Arctic aerosol and Arctic climate: Results from an energy budget model

An energy budget model is used to study the effect on Arctic climate of optically active aerosol in the Arctic atmosphere. The dependence of the change in surface temperature on the vertical distribution of the aerosol and on the radiative properties of the aerosol-free atmosphere, the Arctic surface, and the aerosol, itself, are calculated. An extensive sensitivity analysis is performed to assess the degree to which the results of the model are dependent upon the assumptions underlying it.List of Symbols Used I₀ Solar flux at the top of the Arctic Atmosphere (Arctic here means 70° N latitude to the pole) - a_S Surface albedo of the Arctic (a_S^c is the value of surface albedo at which the sign of the surface temperature perturbation changes) - Reflection coefficient of the aerosol-free Arctic atmosphere - Absorption coefficient of the aerosol-free Arctic atmosphere - Transmission coefficient of the aerosol-free Arctic atmosphere - RI₀ Total flux of sunlight reflected from the Arctic - A_AI₀ Total flux of sunlight absorbed in the Arctic atmosphere - A_SI₀ Total flux of sunlight absorbed at the Arctic surface - A_aerI₀ Total flux of sunlight absorbed in the Arctic aerosol - Q_A Net atmospheric flow of energy, per unit of Arctic surface area, north across 70° N latitude - Q_S Net oceanic flow of energy, per unit of Arctic surface area, north across 70° N latitude - E Convective plus latent heat fluxes from surface to atmosphere - F_A Net flow of energy to the Arctic atmosphere - F_S Net flow of energy to the Arctic surface - T_A An effective temperature of the Arctic atmosphere - T_S Surface temperature of the Arctic - w Single-scattering albedo of the aerosol - t Optical depth of the aerosol - g Fraction of incident radiation scattered forward by the aerosol - Reflection coefficient of the aerosol - Absorption coefficient of the aerosol - Transmission coefficient of the aerosol - p,q Number of atmospheric layers and the inverse of the fraction of incident IR absorbed in each layer in the energy budget model - F,G,H Measures of the amount of IR-active atmosphere above the surface, the aerosol, and the clouds