The “unusual” cloud, as NASA claims, was discovered over the Caspian Sea on May 28. The cloud provides an exciting example of how satellites can detect such events in Earth’s atmosphere.
Scientists have used the NASA satellite Terra to observe the cloud as it travels toward the Earth and then disappears to learn more about how the stratocumulus appears in this single form.
Stratocumulus clouds are often concentrated in the lower atmosphere; this was seen about 1,500 feet (5,000 feet) above the surface of the Earth. However, what stood out in the new images captured by Terra’s Moderate Resolution Imaging Spectroradiometer (MODIS) was the solid boundary of the clouds.
“Sharp ends tend to form when dry, warm air from the land collides with cold, humid air over the ocean, and clouds form on that boundary,” Bastiaan van Diedenhoven, a space scientist at the SRON Netherlands Institute for Space Research, said in a statement. A NASA statement was sent on June 16.
It is not uncommon to see this type of cloud in Eastern Europe, unlike the ocean floor, although its appearance can be described as the Caspian Sea being the largest inland body of water in the world. The sea is surrounded by countries such as Kazakhstan, Iran, Turkmenistan, Georgia, and Azerbaijan, to name a few.
“You often see this [kind of cloud] off the west coast of Africa, but on very large scales,” added van Diedenhoven. He suggested that the cloud could form when warm, dry winds from the Balkans (the area around Greece) hit the cold, moist air over the Caspian Sea.
The cloud began to disappear hours after it was taken very early over the Caspian. In the afternoon, it moved northwest over the coast to Russia’s coast, near Makhachkala in the foothills of the Caucasus mountains. The cloud finally disappeared as it passed over the Earth.
Terra is a long-running global observation machine, launched in December 1999 and continues to operate in good health as it approaches the quarter-century mark in space.