ozone assimilation to improve uv-index and aqhi regional forecast at environment canada j. de...
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Ozone assimilation to improve UV-index and AQHI regional forecast at Environment Canada
J. de Grandpré, Y. Rochon and R. Ménard
Contributors:ARQI (C. McLinden, V. Fioletov, M. Moran, V. Bouchet)AQMAS (S. Gravel) , ARMA (G. Deblonde, L. Fillion), RPN (M. Charron, P. Vaillancourt), CMDA (G. Verner)
Variational chemical data assimilation at EC slide 2 9 December 2011
Outline
• Motivation
• Global system components– Stratospheric chemical modelling
– Chemical measurements
– 3D-FGAT variational assimilation
– Experiments and evaluation
• Nesting approach
• Impact on UV-index and AQHI forecasts
Linearized Stratospheric chemistry (LINOZ)(McLinden et al., 2000)
)()(
)()(
)()(
)( 33
3
oo
oo
o
o
o
o
oocc
c
LPTT
T
LPqq
q
LPLP
dt
dq
q : Ozone mixing ratio
cO3 : Column ozone
T : Temperature
P-L : Photochemical tendency
(O) : Climatological values
No heterogeneous chemistry
3oc
Variational chemical data assimilation at EC slide 5 9 December 2011
Sample ozone observation distributionTangent point orbit tracks for a 6 hour period
(centered about 0 UTC) on 25 July 2008
584
5502
Total column amounts
Thinning: 1 degree separation
Day only cloud free points
20 partial column layers with ~5 layers in the troposphere
~3.2 km layers
Day only
Global deterministic meteorological and chemical analysis and forecasting system
48 hr Forecast 48 hr Forecast 48 hr Forecast
Variational chemical data assimilation at EC slide 7 9 December 2011
Evaluation
• Control cycle: Meteorological assimilation + prognostic ozone (winter and summer cycles)
• Ozone assimilation cycles:
(Use of 6 hrs met analyses + 3D-Var ozone assimilation)
– SBUV/2 – GOME-2
• Evaluation of ozone analyses and forecast against ozonesondes below 10 hPa
July 2008
No Assimilation
SBUV/2
Jan-Feb, 2009
SH
O-A
EQ
NH
Ozone (%)
July, 2008 (WOUDC)
SBUV/2 - WOUDC SBUV/2 & GOME2 [Against OMI]
LINOZ - WOUDC
GEM-MACH Upper Boundary Nesting
• Pilot files (meteo and chem) : [GEM-Global]
• GEM-MACH lid : [.1hPa 10 hPa]
• GEM4-based version (Staggered Grid)
Schematic of nesting (dark grey) and blending (light grey) zones used for UBN implementation. Recent GEM versions use Charney-Phillips vertical staggering with momentum levels dashed and thermodynamic levels solid lines. (Courtesy of R. McTaggart – Cowan)
Variational chemical data assimilation at EC slide 11 9 December 2011
Benefits of the new system
• Improvment of the AQHI forecast
• Delivering of global ozone analyses– Improve radiative heating in the global NWP system
– Use for temperature retrieval
– Research application
• UV-index Forecast
Variational chemical data assimilation at EC slide 12 9 December 2011
Sample ozone observation distributionTangent point orbit tracks for a 6 hour period
(centered about 0 UTC) on 25 July 2008
1748584
5502
Total column amounts
Thinning: 1 degree separation
Day only cloud free points
165-300 km along track
~ 2.5 km in the vertical
(NRT: 0.2 to 68 hPa)
20 usable partial column layers with ~5 ‘no-impact’ tropo. layers
~3.2 km layers
Day only
July 2008
Ozonesondes
No Assimilation (dashed)
SBUV/2 assim (dashed)
Jan-Feb, 2009
SH SH
EQ EQ
NH NH
Ozone Profiles (Pa)
Variational chemical data assimilation at EC slide 14 9 December 2011