The physical properties of stratospheric aerosols determined from HALOE observations

An extensive record of remote aerosol measurements has been obtained since the advent of satellite borne sensors in the 1970's. Although the measurement coverage is excellent, the measured quantity as optical cross section per unit volume, is of limited use to the researcher. Since chemistry and radiative transfer studies require the aerosol size distribution and/or the distribution moments (for example, surface area), inferring these quantities from remote measurements has immediate applications. In this work, techniques are developed to use multi-wavelength aerosol extinction measurements from the Halogen Occultation Experiment (HALOE) to derive the physical properties of stratospheric aerosols. This work has drawn from an extensive record of in situ aerosol observations in combination with model calculations to understand the specific relationships between the aerosol optical and physical characteristics. In one approach, aerosol surface areas and volumes were determined directly from the measured extinctions, using climatological relationships. In a second approach, aerosol size distributions were retrieved from the multi-wavelength extinction measurements. The distributions and distribution moments determined using HALOE are in good agreement with in situ measurements. The results from this work satisfy important needs for investigations of the Earth's radiative and chemical balance.