Radiative properties of the arctic aerosol

Abstract

Absorption coefficients of the Arctic aerosol have been measured by means of diffuse transmission techniques using filter samples collected at Barrow, Alaska. These measurements show a highly absorbing aerosol with an average winter absorption coefficient, σα, of ≈ 1.9 × 10-6 m-1. We have used these absorption measurements, concurrent aerosol composition measurements, and estimates of sizes and refractive indices for the individual aerosol components to model the radiative properties of the Arctic aerosol. Our results show good agreement between observed and modeled quantities and indicate that the Arctic aerosol has optical properties that are quite similar to those of an aged pollutionderived mid-latitude tropospheric aerosol. Our results also indicate that particle growth with increasing relative humidity above the surface may cause the overall climatic impact of the Arctic aerosol to be different from that expected solely on the basis of measurements at the surface. © 1982.