Surface mass balance of the Northern Patagonian Ice Field and links with climate variability modes and atmospheric variables

Abstract Patagonia Icefields are large ice masses with a significant contribution to sea level rise among mountain glaciers in the Southern Hemisphere. In order to improve the estimation of the Northern Patagonia Icefield (NPI) surface mass balance and to better understand its relationship with climate variables and modes, we simulated the surface mass balance over the icefield during the period 1980–2014 with the MAR model. Model reliability was assessed against: weather stations, albedo from MODIS data and previous estimates of the San Rafael glacier’s surface mass balance. We obtain a surface mass balance of –2.48 ± 1.86 Gta –1 and a non-significant trend. Temperature (a physically downscaled variable) was a key variable through its direct impact on melting, but also on solid precipitation. We found that the annual, spring and autumn icefield mean surface mass balance had a significant negative correlation with the Southern Annular Mode (SAM) through air temperature. Over the next century, the impacts of greenhouse gas emissions are projected to keep the SAM in a positive phase and accelerate atmospheric warming. Thus, the NPI is expected to increase its mass loss and its contribution to future sea level rise. However, more in-situ data (precipitation, temperature and accumulation/ablation on the icefield) are needed to improve the projection’s uncertainty.