Reposted from Dr. Roy Spencer’s Weblog
January 1st, 2020 by Roy W. Spencer, Ph. D.
Polar Stratospheric Cloud show (smartphone photograph posted by Reddit person Breuuan on Dec. 31, 2019.)
Rising carbon dioxide within the ambiance will proceed to trigger higher atmospheric cooling within the 2020s, which can result in a few of the most lovely cloud shows ever witnessed by human eyes.
Together with the warming within the decrease ambiance that extra CO2 is theoretically anticipated to provide, the higher ambiance is meant to chill much more strongly. For instance, in our satellite tv for pc observations since 1979, we have now noticed about Three-Four instances as a lot cooling within the center stratosphere as warming within the troposphere over the past 4 many years. This cooling is predicted to exist even greater up, into the higher mesosphere and past, which is on the fringe of outer area and the place meteors expend. The present document photo voltaic minimal situations are in all probability additionally contributing to this cooling.
Polar Stratospheric Clouds and Noctilucent Clouds are Rising
As 2019 got here to a detailed, stories of a few of the most vivid opalescent shows of wintertime polar stratospheric clouds (PSCs) in reminiscence have been coming in from Northern Europe. These clouds require very chilly temperatures within the stratosphere (-80 deg. C or colder). They present up shortly after sundown or earlier than dawn when the solar remains to be shining at that top altitude (15-25 km), whereas the same old weather-related clouds within the troposphere are not illuminated by the solar.
Wintertime polar stratospheric clouds in Sweden, Dec 30, 2019 (by Patricia Cowern Israelsson).
Within the summertime within the polar areas, electric-blue noctilucent clouds (NLCs) are generally seen within the higher mesosphere (80-85 km) the place temperatures plunge to the coldest anyplace on Earth, -100 deg. C. Like PSCs, they’re seen after sundown or earlier than dawn, however as a result of their nice altitude happen when the solar is effectively beneath the horizon and a few brighter stars are starting to shine. These clouds exist at actually the sting of area, above 99.999% of the mass of the ambiance, and are believed to be seeded by meteoric mud.
Summertime noctilucent clouds (Nando Harmsen, FStoppers.com).
These clouds have a rippled look, and time lapse pictures has revealed an incredible number of undulations, like waves from a number of pebbles thrown in a pond interacting. The next 4K time lapse video reveals cloud habits not like any you could have seen earlier than, and is effectively definitely worth the 2 minutes it takes to observe (go full-screen):
2017 NOCTILUCENT CLOUD CHASING SEASON TEASER – 4K (UHD) from Evening Lights Movies on Vimeo.
Final yr (2019) NLCs had been noticed effectively outdoors the polar areas for the primary time in recorded historical past, as far south as southern California and Nevada. This is because of some mixture of colder temperatures and better water vapor quantities (methane is transformed to water vapor at these altitudes, and growing atmospheric methane might be inflicting greater humidity up there).