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The Sahara Desert, famous for its barren, arid landscapes, is considered one of the driest places on Earth. However, NASA’s Earth Observatory satellite images show that the region is experiencing a surprising surge of greenery.
Some areas of Morocco, Algeria, Tunisia and Libya – which receive barely a few inches of rain per year – are now seeing signs of greenery, as an extratropical cyclone inundated parts of the northwestern Sahara on September 7 and 8. The cyclone soaked large, treeless parts of the region.
On September 10, MODIS (Moderate Resolution Imaging Spectroradiometer) on NASA’s Terra satellite took a false color image of the resulting runoff and floodwaters.
In the news image taken on the Terra satellite, NASA combined visible and infrared light and showed water-covered areas that appeared darker and lighter blue. According to the description, the shade of blue is affected by the depth of the water and the amount of suspended sediment.
In the picture taken on August 14, this same area was dry and barren.
Earlier on August 9, France24 The report said torrential rains caused floods that killed at least 11 people and left nine people still missing in Morocco’s southern provinces of Tata, Tiznit and Errachidia. It further said the floods destroyed 40 houses, damaged 93 roads and disrupted electricity, water supply and phone networks in several villages.
Scientists explain why?
Explaining this sudden change, Moshe Armon, a senior lecturer at the Hebrew University of Jerusalem and the Institute of Earth Sciences, said, NASA Quoted, “Although the region receives some amount of rainfall every summer, what is unique about this year is that it also includes an extratropical cyclone.”
He said the cyclone formed over the Atlantic Ocean and moved south, bringing moisture from equatorial Africa into the northern Sahara.
According to preliminary satellite analysis, the affected areas received more than 200 millimetres of rainfall, roughly equivalent to the rainfall the region receives in a year.
Rainfall accumulation estimates are based on NASA’s IMERG (Integrated Multi-satellite Retrieval for GPM) data, as ground-based rain gauges and radar stations are scarce.
“What’s also interesting is that lakes that are usually dry in the Sahara are filling up because of this event,” Armon said.
When viewed up close, several of these lakes appear as dark blue areas, including a lake located in Morocco’s Iriki National Park and Sebkha el Melah, a salt flat in central Algeria.
When Professor Armon and his colleagues analysed two decades of IMERG data (2000-2021) to better understand the frequency of heavy rainfall events, they identified only six prior events that caused the lake to fill.
The researchers identified more than 38,000 heavy rainfall events in the Sahara and found that about 30 percent of these occurred during summer.
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