A251-15
An in-situ characterization of aged stratospheric smoke from the 2017 Pacific Northwest Event pyrocumulonimbus
Thursday, 17 December 2020: 04:42
Virtual
Joseph M Katich1, Eric C Apel2, Ilann Bourgeois3, Charles A Brock4, Thaopaul V Bui5, Pedro Campuzano-Jost6, Roisin Commane7, Bruce C Daube8, Maximilian Dollner9, Michael D Fromm10, Karl D Froyd11, Alan J Hills12, Rebecca S Hornbrook2, Jose L Jimenez6, Agnieszka Kupc9, Kara D. Lamb7, Daniel M Murphy13, Benjamin Nault14, Jeff Peischl15, David A Peterson16, Thomas B Ryerson17, Gregory P Schill11, Jason Clay Schroder18, Chelsea R Thompson19, Bernadett Weinzierl9,20, Christina Williamson21, Stephen Wofsy22, Pengfei Yu23,24 and Joshua Peter Schwarz13, (1)NOAA Chemical Sciences Laboratory, / CIRES, Boulder, CO, United States, (2)National Center for Atmospheric Research, Boulder, CO, United States, (3)NOAA Chemical Sciences Division, Boulder, CO, United States, (4)NOAA Chemical Sciences Laboratory, Boulder, United States, (5)NASA Ames Research Center, Moffett Field, CA, United States, (6)University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences (CIRES) and Department of Chemistry, Boulder, CO, United States, (7)Columbia University in the City of New York, New York, NY, United States, (8)Harvard University, John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA, United States, (9)University of Vienna, Faculty of Physics, Vienna, Austria, (10)Naval Research Laboratory, Washington, DC, United States, (11)NOAA/CIRES, Boulder, CO, United States, (12)NCAR, Boulder, CO, United States, (13)NOAA Chemical Sciences Laboratory (CSL), Boulder, CO, United States, (14)University of California Berkeley, Dept. of Earth and Planetary Science, Berkeley, CA, United States, (15)CIRES and NOAA ESRL, Chemical Sciences Laboratory, Boulder, CO, United States, (16)Marine Meteorology Division, Naval Research Laboratory, Monterey, CA, United States, (17)NOAA ESRL Chemical Sciences Division, Boulder, CO, United States, (18)Colorado Department of Public Health and Environment, Denver, CO, United States, (19)Institute for Arctic and Alpine Research, Boulder, CO, United States, (20)Centreville, MD, United States, (21)NOAA/CIRES, Boulder, United States, (22)Harvard University, Cambridge, MA, United States, (23)CIRES, Boulder, CO, United States, (24)Jinan University China, Institute for Environment and Climate Research, Guangzhou, China
Abstract:
In August 2017, five simultaneous wildfires in Canada and the USA combined to produce a large stratospheric pyrocumulonimbus (pyroCb) injection now known as the Pacific Northwest Event (PNE). The injected mass rivaled that of a moderate volcanic eruption and has been the object of intense study via remote sensing. However, very few in-situ measurements of the smoke exist in the literature. Here, we present a serendipitous in-situ sampling of lingering stratospheric PNE smoke that occurred during NASA’s Atmospheric Tomography mission (ATom) at periods of 7 and 11 weeks after the injection. The extensive ATom payload provides an opportunity to characterize gas and aerosol concentrations as well as bulk and single-particle aerosol properties of the smoke after it had undergone substantial transport and aging. The observations provide much needed constraints on the life-cycle of pyroCb stratospheric injections.
The dataset demonstrates the long-lasting presence of PNE-associated aerosols compared to gas-phase species. Biomass-burning aerosol mass was enhanced by a factor of 4 relative to stratospheric air outside of PNE influence, representing a quarter of the total aerosol mass. Organic aerosol showed clear evidence of significant but slow aging, supporting previous model predictions. Further, we report extreme, unexpected black carbon coatings that can act as a long-lasting fingerprint of large pyroCb injections. These results provide a deeper understanding of both episodic and long-term stratospheric pyroCb injections and likely apply more broadly to stratospheric processes.
