AGINSGP-SUPP

Warm-temperature immersion-mode ice nucleating particles (INPs; i.e., T > 258 K) are important players in the atmosphere due to their ability to initiate freezing processes in mixed-phase clouds. At the ARM Southern Great Plains (SGP) site, previous studies observing warm-temperature INPs have inferred that these particles originate in part from regional emissions of fertile, agricultural soils containing high organic content. Laboratory experiments have shown that soil particles with high organic content are more efficient INPs than inorganic soils.

In an effort to further improve understanding of INPs in the agriculturally dominated central Great Plains, the “Agricultural Ice Nuclei at SGP” (AGINSGP) campaign, in April 2022, will use a variety of ground-deployed measurements to characterize INPs and ambient aerosol properties. At the same time, profiling of aerosol properties onboard the ARM tethered balloon system (TBS) will be supported under an existing FICUS user proposal, “Understanding contributions of agricultural dust to vertical profiles of ice-nucleating particles in the central Great Plains”.

Quantification of warm-temperature INPs can be achieved only via offline methods such as the ARM Ice Nucleation Spectrometer (INS) hosted at Colorado State University (CSU). Currently, ground-based 24-hour samples are collected at SGP for processing by the INS operationally on a six-day frequency. However, this temporal resolution is not sufficient to distinguish between INP concentrations in different airmasses impacted by different particle sources and meteorological conditions. Additionally, this sampling will not provide the quantitative information about the vertical profile of INPs, which is needed for a complete INP closure analysis at higher altitudes.

This supplemental campaign will support the collection of additional samples for IS analysis, including ground-based samples (at a higher sampling frequency) as well as sample collection onboard the TBS, to provide a quantitative vertical profile INP concentrations in parallel to the aerosol properties.

Data Management Plan

Susannah Burrows (susannah.burrows@pnnl.gov) is the point of contact for all data sets. Jessie Creamean (jcream07@colostate.edu) and Thomas Hill (thomas.hill@colostate.edu) will be secondary contacts for any specific questions about INS sample and data processing. Data will be provided at the conclusion of the campaign for submission to the ARM Data Archive. The planned range of operation is April, 2022.

Two data sets are planned from the AGINSGP-SUPP campaign:

1. Ground-based ice nuclei concentrations from the ice nucleation spectrometer, ‘INP-INS-ground’

2. TBS-based ice nuclei concentrations from the ice nucleation spectrometer, ‘INP-INS-TBS’

INP-INS-ground

This data set will include INP concentrations (as a function of temperature) from ground-based filter samples. Data will include the relevant metadata (dates, times, location, total flow), INP concentrations, and upper and lower confidence intervals. Data will be provided in ASCII files (one file per filter sample), with each file on the order of 100s of KB.

INP-INS-TBS

This data set will include the same information as the data set INP-INS-ground, but for samples collected onboard the TBS. Additionally, details of the TBS sampling, including the profiling or loitering altitude(s), will be included.

Timeline