Dust storms over the Red Sea are not uncommon. This sea, after all, is surrounded by deserts. But sometime atmospheric conditions and topography combine to produce a storm that appears extraordinary in satellite imagery.
The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA’s Aqua satellite captured this image of airborne dust at 2:05 p.m. local time (1105 Universal Time) on June 15, 2016. Winds appear to be blowing east-northeast out of Africa.
“Although we see transport from the wide coastal area, the plume is especially dense over the Tokar Delta,” said Georgiy Stenchikov of King Abdullah University of Science and Technology.
Gaps in near-coastal mountain ranges become pathways through which winds can carry dust and sand from inland areas toward the sea. For example Tokar Gap—located about 50 kilometers (30 miles) inland—funnels winds toward the southeast from June to September. These winds spread dust from the Tokar delta out over the Red Sea and toward the Arabian Peninsula.
According to Stenchikov, the wind gusts that caused the dust outbreak on June 15 were due to a cold front moving southeast. The front was related to a cyclone centered near the Persian Gulf, and it caused turbulent mixing of air and a series of associated haboobs.
Scientists have been studying the dust in this area for a number of reasons. In general, dust in cloud-free conditions reflects sunlight and causes radiative cooling of the land and atmosphere. But according to Stenchikov, the effects on the energy balance of the Red Sea have not been well quantified.
In addition, dust generated over the coastal area is often deposited in the sea. This provides an important nutrient supply to the Red Sea, which otherwise has very low nutrient levels, particularly in its more northern reaches.
Which came first, the clouds or the dust? Both clouds and dust can be important factors influencing regional climate, and they are frequently observed together. In this view taken from the International Space Station, two images were merged to create a mosaic of a dust storm and thunderstorm over the Red Sea. By interpreting the mosaic, we make a guess about which came first.