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

BIANCHI, LUCAS OSVALDO; RIVERA, JUAN A.; ROJAS, FACUNDO; BRITOS NAVARRO, MAURO; VILLALBA, RICARDO

HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES HYDROLOGIQUES

IAHS PRESS

Lugar: Wallingford, Oxfordshire; Año: 2016 vol. 62 p. 533 - 545

0262-6667

In the Central Andes of Argentina (30°?37°S), snowmelt 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 relationship 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 relationship between LLA and local rainfall, but rapid increases in LLA result from heavy rainfall around the lagoon. Conversely, rapid reductions in LLA encompass periods with both reduced discharge from Río Malargüe and low local rainfall. The LLA integrates moisture from both Pacific (snowfall in the upper Andes) and Atlantic (lowland rainfall) origins; therefore, we propose to use LLA as an indicator of regional water balance.