Development and climate interpretation of mass balance and future assessment about Alpine glaciers, through theoretical models, included in Project of Interest NextData

Mountains are sentinels of climate change, for their rapid response to environmental modifications (UN A/Res/62/196). The possibility of amplified warming in high-altitude regions and the associated notion of Elevation Dependent Warming, although dependent on the specific geographical area and mountain chain considered, is a topic of current interest and debate. Mountain glaciers are rapidly retreating in most of the world, especially evident on the southern side of the European Alps, where large amounts of ice mass have been lost in the last fifty years. This scenario create the condition to develop theoretical simulation model, assessing glacier response to climate change. To obtain estimates of future glacier conditions, quantitative descriptions of dynamics are adopted. The more complex models provide a detailed and realistic description of glacier dynamics, but also require a larger amount of input data. In case such information is not available, as it is often the case for most mountain glaciers, it could be safer to resort to simplified descriptions that make best use of the existing data. The term Minimal Glacier Model (MGM) indicates a class of models that do not explicitly describe the spatial dependence of the dynamical variables and develop a bulk description of the glacier in terms of glacier-averaged dynamical quantities that depend only on time. The MGMs are a simple but effective way of estimating glacier response to climate change and climate variability. In such approach, the main state variable is glacier length, depends on mean thickness and slope using a numerical experimentation with a Shallow Ice Approximation model. The evolution of the glacier length is obtained from an integrated continuity equation driven by the glacier mass balance. In this work, we adopt a description based on the MGM approach with an intensive use of Geographical Information System GIS to set parameters and geomorphological conditions. Moreover, we analysed the climate condition of Alpine region and we considered temperature and precipitation variables as climate forcing to drive the mass balance input. The aim of my Ph.D research program is to apply MGM – GIS approach with climate drivers on all glaciers of Greater Alpine Region with usable mass balance dataset. The final results are the assessments of glacier retreat until 2100, classifying average values. First of all, I used such enhanced MGM approach to investigate the dynamics of two important glaciers on the southern side of the Alps: the Careser glacier (Ortles-Cevedale group, Eastern Italian Alps), and the Rutor glacier (Aosta Valley, Western Italian Alps). After comparing the model results with the available data, I tried to estimate the future behavior of these two glaciers, using the Global Climate Models (GCM) from the CMIP5 project, considering two Representative Concentration Pathways RCP 4.5 and RCP 8.5 to include the most dramatic and the most conservative scenarios still plausible. At a later stage, I have to apply MGM on all glaciers of the GAR: I used precipitation and temperature data from E-OBS dataset, the first high-resolution gridded dataset of daily climate observations over Europe, by the European Climate Assessment & Dataset (ECA&D). Then, to drive the MGM for future climate conditions, I used the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) dataset: a downscaled climate scenarios for the globe that are derived from the GCM runs conducted under the CMIP5. The simulated average assessments are classified following the geographical location of glaciers, their mass balance trends, their geomorphological parameters (altitude, slope) and the different climate behaviors on the entire GAR.