Meteorological monitoring and glacier shrinkage dynamics in an Alpine environment: the case of the Usellettes glacier in the Rutor area

In the last years climate change exacerbation intensified glaciers’ retreat. The importance of knowing and monitoring the local processes of melting and accumulation of snow and ice is paramount to evaluate the consequences of this phenomena on water resources and ecosystems. Improved knowledge of meteorological conditions allows a better prediction of snow/ice dynamics and of glacial bodies reduction. The objective of this thesis is to explore and compare available solutions for the meteorological monitoring in alpine environment, in relation to the monitoring of temperature and precipitations which determine the glacial retreat. The thesis is therefore divided in two parts. The first part consists in the assessment of a radar rain gauge for precipitation measurements in high mountain environments, and the comparison with a weighing rain gauge and official data collected in situ. Radar rain gauges recognize and quantify precipitation measuring the electromagnetic waves that it reflects, their use would reduce costs and maintenance efforts compared to the usual rain gauges installed at high altitudes. Furthermore, they would enhance monitoring allowing better assessments of environment’s health and better plans for both climate change adaptation and glacier preservation. The data used in this analysis were gathered by difference bodies such as “ARPA Valle d’Aosta” (Agenzia Regionale della Protezione Ambientale), on-site meteorological station installed by GlacierLab PoliTO and others. The results show consistency in the measurement’s precision of liquid precipitation but reveals to be unpredictable in the measurements of solid precipitation, trending towards their overestimation. In the comparison with data from a weighing rain gauge, the correction of the latter for direct evaporation has also been considered and correlated with meteorological variables. The analysis confirms the magnitude of evaporation-driven errors, even in high mountain environments. The second part of the thesis is a display of the capabilities of what enhanced monitoring could achieve: a projection of the evolution of the “Usellettes” small glacier in the Aosta valley close to the Rutor Glacier. To analyze the evolution of the glacier mass balance, a pre-computed future projection was used, carried out with the “Open Glacier Global Model” (OGGM) which is an open-source glacier evolution model, developed in python, that is capable of producing per-glacier results using a large quantity of data and parameters (Digital Elevation Models, Gridded Climate Datasets, Geodetic Mass Balances and others). The results are then discussed after the comparison of the calibration data used by the model and an estimation of historical data based on the measurements gathered by meteorological monitoring systems available in the area.