It is common to observe rivers on the surface of glaciers. These feed on surface melting and are constantly changing. These changes are due to the sunlight melting the ice around the river and, to a certain extent, the river bed since the waters are transparent. Simultaneously, rain and warm air cause the melting of the ice surrounding the river, and the flow of water causes the melting of its bed. It is not yet known how all these factors interact, resulting in some cases in supraglacial river beds that stay stable near the surface level, and in other cases, river beds deeply incised into the ice.
These questions gained renewed interest after the 2021 drainage of Cachet II Lake in the Northern Patagonian Icefield. Unlike previous drainage events, the 2021 drainage did not evacuate the water under the glacier but rather on top of the glacier due to the runaway growth of a supraglacial river.
This project seeks to understand the factors that influence the deepening of supraglacial rivers to determine what conditions must exist for drainage events (GLOF), such as the 2021 event on Lake Cachet II.

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Project's objectives

• Measure the rate of subaerial ablation around supraglacial rivers.

• Measure the rate of underwater ablation in the bed of supraglacial rivers with and without the influence of solar radiation.

• Determine what fraction of the energy dissipated by the flow of water is invested in melting the bed in supraglacial rivers and under what conditions this fraction becomes dominant in the river's evolution.

Study of local meteorological variations

Rising temperatures are one of the factors contributing to the retreat of glaciers. However, the increase in temperature is not equal at different altitudes and might be affected by local variations. We often extrapolate meteorological variables from nearby weather stations or meteorological models (forecast or reanalysis) to model glacier melt. Studying real temperature variations across vertical profiles and comparing conditions on the glacier surface and the surrounding rock is essential to understanding how the temperatures and winds of the meteorological models and weather stations are related to those observed above and on the glacier's surface, determining the ablation rate.
In this research project, we will use temperature loggers distributed in and around the glacier, taking advantage of the rugged terrain to sample different elevations. We can also use UAVs and low-latency meteorological sensors (custom-built using the open hardware framework at the University of Magallanes). The UAV will be equipped with sensors capable of measuring altitude and rapid changes in temperature, humidity, and wind speed, allowing it to measure vertical weather profiles of 3,000 meters or more in just a few minutes.
In addition, the results will be compared with measurements made with professional instruments, as the Automatic Weather Station operating near the glacier front.

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Project's objectives

• Improve and build the low-latency micro weather station used for UAVs in previous campaigns.

• Validate and calibrate measurements using multiple techniques, such as reference ground sensors, UAV drift, UAV attitude and smoke bombs.

• Deploy temperature loggers in and around the glacier.

• Measure the vertical gradient of temperature, humidity and wind over different areas on and around the glacier.

• Study the spatial and temporal variations of the meteorological parameters observed and assess the suitability of simple extrapolation and interpolation techniques.