Browsing by Autor "Gino Casassa"

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Constraining glacier elevation and mass changes in South America
(Nature Portfolio, 2019) Matthias Braun; Philipp Malz; Christian Sommer; David Farías-Barahona; Tobias Sauter; Gino Casassa; Álvaro Soruco; Pedro Skvarca; Thorsten Seehaus
Permafrost and active layer characteristics in the high arid Andes between the Altiplano and high Atacama Desert
(Institute of Arctic and Alpine Research, 2025) Kenji Yoshikawa; Gino Casassa; Guillermo Azócar; Pablo Iribarren Anacona; Pablo Masías; Takashi Miyata; Nori Takahashi; Norbert Schörghofer; Edson Ramírez; Bolívar Cáceres Correa
The thermal and hydrological regime of permafrost in the arid Andes is unique due to the combination of extreme aridity, high solar radiation, and significant diurnal temperature fluctuations. Drilling at Chachani (6,057 m.a.s.l.), Aucanquilcha (6,176 m.a.s.l.), Chajnantor (5,640 m.a.s.l.), and Ojos del Salado (6,893 m.a.s.l.) volcanoes revealed both dry permafrost and ice-rich permafrost in one of the driest areas on Earth. We monitored solar radiations and ground temperature conditions at twenty-four sites on eleven mountains between 1° and 33° S. At elevations above 5,800 m, the active layer is about 10 to 30 cm thick and is controlled by diurnal fluctuations. Near the lower limit of mountain permafrost (LLMP), the thermal offset is positive and ice-rich terrains are found that are associated with moisture percolating from penitentes. Above 6,400 m, the surface energy balance is dominated by sublimation and dry permafrost was found. Near LLMP elevation, snow ablation was dominated by melting during summer, and ice-rich permafrost was present. We found that the type of snow ablation varies with elevation and affects the thermal properties of the permafrost in the arid Andes.
Pollution and its Impacts on the South American Cryosphere
(American Geophysical Union, 2015) L. T. Molina; Laura Gallardo; Marcos Andrade; Darrel Baumgardner; Mercy J. Borbor‐Cordova; Roxana Bórquez; Gino Casassa; Francisco Cereceda‐Balic; Laura Dawidowski; René Garreaud
Abstract This article is a review of the science goals and activities initiated within the framework of the P ollution and its I mpacts on the S outh A merican C ryosphere ( PISAC ) initiative. Air pollution associated with biomass burning and urban emissions affects extensive areas of South America. We focus on black carbon ( BC ) aerosol and its impacts on air quality, water availability, and climate, with an emphasis on the Andean cryosphere. BC is one of the key short‐lived climate pollutants that is a topic of growing interest for near‐term mitigation of these issues. Limited scientific evidence indicates that the Andean cryosphere has already responded to climate change with receding glaciers and snow cover, which directly affect water resources, agriculture, and energy production in the Andean region of South America. Despite the paucity of systematic observations along the Andes, a few studies have detected BC on snow and glaciers in the Andes. These, in addition to existing and projected emissions and weather patterns, suggest a possible contribution of BC to the observed retreat of the Andean cryosphere. Here we provide an overview of the current understanding of these issues from scientific and policy perspectives, and propose strategic expansions to the relevant measurement infrastructure in the region.