Glacier albedo reduction and drought effects in the extratropical Andes, 1986-2020

Shaw, Thomas E.; Ulloa, Genesis; Farias-Barahona, David; Fernandez, Rodrigo; Lattus, Jose M.; McPhee, James

Abstract

Surface albedo typically dominates the mass balance of mountain glaciers, though long-term trends and patterns of glacier albedo are seldom explored. We calculated broadband shortwave albedo for glaciers in the central Chilean Andes (33-34 degrees S) using end-of-summer Landsat scenes between 1986 and 2020. We found a high inter-annual variability of glacier-wide albedo that is largely a function of the glacier fractional snow-covered area and the total precipitation of the preceding hydrological year (up to 69% of the inter-annual variance explained). Under the 2010-2020 'Mega Drought' period, the mean albedo, regionally averaged ranging from similar to 0.25-0.5, decreased by -0.05 on average relative to 1986-2009, with the greatest reduction occurring 3500-5000 m a.s.l. In 2020, differences relative to 1986-2009 were -0.14 on average as a result of near-complete absence of late summer snow cover and the driest hydrological year since the Landsat observation period began (similar to 90% reduction of annual precipitation relative to the 1986-2009 period). We found statistically significant, negative trends in glacier ice albedo of up to -0.03 per decade, a trend that would have serious implications for the future water security of the region, because glacier ice melt acts to buffer streamflow shortages under severe drought conditions.

Más información

Título según WOS: Glacier albedo reduction and drought effects in the extratropical Andes, 1986-2020
Título de la Revista: JOURNAL OF GLACIOLOGY
Volumen: 67
Número: 261
Editorial: CAMBRIDGE UNIV PRESS
Fecha de publicación: 2021
Página de inicio: 158
Página final: 169
DOI:

10.1017/JOG.2020.102

Notas: ISI