Recent geodetic mass balance of Monte Tronador glaciers, northern Patagonian Andes

RUIZ, LUCAS; BERTHIER, E.; VIALE, MAXIMILANO; PITTE, P.; MASIOKAS, M.H.

The Cryosphere

Copernicus Publications

Lugar: Munich; Año: 2017 vol. 11 p. 619 - 634

1994-0416

Glaciers in the northern Patagonian Andes (35?46 °S) have shown a dramatic decline in area in the last decades. However, little is known about glacier mass balance changes in this region. This study presents a geodetic mass balance estimate of Monte Tronador (41.15 °S; 71.88 °W) glaciers by comparing a Pléiades digital elevation model (DEM) acquired in 2012 with the Shuttle Radar TopographyMission (SRTM) X-band DEM acquired in 2000. We find a slightly negative Monte-Tronador-wide mass budget of -0.17 m w.e./year (ranging from -0.54 to 0.14 m w.e./year for individual glaciers) and a slightly negative trend in glacierextent (-0.16 %/year over the 2000?2012 period. With a few exceptions, debris-covered valley glaciers that descend below a bedrock cliff are losing mass at higher rates, while mountain glaciers with termini located above this cliff arecloser to mass equilibrium. Climate variations over the last decades show a notable increase in warm season temperatures in the late 1970s but limited warming afterwards. These warmer conditions combined with an overall dryingtrend may explain the moderate ice mass loss observed at Monte Tronador. The almost balanced mass budget of mountain glaciers suggests that they are probably approaching a dynamic equilibrium with current (post-1977) climate, whereas the valley glaciers tongues will continue to retreat. The slightly negative overall mass budget of Monte Tronador glaciers contrasts with the highly negative mass balance estimates observed in the Patagonian ice fields further south.