Identifying the relationship between buried ice and the persistence of snow cover in the Dry Andes of Argentina

• Main Author: MacDonald, Claire
• Format: Thesis
• Language: English
• Published: University of Delaware 2020
• Subjects: Buried Ice; Dry Andes; Rock Glaciers; Snow Accumulation; Austral; San Juan; Argentina; Ice; permafrost
• Online Access: https://udspace.udel.edu/handle/19716/28160

In the Dry Andes of Argentina, rock glaciers and buried ice play a fundamental role in the regional water budget. However, the driving forces for growing and sustaining these ice features are not readily understood. This study aims to explore potential climate forcing by investigating snow distribution over time and comparing it with maps of known rock glaciers and modeled zones of permafrost in the El Altar valley of San Juan, Argentina. Using remotely sensed imagery from LandSat satellites, data were converted to snow extent using the Normalized Difference Snow Index model. Results indicate a strong seasonal cycle of snow cover, with peak coverage in July or August, and snow completely melting during the austral summer months. Statistical analysis of snow cover with known rock glaciers suggests a relationship between their location and higher levels of snow accumulation. However, when comparing the average snow accumulation for areas designated as containing or possibly containing permafrost, no such relationship was found. Tritium data taken from ice samples suggest that the rock glaciers either have not been accumulating new ice since the 1950s, or that any recent accumulation since that time has already melted in the prevailing climate. Thus, we are able to infer that the snow gathering on the glaciers is not feeding them at this time. However, it is still possible that the higher levels of snow accumulation found on glaciers compared to areas outside their boundaries indicate that the snow is insulating them from further melting and sustaining them even if it is not contributing to their long-term growth. O'Neal, Michael A. Hanson, Brian M.S. University of Delaware, Department of Earth Sciences