Due to the effects of climate change, coastal erosion is an emerging and pressuring phenomenon commonly accompanied by significant consequences, resulting in land loss and infrastructure damage while threatening the wellbeing of local communities.
Monitoring the dynamic evolution of the coastline has become essential for risk management, especially from the perspective of sea level rise that exacerbates the vulnerability of the exposed coastal regions.
In this sense, an increasing number of institutions and political and organisational structures shift away from emergency response and towards disaster risk reduction and planning.
This proved to be the case for the Managing Authority of the Region of Central Macedonia (RCM), that assigned Consortis Geospatial with the “Monitoring climate change induced coastal erosion in the region of Central Macedonia with satellite and in-situ data” project.
In this blog, Consortis Geospatial explain the project in more detail, where Earth Observation combined with in situ data, advanced algorithms and models were used to elaborate knowledge on hazard exposure and vulnerability.
The applied methodology included three thematic phases, referring to the design of the web GIS application that hosts the observatory, its services, and derived datasets (Phase A), the creation of the algorithms and tools for the calculation of all the necessary indicators (Phase B) and the evaluation of the current state and the proposal of alternatives for risk management (Phase C).
The spatial databases were being re-evaluated throughout the project in order to host the digital products created by applying specialized algorithms that processed optical images from the Sentinel-2 and Landsat-8 satellites to create timeseries of multiple indicators such as Chl-a and coastline alterations, Sentinel-1 SAR acquisitions to extract a low resolution Surface Deformation Rates model and OCN Component Extractor Speed and Direction; satellite altimetry observations from the Cryosat-2, Jason1/2/3, SARAL and Sentinel-3a/3b missions for monitoring Sea Level Anomalies and the variations of the Sea Surface Temperature, as well as in-situ observations of the coastal area to calculate high resolution models of the topography and bathymetry via GNSS, UAV mapping and echo sounding.
The large database of the monitoring was not only used to estimate the correlation between the gradual change of the derived indicators with the human activity, but also to calculate 50- and 100-year simulation indicator of the vulnerability of the coastal area under the pressure of tidal waves and develop a tool for determining passive flood mapping in the case of four different sea level rise scenarios using the bathtub approach.
All generated products, the erosion simulation model and the detailed delineation of the phenomenon at the test areas (listed in Table 1) were integrated into the web Observatory that was developed during Phase A. The online tool was enriched with other geospatial datasets, such as the CORINE Land Cover maps, for extracting land use information, geomorphological maps and real time wind direction and speed. The aim was the creation of an interactive application that would enable the correlation between the factors that were measured or used throughout the project with the human activity and the coastal vulnerability.