Effects of Monsoon Winds and Topographical Features on the Vertical Thermohaline and Biogeochemical Structure in the Gulf of Tadjourah (Djibouti)
| العنوان: | Effects of Monsoon Winds and Topographical Features on the Vertical Thermohaline and Biogeochemical Structure in the Gulf of Tadjourah (Djibouti) |
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| المؤلفون: | Eric Duvielbourg, Abdourahman Daher, Youssouf Moussa Omar, Laurent Memery, Xavier Carton |
| المساهمون: | Centre d’Etudes et de Recherche de Djibouti (CERD), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
| المصدر: | Open Journal of Marine Science Open Journal of Marine Science, Scientific Research Publishing, 2016, 06 (03), pp.440-455. ⟨10.4236/ojms.2016.63037⟩ Open Journal of Marine Science (2161-7384) (Scientific Research Publishing, Inc,), 2016, Vol. 06, N. 03, P. 440-455 Open Journal of Marine Science, 2016, 06 (03), pp.440-455. ⟨10.4236/ojms.2016.63037⟩ |
| بيانات النشر: | HAL CCSD, 2016. |
| سنة النشر: | 2016 |
| مصطلحات موضوعية: | 0106 biological sciences, Topography, 010504 meteorology & atmospheric sciences, Mixed layer, Monsoon Wind, Stratification (water), Monsoon, 01 natural sciences, Water column, Mixed Layer Depth, Thermocline, 14. Life underwater, ACLN, Biogeochemical Structures, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010604 marine biology & hydrobiology, 6. Clean water, Sea surface temperature, Oceanography, 13. Climate action, Thermohaline, Upwelling, Thermohaline circulation, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Geology |
| الوصف: | International audience; The vertical thermohaline and biogeochemical structures of the upper layer (0 - 200 m) were studied in the Gulf of Tadjourah using high-resolution hydrographic data collected in July-August 2013, September 2013 and February 2014. During summer, the superficial layer consisted of the mixed layer (ML) extending to a depth of about 20 - 30 m followed by the thermocline located between 30 and 50 m depth. The ML was thicker in the west and the southeast where the thermal gradient and chlorophyll a concentrations were particularly high. During September, this stratification persisted but the ML became warmer and saltier and the thermocline moved slightly deeper. In February, the ML extended to about 120 m, and the thermocline was less pronounced. A comparison of the directly measured currents to the wind induced Ekman current and to geostrophic velocity profiles revealed that the thermohaline and the biogeochemical features in summer were related to the southwest monsoon (SWM). The SWM drives surface water from the Gulf of Tadjourah to the Gulf of Aden and thus induces westward intrusion of the high salinity thermocline water from the Gulf of Aden; this near surface flow mixes surface waters in the extreme west of the Gulf of Tajourah. In contrast, the northeast monsoon (NEM), predominant in winter, brings cold water toward the Gulf of Tadjourah and thickens the ML through convective mixing. Our study shows that the SWM plays a crucial role in the stratification of the water column during summer but bathymetry influences its effects. The bowl-shape of the basin and its elongated slope in the west enhance the upwelling in this area where negative sea surface temperature anomalies and high chlorophyll a concentrations were observed. |
| وصف الملف: | application/pdf |
| اللغة: | English |
| تدمد: | 2161-7384 2161-7392 |
| DOI: | 10.4236/ojms.2016.63037⟩ |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cf322b081a4c925a2dc3d97872bb7727 https://hal.archives-ouvertes.fr/hal-02566607 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....cf322b081a4c925a2dc3d97872bb7727 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 21617384 21617392 |
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| DOI: | 10.4236/ojms.2016.63037⟩ |