OVERVIEW OF CMAQ 5.0 AND CAMX 5.4 5/17/2012 1

Transcription

1 OVERVIEW OF 5.0 AND CAMX 5.4 5/17/2012 1

2 Modeling Photochemical models are numerical models that simulate the emission, chemical transformation, transport, and deposition of gases and aerosols Advances in computing have ld led to modeling dl larger domains and more pollutants 5/17/2012 2

3 Purpose Present an overview of the features and science options in the latest versions of and, which hhave both been used extensively to support multi pollutant regulatory modeling This overview emphasizes areas the developers consider new features to the most recent version (with yellow text) 5/17/2012 3

4 Community Multi scale l Air Quality model dl Version model.org/ / User s Manual: 5.0_%28February_2010_release%29_OGD Support software: model.org/ 5/17/2012 4

5 Comprehensive Air quality Model with extensions Version User s s Guide: Support software (pre and post processors): 5/17/2012 5

6 Gas Phase Chemistry SAPR07TB CB05 Additional explicit species that have either high emissions, high toxicity, or high h SOA formation potential ti xylene, a pinene, benzene, 1,3 butadiene, etc. Updated toluene mechanism by Whitten et al. (2010) shows impacts in urban areas Updates to both Mechanisms SO2+OH rate constant update Updated N2O5 hydrolysis reactions CB6 CB05 emissions are forward compatible with CB6 Rate constants updated to 2011 Added SOA precursor species Toluene updates extended to xylenes and benzene New isoprene chemistry with OH production at low NOx CB05 All updates are in CB6 SAPRC99 Gas and heterogeneous N2O5 hydrolysis for all mechanisms (Brown et al., 2007) 5/17/2012 6

7 Photolysis Read input data (e.g., quantum yield, cross section) from an ascii file (created by a preprocessor) Ozone column data from satellite (1978 present) for whole globe included as single model input file Rates adjusted for model predicted aerosols Surface albedo by wavelength and landuse Temporal and spatial (fractional land use) variations Includes albedo for snow and sea ice from WRF External photolysis module based on NCAR TUV radiative transfer model Photolysis as a function of solar angle, altitude, ozone column, albedo, haze turbidity Mechanism specific data (quantum yield, cross section) Ozone column can be input based on satellite data (using pre processor) Rates adjusted for clouds and modelpredicted aerosols using in line fast TUV Surface albedo set by fractional land use variations Includes albedo for snow/ice 5/17/2012 7

8 Inorganic Chemistry ISORROPIA II (v2.1) (Fountoukis and Nenes, 2007) Includes chemistry of additional crustal species (Mg, K, Ca) ISORROPIA (version 1) (Nenes et al 1998) 5/17/2012 8

9 Aqueous Phase Chemistry Updated SO2 oxidation rates via H2O2 and O3 based on Jacobson, AE, 1997 Updated SO2 oxidation rate via metal catalysis based on Martin and Good, AE, 1991 Model now uses predicted Fe and Mn in catalyzed sulfur oxidation instead of prescribed background values Aqueous sulfate and nitrate formation in resolved cloud water using the RADM aqueous chemistry algorithm (Chang et al., 1987) Uses prescribed background values of metals for metal catalytic reactions 5/17/2012 9

10 Organic Chemistry (Secondary Organic Aerosol) Partitioning of condensable organic gases to secondary organic aerosols (Carlton et al., 2010). SOA production from toluene, xylene, benzene, alkanes, isoprene, monoterpenes, sesquiterpenes, methylglyoxal and glyoxal Includes parameterization for aging or polymerization or oligermization for anthropogenic, biogenic, and aqueous phase produced SOA Partitioning of condensable organic gases (CG1 CG7) to secondary organic aerosols (SOA1 SOA7) (SOAP) (Strader et al., 1999). SOA production from toluene, xylene, isoprene, monoterpenes, and sesquiterpenes Includes parameterization for aging or polymerization or oligermization for anthropogenic and biogenic SOA 5/17/

11 Primary Organic Carbon Treatment Source specific OM/OC ratios in primary emissions Simulate oxidation of primary OC NCOM Better agreement with OCM measurements at IMPROVE sites, especially in summer Will treat source specific OM/OC ratios (NCOM) as primarily emitted PM2.5 which will not be oxidized 5/17/

12 Mercury Chemistry 5/17/

13 Toxics (non mercury) Treats 40 hazardous air pollutants (most as reactive gas phase tracers or inert PM) Acrolein and 1 3,butadiene reactions (Yarwood 2005) Formaldehyde and acetaldehyde treated with primary reactive tracers + secondary component from CB05 gas phase chemistry Acrolein yield from 1_3_butadiene decreased based on MCM Reactive Tracer (RTRAC) for primary and secondary toxics 5/17/

14 Dry Deposition M3DRY 24 landuse categories (from WRF) Includes leaf area index (LAI), surface roughness, and snow cover estimated by WRF Updates to deposition velocities based on changes to stomatal resistance Zhang 2001/ landuse categories Wesely 1989/Slinn and Slinn landuse categories Includes surface roughness, optional satellite derived LAI, gridded snow cover & drought stress 5/17/

15 Mass Transport Updates in 5.0 include a zeroflux model top similar to WRF treatment of top layer Leads to less diffusion in upper layers Allows small deviations from mass conservation New scheme for stable boundary layer in WRF and More mixing after evening transition Lower minimum Kz to reduce over night mixing Fully mass conservative and mass consistent 2 nd order vertical advection to control numerical diffusion Zero gradient top boundary condition K theory and ACM2 vertical diffusion options User set Kz minimum Kz can be adjusted with an offline processing utility (e.g., function of landuse) 5/17/

16 Emissions Calculates plume rise internally Special treatment of point fire emissions Can read in single gridded 2D file and multiple point source input files (or a single gridded 3D file) Capability to handle additional inert primary PM2.5 emissions species (Required for AERO6/AQ chemistry) In line sea salt emissions updated speciation Calculates plume rise internally Option to input plume release height (e.g., fires, LNOx) Plume injected over potentially several layers as f(plume rise, stability) Reads a single gridded 2D file per grid and a single point source file Easy to include additional inert primary PM2.5 species 5/17/

17 Optional Emissions Coupling Bi directional surface flux for ammonia (NH3) and mercury Need additional i input files for NH3 Options for lightning NOx emissions Generated offline from NLDN data & merged with other emissions NOx parameterized based on WRF estimated convective precipitation Read flash counts from user provided file Wind blown dust algorithm Need additional input files Biogenic (BEIS) emissions estimation online need additional input files There are no online emissions or bidirectional flux options in 5.40 Emissions for lightening, windblown dust, sea salt and biogenics can be estimated off line and merged with other emissions for input to or 5/17/

18 Instrumentation Process analysis Note: has several options 1 st order particulate DDM 2 nd order gas DDM (HDDM) sulfur tracking primary carbon tracking Process analysis Source apportionment t Ozone (OSAT or APCA) Speciated PM2.5 (PSAT) 1 st and High Order Decoupled Direct Method (DDM/HDDM) Gas chemistry 5/17/

19 Sub Grid Plume Chemistry Two Plume in Grid (PiG) options: GREASD PiG (large NOx sources, inorganic chemistry) IRON PiG (VOC & NOx chemistry) Sub grid plume sampling 5/17/

20 Meteorological Data Processing MCIP4 translates WRF and MM5 output to input files WRF coupled version of both models dl WRFCAMX translates WRF output to Direct interface with Grell sub grid convection option New Kz algorithm (YSU) MM52CAMX translates MM5 output to RAMS2CAMX translates RAMS output to 5/17/

21 Grid Structure Generalized terrainfollowing coordinate sstem system Multiple map projections Serial 1 way grid application only Supports sequential 1 way grid nesting Nest boundary conditions extracted from results on parent grid Terrain following height coordinate system Multiple map projections Simultaneous 2 way grid nesting Improves mass conservation for multi grid runs Flexi Nesting Introduce/remove nested grids anytime Optional inputs per grid 5/17/

22 Code Parallelization Message Passing Interface (MPI) for distributed memory (networked) systems Domain decomposition configured by user Message Passing Interface (MPI) for distributed memory (networked) systems Domain decomposition configured by user OpenMP (OMP) for shared memory (multi core) systems Easier to configure than MPI MPI & OMP most effective when used in combination 8 MPI slices each running 3 OMP threads = 24 processors Intel hyper threading may be beneficial i 5/17/

23 Conclusions Some options and capabilities i may have been unintentionally left out or mischaracterized New versions of both models dlexpected by the end of 2012 Anticipated features of upcoming model releases are not included in this presentation Acknowledge Heather Simon, Greg Yarwood, and Chris Emery for contributions 5/17/