Recent geodetic mass balance of Monte Tronador glaciers, Northern Patagonain Andes

RUIZ, L.; BERTHIER, E.; VIALE, M. ; PITTE, P.; MASIOKAS, M.

The Cryosphere

Copernicus Publications on behalf of the European Geosciences Union

Año: 2017 vol. 11 p. 619 - 634

1994-0416

Glaciers inthe northern Patagonian Andes (35?46 S) have shown a dramatic decline in areain the last decades. However, little is known about glacier mass balancechanges in this region. This study presents a geodetic mass balance estimate ofMonte Tronador (41.15 S; 71.88 W) glaciers by comparing a Pléiades digitalelevation model (DEM) acquired in 2012 with the Shuttle Radar Topography Mission(SRTM) X-band DEM acquired in 2000. We find a slightly negative Monte-Tronador-wide mass budget of -0.17mw.e. a-1 (ranging from -0.54 to 0.14mw.e. a-1 for individual glaciers) and aslightly negative trend in glacier extent (-0.16%a-1) over the 2000?2012period. With a few exceptions, debris-covered valley glaciers thatdescend below a bedrock cliff are losing mass at higher rates, while mountainglaciers with termini located above this cliff are closer to mass equilibrium.Climate variations over the last decades show a notable increase in warm seasontemperatures in the late 1970s but limited warming afterwards. These warmerconditions combined with an overall drying trend may explain the moderate icemass loss observed at Monte Tronador. The almost balanced mass budget of mountainglaciers suggests that they are probably approaching a dynamic equilibrium withcurrent (post-1977) climate, whereas the valley glaciers tongues will continueto retreat. The slightly negative overall mass budget of Monte Tronador glacierscontrasts with the highly negative mass balance estimates observed in thePatagonian ice fields further south