Examining the Ice-Nucleating Particles from SGP II

19 November 2020 - 19 April 2021

Lead Scientist: Naruki (seonggi) Hiranuma

Observatory: sgp, sgp

Knowledge of the airborne particulate components, especially the ones that have diameters larger than one micrometer, is crucial for understanding ice-nucleating particles (INPs). Recent INP measurements at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site (SGP; 36° 36′ 18″ N, 97° 29′ 6″ W) during multiple campaigns, such as SINCE-2014, ExINP-2019, and AEROICESTUDY, show strong indications of the contribution of supermicron aerosol particles to observed INP abundance at SGP. However, verification of this hypothesis is hampered since additional offline and online laboratory analyses require sufficient amounts of collected airborne particulate matter, which is currently lacking. Here, we propose to use a passive particle sampler at SGP to collect airborne particles from this winter to the next summer that include agricultural activities resulting in local soil emissions. This will allow collection of sufficient airborne particle sample for analysis and re-suspension for ice nucleation experiments (to be compared with previous INP campaign measurements). Upon successful collection of source-specific samples, a set of organized offline measurement activities will be scheduled to complement SGP datasets. The duration of the sampler deployment at SGP will continue until the next summer or until a few grams of aerosol particles have been collected. SGP is an ideal location for sampling aerosol particles from many different sources, including local agricultural activities while harvesting and/or replanting, regional burning smokes, and intra-continental dust transports. We will monitor the SGP baseline instruments and use backward trajectory analysis to characterize our airborne samples. This field campaign opportunity provides a foundation to advance the mission of ARM particularly related to improve our understanding of aerosol-cloud interactions. Moreover, the proposed project will lead to a more comprehensive understanding of atmospheric processes that impact the Earth’s energy budget, including ‘microphysical properties’, ‘mixed-phase microphysical properties’, which match with the scope of the Atmospheric Processes research within the Biological and Environmental Research program.


Daniel Knopf