New Understanding of Cloud Formation May Improve Climate Projections over Antarctica

Atmospheric Chemistry and Physics, January 19

The ratio of ice to water in clouds strongly influences how much they reflect the sun’s rays, and whether they are primarily warming or cooling.  Scientists have struggled however to explain the large number of ice particles found in clouds above the coasts of Antarctica during the summer.  New observations have revealed that when cloud temperatures average around -15°C, ice particles randomly collide and break apart into smaller fragments, facilitating the formation of larger ice crystals that are able to reflect and partly block sunlight from reaching the surface. Incorporating this breakup mechanism in climate models will help improve their accuracy in predicting the impact of these clouds (warming or cooling), which is especially important in projecting surface melting of sea ice and ice shelves in the Weddell Sea region, east of the Antarctic Peninsula.  The Weddell Sea, slightly larger than the Caribbean plays a critical role in determining the rate of ice sheet loss in this region of Antarctica.

https://acp.copernicus.org/articles/21/755/2021/

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