Microphysical parameterizations based on ISDAC aircraft observations and aerosol-cloud effects on radiative fluxes

 

Authors

Eric Girard — University of Quebec, Montreal
Ismail Gultepe — Environment Canada
J. Walter Strapp — Environment Canada
Peter Liu — Environment Canada
Nicole Shantz — Environment Canada

Category

Aerosol-Cloud-Radiation Interactions

Description

The Indirect and Semi-Direct Aerosol Campaign (ISDAC) took place in Alaska in the vicinity of Barrow, Alaska, near the Atmospheric Radiation Measurement (ARM) North Slope of Alaska site from April 1–30, 2008. During this project, a Convair-580 aircraft flew through a variety of aerosol and cloud conditions. Aircraft observations obtained along constant altitude flights and profiles are used for microphysical parameterizations that include cloud fraction, total ice crystal number concentration, and total droplet number concentration as a function of one or more of the following parameters: temperature, vertical air velocity, effective size, aerosol total number concentrations, and relative humidity. Profiles of the total number concentration as well as the size distributions of aerosol particles are studied in a variety of conditions, including polluted and clean environments when there were no clouds or precipitation present. In situ broad band radiative fluxes (e.g., SW and IR) are then used to assess the aerosol and cloud effects on the surface heat budget. Overall, the results will be compared to these from the earlier studies, and applications to numerical modeling will be proposed.