The Radiative Impact of Clouds over the Antarctic Peninsula and Southern Ocean

Clouds exert a strong impact on the surface radiation budget, but the role of clouds on the Antarctic Peninsula and Southern Ocean is not well understood. Supercooled liquid clouds, in particular, are common along the coast of Antarctica, with important radiative consequences, but the amount of supercooled liquid water in polar clouds is typically underestimated by GCMs. Furthermore, in the Southern Ocean (SO) climate models and reanalyses have biases in absorbed shortwave radiation attributed to biases in clouds and albedo. Despite the need for a detailed understanding of Antarctic clouds, in situ measurements are limited. Here we present the infrared and shortwave radiative effects of clouds at Escudero Station on King George Island, Antarctica (lat/lon) during the Austral summer of 2017/2018. Cloud height and phase is determined with a mini-micropulse lidar and correlations with the broadband infrared radiance and both broadband and spectral shortwave radiance are investigated. In addition, radiosoundings were made up to 5 times per week. Preliminary results suggest a variety of interesting features of clouds over King George Island. Identified cloud types include thin, multi-layers of liquid or ice cloud, geometrically thick ice clouds, and mixed-layer clouds. Mixed-layer clouds appear to be distinct from their Arctic counterparts in that they are rarely composed of an ice layer topped by a thin liquid layer, but instead are generally mixed throughout, or contain a liquid layer within the ice layer.