Impact of Lightning NO_x Emissions on Atmospheric Composition and Meteorology in Africa and Europe

• Main Authors: Laurent Menut, Bertrand Bessagnet, Sylvain Mailler, Romain Pennel, Guillaume Siour
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Atmosphere
• Subjects: Lightning; Atmospheric composition; modelling
• Online Access: https://www.mdpi.com/2073-4433/11/10/1128

NO<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mi>x</mi></msub></semantics></math></inline-formula> emissions from lightning have been added to the CHIMERE v2020r1 model using a parameterization based on convective clouds. In order to estimate the impact of these emissions on pollutant concentrations, two simulations, using the online coupled WRF-CHIMERE models with and without NO<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mi>x</mi></msub></semantics></math></inline-formula> emissions from lightning, have been carried out over the months of July and August 2013 and over a large area covering Europe and the northern part of Africa. The results show that these emissions modify the pollutant concentrations as well as the meteorology. The changes are most significant where the strongest emissions are located. Adding these emissions improves Aerosol Optical Depth in Africa but has a limited impact on the surface concentrations of pollutants in Europe. For the two-month average we find that the maximum changes are localized and may reach ±0.5 K for 2 m temperature, ±0.5 m s<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> for 10 m wind speed, 10 W m<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></semantics></math></inline-formula> for short wave radiation surface flux, and 50 and 2 <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>g m<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></semantics></math></inline-formula> for dust and sea salt surface concentrations, respectively. This leads to maximum changes of 1 <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>g m<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></semantics></math></inline-formula> for surface concentrations of PM<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mrow><mn>2</mn><mo>.</mo><mn>5</mn></mrow></msub></semantics></math></inline-formula>.