Modeling Diamond Dust Formation and its Radiative Effects
Khvorostyanov, V.I. and Curry, J.A., University of Colorado
Ninth Atmospheric Radiation Measurement (ARM) Science Team Meeting
Diamond dust consists of small ice crystals that are frequently observed in the lower troposphere during winter in the polar regions. Diamond dust has been hypothesized to influence surface radiation budget, formation of polar anticyclones and precipitation amount on the Antarctic Plateau Diamond. Diamond Dust is not included in conventional cloud climatologies based on surface observations. Additionally, many general circulation models (GCMs) underestimate wintertime cloud cover in the Arctic, which may reflect inappropriate representation of diamond dust in the models. Diamond dust may form via two different modes of nucleation: 1) homogeneous nucleation (deliquescence and freezing of submicron aerosol particles at subsaturation with respect to water) and 2) heterogeneous nucleation (freezing of liquid water drops in the presence of ice nuclei aerosols). In this paper, we simulate the formation of diamond dust using a cloud model that includes: two kinetic equations for droplet and crystal size distribution functions (30 bins); transport of cloud condensation nuclei and ice nuclei; supersaturation and radiative transfer calculations; deliquescent aerosol; parameterizations of cloud condensation and ice nuclei activation, condensation-deposition, and coalescence-accretion growth; and parameterization of homogeneous nucleation rate, with account for solution and curvature effects. We will compare our model simulations with data from the Surface Heat Budget of the Arctic Ocean (SHEBA).
Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).
