Antarctic cloud physics

Observations were made of clouds over the Antarctic Peninsula during the summer of 2010 and 2011 using one the BAS Twin Otter aircraft fitted with a range of atmospheric instruments.

Clouds at high southern latitudes, during the summer, contain both ice crystals and super-cooled liquid water drops, and the number and size of these particles has an impact on how the clouds develop and the way solar radiation passes through them. It is important that clouds are properly represented within climate models if these models are to correctly represent the effects of change in the Polar Regions.

These observations are the first detailed in situ observations of clouds over the Antarctic Peninsula. Cloud particles, both ice crystals and drops, require a dust particle to act as a seed, or nuclei, for the cloud particle to grow on. Not all particles in the atmosphere will act as the seed for cloud formation and this paper looks at the number and source of these nuclei. In the clean Antarctic atmosphere, the supply of dust particles is limited and it was originally thought that over the Antarctic Peninsula the surrounding open water would be the main source, in the form of salt particles, while the nearby frozen sea ice would supply few particles. However, it was found that air that had passed over the sea ice contained more nuclei than air with a source over the open ocean. This work will have an impact on the representation of clouds within climate models and the ability of these models to predict future change.

More information:
Tom Lachlan-Cope et al. The microphysics of clouds over the Antarctic Peninsula; Part 1: Observations, Atmospheric Chemistry and Physics (2016). DOI: 10.5194/acp-16-15605-2016

Constantino Listowski et al. The Microphysics of Clouds over the Antarctic Peninsula; Part 2:modelling aspects within Polar WRF, Atmospheric Chemistry and Physics Discussions (2017). DOI: 10.5194/acp-2016-1135

Provided by British Antarctic Survey