Air quality modelling in a stable polar environment—Ross Island, Antarctica

The CALMET meteorological model and its puff dispersion model CALPUFF have been used in a complex orographic and very stable polar environment to confirm observed plume trajectories under worst case conditions from Scott Base, Ross Island, Antarctica. CALMET has been used to predict the meteorological fields of two characteristic low dispersion days and CALPUFF to predict the pollutant footprint and trajectory for each event. Field work in 1994 used constant density balloon flights to follow the trajectories of air parcels. A commonly occurring light wind condition develops when the prevailing southerly flow is locally deflected by the mountains of Ross Island. This deflection in the wind field produces a light northeasterly flow over Scott Base, which together with a light southeast flow can be associated with the low dispersion of effluent material. The relationship between the synoptic scale southerly flow and the local northeasterly at Scott Base is clearly shown by the diagnostic model and the plume derived by CALPUFF for the Scott Base emissions. The model output is shown to be realistic by the trajectories of constant density balloons.