Global Analysis of Coastal Gradients of Sea Surface Salinity
Sea surface salinity (SSS) is a key variable for ocean–atmosphere interactions and the water cycle. Due to its climatic importance, increasing efforts have been made for its global in situ observation, and dedicated satellite missions have been launched more recently to allow homogeneous coverage at...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-06-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/13/2507 |
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| author | Alina N. Dossa Gaël Alory Alex Costa da Silva Adeola M. Dahunsi Arnaud Bertrand |
| author_facet | Alina N. Dossa Gaël Alory Alex Costa da Silva Adeola M. Dahunsi Arnaud Bertrand |
| author_sort | Alina N. Dossa |
| collection | DOAJ |
| description | Sea surface salinity (SSS) is a key variable for ocean–atmosphere interactions and the water cycle. Due to its climatic importance, increasing efforts have been made for its global in situ observation, and dedicated satellite missions have been launched more recently to allow homogeneous coverage at higher resolution. Cross-shore SSS gradients can bear the signature of different coastal processes such as river plumes, upwelling or boundary currents, as we illustrate in a few regions. However, satellites performances are questionable in coastal regions. Here, we assess the skill of four gridded products derived from the Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) satellites and the GLORYS global model reanalysis at capturing cross-shore SSS gradients in coastal bands up to 300 km wide. These products are compared with thermosalinography (TSG) measurements, which provide continuous data from the open ocean to the coast along ship tracks. The comparison shows various skills from one product to the other, decreasing as the coast gets closer. The bias in reproducing coastal SSS gradients is unrelated to how the SSS biases evolve with the distance to the coast. Despite limited skill, satellite products generally agree better with collocated TSG data than a global reanalysis and show a large range of coastal SSS gradients with different signs. Moreover, satellites reveal a global dominance of coastal freshening, primarily related to river runoff over shelves. This work shows a great potential of SSS remote sensing to monitor coastal processes, which would, however, require a jump in the resolution of future SSS satellite missions to be fully exploited. |
| first_indexed | 2024-03-09T04:51:25Z |
| format | Article |
| id | doaj.art-e6e6000c0c224beb983cb5eeeaa75006 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-09T04:51:25Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-e6e6000c0c224beb983cb5eeeaa750062023-12-03T13:10:45ZengMDPI AGRemote Sensing2072-42922021-06-011313250710.3390/rs13132507Global Analysis of Coastal Gradients of Sea Surface SalinityAlina N. Dossa0Gaël Alory1Alex Costa da Silva2Adeola M. Dahunsi3Arnaud Bertrand4Laboratório de Oceanografia Física Estuarina e Costeira, Depto. Oceanografia, UFPE, Av. Arquitetura, s/n, Cidade Universitária, Recife CEP 50740-550, PE, BrazilLaboratoire d’Études en Géophysique et Océanographie Spatiale (LEGOS), Université de Toulouse, CNES/CNRS/IRD/UPS,14, Avenue Edouard Belin, 31400 Toulouse, FranceLaboratório de Oceanografia Física Estuarina e Costeira, Depto. Oceanografia, UFPE, Av. Arquitetura, s/n, Cidade Universitária, Recife CEP 50740-550, PE, BrazilInternational Chair in Mathematical Physics and Applications (ICMPA), Université d’Abomey-Calavi, 072 BP 50 Cotonou, BeninLaboratório de Oceanografia Física Estuarina e Costeira, Depto. Oceanografia, UFPE, Av. Arquitetura, s/n, Cidade Universitária, Recife CEP 50740-550, PE, BrazilSea surface salinity (SSS) is a key variable for ocean–atmosphere interactions and the water cycle. Due to its climatic importance, increasing efforts have been made for its global in situ observation, and dedicated satellite missions have been launched more recently to allow homogeneous coverage at higher resolution. Cross-shore SSS gradients can bear the signature of different coastal processes such as river plumes, upwelling or boundary currents, as we illustrate in a few regions. However, satellites performances are questionable in coastal regions. Here, we assess the skill of four gridded products derived from the Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) satellites and the GLORYS global model reanalysis at capturing cross-shore SSS gradients in coastal bands up to 300 km wide. These products are compared with thermosalinography (TSG) measurements, which provide continuous data from the open ocean to the coast along ship tracks. The comparison shows various skills from one product to the other, decreasing as the coast gets closer. The bias in reproducing coastal SSS gradients is unrelated to how the SSS biases evolve with the distance to the coast. Despite limited skill, satellite products generally agree better with collocated TSG data than a global reanalysis and show a large range of coastal SSS gradients with different signs. Moreover, satellites reveal a global dominance of coastal freshening, primarily related to river runoff over shelves. This work shows a great potential of SSS remote sensing to monitor coastal processes, which would, however, require a jump in the resolution of future SSS satellite missions to be fully exploited.https://www.mdpi.com/2072-4292/13/13/2507SSSthermosalinographSMOSSMAPGLORYSAmazon River plume |
| spellingShingle | Alina N. Dossa Gaël Alory Alex Costa da Silva Adeola M. Dahunsi Arnaud Bertrand Global Analysis of Coastal Gradients of Sea Surface Salinity Remote Sensing SSS thermosalinograph SMOS SMAP GLORYS Amazon River plume |
| title | Global Analysis of Coastal Gradients of Sea Surface Salinity |
| title_full | Global Analysis of Coastal Gradients of Sea Surface Salinity |
| title_fullStr | Global Analysis of Coastal Gradients of Sea Surface Salinity |
| title_full_unstemmed | Global Analysis of Coastal Gradients of Sea Surface Salinity |
| title_short | Global Analysis of Coastal Gradients of Sea Surface Salinity |
| title_sort | global analysis of coastal gradients of sea surface salinity |
| topic | SSS thermosalinograph SMOS SMAP GLORYS Amazon River plume |
| url | https://www.mdpi.com/2072-4292/13/13/2507 |
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