A thick plume of Saharan dust swirls over the Red Sea in this image captured by the Suomi NPP satellite’s VIIRS instrument on April 1, 2018. The dust storm is one of several seen by satellites over the Sahara Desert during the past week. These events are common during the springtime, when southerly winds associated with low pressure systems moving across the Mediterranean Sea stir up large amounts of dust and sand. Known locally as the khamsin, these winds can carry dust across the Red Sea and the Arabian Peninsula, and occasionally into central and eastern Europe, as seen just last week.
Although true-color images like this may appear to be photographs of Earth, they aren't. They are created by combining data from the three color channels on the VIIRS instrument sensitive to the red, green and blue (or RGB) wavelengths of light into one composite image. In addition, data from several other channels are often also included to cancel out or correct atmospheric interference that may blur parts of the image.