AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July D modeling with Mso-NH over West Africa Marielle SAUNOIS, Cline MARI, Valrie THOURET, Jean-Pierre CAMMAS,.. Laboratoire dArologie, Toulouse AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July 2007 Mso-NH model configuration -Built to provide a latitudinal representation of the monsoon and the associated circulation between 10W and 10E (Peyrill et al, 2007) -Domain : 30S-40N, surface - 20 km altitude -Resolution : 70 km -African continent : flat between 5N and 30N -30 days of simulation (perpetual day 15 july) -Lightning parametrization (Mari et al, 2006) -Chemistry scheme ReLACs -Sets of surface emissions (biogenic) (function of latitude, taken from POET/GEIA) x y AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July 2007 Upper troposphere study Motivation : analysis of measurements performed on board of MOZAIC flights over West Africa showing a meridional gradient of ozone What are the relative contribution between photochemical ozone production and transport ? Between surface and lightning sources ? Saunois et al, 2007, paper in revision in JGR Ozone (ppbv) RH (%) V(m/s) AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July 2007 Results Without LiNOxWith LiNOx NO x O 3 Precusors emitted on surface: - Convective transport - Meridional transport (Hadley cells) LiNOx impact: - NOx addition in the upper and mid troposphere - O 3 production enhanced - O 3 minimum more pronounced Instantaneous latitude-altitude cross sections between -10S et 40N and km AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July 2007 Results tendencies and gradients Without LiNOxWith LiNOx Convection : O 3 -poor air masses source for the UT Chemical tendency : max where NOx max Ozone chemical production with LiNOx ITCZ : convection balance the high chemical production => minimum Both sides of the ITCZ : weak convection, high chemical production => N and S gradients Gradients values higher with LiNOx (to the North: pb with the cell expand and O3 accumulation around 25N) AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July 2007 Lower troposphere study (coll. with C. Reeves) Motivation: analysis of measurements performed on the BAe board in July-August 2006 (ozone, isoprene, NOx, CO, .) What are the processes controlling the ozone distribution and levels in the boundary layer over West Africa ? What is the budget of ozone source and sinks as a function of latitude ? Courtesy C. Reeves Bare soil SeaTrees AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July 2007 Results Instantaneous latitude-altitude cross sections between 0N et 25N and km, day time Ozone(ppbv)Biogenics (pptv) NOx (ppbv) Ozone: sharp increase around 13N mixing ratios > 45ppb around 17N order of magnitude ~ BAe NOx: meridional distribution controlled by the soils emissions (maxima at N) Biogenics: Close to the source (short life time) Diurnal cycle for emissions => diurnal cycle marked also for mixing ratios (not shown) AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July 2007 Results tendencies and profiles Ozone, chemistry (ppbv/h) Ozone, turbulence (ppbv/h) Day time Convection: thin lines (+/- 1 ppbv/h) Near surface: Convection >0: O3 rich air source (downdrafts) Turbulence 0: ozone production (0 during night time) Over ocean, below 700 m:0 weak, chemical production balanced by deposition Over bare soils, below 700 m : >0 strong, chemical production AMMA WP4.1.3 meeting at Service d'Aronomie, Jussieu, Paris 2-3 July 2007 Profiles analysis - observations available soon Air Namibia (MOZAIC) Cotonou Windhoek Cotonou: ozone soundings (SHADOZ), WARNING!! undergoing re-processing Study in progress: Characterization of air masses over Cotonou during the West African monsoon (biomass burning plume intrusion from the southern hemisphere, influence of JEA position, meteorological situation ) Air Namibia: daily flight between Europe and Windhoek since Dec Studies in progress: Climatology of ozone, CO, RH, and winds vertical profiles over Windhoek during Characterization of air masses over Windhoek. Climatology of ozone, CO, RH, and winds meridional prodiles in the W. African upper troposphere. => meridional transect