? Annelie Klint Nilsson @irf_space .
? #Kiruna #Sweden #IRF .
? 220120.
Swedish Institute of Space Physics .
Mother-of-pearl #clouds (Polar Stratospheric Clouds) are one kind of stratospheric cloud. Today over Kiruna and #Rymdcampus! .
Stratospheric clouds are condensates of sulphuric acid, nitric acid and water which form between 15 km and 30 km height .
These substances occur naturally in the atmosphere and condense to form clouds when temperatures fall below about -80 C .
Such cold temperatures are found in the stratosphere during #winter in the #polar regions.
In the Antarctic stratosphere, temperatures well below -80 C are found for several months every winter .
In the #Arctic such low temperatures rarely last for long, but when they do, thick layers of stratospheric #clouds can form .
In recent decades, stratospheric clouds have become an important player in ozone depletion. #Ozon is destroyed by #chlorine, released into the atmosphere in the form of #freons.
#Stratospheric #cloud droplets provide surfaces on which important chemical reactions can occur more readily than in the air alone. The result is up to 100 times faster ozon depletion than without the clouds .
Release of freons into atmosphere is nowadays forbidden in most countries and the amount of freons in the atmosphere has started to decline .
By 50 or 100 years from now the freons are expected to have disappeared from the atmosphere and we will again be able to admire the stratospheric clouds without worrying about their unfortunate side effects on the #ozonelayer .
#institutetförrymdfysik #swedishinstituteofspacephysics #polarstratosphericclouds #PSC #atmosphericresearch #atmospher #atmosfarforskning #sverige #AuroraHunters #AuroraHuntersStockholm #NorrskenSverige #NaturHistoriska #TweetAurora #AirPollution #Pollution
