Updates on aerosol and cloud

Abstract

Several improvements to the representations of clouds, aerosols, and cloud-aerosol interactions planned for the ACME V1 model have been implemented and tested, or are underway. In this presentation, we will update on our recent progresses made in the more physically-based treatment of aerosol resuspension from evaporating raindrops and in a new parameterization of ice-crystal-to-snow conversion. An additional coarse mode has been added to the MAM aerosol treatment for resuspended carbonaceous aerosol species (i.e., BC, POM, and SOA). Simulations were performed with and without the new treatment, and aerosol mass budget diagnostics and distributions were evaluated. Regarding the treatment of ice-crystal-to-snow conversion, temperature-dependent threshold sizes of ice crystals, instead of a globally constant value, are used in the model. Short (nudged) hindcast simulations were performed to investigate the impact of this new parametrization. We have also started processing satellite and ground-based remote sensing data for model evaluation, including MODIS cloud top ice effective radius, CloudSat ice water path, and ice water content and ice effective radius retrievals at the ARM SGP site.