1. Atmosphere–cryosphere interactions during the last phase of the Last Glacial Maximum (21 ka) in the European AlpsCostanza Del Gobbo, Renato R. Colucci, Giovanni Monegato, Manja Žebre, Filippo Giorgi, 2023, original scientific article Abstract: 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.
Keywords: Quaternary, ice age, atmosphere, glaciers, climate change, the Alps
Published in DiRROS: 19.09.2023; Views: 333; Downloads: 118
 Full text (10,56 MB) |
2. An early glacial maximum during the last glacial cycle on the northern Velebit Mt. (Croatia)Manja Žebre, Mehmet Akif Sarikaya, Uroš Stepišnik, Renato R. Colucci, Cengiz Yildirim, Attila Çiner, Adem Candaş, Igor Vlahović, Bruno Tomljenović, Bojan Matoš, Klaus M. Wilcken, 2021, original scientific article Abstract: Comprehensive glacial Quaternary studies involving geochronological methods, modelling of ice topography with the support of field geomorphological and geological data in the Balkan Peninsula are relatively scarce, although there is evidence of past glaciations in several mountain ranges. Here, we present research on the extent and timing of past glaciations on the northern Velebit Mt. in coastal Croatia and inferences of the climate during that time. Based on geomorphological and sedimentological evidence and using cosmogenic 36Cl surface exposure dating of moraine boulders, we provide an empirical reconstruction of past glaciers and compare this with the Parallel Ice Sheet Model (PISM) simulations under different palaeoclimate forcings. The dating results show that the northern Velebit glaciers reached their maximum extent during the last glacial cycle before the global Last Glacial Maximum (LGM). Maximum ice extent likely correlates with Marine Isotope Stage 5–4, although the exact timing cannot be determined at this point due to poorly known site- and time-specific denudation rates. Empirical reconstruction of the maximum extent suggests that the area covered by glaciers was ~116 km2. The-best fit PISM simulation indicates that the most likely palaeoclimate scenario for the glaciers of this size to form is a cooling of ~8 °C and a 10% reduction in precipitation from present-day levels. However, the best-fit simulation does not correctly model all mapped ice margins when changes in climatological parameters are applied uniformly across the model domain, potentially reflecting a different palaeoprecipitation pattern to today.
Keywords: Pleistocene, cosmogenic isotopes, glacial geomorphology, Dinarides, PISM
Published in DiRROS: 04.03.2022; Views: 626; Downloads: 248
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