A regional water balance indicator inferred from satellite images of an Andean endorheic basin in central-western Argentina

FACUNDO ROJAS; JUAN ANTONIO RIVERA; RICARDO VILLALBA; LUCAS BIANCHI; MAURO BRITOS NAVARRO

HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES HYDROLOGIQUES

IAHS PRESS

Lugar: Wallingford; Año: 2017 vol. 62 p. 533 - 545

0262-6667

In the Central Andes of Argentina (30°?37°S), snowmelting is the main source of freshwater, an essential natural resource for ~2.2 million people in the adjacent arid lowlands. In this region, Laguna Llancanelo collects the water inputs from the Malargüe endorheic basin. Previous studies concerning the annual and intra-annual variations of this lagoon and its relationships with regional climate are rare. We obtained a monthly record of Laguna Llancanelo Area (LLA, 1984-2013) using the Modified Normalized Difference Water Index derived from Landsat images. Monthly LLA ranges between 35 and 411 km2 and is significantly related to Río Malargüe variations, the main snow-fed tributary river to the lagoon. There is no long-term relationships between LLA and local rainfalls, but rapid increases in LLA result from heavy rainfalls around the lagoon. Conversely, rapid reductions in LLA encompass periods with both reduced discharge from Río Malargüe and low local rainfalls. The LLA integrates moisture from both Pacific (snowfall in the upper Andes) and Atlantic (lowland rainfalls) origins; therefore, we propose to use LLA as an indicator of regional water balance.