ARL Weekly News – September 10, 2021

Recent Events

Bronze Medal Winners

This week, NOAA Administrator Rick Spinrad announced the Bronze medal awards. ARL was awarded two bronze medals, the highest honor award granted by the Under Secretary of Commerce for Oceans and Atmosphere. The Bronze Medal recognizes federal employees for superior performance and is awarded to individuals, groups (or teams), and organizations.

Organizational Development: Ariel Stein

Ariel was cited: For expeditiously and skillfully coordinating research that leveraged the unique scientific opportunity resulting from the COVID-19 global pandemic. Publication of one ARL Covid research paper is reported at the end of this report – Campbell, et. al:

Scientific or Engineering Achievement: Rick Saylor
Rick was part of the team that developed the Global Ensemble Forecast System – Aerosols (GEFS- Aerosols) model to support air quality alerts and visibility forecasts. GEFS-Aerosols is an atmospheric composition model that integrates weather and air quality using the Finite Volume Cubed Sphere (FV3) core and was transitioned to operations on September 23, 2020. A new dust emissions algorithm was created and implemented in GEFS-Aerosols by ARL to improve the model’s estimates of dust in the global atmosphere, thereby potentially improving weather and air quality forecasts.

Upcoming Events

Denver-Julesburg Basin Field Campaign Begins

ARL is participating in an aircraft study to measure emissions from oil and natural gas facilities in the Denver-Julesburg Basin (DJB) in September/October 2021.  The University Research Foundation’s Cessna 402B research aircraft is being deployed to make continuous measurements of (1) methane, carbon dioxide, and carbon monoxide from the University of Maryland’s Picarro analyzer; (2) ethane from the University of Colorado University’s Compact Airborne Multispecies Spectrometer; (3) ozone and nitrogen dioxide from the NOAA ARL’s ozone and nitrogen dioxide analyzers; (4) selected volatile organic compounds from the TOFWERK’s Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS), and (5) meteorological parameters of air temperature, pressure, relative humidity, wind speed and wind direction from a Vaisala instrument and a differential GPS. The objectives of this study are to carry out area-wide airborne surveys of trace gas emissions over the DJB, to provide top-down flux estimates of methane and ethane, and to assess the contribution of emissions from the DJB to ozone formation to help the State of Colorado in their efforts to address the Front Range serious EPA’s ozone nonattainment classification.

Papers Published

Airborne Observations of CFCs Over Hebei Province, China in Spring 2016

Benish, S. E., Salawitch, R. J., Ren, X., He, H., & Dickerson, R. R. (2021). Airborne observations of CFCs over Hebei Province, China in Spring 2016. Journal of Geophysical Research: Atmospheres, 126, e2021JD035152.

In Spring 2016, 27 whole air samples were collected from an aircraft ∼500–∼3,500 m over Hebei Province, China and analyzed for 16 halocarbons, including chlorofluorocarbons (CFCs). Mixing ratios (median, 25th–75th percentiles) of CFC-11 (281, 255–318 ppt), CFC-12 (546, 473–591 ppt), CFC-113 (79, 73–85 ppt), CFC-114 (22, 19–25 ppt), HCFC-22 (345, 308–432 ppt), and CCl4 (88, 75–104 ppt) were often observed to be higher than their global tropospheric background levels. The significantly elevated mixing ratios of ozone depleting substances (ODSs) combined with strong correlations with anthropogenic tracers known to have substantial use and emission in this region (HCFC-22 and CH2Cl2) suggest continuing emissions of multiple Montreal Protocol-controlled gases at the time of measurement. We use HYSPLIT trajectory clusters and potential source contribution function methods to identify principal transport pathways of CFCs. We find the highest mixing ratios of ODSs in air originating from Inner Mongolia, Hebei, and Shandong. The strong correlations between CFC-11 and CFC-12 with the feedstock CCl4 suggest new production is prevalent in all three regions. We find no evidence for new production of CFC-113, but the strong correlation of CFC-114 with the feedstock C2Cl4 suggests new production of CFC-114 from the southeast of China. The findings of this study confirm high mixing ratios of ODSs over Hebei in Spring 2016 and suggest new production and use (rather than release from banks), which is in conflict with the Montreal Protocol agreement that bans the production of CFCs.

Impacts of the COVID-19 Economic Slowdown on Ozone Pollution in the U.S.

The analysis of observations and experimental emissions of NOAA’s National Air Quality Forecasting Capability show that the COVID-19 economic slowdown led to disproportionate impacts on near-surface ozone concentrations across the contiguous U.S. The COVID-19 related economic slowdown generally led to decreased NOx emissions, but with widespread  state-to-state variability. The widespread emissions decreases lead to widespread ozone decreases in rural regions, but some local increases in urban regions.
Patrick C. Campbell, Daniel Tong, Youhua Tang, Barry Baker, Pius Lee, Rick Saylor, Ariel Stein, Siqi Ma, Lok Lamsal, Zhen Qu, Impacts of the COVID-19 Economic Slowdown on Ozone Pollution in the U.S., Atmospheric Environment,  4 September 2021, 118713.