Last Glacial Maximum temperatures over the North Atlantic, Europe and western Siberia: a comparison between PMIP models, MARGO sea–surface temperatures and pollen-based reconstructions

Kageyama, Masa; Laîné, Alexandre; Abe‐Ouchi, Ayako; Braconnot, Pascale; Cortijo, Elsa; Crucifix, Michel; Vernal, Anne de; Guiot, Joël

doi:10.1016/j.quascirev.2006.02.010

Cited by 186 publications

(164 citation statements)

References 65 publications

Supporting

Mentioning

139

Contrasting

Order By: Relevance

“…They reproduce the south-west to north-east temperature gradient, with a decrease of MTCO cooling from Europe to Siberia, and the absence of significant MTWA gradient, as in the PMIP1 and PMIP2 model-pollen data comparisons carried out by Kageyama et al (2001Kageyama et al ( , 2006. Our results show a better agreement with the data, in particular over Western Europe, as we include the vegetation contribution, not taken into account in the PMIP1 simulations.…”

Section: Consistency With Palaeo Datasupporting

confidence: 67%

Impacts of land surface properties and atmospheric CO<sub>2</sub> on the Last Glacial Maximum climate: a factor separation analysis

Henrot¹,

François

Brewer

et al. 2009

Clim. Past

View full text Add to dashboard Cite

Abstract. Many sensitivity studies have been carried out, using climate models of different degrees of complexity to test the climate response to Last Glacial Maximum boundary conditions. Here, instead of adding the forcings successively as in most previous studies, we applied the separation method of U. Stein et P. Alpert 1993, in order to determine rigorously the different contributions of the boundary condition modifications, and isolate the pure contributions from the interactions among the forcings. We carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the ice sheet expansion and elevation, the lowering of the atmospheric CO 2 and of the vegetation cover change on the LGM climate.The separation of the ice cover and orographic contributions shows that the ice albedo effect is the main contributor to the cooling of the Northern Hemisphere, whereas orography has only a local cooling impact over the ice sheets. The expansion of ice cover in the Northern Hemisphere causes a disruption of the tropical precipitation, and a southward shift of the ITCZ. The orographic forcing mainly contributes to the disruption of the atmospheric circulation in the Northern Hemisphere, leading to a redistribution of the precipitation, but weakly impacts the tropics. The isolated vegetation contribution also induces strong cooling over the continents of the Northern Hemisphere that further affects the tropical precipitation and reinforce the southward shift of the ITCZ, when combined with the ice forcing. The combinations of the forcings generate many non-linear interactions that reinforce or weaken the pure contributions, depending on the climatic mechanism involved, but they are generally weakerCorrespondence to: A.-J. Henrot (alexandra.henrot@ulg.ac.be) than the pure contributions. Finally, the comparison between the LGM simulated climate and climatic reconstructions over Eurasia suggests that our results reproduce well the southwest to north-east temperature gradients over Eurasia.

show abstract

Section: Consistency With Palaeo Datasupporting

confidence: 67%

Impacts of land surface properties and atmospheric CO<sub>2</sub> on the Last Glacial Maximum climate: a factor separation analysis

Henrot¹,

François

Brewer

et al. 2009

Clim. Past

View full text Add to dashboard Cite

show abstract

“…The modeled sea ice distribution produces sea ice all year round in the Nordic Seas, while this area is thought to have been seasonally ice-free [Pflaumann et al, 2003;Kucera et al, 2005], which also indicates our model is too cold in the northern North Atlantic. Other coupled atmosphere-ocean models from the PMIP project have similar problems obtaining LGM-PD temperature anomalies similar to those of MARGO [Kageyama et al, 2006]. In these PMIP simulations the main area of LGM-PD cooling is not over Europe as is the case in the MARGO reconstruction.…”

Section: Climate Modelmentioning

confidence: 69%

“…The possible cold bias in the CLIMAP reconstructions can influence our model results through the wind stress. This has been seen in the PMIP project, where the use of CLIMAP SST data as a boundary condition in atmospheric GCMs leads to sea surface temperatures (from slab ocean models) that are more consistent with CLIMAP than MARGO data [Kageyama et al, 2006].…”

Section: Climate Modelmentioning

confidence: 85%

Sensitivity of the glacial ocean to Heinrich events from different iceberg sources, as modeled by a coupled atmosphere‐iceberg‐ocean model

2008

View full text Add to dashboard Cite

[1] We introduce explicit icebergs from a dynamic and thermodynamic iceberg model into an intermediate complexity climate model, which includes the coupled atmosphere-ocean system. This modeling approach allows iceberg meltwater to be injected into the ocean on the basis of thermodynamical considerations along the iceberg trajectories. Icebergs are seeded from known ice sheets in both hemispheres. Adding icebergs to the present-day climate model has a minimal impact, but during the Last Glacial Maximum (LGM), Atlantic overturning strength is reduced by a third, while producing a model state that is consistent with a steady state climate. We test the sensitivity of the model at the LGM to additional Heinrich event-scale fluxes of icebergs from three possible sources: Hudson Strait, the Gulf of Saint Lawrence, and the Norwegian Channel Ice Stream (NCIS). The sensitivity of the ocean is similar for all locations, with differences dominated by the length of the iceberg meltwater pathways to the main ocean convection region. The NCIS events result in more variability and a distinctly different, more northerly, salinity anomaly. We compare these results to a more typical modeling approach, whereby meltwater is injected directly into the ocean at the iceberg source locations, and find that these floods overestimate the oceanic response compared to the iceberg events. Our results suggest that 0.3-0.4 Sv of additional freshwater flux, either as icebergs or freshwater, is required to shut down the North Atlantic meridional overturning, a larger freshwater flux than sometimes suggested because of the localized nature of the release of the freshwater.Citation: Levine, R. C., and G. R. Bigg (2008), Sensitivity of the glacial ocean to Heinrich events from different iceberg sources, as modeled by a coupled atmosphere-iceberg-ocean model, Paleoceanography, 23, PA4213,

show abstract

“…These Patella SST records indicate that both the absolute SST and the seasonal distribution of SST in current model outputs for the LGM (Kageyama et al, 2006) are not well represented. Six models run during PMIP2 (Braconnot et al, 2007) show a cooling of~3.5°C in summer SST and~3°C in winter SST at 21 kyrs BP relative to presentday model runs (Supplementary Fig.…”

Section: Past Seasonality In Sst At Gibraltarmentioning

confidence: 94%

Increased seasonality in the Western Mediterranean during the last glacial from limpet shell geochemistry

Ferguson

Henderson

et al. 2011

Earth and Planetary Science Letters

View full text Add to dashboard Cite

Editor: P. DeMenocalKeywords: mollusc seasonality Gibraltar palaeoclimate oxygen isotopesThe seasonal cycle is a fundamental aspect of climate, with a significant influence on mean climate and on human societies. Assessing seasonality in different climate states is therefore important but, outside the tropics, very few palaeoclimate records with seasonal resolution exist and there are currently no glacial-age seasonal-resolution sea-surface-temperature (SST) records at mid to high latitudes. Here we show that both Mg/Ca and oxygen isotope (δ 18 O) ratios in modern limpet (Patella) shells record the seasonal range of SST in the western Mediterranean -a region particularly susceptible to seasonal change. Analysis of a suite of fossil limpet shells from Gibraltar shows that SST seasonality was greater during the last glacial by~2°C as a result of greater winter cooling. These extra-tropical seasonal-resolution SST records for the last glacial suggest that the presence of large ice-sheets in the northern hemisphere enhances winter cooling. This result also indicates that seasonality in the Mediterranean is not well-represented in most palaeoclimate models, which typically show little change in seasonal amplitude, and provides a new test for the accuracy of climate models.

show abstract

Last Glacial Maximum temperatures over the North Atlantic, Europe and western Siberia: a comparison between PMIP models, MARGO sea–surface temperatures and pollen-based reconstructions

Cited by 186 publications

References 65 publications

Impacts of land surface properties and atmospheric CO<sub>2</sub> on the Last Glacial Maximum climate: a factor separation analysis

Impacts of land surface properties and atmospheric CO<sub>2</sub> on the Last Glacial Maximum climate: a factor separation analysis

Sensitivity of the glacial ocean to Heinrich events from different iceberg sources, as modeled by a coupled atmosphere‐iceberg‐ocean model

Increased seasonality in the Western Mediterranean during the last glacial from limpet shell geochemistry

Contact Info

Product

Resources

About

Last Glacial Maximum temperatures over the North Atlantic, Europe and western Siberia: a comparison between PMIP models, MARGO sea–surface temperatures and pollen-based reconstructions

Cited by 186 publications

References 65 publications

Impacts of land surface properties and atmospheric CO&lt;sub&gt;2&lt;/sub&gt; on the Last Glacial Maximum climate: a factor separation analysis

Impacts of land surface properties and atmospheric CO&lt;sub&gt;2&lt;/sub&gt; on the Last Glacial Maximum climate: a factor separation analysis

Sensitivity of the glacial ocean to Heinrich events from different iceberg sources, as modeled by a coupled atmosphere‐iceberg‐ocean model

Increased seasonality in the Western Mediterranean during the last glacial from limpet shell geochemistry

Contact Info

Product

Resources

About

Impacts of land surface properties and atmospheric CO<sub>2</sub> on the Last Glacial Maximum climate: a factor separation analysis

Impacts of land surface properties and atmospheric CO<sub>2</sub> on the Last Glacial Maximum climate: a factor separation analysis