Variation of Sodium and Chloride Concentrations with Rainfall Intensity in Hawaiian Trade Wind Showers

Abstract

The variation of sodium and chloride concentrations with rainfall intensity in Hawaii was investigated in 13 trade wind showers. The variation was found to be inversely dependent on rainfall intensity, although the ratio of Na to Cl appeared to be independent of the intensity. Several factors which may affect the dependence of concentration on rainfall intensity are discussed, and it is concluded that: (1) washout and evaporation, more than any process which may occur within the cloud, are the dominant factors in increasing the salinity of the small raindrops collected below the cloud base, and (2) exchange of gaseous and dissolved chlorine is a minor factor affecting the variation of chloride concentration with rainfall intensity.