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Dust Modelling Workshop, Reading U., 26 February 2008 Modelling dust aerosols for the ECMWF IFS

Dust Modelling Workshop, Reading U., 26 February 2008 Modelling dust aerosols for the ECMWF IFS. J.-J. Morcrette, A. Benedetti, L. Jones, J.W. Kaiser, O. Boucher 1 , S. Kinne 2 ECMWF, Reading; 1 MetOffice, Exeter; 2 Max-Planck Institute, Hamburg

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Dust Modelling Workshop, Reading U., 26 February 2008 Modelling dust aerosols for the ECMWF IFS

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  1. Dust Modelling Workshop, Reading U., 26 February 2008Modelling dust aerosols for the ECMWF IFS J.-J. Morcrette, A. Benedetti, L. Jones, J.W. Kaiser, O. Boucher1, S. Kinne2 ECMWF, Reading; 1 MetOffice, Exeter; 2 Max-Planck Institute, Hamburg As part of the GEMS project (Global Environmental Monitoring using Satellite and in-situ measurements) ECMWF is developing a version of its assimilation/forecast system including aerosols Here emphasis is put on the forward modelling of dust aerosols 3-bin representation: 0.03 – 0.55 – 0.9 – 20 mm (representing roughly 10, 20 and 70% of the mass of dust aerosols) Dust Modelling Workshop, 26 Feb’08

  2. Dust production - 1 • Based loosely on • Marticorena and Bergametti, 1995 • Ginoux et al., 2001 • Engelstaedter and Washington, 2007 • Delineation of areas likely to be sources of dust aerosols by • Soil moisture in first model layer: sm1 • Fraction of bare soil within a model grid: fbs • Total albedo: a • UV-vis albedo (l < 0.7 mm; from MODIS): auv • Wind at lowest model level (lml = 10m) v • Wind at lml but including gustiness: vg • Dust emission potential: dep Dust Modelling Workshop, 26 Feb’08

  3. Dust production - 2 Delineation of areas likely to be sources of dust aerosols by: • Lifting threshold speed lts = f( sm1 , bin mean particle radius) • Wind factor: v = v or vg v3 = ( v – lts ) * v2 Two possible formulations: if ( land .and. v > lts .and. fbs > 0.1) then if (a < 0.5 .and. 0.08 < auv < 0.5 ) then flux= dep(i) * auv * v3 endif endif if ( land .and. v > lts .and. fbs > 0.1) then if (sm1 < 0.2 sm1sat) then flux = C * dep(i) * (1-sm1) * v3 endif endif Albedo-based Soil moisture-based Dust Modelling Workshop, 26 Feb’08

  4. “original” June 2003 “original” June 2007 Tau 550 nm DU only Revised DEP + gusts June 2007 Revised DEP June 2007 Dust Modelling Workshop, 26 Feb’08

  5. Forward modelling of aerosols • As part of the GEMS project, the IFS has been modified to include prognostic aerosols (sea-salt SS, dust DU, organic OM and black carbon BC, sulphate SU). • Sources for SS and DU are linked to some of the model surface parameters (U10, soil moisture, UVis albedo, stdev orography, snow mask, gustiness). • Sources for OM, BC and SU are taken from climatologies and/or inventories (GFEDm, GFED8d, SPEW, EDGAR databases). • Aerosols are transported by advection, vertical diffusion and convection, and undergo their specific processes, i.e., sedimentation, dry deposition, wet deposition by large-scale and convective precipitation, and for OM and BC hygroscopic effects. • The TL159 L60 model has been simulating aerosols for the 2003-2004 GEMS-AER reference period (with climatological and 8day OM, BC and SU emissions). • Comparisons with observational data (MODIS, CloudSat/CALIPSO, AERONET). • Since 1 June 2007, the ECMWF operational model is used for experimental near-real time 72-hour aerosol forecasts, at TL159 L91, and without any analysis. http://www.ecmwf.int/products/forecasts/d/inspect/catalog/research/gems/aer/optical_depth/ Dust Modelling Workshop, 26 Feb’08

  6. An experimental version of ECMWF IFS now produces in near-real time a 72-hour forecast (FC only, no analysis yet) of the total optical depth for an ensemble of aerosols (sea-salt, desert dust, organic matter, black carbon, and sulphate) Total optical depth 550 nm 20080108_00 + 39hr Dust Modelling Workshop, 26 Feb’08

  7. “natural” = SS+DU “anthropogenic” = OM + BC + SU Dust Modelling Workshop, 26 Feb’08

  8. Assessment • Comparison with MODIS-derived aerosol optical depth at 550 nm • Comparison with CALIPSO-derived cloud and aerosol masks • Comparison with AERONET aerosol optical depth at various wavelengths Dust Modelling Workshop, 26 Feb’08

  9. MODIS MODIS July 2003 IFS Sum 12hr-FCs July 2003 Dust Modelling Workshop, 26 Feb’08

  10. MODIS MODIS Jan’2004 IFS Sum 12hr-FCs Jan’2004 Dust Modelling Workshop, 26 Feb’08

  11. Orbit Modis Aqua ECMWF model FC only at TL159 L91 MODIS Dust Modelling Workshop, 26 Feb’08

  12. Dust Modelling Workshop, 26 Feb’08

  13. Modis Aqua missing ECMWF model FC only at TL159 L91 Dust Modelling Workshop, 26 Feb’08

  14. Modis Aqua ECMWF model FC only at TL159 L91 Dust Modelling Workshop, 26 Feb’08

  15. Modis Aqua ECMWF model FC only at TL159 L91 Dust Modelling Workshop, 26 Feb’08

  16. AERONET Model July 2007 Dust Modelling Workshop, 26 Feb’08

  17. Dust Modelling Workshop, 26 Feb’08

  18. Comparison Analysis / Forecast • Comparison A/F for DU aerosol type only • Comparison A/F for each MODIS SW wavelength and all tropospheric aerosols Dust Modelling Workshop, 26 Feb’08

  19. Comparison Analysis / Forecast Comparison of monthly averaged optical depth of dust for July 2003: for a forecast only (left) and for the analysis system (right) Forecast DU Analysis DU Dust Modelling Workshop, 26 Feb’08

  20. LSCE-AEROCOM_B 2000 LOA-AEROCOM_B 2000 ECMWF-GEMS_AER 2003 GOCART-AEROCOM_B 2000 Watch the scales! Dust Modelling Workshop, 26 Feb’08

  21. Dust Modelling Workshop, 26 Feb’08

  22. Dust Modelling Workshop, 26 Feb’08

  23. Dust Modelling Workshop, 26 Feb’08

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  29. Dust Modelling Workshop, 26 Feb’08

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