The global hydroclimate response during the Younger Dryas event
To analyze the global hydroclimate response during the Younger Dryas cold event, we evaluate climate model results that have been constrained with proxy-based temperatures from the North Atlantic region. We find that both the temperature and the hydroclimate response have a clear global signature. A...
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Online Access: | http://hdl.handle.net/2078.1/200245 https://doi.org/10.1016/j.quascirev.2018.05.033 |
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ftunistlouisbrus:oai:dial.uclouvain.be:boreal:200245 2023-05-15T16:30:39+02:00 The global hydroclimate response during the Younger Dryas event Renssen, Hans Goosse, Hugues Roche, Didier Seppä, Heikki UCL - SST/ELI/ELIC - Earth & Climate 2018 http://hdl.handle.net/2078.1/200245 https://doi.org/10.1016/j.quascirev.2018.05.033 eng eng boreal:200245 http://hdl.handle.net/2078.1/200245 doi:10.1016/j.quascirev.2018.05.033 urn:ISSN:0277-3791 info:eu-repo/semantics/openAccess Quaternary science reviews, Vol. 193, p. 84-97 (2018) Global Paleoclimate modelling Younger Dryas Atmospheric chemistry Atmospheric movements Atmospheric radiation Climate change Climate models Glacial geology Soil moisture Tropics Atlantic meridional overturning circulations Atmospheric methanes Intertropical convergence zone Melt-water discharges North Atlantic Ocean Oceanography info:eu-repo/semantics/article 2018 ftunistlouisbrus https://doi.org/10.1016/j.quascirev.2018.05.033 2021-11-24T23:19:47Z To analyze the global hydroclimate response during the Younger Dryas cold event, we evaluate climate model results that have been constrained with proxy-based temperatures from the North Atlantic region. We find that both the temperature and the hydroclimate response have a clear global signature. A marked cooling is simulated over the North Atlantic Ocean (more than 5 °C) and the downwind continents (2–4 °C). This response is related to the weakening of the Atlantic meridional overturning circulation under influence of meltwater discharges. The hydroclimate response is most expressed over Eurasia in a belt between 40 and 60°N, and over Northern Africa in the Sahel region. In both areas, a strong decrease in soil moisture is simulated (up to 20% reduction). In contrast, a striking increase in moisture is found over southeastern North America (15% increase), where southerly atmospheric flow brings moist air to the continent. Outside these areas that are clearly affected by the cold North Atlantic Ocean, the responses of temperature and moisture are decoupled, with different causes for these temperature and hydroclimate responses. In the tropics, the hydroclimate response is governed by the southward shift of the intertropical convergence zone (ITCZ) due to the cooling of the North Atlantic Ocean. This causes drier conditions north of the equator and wetter conditions in the Southern Hemisphere tropics. The associated changes in soil moisture are relatively gradual here, taking up to two centuries to complete, suggesting that the impact of the ITCZ shift on the tropical hydroclimate is building up. Our experiment indicates that Southern Hemisphere continents experienced a small cooling (less than 0.5 °C) during the Younger Dryas, caused by the negative radiative forcing associated with reduced atmospheric methane concentrations and enhanced dust levels. In our simulation, the bi-polar seesaw mechanism is relatively weak, so that the associated warming of the South Atlantic Ocean is not overwhelming the reduction in radiative forcing. Our results thus indicate that in the tropics and/or Southern Hemisphere, the cooling is a response to the negative radiative forcing, while the hydroclimatic changes are predominantly resulting from ITCZ variations. Consequently, when interpreting hydroclimatic proxy records from these regions, data should not be compared directly to key records from high latitudes, such as Greenland ice core stable isotope records. © 2018 Elsevier Ltd Article in Journal/Newspaper Greenland Greenland ice core ice core North Atlantic South Atlantic Ocean DIAL@USL-B (Université Saint-Louis, Bruxelles) Greenland Quaternary Science Reviews 193 84 97 |
institution |
Open Polar |
collection |
DIAL@USL-B (Université Saint-Louis, Bruxelles) |
op_collection_id |
ftunistlouisbrus |
language |
English |
topic |
Global Paleoclimate modelling Younger Dryas Atmospheric chemistry Atmospheric movements Atmospheric radiation Climate change Climate models Glacial geology Soil moisture Tropics Atlantic meridional overturning circulations Atmospheric methanes Intertropical convergence zone Melt-water discharges North Atlantic Ocean Oceanography |
spellingShingle |
Global Paleoclimate modelling Younger Dryas Atmospheric chemistry Atmospheric movements Atmospheric radiation Climate change Climate models Glacial geology Soil moisture Tropics Atlantic meridional overturning circulations Atmospheric methanes Intertropical convergence zone Melt-water discharges North Atlantic Ocean Oceanography Renssen, Hans Goosse, Hugues Roche, Didier Seppä, Heikki The global hydroclimate response during the Younger Dryas event |
topic_facet |
Global Paleoclimate modelling Younger Dryas Atmospheric chemistry Atmospheric movements Atmospheric radiation Climate change Climate models Glacial geology Soil moisture Tropics Atlantic meridional overturning circulations Atmospheric methanes Intertropical convergence zone Melt-water discharges North Atlantic Ocean Oceanography |
description |
To analyze the global hydroclimate response during the Younger Dryas cold event, we evaluate climate model results that have been constrained with proxy-based temperatures from the North Atlantic region. We find that both the temperature and the hydroclimate response have a clear global signature. A marked cooling is simulated over the North Atlantic Ocean (more than 5 °C) and the downwind continents (2–4 °C). This response is related to the weakening of the Atlantic meridional overturning circulation under influence of meltwater discharges. The hydroclimate response is most expressed over Eurasia in a belt between 40 and 60°N, and over Northern Africa in the Sahel region. In both areas, a strong decrease in soil moisture is simulated (up to 20% reduction). In contrast, a striking increase in moisture is found over southeastern North America (15% increase), where southerly atmospheric flow brings moist air to the continent. Outside these areas that are clearly affected by the cold North Atlantic Ocean, the responses of temperature and moisture are decoupled, with different causes for these temperature and hydroclimate responses. In the tropics, the hydroclimate response is governed by the southward shift of the intertropical convergence zone (ITCZ) due to the cooling of the North Atlantic Ocean. This causes drier conditions north of the equator and wetter conditions in the Southern Hemisphere tropics. The associated changes in soil moisture are relatively gradual here, taking up to two centuries to complete, suggesting that the impact of the ITCZ shift on the tropical hydroclimate is building up. Our experiment indicates that Southern Hemisphere continents experienced a small cooling (less than 0.5 °C) during the Younger Dryas, caused by the negative radiative forcing associated with reduced atmospheric methane concentrations and enhanced dust levels. In our simulation, the bi-polar seesaw mechanism is relatively weak, so that the associated warming of the South Atlantic Ocean is not overwhelming the reduction in radiative forcing. Our results thus indicate that in the tropics and/or Southern Hemisphere, the cooling is a response to the negative radiative forcing, while the hydroclimatic changes are predominantly resulting from ITCZ variations. Consequently, when interpreting hydroclimatic proxy records from these regions, data should not be compared directly to key records from high latitudes, such as Greenland ice core stable isotope records. © 2018 Elsevier Ltd |
author2 |
UCL - SST/ELI/ELIC - Earth & Climate |
format |
Article in Journal/Newspaper |
author |
Renssen, Hans Goosse, Hugues Roche, Didier Seppä, Heikki |
author_facet |
Renssen, Hans Goosse, Hugues Roche, Didier Seppä, Heikki |
author_sort |
Renssen, Hans |
title |
The global hydroclimate response during the Younger Dryas event |
title_short |
The global hydroclimate response during the Younger Dryas event |
title_full |
The global hydroclimate response during the Younger Dryas event |
title_fullStr |
The global hydroclimate response during the Younger Dryas event |
title_full_unstemmed |
The global hydroclimate response during the Younger Dryas event |
title_sort |
global hydroclimate response during the younger dryas event |
publishDate |
2018 |
url |
http://hdl.handle.net/2078.1/200245 https://doi.org/10.1016/j.quascirev.2018.05.033 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Greenland ice core ice core North Atlantic South Atlantic Ocean |
genre_facet |
Greenland Greenland ice core ice core North Atlantic South Atlantic Ocean |
op_source |
Quaternary science reviews, Vol. 193, p. 84-97 (2018) |
op_relation |
boreal:200245 http://hdl.handle.net/2078.1/200245 doi:10.1016/j.quascirev.2018.05.033 urn:ISSN:0277-3791 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.quascirev.2018.05.033 |
container_title |
Quaternary Science Reviews |
container_volume |
193 |
container_start_page |
84 |
op_container_end_page |
97 |
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1766020393172205568 |