Satellite images reveal the appearance of lakes scattered across the Sahara Desert after a cyclone dropped the annual rainfall amount for North Africa in just a few days.
Sebkha el Melah lake captured on September 29 by Landsat 9 satellite. (Photo: U.S. Geological Survey)
Lakes have emerged in the Sahara following a storm that brought heavy rainfall to North Africa, flooding many areas of the largest hot desert on Earth, according to satellite images. The extratropical cyclone swept through parts of Morocco, Algeria, Tunisia, and Libya on September 7 and 8, delivering rainfall of up to 20 cm in affected areas, equivalent to a year’s worth of rain in just a few days, according to NASA’s Earth Observatory.
The deluge filled many temporary lakes in the Sahara, including Sebkha el Melah in Algeria and several other lakes around Erg Chebbi, the vast star-shaped dune region in Morocco. NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite also captured images of several temporary lakes appearing across Morocco and Algeria.
New lake appearing at the edge of Erg Chebbi sand dunes on October 1. (Photo: Google Earth/European Union).
The lakes at Erg Chebbi are filled with water after rivers from the nearby Atlas Mountains overflowed near Merzouga, a town not far from the Algerian border, acting as an entry point to the star-shaped dunes. Images taken on October 1 by one of the Copernicus Sentinel-2 satellites show several new lakes scattered around the edge of Erg Chebbi.
NASA’s Landsat 9 satellite captured images of the water-filled Sebkha el Melah lake in Algeria. Images taken between August 12 and September 29 shared by the Earth Observatory show significant landscape changes, with the lake appearing as a brilliant blue spot on the desert. The lake covers an area of 191 km² and is approximately 2.2 meters deep, according to calculations by Moshe Armon, a lecturer at the Hebrew University of Jerusalem. Armon utilized satellite images to determine water coverage in conjunction with a 3D map of the lake.
Lakes appearing throughout Algeria and Morocco from August 14 to October 9. (Photo: NASA).
Since 2000, there have been two instances when the water level in Sebkha el Melah was higher than it is currently. In 2008, the lake was full after an extratropical cyclone caused exceptionally heavy rainfall. Four years later, the lake dried up completely once again. The water filling Sebkha el Melah is likely to persist for a while. “If there is no further rainfall, the current depth of 2.2 meters will take about a year to completely evaporate,” Armon stated.
Understanding how the cyclone-induced rainfall event in September affected the Sahara Desert will help researchers gain insights into what this desert looked like thousands of years ago and how the landscape may change in the future due to climate change. Researchers predict that many areas in the Sahara will experience increased rainfall.
