A COMPARISON OF THE STRUCTURE OF THE ATMOSPHERIC BOUNDARY-LAYERS IN CENTRAL LONDON AND A RURAL SUBURBAN SITE USING ACOUSTIC SOUNDING

Comparisons are presented of acoustic sounder (SODAR) records from a site in the center of a major urban area. London, and a rural/suburban site at Warren Spring Laboratory, Stevenage, some 50 km to the north. The records form a continuous data set for the 2-year period from April 1981 to March 1983. The data are examined for differences due to the urban influence on the lower boundary layer and variations on diurnal and seasonal timescales are discussed. In general it is found that the mixing height in London is between 50 and 100 m higher than that at Stevenage. The usefulness of SODAR in analyzing and interpreting hourly variations in pollutant concentrations is illustrated in the context of a period of elevated O//3 concentrations measured at the two sites in question.