In January 2020, the Swedish sky passed the early anniversary in the form of a heart-shaped hole in the clouds of people on the ground. Unfortunately, the sky appeared heartless NASA the satellites are looking down. But other unusual atmospheric displays, so-called “falling holes”, were spotted in the sky over the southern United States.
This page, taken on January 29, 2021, shows the natural color (top) and fake color (bottom) of this page showing the flow holes west of Atlanta, Atlanta. The natural color image below shows a similar scene on January 7, 2021, northwest of Miami, Florida. The locations are more than 500 miles away, but the physics underlying the phenomenon are the same. All images were obtained by NASA’s Terra Satellite Moderate Resonance Imaging Spectrometer (MODIS).
Fallstreak holes, also known as piercing clouds, are the result of cold air temperature and atmospheric instability. From the inside, it may seem as if part of the cloud is falling from the sky. As it turned out, this is actually happening.
The phenomenon occurs in medium-level clouds, which consist of drops of liquid water that are super-frozen. that is, the droplets remain liquid, even when the temperature is below the typical freezing point of water (32 ° F, or 0 ° C). But even super-frozen drops have their limits. The additional cooling that takes place on the wings of an aircraft, for example, can push the droplets to the point of freezing as the aircraft passes through the cloud layer. Ice crystals produce more ice crystals as liquid droplets continue to freeze. Eventually, they become so heavy that ice crystals fall from the sky, leaving a barren layer of emptiness.
Falling ice crystals are often visible in the center of the holes. These are especially evident in the fake color image at the top of this page, which uses an infrared-visible light combination (MODIS zones 7-2-1) to distinguish between water and ice. From this point of view, icy clouds (blue) are concentrated in the gaps in water clouds (white).
Both ascending and descending, the planes will fall into a general trigger for the flow holes, their longer, skinny cousins, the clouds of canals. It is no coincidence that the holes are located near the busy centers of the airport.
NASA Earth Observatory images by osh oshua Stevens using MODIS data from NASA EOSDIS LANCE և GIBS / Worldview.