The Main Hydrological Features of Patagonia´s Santa Cruz River: An Updated Assessment

Abstract

Patagonia’s Santa Cruz River exhibits the second largest discharge in the region (i.e. ~23 km3 y−1) and an outstanding runoff (i.e. ~1500 mm y−1). Several glaciers with accumulation zones in the Southern Patagonia Ice field calve into two large proglacial lakes, Argentino (~1400 km2) and Viedma (~1100 km2), which are themain Santa Cruz River water sources. Trend analyses of the 1955–2020 discharge series have shown a previously undetected positive trend, possibly established during the last decade. The months with significantly increased discharge (i.e. August– December) suggest that the augmented water volume is supplied by snow/ice melt determined by the current global climate change. Harmonic analysis led to discard the previously suggested connectionwith the SouthernAnnular Mode, but reinforced the earlier evidence of an operating remote connection with El Niño Southern Oscillation, which possibly influences river discharge by promoting the ice-dam rupture mechanism which periodically operates in the Perito Moreno glacier.