Parameterization of the nitric acid effect on CCN activation

[摘要] In this paper we present a parameterization of the nitric acid effect oncloud droplet formation. The new parameterization is intended to beused inlarge scale models in order to obtain regional and global estimatesof the effect of nitric acid on cloud drop concentrations and theradiative balance.The parameterization is based on numerical airparcel model simulations and can be applied for unimodal and bimodallognormal aerosol particle size distributions in a large variety ofdifferent conditions. In addition to the aerosol particle distributionand gas-phase HNO₃ concentration, the parameterization requirestemperature, total pressure, updraft velocity, and the numberconcentration of cloud droplets formed at zero nitric acidconcentration, as input parameters. The parameterization is alsosuitable for describing the effect of hydrochloric acid on the clouddrop concentrations, and in practice, the HNO₃ and HClconcentrations can be summed up to yield the total effect. Thecomparison between the parameterization and the results from numericalair parcel model simulations show good consistency.

[学科分类] 大气科学