Observing submesoscale activity in the Bay of Biscay with satellite-derived SST and Chlorophyll concentration

Özge Yelekçi 1, * Guillaume Charria 2 Daneeja Mawren 1 Xavier Capet 3 Gilles Reverdin 4 Francis Gohin 1 Joël Sudre 5, 6 Hussein Yahia 7
* Auteur correspondant
3 PEPS - Processus de couplage à Petite Echelle, Ecosystèmes et Prédateurs Supérieurs
LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques
4 IPSO - Interactions et Processus au sein de la couche de Surface Océanique
LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques
5 DYNBIO LEGOS
LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
Abstract : Submesoscale activity in the upper ocean is linked to vertical velocities that enable transport of nutrients to the euphotic zone and trigger primary production, and yet its contribution to the global production budget is still to be fully investigated. Sampling the submesoscales is a challenge, due to their spatial scales of O(1-10) km and their life spans of a few days. Thus, we utilized high resolution (∼ 1km) satellite images of sea surface tempera- ture (SST) and chlorophyll concentration (Chl) for the purpose of identification and classification of submesoscale activity over the Bay of Biscay continental shelf. For our analysis, we applied an event-based approach. We con- structed a large data set of the last ten years' (2003 - 2013) MODIS images of both Aqua and Terra satellites. Due to cloud coverage, number of quality images covering the entire region is limited making the data set discontinuous in time and space. To maximize the portion of usable images covering the temporal and spatial scales we wanted to investigate, we discretized our data set. Given the fact that submesoscale features are highly localized, instead of the entirety of the Bay, we divided the domain into sub-regions that are defined by their hydrological features, such as river plumes. Then, we selected "events" of cloud-free, consecutive daily images of SST and corresponding Chl. For an understanding of the driving mechanisms of submesoscale activity and its outcome as enhanced production, together with satellite images, background environmental conditions such as turbidity, and forcing fields such as wind stress distribution and river runoff before and during these events were analyzed. As a quantitative measure, correlation (or lack thereof) between occurrence and strength of submesoscale features and these factors is pre- sented. As a result of this effort, a classification of the submesoscale features based on their driving mechanisms is proposed.
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https://hal.inria.fr/hal-00942221
Contributeur : H. Yahia <>
Soumis le : mardi 28 octobre 2014 - 12:04:23
Dernière modification le : mardi 29 mai 2018 - 12:51:07
Document(s) archivé(s) le : jeudi 29 janvier 2015 - 10:36:46

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  • HAL Id : hal-00942221, version 1

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Özge Yelekçi, Guillaume Charria, Daneeja Mawren, Xavier Capet, Gilles Reverdin, et al.. Observing submesoscale activity in the Bay of Biscay with satellite-derived SST and Chlorophyll concentration. European Geosciences Union General Assembly 2014, Apr 2014, Vienne, Austria. 2014. 〈hal-00942221〉

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