Comparison and evaluation of updates to WRF-Chem (v3.9) biogenic emissions using MEGAN
<p>Biogenic volatile organic compounds (BVOCs) emitted from the natural ecosystem are highly reactive and can thus impact air quality and aerosol radiative forcing. BVOC emission models (e.g., Model of Emissions of Gases and Aerosols from Nature – MEGAN) in global and regional chemical transpo...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-08-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/15/6311/2022/gmd-15-6311-2022.pdf |
| Summary: | <p>Biogenic volatile organic compounds (BVOCs) emitted from
the natural ecosystem are highly reactive and can thus impact air quality
and aerosol radiative forcing. BVOC emission models (e.g., Model of
Emissions of Gases and Aerosols from Nature – MEGAN) in global and regional
chemical transport models still have large uncertainties in estimating
biogenic trace gases because of uncertainties in emission activity factors,
specification of vegetation type, and plant emission factors. This study
evaluates a set of updates made to MEGAN v2.04 in the Weather Research and
Forecasting model coupled with chemistry (WRF-Chem version 3.9). Our study
considers four simulations for each update made to MEGAN v2.04: (i) a
control run with no changes to MEGAN, (ii) a simulation with the emission
activity factors modified following MEGAN v2.10, (iii) a simulation
considering the changes to the plant functional type (PFT) emission factor,
and (iv) a simulation with the isoprene emission factor calculated within
the MEGAN module instead of being prescribed by the input database. We evaluate
two regions, Europe and the southeastern United States, by comparing WRF-Chem
results to ground-based monitoring observations in Europe (i.e., AirBase
database) and aircraft observations obtained during the NOMADSS field
campaign. We find that the updates to MEGAN v2.04 in WRF-Chem caused
overpredictions in ground-based ozone concentrations in Europe and in
isoprene mixing ratios compared to aircraft observations in the southeastern
US. The update in emission activity factors caused the largest biases. These
results suggest that further experimental and modeling studies should be
conducted to address potential shortcomings in BVOC emission models.</p> |
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| ISSN: | 1991-959X 1991-9603 |