**Acknowledgements**

Part of this work was supported by CANDELA—the Copernicus Access Platform Intermediate Layers Small-Scale Demonstrator—a H2020 research and innovation project under grant agreement no. 776193.

Another part of the work was supported by EOLib—the Earth Observation Image Librarian—an ESA technological project.

The TerraSAR-X image data being used in this study were provided by the TerraSAR-X Science Service System (Proposal MTH 1118), while the WorldView-2 image data were provided by the European Space Imaging (EUSI).
