| Titre | Freshwater forcing modified the Labrador Current vigor and northwest Atlantic slope waters during the Little Ice Age and Medieval Climate Anomaly |
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| Auteur | Rashid, H; Xu, Y; Li, G; Zhu, M; Xing, J; Piper, D |
| Source | 20th EGU General Assembly, EGU2018, proceedings; 2018 p. 11257  Accès ouvert |
| Liens | Online - En ligne
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| Image |  |
| Année | 2018 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20180312 |
| Éditeur | European Geophysical Union |
| Réunion | EGU2018: 20th European Geophysical Union General Assembly; Vienna; AT; avril 4-13, 2018 |
| Document | site Web |
| Lang. | anglais |
| Media | papier; en ligne; numérique |
| Formats | html; pdf |
| Province | Région extracotière du nord; Terre-Neuve-et-Labrador |
| SNRC | 14; 15; 16; 24; 25; 26; 27 |
| Région | Labrador; Mer du Labrador; Fram Strait; Détroit de Davis; Détroit d'Hudson |
| Lat/Long OENS | -70.0000 10.0000 81.0000 59.0000 |
| Sujets | courants; circulation du courant; marges continentales; talus continental; climatologie; mécanismes de transport; Plate-Forme du Labrador; Eau douce; géologie marine; géologie de l'environnement; Nature
et environnement; Sciences et technologie |
| Programme | Géoscience en mer |
| Diffusé | 2018 04 01 |
| Résumé | (disponible en anglais seulement)
The Arctic witnessed unprecedented changes during the last millennium including the Little Ice Age (LIA) and Medieval Climate Anomaly (MCA) resulting in changes
due to freshwater transport through Fram, Davis and Hudson straits into the Labrador Sea. A change in the freshwater supply is hypothesized to weaken/strengthen the Labrador Current vigor and perturbed the Atlantic meridional overturning circulation
(AMOC). Understanding the impact of Labrador Current in providing freshwater to the North Atlantic is pivotal due to its role in modulating the AMOC. However, the extent to which the freshwater changed the Labrador Current vigor during the LIA and
MCA is unknown due simply to the lack of high resolution and quantitative data. Moreover, studies suggested (e.g., Keigwin et al., 2003) no changes on the vast eastern Canadian continental margin shelf and slope waters during the LIA and MCA. Here we
used two sediment cores from the eastern Canadian continental margin which were retrieved from the Labrador shelf and upper slope that are bathed by the Labrador Current to reconstruct changes during the LIA and MCA. The Labrador Current vigor was
reconstructed using dynamic sediment proxy for the past 1,620 years. In addition, two sea-surface temperature proxies were also used to reconstruct the accompanied changes from the same samples. The data suggest that the Labrador Current was vigorous
during the LIA due to increased freshwater delivery into the Labrador Sea. Further, the MCA and LIA cooled and warmed the slope waters but warmed and cooled the offshore Labrador Sea. We also report the Late Antique Little Ice Age cooling event
nested within the poorly constrained Dark Ages Cold Period from the northwest Atlantic coinciding with the onset, establishment, and reorganization of many human settlements (Büntgen et al., 2016) including the collapse of Chinese Wei dynasty.
Büntgen, U et al. (2016) Nature Geoscience 9, 231-236 Keigwin, LD et al. (2003) Climate Dynamics 21, 53-62. |
| Sommaire | (Résumé en langage clair et simple, non publié)
L'étude d'un échantillon à vitesse de sédimentation élevée des 1500 dernières années montre que les changements de vitesse du Courant du
Labrador influence les températures océaniques dans le sud de la passe Flamande. L'étude des variations spatiales des températures océaniques au large de Terre-Neuve durant la période chaude médiévale montre qu'il s'agit d'un analogue possible pour
le réchauffement planétaire à venir. |
| GEOSCAN ID | 313232 |
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