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Accueil du site → Master → Etats Unis → 2012 → Combined effects of global warming and a shutdown of the Atlantic meridional overturning circulation on West African and European climate

University of Texas at Austin (2012)

Combined effects of global warming and a shutdown of the Atlantic meridional overturning circulation on West African and European climate

Brown, Meredith Guenevere Longshore

Titre : Combined effects of global warming and a shutdown of the Atlantic meridional overturning circulation on West African and European climate

Auteur : Brown, Meredith Guenevere Longshore

Université de soutenance : University of Texas at Austin

Grade : Master of Science in Geological Sciences 2012

Résumé
The Atlantic meridional overturning circulation has a vast potential for abrupt climate change due to its large heat transport through the ocean and its nonlinear dynamics. Because of these unique properties, this paper investigates how the climate of West Africa and Europe will respond to a shutdown of the Atlantic meridional overturning circulation at the end of the 21st century. Here we use a regional climate model with 90-km grid spacing is forced by an idealized sea-surface temperature anomaly, based upon coupled atmosphere/ocean global model water hosing experiments, with a business-as-usual global warming scenario to discover how West African and European climate will change. In both the boreal spring and summer, cooling in the eastern Atlantic is associated with a strong intensification and eastward extension of the North Atlantic subtropical high over Europe throughout the depth of the atmosphere, a strengthening of the heat low over West Africa at low levels, and a weakening of the Saharan High in the upper atmosphere. Rainfall rates also decrease markedly throughout most of West Africa and Europe : in spring, rainfall rates decrease by 50-80% over Sahelian Africa, in summer rainfall over Europe decreases by up to 90%, while precipitation over West Africa is reduced by 40%.

Mots Clés : Global warming – Thermohaline — West Africa – Europe — End of 21st century

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Page publiée le 5 novembre 2012, mise à jour le 12 juillet 2018