Recent developments in CHIMERE

Accuracy and Realism for research and operational applications Accuracy Realism/Complexity Time

Code Structure

Building a new application from scratch Download all source codes and files Make model domain files. This can be complicated if domain outside Europe (atmosphere-biosphere interface). Build emission files Build meteorological files (MM5 or other) Optimize by testing options

Model domain files Europe:  not russia, not Scandinavia Use the prepdomains interface as a first attempt. Then possibly replace the biogenic emissions, landuse Outside Europe: Construct landuse independently from GLCF or anything else Construct biogenic emission potentials or provide a file with hourly biogenic emissions in the required format. Change Bcalbio.f for growing season if necessary, change DEPO_PARS if necessary

Dealing with meteorology Using MM5 Now MM5 interface quite general, MM5 domain must include CHIMERE domain Changes in MM5 V3.6 recommended (V3.7 not tested): see website. Define MM5 domain, compute TERRAIN, run MM5 and provide a COORD_MM5 file in meteo dir (utility program). Using another model Provide an interface giving mandatory and possibly optional variables interpolated horizontaly to the CHIMERE grid, a METINFOS file for options. Add lines in the top script to call this interface

Dealing with anthropic emissions Use the existing interface and build ASCII monthly emission data files with exactly the same format as specified for 3 day types, for the MELCHIOR primary species (file ANTHROPIC). Example EMEP interface soon available on website. Provide an interface that gives hourly MELCHIOR species emissions (VOC aggregation necessary, no « standard » procedure). Change the calling sequence in the top script.

Optimization CHIMERE, like any other CTM, is NOT a plug and play tool. Test various options: recalculation of PBL height, u*, cloud attenuation using RH or CLW. Care must be taken for dust emission, due to high sensitivity to soil water. Testing needed, first without dust emission, then with and tuning of constants in Bcalbio.f may be necessary for some regions. Use (or not) the emission layer option for comparing with more « traffic stations ».

Bio 1997 : 5 box model for Paris 1998 : 3 layers, 6km grid for Paris 1999 : 3 layers, continental scale 2000 : First forecasts over Europe 2002 : Aerosols 2003 : More physics, 8 layers, interface AVN+MM : Erosion, saharan dust boundary conditions with GOCART/NASA 2005 : Aerosol/GP merged, Sea salt, improved dry deposition

Recent developments Merging of aerosol and gas phase versions Dry deposition from Emberson et al. (2000) Aerosol changes, species change, dust emission, sea salt [in test]. Meteorological interface, minor changes/options

Dry deposition Use of the Emberson et al (2000) surface resistance model, the multiplicative moldel for O3 surface conductance in src/Bdepvel.f max Takes into account temperature, radiation, phenology, growth, relative humidity, soil water [potentially].

Aerosols V200501G+: New species list: ASOA and BSOA grouped, DUST added, SALT for inert/active salt versions [in test, not fully recommended yet] V200410A+: 1.Boundary conditions. 2.Dust biogenic emissions from local erosion, resuspension. The aerosol « missing mass » After van Loon 2004

Aerosol Boundary Conditions From GOCART NASA model PM10 at the spanishZarra EMEP Station

Dust local emission Adapted from White (1979), Marticorena and Bergametti (1995) Depends on the saltation friction velocity u*s, the threshold velocity (depends on soil water). Does not depend on land use. Highly sensitive to soil water, needs testing PM10 Increase for Summer 2003

Resuspension Adapted from Loosmore (2003) Bulk formula. Depends on soil water, friction velosity. Also highly sensitive to SW. SUMMERRural SRural NAll Base Model With bound. Dust With erosion With resuspension

Meteorology V200501G: MM5 interface problems fixed (now general interface). Problems with recalculation of u*, PBL height now fixed. Urban corrections, in compensation of the lack of anthropogenic heat fluxes. Minimal PBL over urban area (150m for Paris), additional flux (50W/m2). Work to be done in MM5 itself. Bad UHI in MM5: Changes to V3.6 proposed by Liu in MM5.