Special Issue "Applications of Sentinel Satellite for Geohazards Prevention"

In the last few decades, the increasing complexity of society and rapid and uncontrolled urbanization has led to an increase in geohazard-related economic and social losses. Considering hydrogeological events, their temporal repeatability and intensity are exacerbated by man-induced environmental transformations, as well as by global climate changes. Nowadays, the use of Earth Observation products for geohazards prevention, mapping, and monitoring is well established in the scientific community and is being recognized as a valuable tool for risk management and reduction by administrative entities and civil protection authorities. Recent hydrogeological disasters in nations extremely exposed to geohazards have shown that, not only are civil and political society unprepared for catastrophes, but also that there is sometimes a lack of frequently-updated monitoring and forecasting data. The launch of the Sentinel constellation (Sentinel-1 in 2014 and Sentinel-2 in 2015) by the European Space Agency opened new frontiers for forecasting, mapping and monitoring geohazards. This new constellation of radar and optical sensors has been specifically designed for civilian use, focusing on the scientific exploitation of images in the framework of the Copernicus service. For the first time, a satellite constellation offers regularly acquired (every six and five days for Sentinel-1 and Sentinel-2, respectively) and free-to-use data to the large group of scientists interested in environmental analyses and risk management. The combination of short revisiting times, rapid product delivery (less than 3 hours) and a wide area coverage are ideally suited for implementing regional-scale monitoring strategies based on optical and radar Sentinel images or on a data fusion of both. This Special Issue will focus on innovative algorithms, analytical approaches and procedures for Sentinel image exploitation. We encourage not only to submit technical issues, but also practical methodologies on the use and understanding of Sentinel-derived products outside the scientific community. Papers proposing the combination of optical and radar Sentinel data or data fusion approaches are also very welcome. In particular, research papers are encouraged to cover a wide range of subjects, which may include, but are not limited to, the following topics: Geohazards forecasting, mapping and monitoring using Sentinel satellites; Vulnerability and risk assessment procedures based on Sentinel data; Data fusion approaches for risk management and reduction; Long-term monitoring services based on Sentinel data; New image algorithms; Innovative time series analysis.