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Cloud condensation nuclei closure study using HI-SCALE field campaign data

 
Poster PDF

Authors

Gourihar Kulkarni — Pacific Northwest National Laboratory
Lizabeth M Alexander — Pacific Northwest National Laboratory
Connor J. Flynn — University of Oklahoma School of Meteorology
Anne Jefferson — NOAA- Earth System Research Laboratory
Chongai Kuang — Brookhaven National Laboratory
Fan Mei — Pacific Northwest National Laboratory
John E Shilling — Pacific Northwest National Laboratory
Janek Uin — Brookhaven National Laboratory
Jian Wang — Washington University in St. Louis
Alla Zelenyuk-Imre — Pacific Northwest National Laboratory
Jerome D Fast — Pacific Northwest National Laboratory

Category

Convective clouds, including aerosol interactions

Description

Cloud condensation nuclei (CCN) closure studies involve comparing measured CCN concentrations with theoretical predictions that are based on simultaneously measured aerosol physical and chemical composition data. Such closure experiments provide a theoretical basis to predict the CCN concentrations of the aerosol that is essential for understanding and modeling aerosol-cloud interactions. We will present both ground- and aircraft-based closure studies based on ambient aerosol measurements that were carried out in 2016 during the Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecosystems (HI-SCALE) field campaign. HI-SCALE campaign consisted of two four-week intensive observation periods (spring and summer) over the ARM Climate Research Facility’s Southern Great Plains (SGP) site. Ground-based CCN measurements were performed at 0.2, 0.4, 0.6, 0.8 and 1.0 %, whereas aircraft CCN measurements were performed at 0.24 and 0.46 % water supersaturation. Real-time particle chemical composition was measured by an AMS and a SPLAT-II and aerosol size-distribution was characterized by a SMPS and a FIMS at the ground site and onboard aircraft, respectively. The CCN number concentration is computed using these measurements and kappa-Köhler theory under different assumptions concerning aerosol mixing and composition dependency on size and compared with the CCN measurements. This comprehensive understanding will ultimately be used to examine how aerosols in the boundary layer influence convective cloud properties over the SGP site.