Aerosol Populations in the Marine Atmosphere

Abstract

Since 1975 Calspan has acquired considerable data describing marine boundary-lay er aerosol properties at sea and in maritime locales of North America and Europe. The data show that the marine aerosol population varies considerably in composition, both temporally and spatially, and does not necessarily comprise primarily sea salt particles. At sea, the aerosol burden is dependent on RH, winds and sea state; but a continental/anthropogenically-derived component to the marine aerosol population is generally always observed, even in remote marine areas. In coastal regions, dramatic changes in the aerosol population occur with wind shifts or airmass changes. As a result of compositional differences, response of the aerosol to fluctuations in relative humidity is expected to differ from one locale or airmass to another. Therefore, aerosol size spectra alone are not sufficient for the prediction of visibility or the potential performance of EO systems under changing humidity conditions.