High-resolution simulations of the last glacial maximum climate over Europe: a solution to discrepancies with continental palaeoclimatic reconstructions?
- First Online:
- 551 Downloads
The analyses of low-resolution models simulations of the last glacial maximum (LGM, 21 kyr BP) climate have revealed a large discrepancy between all the models and pollen-based palaeoclimatic reconstructions. In general, the models are too warm relative to the observations, especially in winter, where the difference is of the order of 10°C over western Europe. One of the causes of this discrepancy may be related to the low spatial resolution of these models. To assess the impact of using high-resolution models on simulated climate sensitivity, we use three approaches to obtain high-resolution climate simulations over Europe: first an atmospheric general circulation model (AGCM) with a stretched grid over Europe, second a homogeneous T106 AGCM (high resolution everywhere on the globe) and last a limited area model (LAM) nested in a low-resolution AGCM. With all three methods, we have performed simulations of the European climate for present and LGM conditions, according to the experimental design recommended by the Palaeoclimate Modeling Intercomparison Project (PMIP). Model results have been compared with updated pollen-based palaeoclimatic indicators for temperature and precipitation that were initially developed in PMIP. For each model, a low-resolution global run was also performed. As expected, the low-resolution simulations underestimate the large cooling indicated by pollen data, especially in winter, despite revised slightly warmer reconstructions of the temperatures of the coldest month, and show results in the range of those obtained in PMIP with similar models. The two high-resolution AGCMs do not improve the temperature field and cannot account for the discrepancy between model results and data, especially in winter. However, they are able to reproduce trends in precipitation more closely than their low-resolution counterparts do, but the simulated climates are still not as arid as depicted by the data. Conversely, the LAM temperature results compare well with climate reconstructions in winter but the simulated hydrological cycle is not consistent with the data. Finally, these results are discussed in regard of other possible causes for discrepancies between models and palaeoclimatic reconstructions for the LGM European climate.
- Beaudouin C (2003) Effets du dernier cycle sur la végétation de la basse vallée du Rhône et sur la sédimentation de la plate-forme du golfe du Lion d’après la palynologie. PhD Thesis, Claude Bernard University of Lyon 1, France 417 pGoogle Scholar
- Braconnot P, Joussaume S, Harrison SP, Hewitt C, Valdes PJ, Ramstein G, Stouffer RJ, Otto-Bliesner B, Taylor T (2003) The second phase of the Paleoclimate Modelling Intercomparison Project (PMIPII). Clivar ExchangesGoogle Scholar
- CLIMAP (1981) Seasonal reconstructions of the Earth’s surface at the last glacial maximum. Map Chart Series MC–36 Geological Society of America, Boulder, ColoradoGoogle Scholar
- Harrison SP, Braconnot P, Joussaume S, Hewitt C, Stouffer RJ (2002) Fourth international workshop of the Palaeoclimate Modelling Intercomparison Project (PMIP): launching PMIP Phase II. EosGoogle Scholar
- Joussaume S, Taylor KE (1995) Status of the Paleoclimate Modelling Intercomparison Project (PMIP). In: Proceedings of the first international AMIP scientific conference, Monterrey, California, USA, 15–19 May 1995, WRCP–92, pp 425–430Google Scholar
- Kageyama M, Harrison SP, Abe-Ouchi A (2004) The depression of tropical snowlines at the last glacial maximum: what can we learn from climate model experiments? Quatern Int (in press)Google Scholar
- Kislov AV, Tarasov PE, Sourkova GV (2002) Pollen and other proxy-based reconstructions and PMIP simulations of the last glacial maximum mean annual temperature: an attempt to harmonize the data-model comparison procedure. Acta Palaeontol Sinica 41:539–545Google Scholar
- Numaguti A, Takahashi M, Nakajima T, Sumi A (1997) Description of CCSR/NIES Atmospheric General Circulation Model. In: CGER’s Supercomputer Monograph Report, Center for Global Environmental Research, National Institute for Environmental Studies, vol3, pp 1–48Google Scholar
- Peyron O, Bégeot C, Brewer S, Heiri O, Magny M, Millet L, Ruffaldi P, Van Campo E, Yu G (2004) Lateglacial climate in the Jura Mountains (France) based on different quantitative reconstruction approaches from pollen, lake-levels, and chironomids. Q ResGoogle Scholar
- Poutou E (2003) Etude numérique du rôle des interactions entre la surface et l’atmosphère dans le cadre d’un changement climatique aux hautes latitudes nord. PhD Thesis, Joseph Fourier University of Grenoble 1, France 336 pGoogle Scholar
- Weinelt M, Sarnthein M, Pflaumann U, Schulz H, Jung S, Erlenkeuser H (1996) Ice-free nordic seas during the last glacial maximum? Potential sites of deepwater formation. Paleoclimates 1:283–309Google Scholar