ARL Weekly News – May 20, 2024

Publications and Presentations 


UrbanNet: the NOAA Air Resources Laboratory’s Urban Observing Program

On May 22, Nebila Lichiheb presented an overview of the UrbanNet observing program; including the history of its predecessor, DCNet, a description of the currently established UrbanNet sites and the future of the project. This presentation was for the Oak Ridge Associated Universities community.


Published: Underestimation of Thermogenic Methane Emissions in New York City

Pitt, J.R., I. Lopez-Coto, A. Karion, K.D. Hajny, J. Tomlin, R. Kaeser, T. Jayarathne, B.H. Stirm, C.R. Floerchinger, C.P. Loughner, R. Commane, C.K. Gately, L.R. Hutyra, K.R. Gurney, G.S. Roest, J. Liang, S. Gourdji, K.L. Mueller, J.R. Whetstone, and P.B. Shepson (2024), Underestimation of Thermogenic Methane Emissions in New York City, Environmental Science & Technology, doi:10.1021/acs.est.3c10307.


Recent studies have shown that methane emissions are underestimated by inventories in many US urban areas. This has important implications for climate change mitigation policy at the city, state, and national levels. Uncertainty in both the spatial distribution and sectoral allocation of urban emissions can limit the ability of policy makers to develop appropriately focused emission reduction strategies. Top-down emission estimates based on atmospheric greenhouse gas measurements can help to improve inventories and inform policy decisions. This study presents a new high-resolution (0.02 × 0.02°) methane emission inventory for New York City and its surrounding area, constructed using the latest activity data, emission factors, and spatial proxies. The new high-resolution inventory estimates of methane emissions for the New York-Newark urban area are 1.3 times larger than those for the gridded Environmental Protection Agency inventory. We used aircraft mole fraction measurements from nine research flights to optimize the high-resolution inventory emissions within a Bayesian inversion. These sectorally optimized emissions show that the high-resolution inventory still significantly underestimates methane emissions within the New York-Newark urban area, primarily because it underestimates emissions from thermogenic sources (by a factor of 2.3). This suggests that there remains a gap in our process-based understanding of urban methane emissions.


Decadal increases in carbon uptake offset by respiratory losses across northern permafrost ecosystems

A research article, Decadal increases in carbon uptake offset by respiratory losses across northern permafrost ecosystems, has been submitted for publication in Nature Climate Change