A251-14
The Impact of the August 2017 Pacific-Northwest Pyrocumulonimbus Event on the Lower Stratospheric Composition

Thursday, 17 December 2020: 04:39
Virtual
Giorgio Doglioni1, Valentina Aquila2, Sampa Das3, Peter Richard Colarco4, Ghassan Taha5, Dino Zardi6 and Gianluca Lattanzi1, (1)University of Trento, Department of Physics, Trento, Italy, (2)American University, Department of Environmental Science, Washington, DC, United States, (3)Universities Space Research Association Greenbelt, Greenbelt, MD, United States, (4)NASA GSFC, Greenbelt, MD, United States, (5)Universities Space Research Association, NASA/code 614, Greenbelt, MD, United States, (6)University of Trento, Department of Civil, Environmental and Mechanical Engineering, Atmospheric Physics Group, Trento, Italy
Abstract:
On August 12 2017, five pyrocumulonimbi in western North America injected around 300 kt of carbonaceous aerosol into the lower stratosphere. This event, known as the Pacific Northwest Event (PNE), injected into the stratosphere an amount of aerosol comparable to a moderate volcanic eruption. Here, we present results from model simulations with the Goddard Earth Observing System (GEOS) model to quantify the perturbation of the lower stratospheric aerosol layer caused by the pyroCb smoke. These simulations cover the period from August 2017 to July 2018 and are driven by meteorological fields from the MERRA-2 reanalysis. Temperature and specific humidity above the tropopause are not adjusted to the reanalysis values, so that perturbations in the local meteorology by the pyroCb smoke can be taken into consideration. Here, we present an analysis of the contribution of the PNE to the stratospheric aerosol loading and composition in 2017-2018, as well as quantify its stratospheric lifetime and removal pathways. Lastly, we will compare the UTLS aerosol loading in 2017-2018 to years with moderate volcanic activity from the MERRA-2 reanalysis, to identify how similar injection magnitudes of volcanic sulfate vs biomass burning carbonaceous aerosol impact the Earth's radiative budget.
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