Effect of sea-level lowering on ELA depression during the LGM

摘要: Abstract Decreases in equilibrium-line altitudes (ELAs) varied geographically during the last glacial maximum (LGM), with a mid-range value of ~ 900 m commonly deduced from altitude ratio and accumulation–area calculations. Sea level, however, was 120 m lower LGM, so ELA lowering relative to sea level would only be 780 m for 900-m absolute lowering. With lapse rate 0.006°C m−1, this implies 4.7°C global temperature. It has been argued that correction sea-level change is unnecessary, but logic on which based requires adiabatic compression apply over much longer time scales than typically invoked. We find necessary. In addition, geometric changes atmosphere pointed out by Osmaston (2006), could lead 0.4°C decrease average temperature troposphere. Additionally, orographic effects significantly snow distribution mountain masses near level.