint observation–model approach to investigate the mixed-layer heat and salt annual mean as well as seasonal budgets in the eastern tropical Atlantic. The regional PREFCLIM (PREFACE Climatology) observational climatology provides the budget terms with a relatively low spatial and temporal resolution compared to the online NEMO (Nucleus for European Modeling of the Ocean; Madec, G., 2014) model, and this is later resampled as in PREFCLIM climatology. In addition, advection terms are recomputed offline from the model as PREFCLIM gridded advection computation. In the Senegal, Angola, and Benguela regions, the seasonal cycle of mixed-layer temperature is mainly governed by surface heat fluxes; however, it is essentially driven by vertical heat diffusion in the equatorial region. The seasonal cycle of mixed-layer salinity is largely controlled by freshwater flux in the Senegal and Benguela regions; however, it follows the variability of zonal and meridional salt advection in the equatorial and Angola regions, respectively. Our results show that the time-averaged spatial distribution of NEMO offline heat and salt advection terms compares much better to PREFCLIM horizontal advection terms than the online heat and salt advection terms. However, the seasonal cycle of horizontal advection in selected regions shows that NEMO offline terms do not always compare well with PREFCLIM, sometimes less than online terms. Despite this difference, these results suggest the important role of small-scale variability in mixed-layer heat and salt budgets. |
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