Modeling lightning-NOx chemistry on a sub-grid scale in a global chemical transport model
Item
Title (Dublin Core)
Modeling lightning-NOx chemistry on a sub-grid scale in a global chemical transport model
Description (Dublin Core)
For the first time, a plume-in-grid approach is implemented in a chemical transport model (CTM) to parameterize the effects of the nonlinear reactions occurring within high concentrated NO<sub><i>x</i></sub> plumes from lightning NO<sub><i>x</i></sub> emissions (LNO<sub><i>x</i></sub>) in the upper troposphere. It is characterized by a set of parameters including the plume lifetime, the effective reaction rate constant related to NO<sub><i>x</i></sub>–O<sub>3</sub> chemical interactions, and the fractions of NO<sub><i>x</i></sub> conversion into HNO<sub>3</sub> within the plume. Parameter estimates were made using the Dynamical Simple Model of Atmospheric Chemical Complexity (DSMACC) box model, simple plume dispersion simulations, and the 3-D Meso-NH (non-hydrostatic mesoscale atmospheric model). In order to assess the impact of the LNO<sub><i>x</i></sub> plume approach on the NO<sub><i>x</i></sub> and O<sub>3</sub> distributions on a large scale, simulations for the year 2006 were performed using the GEOS-Chem global model with a horizontal resolution of 2° × 2.5°. The implementation of the LNO<sub><i>x</i></sub> parameterization implies an NO<sub><i>x</i></sub> and O<sub>3</sub> decrease on a large scale over the region characterized by a strong lightning activity (up to 25 and 8 %, respectively, over central Africa in July) and a relative increase downwind of LNO<sub><i>x</i></sub> emissions (up to 18 and 2 % for NO<sub><i>x</i></sub> and O<sub>3</sub>, respectively, in July). The calculated variability in NO<sub><i>x</i></sub> and O<sub>3</sub> mixing ratios around the mean value according to the known uncertainties in the parameter estimates is at a maximum over continental tropical regions with ΔNO<sub><i>x</i></sub> [−33.1, +29.7] ppt and ΔO<sub>3</sub> [−1.56, +2.16] ppb, in January, and ΔNO<sub><i>x</i></sub> [−14.3, +21] ppt and ΔO<sub>3</sub> [−1.18, +1.93] ppb, in July, mainly depending on the determination of the diffusion properties of the atmosphere and the initial NO mixing ratio injected by lightning. This approach allows us (i) to reproduce a more realistic lightning NO<sub><i>x</i></sub> chemistry leading to better NO<sub><i>x</i></sub> and O<sub>3</sub> distributions on the large scale and (ii) to focus on other improvements to reduce remaining uncertainties from processes related to NO<sub><i>x</i></sub> chemistry in CTM.
Creator (Dublin Core)
Gressent, Alicia
Sauvage, Bastien
Cariolle, Daniel
Evans, Mathew
Leriche, Maud
Mari, Céline
Thouret, Valérie
Date (Dublin Core)
2018-09-10
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-16-5867-2016
https://acp.copernicus.org/articles/16/5867/2016/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
