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A school of cavum in the Gulf of Mexico off the west coast of Florida, captured by NASA’s Terra satellite on January 30, 2024.
Scientists have speculated about these holes for decades, but it is now well understood that hollow clouds are caused by airplanes.
Cavum clouds, also called hole-punch clouds or false-streak holes, look so strange that people sometimes claim they are the remains of flying saucers or other unidentified anomalous phenomena. When viewed from below, it looks like a large circle or oval has been neatly cut out of the cloud, leaving a feather-like part in the center of the hole.
It’s equally impressive from above. This image shows a cluster of cavities in the Gulf of Mexico off the west coast of Florida on January 30, 2024. NASAterra satellite.
Scientific explanation for otherworld theory
No otherworldly explanation is needed to explain the eye-catching cloud formations. Scientists have regularly mentioned the phenomenon in scientific journals since the 1940s and speculated about its causes, but in 2010 and 2011 scientists at the University for Atmospheric Research (UCAR) led the publication. A pair of studies offered explanations that justified the other theory. rest. They are caused by airplanes passing through banks of altocumulus clouds.
These mid-level clouds are composed of supercooled liquid water droplets. This means that the droplets remain liquid even when the temperature is below the typical freezing point of water (32 degrees Celsius). Fahrenheitor 0 degrees Celsius). Supercooling occurs when water droplets are very pure and do not contain small particles such as dust, fungal spores, pollen, or bacteria. Ice crystals usually form around these particles.
Supercooling may sound strange, but it occurs regularly in Earth’s atmosphere. Altocumulus clouds cover about 8 percent of the Earth’s surface at any given time and are mostly composed of liquid water droplets that are supercooled to temperatures of about -15 °C.
The process behind Cavum cloud formation
However, even supercooled clouds have their limits. As the air moves around the plane’s wings and passes through the propeller, a process known as adiabatic expansion cools the water an additional 20°C or more, pushing the liquid water droplets to their freezing point without the aid of suspended particles. You may. Ice crystals produce more ice crystals as the droplet continues to freeze. The ice crystals eventually become heavy enough and begin to fall from the sky, leaving cavities in the cloud layer. Falling ice crystals are often seen in the center of the hole as a thin trail of precipitation that never reaches the ground. This is a feature called “Birga”.
Unlike previous attempts to explain this phenomenon, UCAR researchers, along with colleagues at several other institutions, including NASA’s Langley Research Center, used aircraft flight data, satellite observations, and weather models to They were used in combination to explain how clouds are formed and tracked. How long did it last? The researchers found that when a plane passes through a cloud at a fairly sharp angle, a small circular cavity appears. As the cloud passed through the cloud at a shallow angle, a long “canal cloud” with a long virga trail like the one shown above became visible.
Other factors that can influence the length of these clouds include the thickness of the cloud layer, temperature, and the degree of horizontal wind shear, the researchers reported. Their analysis showed that all types of aircraft can generate cavity and canal clouds, including large airliners, regional jets, private jets, military jets, and turboprop aircraft. With more than 1,000 flights arriving at Miami International Airport each day, planes have many opportunities to encounter the atmospheric conditions necessary for the formation of cavity clouds.
NASA Earth Observatory image by Michala Garrison using NASA EOSDIS LANCE and MODIS data from GIBS/Worldview.
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