The effects of late Cenozoic climate change on the global distribution of frost cracking

[摘要] Frost cracking is a dominant mechanical weathering phenomenonfacilitating the breakdown of bedrock in periglacial regions. Despite recentadvances in understanding frost cracking processes, few studies haveaddressed how global climate change over the late Cenozoic may have impactedspatial variations in frost cracking intensity. In this study, we estimateglobal changes in frost cracking intensity (FCI) by segregation ice growth.Existing process-based models of FCI are applied in combination with soilthickness data from the Harmonized World Soil Database. Temporal and spatialvariations in FCI are predicted using surface temperature changes obtainedfrom ECHAM5 general circulation model simulations conducted for fourdifferent paleoclimate time slices. Time slices considered includepre-industrial ( ∼  1850 CE, PI), mid-Holocene ( ∼  6 ka, MH), Last Glacial Maximum ( ∼  21 ka, LGM), and Pliocene( ∼  3 Ma, PLIO) times. Results indicate for all paleoclimatetime slices that frost cracking was most prevalent (relative to PI times) inthe middle- to high-latitude regions, as well as high-elevation lower-latitudeareas such the Himalayas, Tibet, the European Alps, the Japanese Alps, the USRocky Mountains, and the Andes Mountains. The smallest deviations in frostcracking (relative to PI conditions) were observed in the MH simulation,which yielded slightly higher FCI values in most of the areas. In contrast,larger deviations were observed in the simulations of the colder climate(LGM) and warmer climate (PLIO). Our results indicate that the impact ofclimate change on frost cracking was most severe during the PI–LGM perioddue to higher differences in temperatures and glaciation at higherlatitudes. The PLIO results indicate low FCI in the Andes and higher valuesof FCI in Greenland and Canada due to the diminished extent of glaciation inthe warmer PLIO climate.

[学科分类] 土壤学