Climatological analysis of Arctic aerosol quantity and optical properties at resolute, N.W.T

Climatologically representative aerosol optical depths for Resolute (75°N, 95°W) are derived by two methods. Results exhibit the well established seasonal dependence of aerosol optical depth, τ_ae, (e.g. Shaw, 1982). A maximum of τ_ae is reached in spring (April/May) ( = 0.13) followed by a rapid decrease to a low summer value of around 0.05. Results show a low interannual variability and a slight upward trend in optical depth over the period often years for which data were analysed (1970-1979). Use of a 24-band delta-Eddington radiative transfer model has permitted a quantitative estimate to be made of the single scattering albedo of the aerosol present at Resolute. Aerosol single scattering albedo ω₀ is found to reach a low value of 0.85 (68 % confidence: + 0.02, - 0.04) in April and attain its highest value of 0.95 (68 % confidence: + 0.02, -0.04) in June, indicating a different composition of the aerosol at these times.