MOCAGE first results on the AMMA region Béatrice Josse1, David Kaczka1 and Brice Barret2 AMMA Workshop, 2-3 July 2007 1 Météo France CNRM/GMGEC/CARMA 2 CNRS Laboratoire d’Aérologie

Plan I . Which simulations? II . Some annual results III . Special look at August 2006 IV. Next step : LiNOx in MOCAGE

MOCAGE configuration for AMMA I. Which simulations? MOCAGE configuration for AMMA MOCAGE 47 hybrid levels GLOBE 2°x2° AMMA 0.5°x0.5° Chemscheme : RACMOBUS (strato-tropo) Subgrid parameterization : - convection (Bechtold, 2001) scavenging (Mari et al, 2000 + Liu et al, 2001) dry deposition (Wesely, 1989) eddy diffusion (Louis, 1979) Resolved-scale transport : Semi-lagrangian (Williamson et Rasch,1989)

MOCAGE configuration for AMMA I. Which simulations? MOCAGE configuration for AMMA Emissions : as prescribed by IPCC on a 1 x1º grid averaged for 2 x 2 º global resolution, simply interpolated for 0.5 x 0.5 º Biomass burning emissions : directly injected up to 6km. Other emissions : at the surface Meteorological forcings : ARPEGE Météo-France operational model Year 2006 simulated, 3-hour results.

Improvement of resolution Does it improve results? I. Which simulations? Improvement of resolution Does it improve results? 2x2º 0.5x0.5º 400hPa ozone mixing ratio, Aug 10th, 12hUTC Structures are the same Significative differences : more poor-ozone air at 0.5º Convection is more efficient

Improvement of resolution Does it improve results? I. Which simulations? Improvement of resolution Does it improve results? ozone mixing ratio, Aug 10th, 12hUTC 2° 0.5° Convection more efficient, and realistic (better chemical tropopause ) 0.5º grid resolution OK

Ozone tropospheric column II. Annual results Ozone tropospheric column Monthly means of O3 tropospheric columns MOCAGE OMI February 2006 MOCAGE OMI August 2006 Principal structures are well seen August : very good February : too high amplitude for MOCAGE concentrations

Low troposhere CO MOCAGE MOCAGE II. Annual results Low troposhere CO Monthly mean of CO mixing ratio (ppb) at 850 hPa MOCAGE MOPITT MOCAGE MOPITT Dry season Wet season Intensity and position of biomass fires well represented Atlantic export well seen Underestimation of concentrations above Sahara, Persian Gulf and southern Europe.

NOx Intensity and position of biomass fires well represented II. Annual results NOx Monthly means of NO2 tropospheric columns MOCAGE Satellite OMI Satellite OMI Intensity and position of biomass fires well represented LiNOx and wet ground-emissions are lacking

O3 and NO2 annual cycles at Nangatchori II. Annual results O3 and NO2 annual cycles at Nangatchori Annual cycles are correct Over estimation of ozone during the dry season Under-estimation of NO2 : Lack of ground-emissions?

Vertical sections around Cotonou III. August 2006 Vertical sections around Cotonou CO longitudinal section (crossing Cotonou) CO at 850 hPa CO transport from the Southern Hemisphere fires to the Guinea Gulf Very high concentrations around 800hPa

Vertical sections around Cotonou III. August 2006 III. August 2006 Vertical sections around Cotonou Ozone at 850 hPa S N Ozone longitudinal section (crossing Cotonou) Ozone production in the region of the fires, near CO production Very high low-levels concentrations, around 800hPa again

Where do high CO concentrations come from? III. August 2006 Where do high CO concentrations come from? Running MOCAGE in inverse mode : Starting from a high CO concentration surface point Running back 10 days Back long-range transport Eddy diffusion, scavenging (self – adjoint) No convection ( ajoint needed) Interpretation has to be careful : this only gives the origin of the air mass

Where do high CO concentrations come from? III. August 2006 Where do high CO concentrations come from? Back trajectories at 870 hPa

O3 Observations at the surface III. August 2006 O3 Observations at the surface Diurnal cycle OK Ground concentrations OK Mean diurnal cycle of O3 at Nangatchori

Altitude observations III. August 2006 Altitude observations FALCON flight 16/08/06 6 km All flights ATR-42 07/08/06 lower altitudes O3(MOCAGE)-O3(Obs) For all flights: In the middle troposphere : good representation Significative over-estimation in low levels.

Altitude observations III. August 2006 Altitude observations Gradients and ground concentrations OK Tropopopause well seen Maxima too low in altitude : dipole between low and middle troposphere CO measured by AMMA fleet MOCAGE CO zonal (10W-10E) mean for August 2006 MOCAGE O3 zonal (10W-10E) mean for August 2006 O3 measured by AMMA fleet

Why this dipole? 2 explanations : III. August 2006 Why this dipole? 2 explanations : Not enough exchange between PBL and free troposphere Altitude injection of emissions too weak Percentage of emissions injected lower than 1km

Conclusions and plans Relatively good agreement with observations, but still work to do! Plans : Go on with comparison to observations Work on the PBL and export in the free troposphere (tuning of Louis’scheme, new one?) Data assimilation (MOPITT, OMI) Evaluate global and regional budgets of ozone, OH… Participate in the model intercomparisons Include soil emissions and LiNOx

LiNOx parametrisation in the MOCAGE CTM IV. LiNOx in MOCAGE LiNOx parametrisation in the MOCAGE CTM Parametrisation based on the mass flux formalism of KFB convective scheme (Mari et al., 2006) Consistent with transport and scavenging of species No a priori vertical/horizontal NOx production No global yearly a priori NOx production Sommet du nuage 0°C -10°C IC Condensation CG Lightning frequencies parametrised with cloud top height (Hct) Lfcontinents~ Hct4.9 Lfocéans~ Hct1.7 (Price and Rind, 1992) Production of NOx per flash P(IC)=P(CG)=2.2x1026 molecs. (Ridley et al., 2005)

Convection and lightnings in the model IV. LiNOx in MOCAGE Convection and lightnings in the model Convection Lightnings Mars 2005 MOCAGE ECMWF Observations OLR LIS W/m2 Flashes/ km2/day Good representation of the location of deep convection Lightning frequencies too strong over the Amazon bassin and too weak over the Congo bassin

Impact of LiNOx on the NOx ditributions IV. LiNOx in MOCAGE Impact of LiNOx on the NOx ditributions South America Africa Tropopause (NOx with LiNOx) / (NOx without LiNOx) Maximum increase in the upper troposphere over continental convective regions consistent with lightning frequencies

Impact of LiNOx on the O3 ditributions IV. LiNOx in MOCAGE Impact of LiNOx on the O3 ditributions (O3 with LiNOx) / (O3 without LiNOx) Maximum O3 production from lightnings in the upper troposphere over convective regions (Bolivian and South-African highs) Recirculation over the oceans by the Subtropical Westerly Jets

Validation of the simulated O3 ditributions IV. LiNOx in MOCAGE Validation of the simulated O3 ditributions 200 TROCCINOX (Geophysica) Obs. No LiNOx LiNOx Colonnes troposphériques d’O3 (Mars 2005) +25% SHADOZ TROCCINOX -25% Improved tropospheric columns in the southern hemispehere SHADOZ (Radiosoundings at 8 tropical stations) 200 Improved ozone vmr in the middle to upper troposphere LiNOx  correction of the negative bias in the simulated tropospheric O3 +25% -25%