The Copernicus Sentinel-1 mission brings us a false-color radar image of central Ethiopia. The depicted area spans 600 kilometers in length and 500 kilometers in width, covering a significant portion of central Ethiopia. It includes multiple Sentinel-1 images from spring, summer and autumn 2023, which have been overlaid to create this single image.
Radar images capture surface texture rather than reflected light so they are naturally black and white but here images from each season have been assigned a different color: red, green and blue respectively. When the images are combined, the different colors reveal variations that occurred in the different seasons.
Built-up areas and constructions are easy to identify as they usually appear as bright patches. Ethiopia’s capital, Addis Ababa, visible in the top right, stands out as does the black outline of the international airport to the south of the city.
Ethiopia’s terrain is one of the most rugged in Africa. South from Addis Ababa, the Main Ethiopian Rift traverses the middle of the image, featuring chain of volcanoes, faults and Ethiopia’s Lakes Region. The valley holds many small rivers that drain into several lakes, with the largest captured in the image being Lake Abaya. These lakes cover more than 3,108 square kilometers.
While radar is particularly useful for picking out relief, water bodies show up dark because flat water surfaces reflect the radar signal away from the satellite. The various colors visible in some lakes are due either to the changing surface currents and sediments from rivers or to variations in water level.
At the bottom of the image, Lake Turkana (left) and Lake Chew Bahir (right) show different shades of colors because of alternating water levels. Different colors can also be seen along the Omo River delta, which enters Lake Turkana from the north. The basin, which results from the Gilgel Gibe III Dam blocking the river water flow, can be seen as a black feature resembling a lizard in the center of the image.
Image credit: Contains modified Copernicus Sentinel data (2023), processed by ESA
