  Removing the North Pacific halocline: effects on global climate, ocean circulation and the carbon cycle; ; et al in Deep-Sea Research Part II, Topical Studies in Oceanography (2012), 61-64 Detailed reference viewed: 13 (2 ULg)Variability in North Pacific intermediate and deep water ventilation during Heinrich events in two coupled climate models; ; et al in Deep-Sea Research Part II, Topical Studies in Oceanography (2012), 61-64 Detailed reference viewed: 7 (0 ULg)Deconstructing the Last Glacial Termination: the role of millennial and orbital-scale forcings; ; et al in Quaternary Science Reviews (2011), 30 Detailed reference viewed: 5 (0 ULg)Climate and biogeochemical response to a rapid melting of the West-Antarctic Ice Sheet during interglacials and implications for future climate; ; et al in Paleoceanography (2010), 25 Detailed reference viewed: 8 (1 ULg)Deep Water Formation in the North Pacific during the Last Glacial Termination; ; et al in Science (2010), 329 Detailed reference viewed: 38 (9 ULg)The mechanism behind internally generated centennial-to-millennial scale climate variability in an earth system model of intermediate complexity; ; et al in Geoscientific Model Development (2010), 3(2), 377--389 Detailed reference viewed: 8 (0 ULg)Biogeochemical changes in the North Pacific in response to a shut down of the Atlantic meridional overturning; ; et al Conference (2009, May) Detailed reference viewed: 1 (0 ULg)Climate and marine carbon cycle response to changes in the strength of the Southern Hemispheric westerlies; ; Mouchet, Anne  et alin Paleoceanography (2008), 23(4), It has been previously suggested that changes in the strength and position of the Southern Hemisphere westerlies could be a key contributor to glacial-interglacial atmospheric CO2 variations. To test this ... [more ▼] It has been previously suggested that changes in the strength and position of the Southern Hemisphere westerlies could be a key contributor to glacial-interglacial atmospheric CO2 variations. To test this hypothesis, we perform a series of sensitivity experiments using an Earth system model of intermediate complexity. A strengthening of the climatological mean surface winds over the Southern Ocean induces stronger upwelling and increases the formation of Antarctic Bottom Water. Enhanced Ekman pumping brings more dissolved inorganic carbon (DIC)-rich waters to the surface. However, the stronger upwelling also supplies more nutrients to the surface, thereby enhancing marine export production in the Southern Hemisphere and decreasing the DIC content in the euphotic zone. The net response is a small atmospheric CO2 increase (similar to 5 ppmv) compared to the full glacial-interglacial CO2 amplitude of similar to 90 ppmv. Roughly the opposite results are obtained for a weakening of the Southern Hemisphere westerly winds. [less ▲] Detailed reference viewed: 10 (0 ULg)Meridional reorganizations of marine and terrestrial productivity during Heinrich events,; ; Mouchet, Anne et alin Paleoceanography (2008), 23 To study the response of the global carbon cycle to a weakening of the Atlantic Meridional Overturning Circulation (AMOC), a series of freshwater perturbation experiments is conducted both under ... [more ▼] To study the response of the global carbon cycle to a weakening of the Atlantic Meridional Overturning Circulation (AMOC), a series of freshwater perturbation experiments is conducted both under preindustrial and glacial conditions using the earth system model of intermediate complexity LOVECLIM. A shutdown of the AMOC leads to substantial cooling of the North Atlantic, a weak warming of the Southern Hemisphere, intensification of the northeasterly trade winds, and a southward shift of the Intertropical Convergence Zone (ITCZ). Trade wind anomalies change upwelling in the tropical oceans and hence marine productivity. Furthermore, hydrological changes associated with a southward displacement of the ITCZ lead to a reduction of terrestrial carbon stocks mainly in northern Africa and northern South America in agreement with paleoproxy data. In the freshwater perturbation experiments the ocean acts as a sink of CO2, primarily through increased solubility. The net atmospheric CO2 anomaly induced by a shutdown of the AMOC amounts to about +15 ppmv and −10 ppmv for preindustrial and glacial conditions, respectively. This background state dependence can be explained by the fact that the glacial climate is drier and the terrestrial vegetation therefore releases a smaller amount of carbon to the atmosphere. This study demonstrates that the net CO2 response to large-scale ocean circulation changes has significant contributions both from the terrestrial and marine carbon cycle. [less ▲] Detailed reference viewed: 24 (0 ULg) |
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