1. 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

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

3. 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, Liu et al, 2001)
dry deposition (Wesely, 1989)
eddy diffusion (Louis, 1979)
Resolved-scale transport :
Semi-lagrangian (Williamson et Rasch,1989)

4. 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.

5. 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

6. 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

7. 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

8. 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.

9. 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

10. 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?

11. 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

12. 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

13. 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

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

15. 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

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

17. 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

18. 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

19. 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

20. 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)

21. 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

22. 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

23. 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

24. 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%