Arctic cloud modeling and aerosol measurements: seasonal regime changes in aerosol particles and their role on cloud microphysics

Description

Cloud microphysical parameterizations are often based on comparisons with limited observational data sets. In this study, we will use the ARM data set to identify suitable regimes of similar observations with which the modeled microphysics can be compared. Two microphysical models will be tested for each regime by varying the complexity of parameterization schemes. For example, recent aerosol measurements at Barrow, Alaska, confirm seasonal changes in source regions and composition. Chemical signatures of anthropogenic pollutants were observed in particles during the springtime Arctic haze season, which differed dramatically from the summer and winter ocean-derived particles. In addition to these seasonal regimes, other regimes will be classified from the large data pool of ARM meteorology and radiation measurements using the results of Lubin and Vogelmann (see poster). We will monitor changes in simulated properties such as thermodynamic phase, growth rates, and size distributions, and also develop methods to validate model performance with in situ ARM spectral data that is particularly sensitive to cloud microphysics. This framework will yield better characterization of Arctic sensitivity to cloud and aerosol feedbacks, and if needed, allow us to modify the parameterizations. In this poster, a summary of the seasonal microphysical changes at Barrow is presented, along with a comparison of the two model cloud microphysics parameterizations that will be used.