Atmosphere–cryosphere interactions during the last phase of the Last Glacial Maximum (21 ka) in the European Alps

• Published in: Climate of the past 2023-09, Vol.19 (9), p.1805-1823
• Main Authors: Del Gobbo, Costanza, Colucci, Renato R, Monegato, Giovanni, Zebre, Manja, Giorgi, Filippo
• Format: Article
• Language: English
• Subjects: Altitude; Climate change; Climate models; Climatic changes; Comparative analysis; Convection; Cryosphere; Foothills; Glacial drift; Glaciers; Ice sheets; Last Glacial Maximum; Low temperature; Moraines; Mountain glaciers; Palaeoclimate; Paleoclimate; Precipitation; Precipitation patterns; Regional climate models; Regional climates; Sea level; Simulation; Snowfall; Summer; Temperature
• ISSN: 1814-9332; 1814-9324; 1814-9332
• DOI: 10.5194/cp-19-1805-2023

Evidence that during the Last Glacial Maximum (LGM) glaciers extended well into the piedmont plains is still identifiable in the alpine foreland as a system of well-preserved moraines. Glaciers are strongly controlled by temperature and precipitation, and therefore, they are excellent indicators of climate change. Here, we use a regional climate model (RCM) to investigate some of the physical processes sustaining Alpine glaciers during the last phase of the LGM during Greenland Stadial 2 at 21 ka. We find a predominance of convection during summer and increased southwesterly stratiform precipitation over the southern Alps when compared to pre-industrial (PI) conditions. This precipitation pattern, along with lower temperatures, determined summer snowfall extending to low elevations, with a consequent substantial drop of the equilibrium line altitude (ELA), which is consistent with the estimated LGM glacier extent. Our RCM-based estimates of 21 ka ELA at the LGM yield excellent consistency with Alpine ELA reconstructions, further demonstrating the great potential of this technique for use in palaeoclimate studies.