A095-0009
Detecting the Impact of COVID-19 Shutdowns on Anthropogenic Emissions in the Los Angeles and Baltimore/Washington Urban Regions

Thursday, 10 December 2020
Poster
Subhomoy Ghosh1, Vineet Yadav2, Anna Karion3, Kimberly L Mueller4, Sharon Gourdji3, Israel Lopez-Coto3, James R Whetstone3, Geoffrey S Roest5, Charles E Miller2, Riley M Duren6, Kristal R Verhulst6, Jooil Kim7, Nicholas Parazoo8, Steve Prinzivalli9, Elizabeth DiGangi10, Ralph F Keeling11 and Ray F Weiss11, (1)University of Notre Dame, Notre Dame, IN, United States, (2)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (3)National Institute of Standards and Technology Gaithersburg, Gaithersburg, MD, United States, (4)University of Michigan EWRE, Washington, DC, United States, (5)Texas A&M University, San Francisco, CA, United States, (6)Jet Propulsion Laboratory, Pasadena, CA, United States, (7)Scripps Institution of Oceanography, La Jolla, CA, United States, (8)University of California Los Angeles, JIFRESSE, Los Angeles, CA, United States, (9)Earth Networks Inc., Germantown, MD, United States, (10)Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma and NOAA/National Severe Storms Laboratory, Norman, OK, United States, (11)Univ California San Diego, La Jolla, CA, United States
Abstract:
The COVID-19 pandemic has caused a significant shift in economic activity around the world. The cities of Los Angeles, Washington DC, and Baltimore, like many other US counties and cities around the globe took several restrictive measures to contain the spread of the disease leading to a significant, yet temporary, drop in greenhouse gas and pollutant emission.

Given that both the Washington DC/Baltimore (BW) and Los Angeles (Southern California Air Basin, SOCAB) metropolitan areas already have an extensive atmospheric measurement network in place, we explore whether a carbon dioxide (CO2) emission drop in these two cities can be detected using a consistent inversion framework in both urban areas. We also evaluate whether estimated emissions reflect the expected relative change associated with responses to COVID-19 policies. Although both are highly populated metropolitan areas, these two cities have different meteorology, economies, density, and upwind CO2 conditions. Thus, the ability to detect a change may be impacted by each city’s characteristics. For the analysis, we use continuous in-situ concentration measurements from multiple years (2018-2020), footprints from the NAMS-STILT transport and dispersion model, and the Vulcan and Hestia CO2 emission inventories for the BW and SOCAB region respectively. We investigate multiple lines of evidence. We introduce the concept of cumulative enhancement growth and compare 2020 with previous baseline years to detect the timing of the change point in atmospheric observed enhancements. Using cumulative enhancement growth analysis, we are able to detect two change points representing both the onset and recovery period. We also look for shifts in the correlations between the observed enhancements and convolutions with the NAMS-STILT footprints. Finally, we explore relative changes in the a-posteriori emissions from an atmospheric inversion. Initial results show SOCAB area emission reduction to be discernible in all three approaches. The emissions drop is detectable in the BW area as well, despite a small signal to noise ratio due to large inter-annual and seasonal emissions variability.

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