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) q : Ozone mixing ratio c O 3 : Column ozone T : Temperature P-L : Photochemical tendency ( O ) : Climatological values No heterogeneous chemistry

Variational chemical data assimilation at EC slide 5 9 December 2011 Sample ozone observation distribution Tangent point orbit tracks for a 6 hour period (centered about 0 UTC) on 25 July 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

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 - WOUDCSBUV/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 distribution Tangent point orbit tracks for a 6 hour period (centered about 0 UTC) on 25 July Total column amounts Thinning: 1 degree separation Day only cloud free points 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 EQ NH Ozone Profiles (Pa)

Variational chemical data assimilation at EC slide 14 9 December 2011