Abstract View
Evaluating the Consistency of All Submicron Aerosol Mass Measurements (Total and Speciated) for the NASA Atmospheric Tomography Aircraft Mission (ATom)
HONGYU GUO, Pedro Campuzano-Jost, Benjamin A. Nault, Douglas Day, Jason Schroder, Jack Dibb, Eric Scheuer, Maximilian Dollner, Bernadett Weinzierl, Jose-Luis Jimenez, CIRES, University of Colorado, Boulder
Abstract Number: 510
Working Group: Aerosol Standards
Abstract
Aerosol intercomparisons are inherently complex, as they convolve instrument-dependent detection efficiencies vs. size and variations of the sampled aerosol population, in addition to differences in detection principles. The NASA ATom mission sampled the remote marine troposphere 86S-82N and 0-12.5km in four aircraft deployments, carrying an advanced and well-calibrated aerosol payload. This provides a unique opportunity to explore the agreement of the different instruments over a large range of conditions and improve our understanding of the various instrumental uncertainties, including the overall Aerosol Mass Spectrometer (AMS) calibration uncertainties. During ATom, special attention was paid to characterize the AMS size-dependent transmission, which is critical for accurate comparisons across instruments with inevitably different size cuts. Good agreement was found between the AMS calculated volume (including the black carbon from an SP2 instrument) and Aerosol Microphysical Properties (AMP) after applying the AMS inlet transmission (regression slope = 0.949 and 1.083 for ATom-1&2, respectively; SD = 0.003). The comparisons for sulfate, OA, and seasalt (the three main components of the remote PM1 aerosol) measured by AMS with the PALMS showed similar consistency once differences in particle detection at different sizes were accounted for. Similarly, comparisons with sulfate from SAGA (IC) filters showed good consistency once episodes with large supermicron mass were filtered out. Comparisons of the AMS with the SAGA mist chamber IC sulfate were affected by the variable time response of the latter instrument but were overall consistent. Overall, no evidence for AMS calibration artifacts or unknown sources of error was found for the mostly aged air masses encountered in ATom. A comprehensive evaluation of the different sources of uncertainty and their impact on the comparisons was performed, and factors to be considered for performing such intercomparisons and improving the reliability of submicron mass quantification in the future are discussed.