Geodetic mass balance of three glaciers in the Monte San Lorenzo (Patagonian Andes) from 1958 to 2018

LENZANO M. G; RIVERA, ANDRÉS; FALASCHI, DANIEL; BOLCH, TOBIAS; VILLALBA, R; LO VECCHIO, ANDRES

San Francisco

Encuentro; AGU Fall Meeting; 2019

American Geophysical Union

A better understanding of long-term glacier changes in the Patagonian Andes is presently limited by the lack of prolonged observation series. Here we present six-decade geodetic mass and area changes of three valley glaciers in Monte San Lorenzo based on five digital elevation models derived from stereo aerial photos, the Shuttle Radar Topography Mission (SRTM) and stereo satellite imagery (SPOT5 and Pleiades) spanning the period 1958 - 2018. Mass balance was negative at all periods with an average mass loss of -1.35 ±0.08 m w.e. a-1. The 1981-2000 time interval showed the most negative mass budget among the studied glaciers, with an area-averaged mass loss of 1.67 ±0.11 m w.e. a-1 and a maximum of -2.23 ±0.07 m w.e.a−1 at San Lorenzo Sur glacier. Contemporarily, the total glacier area loss between 1958 and 2018 was 14.2 ±0.7 km2 (23 ±1.1 % or 0.4 ±0.02 % a-1). To put the results into a broader context, we calculated the mass balance of other 15 glaciers in the Monte San Lorenzo massif since 2000. We found decreasing mass loss of -0.13 ±0.21 m w.e.a−1 for the period 2012 ? 2018 after a loss of -0.31 ±0.16 m w.e.a−1 for the same glaciers between 2000 and 2012, whereas for the three valley glaciers the mass budget remained mainly unchanged (-1.37 ±0.06 m w.e. a-1 and ?1.36 ±0.17 m w.e. a-1) for the same periods.