CMAQv5.4 Release Notes: Emissions Updates
Ben Murphy, U.S. Environmental Protection Agency
Type of update: Interface Update
Release Version/Date: CMAQv5.4
Description:
The DESID Emission Control file has been restructured and several minor updates have been made to the functionality and features available in the DESID interface. Specific details as follows:
- The Emission control file has been streamlined and split to improve maintainability. There are now three control files including CMAQ_Control_Misc.nml which contains input parameters for non-DESID modules like ELMO and the Budget tool, CMAQ_Control_DESID.nml which contains DESID parameters that are independent of chemical mechanism (e.g. region and are size distribution parameters), and CMAQ_Control_DESID_${MECH}.nml which contains mechanism-dependent scaling rules.
- Area normalization - if offline streams are provided in units of area-normalized flux, DESID can now be told to multiply the flux inputs by the area of each grid cell projected to the real area on the Earth's surface, if appropriate.
- A computational inefficiency was discovered that has been corrected for cases when there are more than 200,000 point sources on a single sub-domain block.
- Diagnostic options have been expanded so that users can choose which variables and sources will populate individual output files.
- A bug in the processing of region-based scaling parameters was discovered and revised.
- Variables and comments have been revised for clarity.
- Chemical families have been revised to so they are accessed globally by other modules like ELMO.
References: N/A
Internal PRs: PR #817, PR #809, PR #766, PR #714, PR #709, PR #648, PR #894, PR #638, PR #772
Jeff Willison, U.S. Environmental Protection Agency
Type of update: Science Update
Release Version/Date: CMAQv5.4
Description:
MEGAN 3.2 is available in CMAQv5.4 as an additional option for inline biogenic emissions. Input files will be available for several domains at release, but users can download the MEGAN preprocessor to create their own (https://bai.ess.uci.edu/megan/data-and-code). Soil NO can be calculated using the Berkeley-Dalhousie Soil NOx Parameterization (BDSNP) or an implementation of Yinger and Levy (YL95) when MEGAN is enabled.
Users may enable MEGAN and BEIS emission streams simultaneously to select species from a given stream through the emission control file. This approach allows the use of BDSNP with BEIS, the use of BEIS-YL95 with MEGAN, etc. See Chapter 4 of the user guide for more information about required inputs, and Chapter 6 for more information about configuration options and recommendations.
References: Guenther, A., Jiang, X., Shah, T., Huang, L., Kemball-Cook, S., and Yarwood, G., Model of Emissions of Gases and Aerosol from Nature Version 3 (MEGAN3) for Estimating Biogenic Emissions: Air Pollution Modeling and its Application XXVI, edited by Mensink, C., Gong, W., and Hakami, A., pp. 187–190, Springer International Publishing, Cham, 2020.
Internal PRs: PR #652, PR #701, PR #889
Jesse Bash, U.S. Environmental Protection Agency
Type of update: Science Update and Bug Fix
Release Version/Date: CMAQv5.4
Description:
Science updates:
- BEIS in CMAQ is streamlined by removing the BIOSEASONS file and the BIOSW_YN and SUMMER_YN options.
Seasonality is now modeled using the 1 meter soil temperature following the WRF PX LSM implementation and was tested with WRF output using both NOAH and PX LSM simulations.
- Canopy temperature and radiation environments are now modeled using the driving meteorological model’s representation of LAI rather than the LAI values in the B3GRD file.
Bug fixes:
- Solar radiation attenuation in the shaded portion of the canopy was using the direct beam photosynthetically active radiation (PAR) when the diffuse beam PAR attenuation coefficient should have been used.
This update had little impact on the total emissions but did result in slightly higher emissions in the morning and evening transition periods for isoprene, methanol and MBO.
- The fraction of solar radiation in the sunlit and shaded canopy layers, SOLSUN and SOLSHADE respectively were estimated using a planar surface. These should have been estimated based on the par intercepted by a hemispheric surface rather than a plane.
This update can result in an earlier peak in leaf temperature, approximately up to an hour.
- The quantum yield for isoprene emissions (ALPHA) was updated to the mean value in Niinemets et al. 2010a ( https://doi.org/10.1029/2010JG001436) and the integration coefficient (CL) was updated to yield 1 when PAR = 1000 following Niinemts et al 2010b ( https://doi.org/10.5194/bg-7-1809-2010).
This updated resulted in a slight reduction in isoprene, methanol, and MBO emissions.
BELD 6 updates:
- Utilizes high resolution tree species and biomass data from Wilson et al. 2013a, and Wilson et al. 2013b.
Scaled to mean grid cell leaf biomass using the allometric relationships in the U.S. Forest Service Forest Inventory and Analysis (FIA) database allometric scaling (Jenkins et al. 2003)
- Species names were changed from non-specific common names to scientific names
- Tree species biogenic volatile organic carbon (BVOC) emission factors for tree species where taken from the NCAR Enclosure database similar to MEGAN 3
- Switch from area based to the leaf biomass based emission factors to utilize the new high resolution data from the US Forest Service and to utilize units more commonly reported in the literature.
Significance and Impact:
The seasonality updates require one less input file and two fewer environment variables. Leaf off and leaf on conditions are now represented as a gradient rather than a binary variable and are in better agreement with long term means from the U.S.A. National Phenological Network observations (USANPN). This change did not have a large impact on BVOC emissions due to the temperature dependence on emissions.
Comparison USANPN observations leaf onset observations for April 15th (top), the BEIS4 parameterization adopted from the WRF PX land surface scheme (bottom left), and the BEIS3 bioseasons file representation (bottom right)
The correction to the canopy light model resulted in similar emissions as BEIS3 but in much higher simulated CMAQ isoprene, methanol, and MBO concentrations due to an increase in emissions during the morning and evening transition where the modeled boundary layer height is relatively low. This resulted in approximately a 30% increase in estimated isoprene concentrations in July. The updates to BELD increased isoprene emissions in the Southeast by approximately another 20% and monoterpene emissions decreased by approximately 20% due to changes in emission factors and differences between the biomass estimates of Wilson et al. 2013 used in BELD 6 and the domain wide assumptions used in BELD 5.
Daily AQS isoprene observations (grey) and July 2016 results from this merge with BELD6 emission factors (red), prior to this merge with BELD6 emission factors (blue), and the research branch with BELD5 emission factors (green)
References: Jenkins, J.C., Chajnocky, D.C., Heath, L.S., Birdsey, R.A., National-scale biomass estimators for United States Tree Species, Forest Science, 49(1), 12-35, https://doi.org/10.1093/forestscience/49.1.12, 2003
Niinemets, U., Copolovici, L., Huve, K., High within-canopy variations in isoprene emission potentials in temperate trees: Implications for predicting canopy-scale isoprene fluxes, J. Geophys. Res. Biogeosci. G04029, ,https://doi.org/10.1029/2010JG001436, 2010a
Niinemets, U., Monson, R.K., Arneth, A., Ciccioli, P., Kesselmeier, J., Kuhn, U., Noe, S.M., Penuelas, J., Staudt, M., The leaf-level emission factor of volatile isoprenoids: caveats, model algorithms, response, shapes and scaling, Biogeosciences, 7, 1809-1832, https://doi.org/10.5194/bg-7-1809-2010, 2010b
Wiedinmyer, C., 2001. NCAR BVOC Enclosure Database. National Center for Atmospheric Research, Boulder, CO
Wilson, Barry Tyler; Lister, Andrew J.; Riemann, Rachel I.; Griffith, Douglas M. 2013a. Live tree species basal area of the contiguous United States (2000-2009). Newtown Square, PA: USDA Forest Service, Rocky Mountain Research Station. https://doi.org/10.2737/RDS-2013-0013
Wilson, Barry Tyler; Woodall, Christopher W.; Griffith, Douglas M. 2013b. Forest carbon stocks of the contiguous United States (2000-2009). Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. https://doi.org/10.2737/RDS-2013-0004
Internal PRs PR #868
Daiwen Kang, U.S. Environmental Protection Agency
Type of update: Bug Fix
Release Version/Date: CMAQv5.4
Description:
The time steps in the lightning NOx diagnostic files were from 1 t0 24 in the previous versions. For CMAQv5.4, the time steps for the diagnostic files are from 0 to 23 in agreement with other output files.
Significance and Impact: No impact on results.
References: N/A
Internal PRs: PR#819
No changes were made to Sea Spray Emissions in CMAQv5.4
Jeff Willison, U.S. Environmental Protection Agency
Type of update: Science Update and Bug Fix
Release Version/Date: CMAQv5.4
Description:
Several updates have been made to the windblown dust routine for CMAQ 5.4. The module has been updated to include additional PX soil texture information from WRF when available. The fugitive dust subroutines tfabove.F and tfbelow.F have been removed, since these were not originally intended to be used with windblown dust sources.
The option of using BELD3 as a windblown dust input has been removed. BELD3 is outdated and in CMAQ 5.3 the windblown dust module did not support BELD4 or BELD5. Beginning in CMAQ 5.4 the necessary land use information for windblown dust is taken from MCIP input files or WRF. For CMAQ 5.4 we strongly recommend the use of WRFv4.1+ and the PX LSM when enabling windblown dust emissions.
Lastly, a bug was corrected that was causing low erodibility values and significantly lower dust emissions when using WRFv4 inputs.
Significance and Impact:
A consequence of removing BELD as an option from windblown dust is that the DUST_LU* files are no longer needed. They have been removed from the CCTM code and the run scripts.
The following plot summarizes the impact of the remaining changes above:
Again, note, in the image above, the impacts of changing windblown dust input data from BELD to MCIP/WRF is not shown, but was not found to be a large contributor to the changes seen. As can be seen the largest change on modeled windblown dust is a result of the bug fix that was causing low erodibility values.
References: N/A Internal PRs: PR #877
