Empirical glacier mass-balance models for South America

We investigate relationships between synoptic-scale atmospheric variability and the mass-balance of 13 Andean glaciers (located 16-55 degrees S) using Pearson correlation coefficients (PCCs) and multiple regressions. We then train empirical glacier mass-balance models (EGMs) in a cross-validated multiple regression procedure for each glacier. We find four distinct glaciological zones with regard to their climatic controls: (1) The mass-balance of the Outer Tropics glaciers is linked to temperature and the El Nino-Southern Oscillation (PCC <= 0.6), (2) glaciers of the Desert Andes are mainly controlled by zonal wind intensity (PCC <= 0.9) and the Antarctic Oscillation (PCC <= 0.6), (3) the mass-balance of the Central Andes glaciers is primarily correlated with precipitation anomalies (PCC <= 0.8), and (4) the glacier of the Fuegian Andes is controlled by winter precipitation (PCC approximate to 0.7) and summer temperature (PCC approximate to -0.9). Mass-balance data in the Lakes District and Patagonian Andes zones, where most glaciers are located, are too sparse for a robust detection of synoptic-scale climatic controls. The EGMs yield R-2 values of similar to 0.45 on average and <= 0.74 for the glaciers of the Desert Andes. The EGMs presented here do not consider glacier dynamics or geometry and are therefore only suitable for short-term predictions.

Automated summary

This study investigates the relationships between global-scale atmospheric variability and the mass-balance of Andean glaciers. Four distinct glaciological zones are identified based on their climatic controls. Empirical glacier mass-balance models are trained to predict the short-term mass-balance of the glaciers.