GIS analysis to apply theoretical Minimal Model on glacier flow line and assess glacier response in climate change scenarios

The development of theoretical work about glacier dynamics has given rise to the construction of mathematical models to assess glacier response in climate change scenarios. Glacier are sentinels of climate condition and the Project of Interest NextData will favour new data production about the present and past climatic variability and future climate projections, as well as new assessments of the impact of climate change on environment. The aim of this specific research program is to develop and apply theoretical models to understand, evaluate and reproduce glacier response in different climate scenarios. These models try to reduce the complexity of a glacier dynamics in a simple description based on physics laws: the background of the numerical algorithms. To investigate glacier evolution we used Minimal Glacier Model (Oerlemans J., 2011): this class of models does not explicitly describe spatial distribution of quantities like ice thickness, basal water pressure, sliding velocity and the glacier evolution is calculated from an integrated continuity equation over the entire volume, based on the perfect plasticity principle. The state variable is glacier length. The analysis is composed also by theoretical equation to estimate mean thickness of glacier (Linsbauer A., 2012), useful to minimal model parameters, that starts from the evaluation of elevation range and slope. In minimal model it is also necessary an exhaustive study about geomorphology of the glacier through the related Digital Elevation Model (DEM) using a GIS. Throw DEMs, it is possible to reconstruct the evolution of area and volume of the glacier with a multitemporal analysis and draw the flow lines that follow the accumulation-ablation dynamic, on which the model is applied. During this work an algorithms were developed to extrapolate from DEMs all the feature of interest to run model and to conduct a complete geomorphometric analysis on glacier. The model input data set are given by the mass balance and the Equilibrium Line Altitude. We relate these with winter precipitation and summer temperature using a theoretical fit as a transfer function of climate forcing on glacier behavior. This meteorological values are recovered in global atmospheric reanalysis or climate model, focusing on the area around the glacier of interest. The first step is the presentation of the model validation on historical real series of glacier parameter and dimension, followed by the run of this validated models to estimate the evolution of glacier in future scenarios. Linsbauer A., Paul F. & Haberli W. 2012. Modeling glacier thickness distribution and bed topography over entire mountain ranger with GlabTop. Journal of Geo. Res., 117. Oerlemans J. 2011. Minimal Glacier Models. Igitur, Utrecht University.