Huascaran . as an indicator of tropical climate during the Last Glacial Maximum

• Main Author: R. T. Pierrehumbert
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1999
• Subjects: ice core
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.41.7435; http://geosci.uchicago.edu/~rtp1/papers/GRLhuascaran/GL714W01.ps

. The interpretation of the isotopic composition of Andes tropical mountain glaciers is reconsidered using a simple Rayleigh distillation model. It is shown that Andes snowline depression and Huascaran ice core # 18 O are consistent with a 3 # C drop in sea surface temperature during the Last Glacial Maximum, accompanied by an increase from 40% at present to 60% during the LGM in the annual mean proportion of atmospheric water lost to continental runo#. Broecker's interpretation of Huascaran # 18 O as a paleo-hygrometer is discussed. 1. Introduction The behavior of the tropics during the Last Glacial Maximum (LGM) has emerged as a crucial test of models used to understand the climate system [Guilderson et al., 1994; Broecker, 1994, 1995; Broccoli and Manabe, 1987]. Tropical glaciers provide an important window into past behavior of this region. The Huascaran ice core recovered by [Thomp- son et al., 1995] represented a breakthrough, providing a continuous record of # 18 O in .