The phenomenon occurred for more than seven hours, under conditions in which the drops should have frozen.
With temperatures below zero degrees Celsius, rain should freeze and fall in the form of hail or snow. However, a particular phenomenon was recorded in Antarctica: a freezing drizzle at 25 degrees below zero.
McMurdo station was the one that detected that water fall for more than seven hours, which also caught the attention of specialists, since when it occurs it does so for shorter periods.RELATED
"We are familiar with drizzle as a process that takes place with warm temperatures," said Israel Silber, a meteorologist at the Department of Atmospheric Sciences at the State University of Pennsylvania (USA) and lead author of the study published in the Journal of Geophysical Research : Atmospheres. "At lower temperatures, processes such as ice formation and growth make the probability of drizzle production significantly lower," he added.
Freezing drizzle was detected with base instruments and satellite information. Its drops are characterized by having 0.5 millimeters in diameter and freezing when they come into contact with the ground.
To explain why it occurred, the research team had to make simulated models of atmospheric conditions and thus verified that for the formation of hail or snow it is necessary that there be impurities. However, Silber clarified that "the air is very clean in Antarctica" and that "there are less pollutants and, therefore, less airborne particles."
That characteristic is what allowed the drizzle to occur for more than seven hours, although the temperature close to 25 degrees below zero should have caused precipitation in solid mode.