# Towards a Digital Twin Prototype of Alpine Glaciers: Proposal for a Possible Theoretical Framework
## 2 Glaciers Monitoring
### The Alpine Ecosystem: A Perfect Site for DT Prototyping  
In the European context, the mountain range of the Alps is of fundamental importance in various aspects, such as geomorphological, natural, historical and cultural ones. Due to its central location with respect to different States, i.e., France, Italy, Switzerland, Liechtenstein, Austria, Germany and Slovenia, the Alpine Region is, in fact, characterized by great cultural diversity and richness. Moreover, the peculiar coexistence between men and nature, since around the year 13,500 a.C., generates a unique biodiversity of this mountain environment [68].  
Thanks to its characteristics, the Alpine chain is therefore a perfect \"test site\", also in the context of the Digital Twin, offering multiple types of applications linked to different scientific fields, also considering the future challenges that Alps will face, such as: climate change, demographic changes, land use abandonment, energy saving/production/supply/storage, conservation of cultural and natural heritages, etc. [69].  
The Alpine ecosystem is a unique and, at the same time, one of the most fragile and endangered natural ecosystems. Actually, the European Alps is one of the regions where glaciers are shrinking most and the melting of glaciers, especially of the permafrost, are destabilizing the slopes of mountains themselves.  
For these reasons, in the last decades, more and more studies and specific projects focused on the Alpine ecosystem are increased, driven by the need to pursue sustainable common territorial development and strengthen joint actions. A dedicated \"Macroregional strategy\" has been developed by the European Council, i.e., the EU Strategy for Alpine Region (EUSALP), which would provide opportunities to improve cooperation in the Alpine States and guide relevant policy instruments at EU, national and regional levels [70].  
The retreat and melting of Alpine glaciers (Figure 4) appear to be increasingly rapid (Table 1), if compared with the observations of past decades, requiring frequent monitoring and equally frequent updating of glacier inventories.  
For this reason, the implementation of a dedicated DT, continuously fed by EO data, in situ measurements and artificial intelligence-based modelling, provides a powerful tool to monitor and simulate the behaviour of glaciers, their characteristics and thus, also permitting the evaluation of any changes and related responses of the ecosystem. In this sense, the DT of the Alpine glaciers can be intended as a decision support tool for local administrators, providing an updated and dynamic overview of the territory useful to understand past and present changes and forecasting their future possible evolution.  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline
**Italian** & **Number of** & **Number of** & **Cumulative** & **Cumulative** & **Cumulative** & **Cumulative** & **Area Change** & **Area Change** \\
**Administrative** & **Glaciers–New** & **Glaciers–CGI** & **Area–New** & **CCII Inventory** & **CCII Inventory** & **Glaciers** & **(km2)** & **Area Change** \\
**Region** & **Inventory** & **Inventory** & **Inventory** & **CCII Inventory** & **CCII Inventory** & **CCII Inventory** & **CCII Inventory** \\ \hline Piemonte & 107 & 115 & 28.55 & 55.84 & \(-8\) & \(-27.29\) & \(-49\)\% \\ Valle d’acosta & 192 & 204 & 132.90 & 180.91 & \(-12\) & \(-48.01\) & \(-27\)\% \\ Lombardia & 230 & 185 & 87.67 & 114.86 & 45 & \(-27.19\) & \(-24\)\% \\ Trentino & 115 & 91 & 30.96 & 46.47 & 24 & \(-15.51\) & \(-33\)\% \\ Alto adige & 212 & 206 & 84.58 & 122.66 & 6 & \(-38.08\) & \(-31\)\% \\ Veneto & 38 & 26 & 3.21 & 5.70 & 12 & \(-2.49\) & \(-44\)\% \\ Friuli v.g. & 7 & 7 & 0.19 & 0.38 & 0 & \(-0.19\) & \(-50\)\% \\ Abruzzo & 2 & 1 & 0.04 & 0.06 & 1 & \(-0.02\) & \(-33\)\% \\ \hline \hline \end{tabular}
\end{table}
Table 1: Area and changes of the Italian glaciers (time span 1957–2015) sorted according to the administrative Italian region where they are located. Data source [71; 72; 73; 74; 75; 76; 77; 78; 79; 80].