North-Atlantic millennial-timescale variability imprint on Western European loess deposits: a modeling study
Abstract
We test if the dust cycle response to the North-Atlantic abrupt climate changes, the Dansgaard-Oeschger (DO) and Heinrich (H) events, could have led to the recording of these events in the Western European loess deposits. The LMDZ AGCM is used to simulate a reference glacial state "DOS", assimilated to a DO stadial, a cold perturbation "HE", resembling a H event, and a warm perturbation "DOI", assimilated to a DO interstadial. The reference state corresponds to the 40-kyr BP context, in the middle of the typical glacial period (75-15 kyr BP). The two perturbations are obtained by applying cold, respectively warm anomalies of up to 2°C to the North-Atlantic surface temperatures in the latitudinal band 30°- 63°N. The simulated climates are compared from the point of view of dust emission, with a focus on the English Channel and the south of the North Sea (ECSNS), important dust sources for the Western European loess deposits. When only considering the changes in wind, precipitation, soil moisture and snow cover over the ECSNS and loess deposit areas, the differences of dust emission flux between the simulations are small, in contradiction with the observed stadial-interstadial loess sedimentation rate variations. However, when including the vegetation effect of inhibiting the eolian erosion, the three climates are clearly differentiated, the dust flux for DOI becoming less than half of that for DOS and HE. This shows that vegetation changes have played a key role in the stadial-interstadial dust cycle variations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMPP12A..07S
- Keywords:
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- 4901 Abrupt/rapid climate change (1605);
- 4904 Atmospheric transport and circulation;
- 4914 Continental climate records;
- 4926 Glacial;
- 4960 Stadial