A Note on Some Bioclimatic Consequences of Coastal Lows

Abstract

Fluctuations in thermal comfort and in air pollution potential are examined in relation to the passage of coastal low pressure systems along the south and east coast of South Africa. The passage of a coastal low past Durban is shown first to raise the level of heat discomfort over the city due to pre-frontal warming and then to provide relief by postfrontal cooling. Fluctuations in the height of the subsidence inversion and in the mixing layer are also illustrated. It is shown schematically that in the period preceding a coastal low squall-front, the mixing layer contracts usually with a concomitant inorease in the level of atmospheric pollution. With the passage of the squall-front the pollutants are dispersed through the well-ventilated atmosphere.