Southern Ocean Clouds

Understanding the key processes driving the climate system and reducing the uncertainties in climate sensitivity is crucial if we want to improve climate projections. The Southern Ocean is an area where there are large biases in the representation of short and long wave fluxes and in the surface temperture - it is thought that poor representation of clouds, both at the micro- and at the macro-scale, is responsible for these errors. This proposal will use a novel multi-scale, multi-platform approach over a variety of temporal and spatial scales that will improve understanding of aerosol and cloud microphysicsmicrophysics over regions with maximum climate model bias, namely both the Southern Ocean and coastal areas around Antarctica, leading to better representation of these processes in climate models.

Observations will be made at land stations in the Antarctic and Sub Antarctic as well measurements on the BAS ship that crosses Southern Ocean many times in the course of a season and observations using BAS's instrumented aircraft. The aim of the observations is to identify the compostions and source of the aerosols that act as cloud forming nuclei. This information will be used to improve the representation of clouds in numerical models.

The "Southern Ocean Clouds" project has clear potential to improve reliability of climate modelling assessments, with consequent impact to policy via government departments and the IPCC. In particular, the focus on cloud-aerosol feedbacks broadens the anticipated outcomes, making them of value not just for present conditions, but in anticipation that sources of cloud-active aerosol will change in the future. This fact becomes absolutely critical when considering the evolution of clouds and cloud-radiative climate influence into the future.

Results will also feed into Numerical Weather Prediction models, which are also sensitive to current inadequacies at high latitudes. Anticipated improvements in cloud-aerosol schemes will improve large-scale atmospheric circulation, with potentially global impacts to weather prediction capabilities. While recognising this fundamental academic and policy impact, we will also use SOC and associated activities when reaching out to the public. The SOC team has a proven record of engaging with the public via a broad sweep of activities (media interviews (TV, radio, print, social), talks at festivals, local, regional and national events). We will use SOC as a further platform to link to audiences about changes in climate and the imperative of responding to climate challenges