Estimación de balance de masa del glaciar Echaurren Norte en el periodo 2020-2060

Abstract

This piece of research estimates the potential future behavior of the glacier mass balance in broadcast scenarios RCP 2,6 and RCP 8,5, between 2020 and 2060, in the Echaurren Norte glacier (ECHN), located in El Yeso basin, Region Metropolitana, Chile. Previous research has shown that ECHN has been losing mass through the years, marking between 1975 and 2016 an accumulation of -20 meters water equivalents (m w. eq.). One hypothesis to explain these results is the increase of temperatures and the decrease of precipitations in the central zone of Chile, emphasizing over the last decade with the so called megadrought. The data used to achieve the estimations came from climatic projections of temperature and precipitations on global models (BCC_CSM1-1, CCSM4, GISS-E2-H), taking as reference the RCP 2,6 and RCP 8,5 scenarios. The results show that the models BCC_CSM1-1 and CCSM4, for both RCP scenarios, have negative values of mass balance, following the currently observed behavior of glacier mass loss on ECHN. The model GISS-E2-H is the only one that estimates some years with positive mass balance values, the main difference compared to the other models is that this model registers precipitations through all the studied period. These results show how the modeled variables on the future could affect the glacier mass balance, and under what conditions it would be possible to obtain positive mass balances within the negative general trend, in this case with high dependence on the projected precipitations of the climate models.