Pacific sea surface temperatures, Andean snowpack and water supply to the semi-arid regions of Chile and Argentina

The Andean snowpack is the primary water source for households, agriculture, industry, hydropower, and ecosystems in semi-arid central Chile and central-western Argentina. Analysis of regional composite data shows that winter snowpack and river streamflow are closely related and influenced by large-scale Pacific surface temperature changes. High snowpack and streamflow coincide with warm El Niño events, while most extreme dry years occur during cold La Niña events. Additionally, shifts in the Pacific Decadal Oscillation (PDO) in the mid-1940s and 1976-77 correspond to a 27% decrease and 28% increase in mean annual river discharges, respectively, suggesting the PDO causes low-frequency hydrologic variations. While lower PDO values in the late 1990s were not matched by streamflow records—possibly due to melting glaciers—the interplay between ENSO and PDO is highlighted as critical for improving water scarcity forecasts under a changing climate.

• Andean snowmelt serves as the primary water source for various sectors, including households, agriculture, industry, hydropower, and ecosystems in semi-arid central Chile and central-western Argentina, with snowmelt being the origin of most annual streamflow in this region.
• Winter snowpack and streamflow levels are linked to the El Niño-Southern Oscillation (ENSO), where warm El Niño years in the tropical Pacific correlate with high snowpack and streamflow, and cold La Niña events generally correlate with extreme dry years, with exceptions in 1968, 1990, and 2004.
• The Pacific Decadal Oscillation (PDO) influences low-frequency hydrologic variations in the Andes of central Chile and Argentina; specifically, PDO shifts in the mid-1940s and 1976-77 coincided with a 27% decrease and 28% increase in mean annual river discharges, respectively.
• Regional streamflow records did not match the lower PDO values observed in the late 1990s, which the document suggests might be caused by an increasing contribution from melting glaciers.

APA

Inter-American Institute for Global Change Research (2012). Pacific sea surface temperatures, Andean snowpack and water supply to the semi-arid regions of Chile and Argentina. https://iai.int/admin/site/sites/default/files/uploads/2014/06/snapshot10_EN.pdf

Chicago

Inter-American Institute for Global Change Research. Pacific sea surface temperatures, Andean snowpack and water supply to the semi-arid regions of Chile and Argentina. 2012. https://iai.int/admin/site/sites/default/files/uploads/2014/06/snapshot10_EN.pdf.

Wikipedia

{{cite report |author=Inter-American Institute for Global Change Research |title=Pacific sea surface temperatures, Andean snowpack and water supply to the semi-arid regions of Chile and Argentina |date=2012 |url=https://iai.int/admin/site/sites/default/files/uploads/2014/06/snapshot10_EN.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{interamericaninstituteforglobalchangeresearch2012pacific, author = {{Inter-American Institute for Global Change Research}}, title = {{Pacific sea surface temperatures, Andean snowpack and water supply to the semi-arid regions of Chile and Argentina}}, institution = {Inter-American Institute for Global Change Research}, year = {2012}, url = {https://iai.int/admin/site/sites/default/files/uploads/2014/06/snapshot10_EN.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }