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Snow surface albedo changes in the last two decades across the South America (11°N-76°S): Some highlights revealed by satellite observations
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  • Tomás R Bolaño-Ortiz,
  • Maria Ruggeri,
  • Lucas Luciano Berná Peña,
  • S. Enrique Puliafito,
  • Francisco Cereceda-Balic
Tomás R Bolaño-Ortiz
Mendoza Regional Faculty – National Technological University

Corresponding Author:[email protected]

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Maria Ruggeri
Universidad Técnica Federico Santa María
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Lucas Luciano Berná Peña
Mendoza Regional Faculty – National Technological University
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S. Enrique Puliafito
Mendoza Regional Faculty – National Technological University
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Francisco Cereceda-Balic
Universidad Técnica Federico Santa María
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Abstract

Snow is among the most reflective of natural surfaces on Earth and in its reflectance, also known as snow surface albedo (SSA), a small SSA decrease can increase its absorption of solar energy. Also, climate models indicate that the reduction of SSA contributes to global warming and near-worldwide melting of cryosphere. The snowpack through South America (SA) is mainly associated to the Andes mountain range, which geologically extends 9000 km approx. from the tropical region (11°N) to the Antarctandes (76°S) in the Antarctic. There, snow is an important source of fresh water for more than 80 million people who live in the 9 countries where this mountain passes. In this study we have analyzed the SSA trend. For that, in accordance with the division proposed by Dussaillant et al. (2019), we have divided the study area into 8 zones: Inner Tropics (11°N-5°S), Outer Tropics (5°S-18°S), Desert Andes (18° S-31°S), Central Andes (31°S-37°S), North Patagonia (37°S-46°S), South Patagonia (46°S-54°S), Fuegian Andes (54°S- 56°S), and Antarctandes (63°S- 76°S). We used daily data of SSA available from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the NASA Terra and Aqua satellites for the last 20 years (Mar 2000 to Feb 2020). The results show that the greatest negative inter and intra-annual trends (i.e. is a decrease in SSA) during the last 20 years were observed in the Central Andes (April, -5.76%; p <0.001), North Patagonia (Nov, -2.33%; p <0.05) and Fuegian Andes (Oct, -1.73%; p <0.05). While the greatest positive variations were detected in Antarctandes (May, 4.76%; p <0.001), Fuegian Andes (Dec, 4%; p <0.05), and Outer Tropics (Dec, 1.67%; p <0.01). The highest SSA decrease observed in the Central Andes is consistent with previous studies carried out by the authors that have shown an association between light-absorbing particles with SSA decrease in various basins there. Our results could serve to better understand the radiative forcing changes generated in the SA cryosphere and its effects on climate change.