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Testing a new aerosol-dependent ice nucleation parameterization for predicting ice nuclei and simulating mixed-phase clouds during ISDAC

 
Poster PDF

Authors

Sonia Kreidenweis — Colorado State University
Mark Branson — Colorado State University
Paul J. DeMott — Colorado State University
Anthony J. Prenni — Colorado State University
Xiaohong Liu — Texas A&M University
Sarah D. Brooks — Texas A&M University
Andrew Glen — Texas A&M University
James M Carpenter — Colorado State University

Category

Aerosol-Cloud-Radiation Interactions

Description

A new aerosol- and temperature-dependent ice nucleation parameterization valid for mixed-phase cloud activation conditions is reviewed and then compared to independent ice nuclei and aerosol measurements made during the Indirect and Semi-Direct Aerosol Campaign (ISDAC). We show good correspondence in many cases, within a factor of two on average, for situations where ice nuclei processing conditions matched those for which the parameterization is considered valid. We then performed cloud-resolving model (System for Atmospheric Modeling–SAM) simulations of a single-layer Arctic stratus case from ISDAC on April 26, 2008. Using prescribed aerosols based on actual measurements on this day, cloud microphysical properties were well reproduced. Sensitivity studies through increasing or decreasing ice nuclei by a factor of 10 did not successfully reproduce cloud properties. The implications that ice nuclei exert a strong controlling factor on proper simulation of these clouds must be further examined in future simulations using fully prognostic ice nuclei.