Evaluation of CMAQ v5.0 Performance for January and July 2006 K. Wyat Appel, Shawn J. Roselle, Jon Pleim, Rohit Mathur and the CMAS Development Team 10th Annual CMAS Conference, Chapel Hill, NC October 26, 2011
Major changes in CMAQ v5.0 • Updated Aerosol Module Code & Structure • Reduced code complexity and improved modularity • Speciation for trace elements added (AERO6) • Updated Carbon Bond 5 Toluene Chemistry • Replace existing toluene chemistry with new condensed toluene chemistry • Primary Organic Aerosol (POA) Aging • Oxidative aging reaction added for POA • No impact on gas phase species (including O3) • Terpene Secondary Organic Aerosol (SOA) Updates • Updated correction to SOA yields based on Carlton et al., 2010 (ES&T) • Wind-blown dust module • Wind-blown dust emissions are generated • Updated In-line Photolysis • Use pre-processor to create photolysis file (inline) • Incorporates effects of aerosol loading on photolysis rates • Implementation of ISORROPIA2 • Updated sea-salt emission speciation • Updated fine and course mode calculations for Ca, Mg and K • Updated calculation of aerosol liquid water content • Updates to Aqueous Chemistry • Cations available in AERO6 affect pH • Mn and Fe used in catalyzed sulfur oxidation react • Inclusion of lightning generated NO emissions • Added capability of including NO emissions from lightning • Primarily affects nitrate wet deposition in summer • Some impact on O3 mixing ratios as well
Effects of model input changes on model estimates • Removal of wind nudging in PBL in WRF • Increases wind speeds, particularly overnight, which improves underestimation of wind speeds (Gilliam presentation) • Results in a decrease in model estimated concentrations due to increased mixing, transport and dry deposition velocities • Changes in WRF and CMAQ affecting the Stable Boundary Layer (SBL) • Better representation of nocturnal low-level jet improves long-range transport • Reduced minimum eddy diffusivity for rural and urban areas in CMAQ • Results in increased concentrations of primary species near the surface mostly in morning and evening • Inclusion of lightning generated NO emissions • Increases NO aloft, particularly in summer when lightning activity high • Improves summertime NO3 wet deposition estimates; increases surface O3 mixing ratios slightly
Hourly Ozone January July Observation CMAQ v4.7.1 CMAQ v5.0 Observation CMAQ v4.7.1 CMAQ v5.0 Nighttime overestimations of ozone much improved in v5.0 simulation due to change in minimum Kz; daytime O3 lower due to higher winds
Hourly O3 Change O3 mixing ratios from v4.7.1 O3 mixing ratios decreases at most sites in July. Absolute Change Change in O3 mixing ratio bias from v4.7.1 Bias in hourly O3 mixing ratios decreases at most sites in July. Change in Bias
Maximum 8-hr average O3 Change in max 8-hr O3 mixing ratios from v4.7.1 maximum 8-hr average O3 mixing ratios decrease at most sites Absolute Change Change in max 8-hr O3 mixing ratios bias from v4.7.1 Bias in maximum 8-hr average O3 mixing ratios decrease in the Northeast and Mid-Atlantic and increases in southern U.S. Change in Bias
Impact of Lightning NO on Monthly Average Surface O3 While lightning NO increases surface O3 mixing ratios in the summer, higher wind speeds from WRF ultimately result in lower O3 mixing ratios.
SEARCH Hourly O3 Yorkville (Rural) Jefferson Street (Urban) Observation CMAQ v4.7.1 CMAQ v5.0 Observation CMAQ v4.7.1 CMAQ v5.0 O3 mixing ratios too low in v5.0 simulation in the evening at SEARCH sites, especially at the urban Jefferson Street site
SEARCH Hourly NO2 Yorkville (Rural) Jefferson Street (Urban) Observation CMAQ v4.7.1 CMAQ v5.0 Observation CMAQ v4.7.1 CMAQ v5.0 NO2 concentrations are too high in the morning and evening. More work needs to be done on minimum Kz setting.
SEARCH Hourly CO Centerville (Rural) Birmingham (Urban) Observation CMAQ v4.7.1 CMAQ v5.0 Observation CMAQ v4.7.1 CMAQ v5.0
Pm2.5
Hourly PM2.5 (All U.S. TEOMs) January July Observation CMAQ v4.7.1 CMAQ v5.0 Observation CMAQ v4.7.1 CMAQ v5.0 PM2.5 increases in v5.0 simulation, especially at night (minimum Kz)
January PM2.5 Change in absolute PM2.5 concentrations from v4.7.1 PM2.5 concentrations decreases at most sites in January (except for North Carolina) Absolute Change Change in PM2.5 bias from v4.7.1 Change in bias is mixed, with the largest increases in bias in the Northeast Change in Bias
July PM2.5 Change in absolute PM2.5 concentrations from v4.7.1 PM2.5 concentrations decreases in the Northeast and increase at most other sites Absolute Change Change in PM2.5 bias from v4.7.1 Bias increases in the Northeast and decreases at most other sites Change in Bias
Monthly Average SO4 January July SO4 concentrations are lower in v5.0 simulation versus 4.7.1 primarily due to higher wind speeds in the WRF simulation.
Monthly Average NH4 January July NH4 concentrations are also lower in v5.0 simulation versus 4.7.1 due to higher wind speeds in the WRF simulation.
Weekly CASTNET TNO3 January July Large improvement in TNO3 overestimation from v4.7.1 to v5.0 due to increased NO and NO2 dry deposition (mesophyll resistance change)
Monthly Average Total Carbon (EC + OC) January July TC increases in v5.0 simulation due change in minimum Kz setting, resulting in larger bias in winter, slightly smaller bias in summer.
Monthly Average Fe January July Fe relatively unbiased at urban CSN sites, while at rural IMPROVE sites Fe is overestimated in January and underestimated in July
Fe NMB Fe concentrations generally overestimated in January, especially in Northeast, Great Lakes, and Northwest. January Fe concentrations generally underestimated in July, except in the Great Lakes region where Fe concentrations are largely overestimated. July
NO3 Wet Deposition Lightning NO Only CMAQ v4.7.1 vs. v5.0 NMB improves from -23.6% to 2.6% NMB improves only slightly from -16.5% vs. -15.0%
Summary • Large improvement in nighttime overestimation of O3 • NOX overestimated in the morning and evening (especially evening) • Daytime O3 mixing ratios slightly lower • Compensating increases in O3 due to lightning NO and decreases due to greater deposition and transport (higher wind speeds) • Results in small improvement of summertime overestimation • Small change in total PM2.5 • SO4 relatively unchanged • TNO3 decreases significantly (improves overestimation) • TC increases (improves underestimation in summer) • Small increase in PMother • Addition of lightning NO improves underestimation of NO3 wet deposition in the summer (see poster by Pinder et al.)
Future Work • Complete annual simulation with CMAQ v5.0 • Simulations currently ongoing • Test CMAQ v5.0 sensitivity to emission reductions (NOX, SO2, VOC) • Compare to sensitivity with CMAQ v4.7.1 • Test CMAQ v5.0 with MOVES mobile emissions • Compare to performance using MOBILE6 emissions • Test MEGAN vs. BEIS biogenic emissions • Ongoing work to improve WRF simulations • Urban heat island effects (improve mixing in urban areas) • Examine minimum Kz setting further • Present some of these results at AMS meeting in January
Extra Slides
Hourly NOX and NO2 AQS NOX July SEARCH NO2 July Observation CMAQ v4.7.1 CMAQ v5.0 Observation CMAQ v4.7.1 CMAQ v5.0
SEARCH Hourly O3 Centerville (Rural) Birmingham (Urban) Observation CMAQ v4.7.1 CMAQ v5.0 Observation CMAQ v4.7.1 CMAQ v5.0
SEARCH Hourly NO2 Centerville (Rural) Birmingham (Urban) Observation CMAQ v4.7.1 CMAQ v5.0 Observation CMAQ v4.7.1 CMAQ v5.0
SEARCH Hourly CO Yorkville (Rural) Jefferson Street (Urban) Observation CMAQ v4.7.1 CMAQ v5.0
Speciated PM2.5 January July
CSN Al January July
CSN Si January July
CSN Ca January July
CSN Ti January July
CSN Mg January July
CSN K January July
CSN Mn January July
IMPROVE Al January July
IMPROVE Si January July
IMPROVE Ti January July
IMPROVE Ca January July
IMPROVE Mg January July
IMPROVE K January July
IMPROVE Mn January July
