Aerosols of the Trade Wind Region

Abstract

A series of aerosol and meteorological observations have been obtained for the trade wind region, from a meteorological tower on the north shore of Oahu. These observations have been supported by aircraft experiments, and observations at the Mauna Loa Observatory. The mean surface concentration found in trade winds is 242 cm?3, the median 262 cm?3, but extreme variation over the range 30 to more than 400 cm?3 occurs. This extreme variation is similar in amplitude to the spatial variation in the vicinity of cumulus clouds, and in agreement with the periodicities in aerosol concentration described by Blanchard. A similar aerosol concentration, of much smaller particles, is found above the trade inversion. This aerosol exhibits less short-term variation than that at the surface, and is the same at the Mauna Loa Observatory as at several miles seaward. This above-inversion aerosol may be representative of the world background tropospheric aerosol.