Abstract:
Atmospheric nitrogen oxides (NOx) impact the overall oxidative capacity of the atmosphere contributing to the formation of ozone and aerosols. NOx emissions originate primarily from combustion sources. However, soils are emerging as an increasingly important sources of emissions of nitrogen containing gasses, including NOx. Soil derived NOx emissions have become relatively more important over the past decades due to reductions of NOx from combustion sources following emission regulations. Recent observations have quantified that a large fraction of NOx can originate from soil surfaces in areas with intensive agriculture contributing to poor air quality. Here, we describe and apply a more mechanistic soil NO and HONO emission model in the U.S. Environmental Protection Agency’s Community Multiscale Air Quality (CMAQ) model. This primarily resulted in a reduction in the model’s bias and error with regionally large impacts, exceeding 5 ppbv in the mean 8 hour maximum ozone value from June to August, when evaluated against the default option in CMAQ. Despite the impact on ozone, directly evaluating soil NOx emission models is difficult due to a lack in appropriate environmental observations and laboratory experiments. The potential of emerging measurement techniques and the modeling of soil NOx as part of the larger soil nitrogen cycle to constrain the uncertainties will be discussed.
Registration:
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What is the Joint Oslo Seminar (JOS):
- Atmospheric and climate sciences have a stronghold in Oslo among the four institutions University of Oslo, the Meteorological Institute, CICERO and NILU.
- This joint seminar invites renowned international experts to contribute to an informal series of lectures, meant to create interaction with the Oslo atmospheric and climate science community on recent highlights and analysis in the field.
- Normally seminars will be held on Thursdays (12:15 pm -1pm).