ARL Weekly News – March 18, 2024

Recent Events

Dr. Stein Speaks to the American Physical Society

Dr. Stein spoke to the APS Senior Physicist Group on Wednesday, March 20. His talk was titled NOAA’s Air Resources Laboratory – 75 Years of Research Linking Earth and Sky: A Historical Perspective.  Afterwards, he gave a demonstration of NOAA’s Air Resource Car.


George Mason University Students Visit ARL’s ARC Mobile Lab and Research Aircraft

On March 21, Phil Stratton, Jiayang Sun, and Xinrong Ren hosted Dr. Daniel Tong and four graduate students from George Mason University for a visit to the ASMD’s Air Resources Car (ARC) mobile lab and the Cessna research aircraft. The group also had the opportunity to tour an air quality monitoring site located at Howard University Beltsville campus. The visit proved to be both informative and inspiring, igniting the curiosity and interest of the visiting students in potential collaboration opportunities at ARL. These firsthand experiences are invaluable in guiding the research and career paths of the students and fostering ongoing relationships between George Mason University and ARL.


AGU Involvement

Nebila Lichiheb was nominated to serve on AGU’s Global Engagement Committee. This is a two-year volunteering appointment that will end in December 2025.


Recent Publications


A paper by Tim Wilson, John Kochendorfer, Howard Diamond, Tilden Meyers, Mark Hall, Temple Lee, Rick Saylor, Praveena Krishnan, Ronald Leeper, and Michael Palecki, titled “Evaluation of soil water content and bulk electrical conductivity across the U.S. Climate Reference Network using two electromagnetic sensors,” has been accepted for publication in the Vadose Zone Journal. The study evaluated the role of bulk soil electrical conductivity in measurements of soil dielectric permittivity to determine soil water content in widely different soil environments across the United States.



Sebol, A. E., T. P. Canty, G. M. Wolfe, R. Hannun, A. M. Ring, and X. Ren, Exploring Ozone Production Sensitivity to NOx and VOCs in the New York City Airshed in the Spring and Summers of 2017-2019, Atmos. Environ., 324, 120417, 2023. DOI: 10.1016/j.atmosenv.2024.120417


Abstract: Reducing ozone in the New York City (NYC) region requires understanding the nonlinearity of ozone production (PO3) and its sensitivity to volatile organic compounds (VOCs) and nitrogen oxides (NOx = NO2 + NO). Using observations from the Long Island Sound Tropospheric Ozone Study (LISTOS) in the late spring and summers of 2017–2019 and a 0-D box model, we test the sensitivity of PO3 to ozone precursors. PO3 is greater in the morning than the afternoon due to increased concentrations of NO2 and VOC. This diurnal variation in PO3 is enhanced in the late summer. Based on the model response of PO3 to changes in initial NO2, 14% of samples are within a VOClimited regime. The metric LROx/LNOx, which compares the radical loss rates via self-reaction to their reaction with NO2, indicates an additional 17% of samples are in transition between NOx and VOC-limited regimes (0.30 <= LROx/LNOx <= 1). We often find PO3 to be VOC-limited in NYC and along the Connecticut coastline (I-95 corridor). In these samples, PO3 is most sensitive to isoprene, propene, and isopentane, and individual VOCs have strong diurnal and seasonal variations. We further compare PO3 calculations using the near explicit Master Chemical Mechanism (MCMv3.3.1) and Carbon Bond 6 revision 2 (CB6r2) for a more direct link to regulatory air quality models. Modeled PO3 is 20% greater in MCMv3.3.1, due largely to the speciation of VOC and organic peroxy radicals, however the bounds of LROx/LNOx used to determine the transition range between PO3 regimes remain the same.