RELEASE NOTES for CAMx v7.31, 08/15/24 The Comprehensive Air Quality Model with extensions (CAMx) is available at www.camx.com. v7.31 Bug Fixes --------------- 1. Fixed species indexing bugs reading SAT point source emission files. Implications: This only occurred when using ozone source apportionment, and led to clearly bad results in core model oozne concentration fields. 2. Reversed a coding error in SAT that led to an NCF routine reading binary top boundary condition input files and a binary routine reading NCF inputs. Implications: This error only affected reading top boundary conditions for source apportionment. 3. Fixed bugs in specifying number of tracer species for DDM and RTRAC in several of their respective setup routines. Implications: This bug was related to the number of new tracers for the SOAP3 routine. RELEASE NOTES for CAMx v7.30, 06/24/24 Overview of Version 7.30 ------------------------ V7.30 includes new features, modifications, and bug fixes from the previous release (v7.20) * Use the chemistry parameters files specifically labeled for v7.3. * Use the TUV photolysis pre-processor specific to v7.3 that supports the CB7 and RACM2 photochemical mechanisms. * Check the CAMx control namelist template for the full list of control variables specific to this version. * The operation of the CAMx makefile has not changed since the last version. Type "make" or "make help" for more information. NOTE: RECENT VERSIONS OF THE GFORTRAN COMPILER WILL NOT COMPILE CAMx WITH OMP PARALLELIZATION BECAUSE OF AN INCOMPATIBILITY WITH BLOCK DATA IN ISORROPIA. THIS IS NOT AN ISSUE WITH OTHER SUPPORTED COMPILERS. OPTIONS: a) USE MPI ONLY WITH GFORTRAN b) REVERT BACK TO AN OLDER VERSION OF GFORTRAN c) USE A DIFFERENT COMPILER v7.30 New Features and Major Updates ------------------------------------ 1. Carbon Bond version 7, revision 1 (CB7r1) photochemical mechanism. * Major update focusing on ozone chemistry of biogenic VOC (isoprene and terpenes). * Updated alkane chemistry larger than propane and associated ketones as they represent a large fraction of anthropogenic VOC emissions. * Updated iodine mechanism for ozone destruction. * Updated rate constants for organic peroxy radical reactions to reflect current information and improve mechanism efficiency. * Adds explicit alpha-pinene SOA precursor for PSAT. | Implications: CB7r1 does not require any changes to how anthropogenic emission inventories are speciated for CAMx since it is backwards compatible with CB6. However, to take full advantage of CB7, α-pinene (APIN) emissions should be separated from other terpenes (TERP) and include sesquiterpene (SQT). CB7 works with all Probing Tools. Use the TUV photolysis pre-processor specific to v7.3 that supports CB7r1. See the CAMx User's Guide for more information. CB7r1 is less responsive to NOx emission reductions than CB6r5. 2. Carbon Bond version 6, Revision 5, is extended with a full updated halogen mechanism (CB6r5h) involving chlorine and bromine. The halogen mechanism is based on an extensive review of recent literature to identify reactions that allow inorganic halogen emissions to interact fully with ozone, VOC and NOx. Current reaction rate constant and photolytic reaction data were obtained from the reviews published by NASA and IUPAC. Implications: CB6r5h replaces the earlier full halogen mechanism in CB6r2h. Inorganic iodine chemistry and associated in-line inorganic iodine emissions from oceans are maintained. CB6r5h works with all Probing Tools. Use the TUV photolysis pre-processor specific to v7.3 that supports CB6r5. See the CAMx User's Guide for more information. 3. Regional Atmospheric Chemistry Mechanism version 2, Spring 2021 update (RACM2s21). Implications: RACM2s21 includes an update to RACM2 based on a review focused on inorganic and photolysis reactions by making use of the most recent data compilation from NASA-JPL. RACM2 works with all Probing Tools. Use the TUV photolysis pre-processor specific to v7.3 that supports RACM2. See the CAMx User's Guide for more information. 4. The SOAP organic chemistry/partitioning module is updated to version 3 (SOAP3). This update substantially revises the formation of organic condensable gases and aerosols from VOC/IVOC/SVOC precursors. See the User's Guide for more information. Implications: 1. SOAP3 species names have been changed to support this update and better reflect precursors, sources, and volatility states. 1. Anthropogenic primary organic aerosol (POA) emissions can fractionally evaporate to a semi-volatile gas species (SVOC) depending on temperature and source type. Emission can continue to specify a simple "POA" species, for which an average evaporation rate is applied, or can specify POA from gas, diesel, general IC engines, meat cooking, biomass burning, or other, for which unique evaporation rates are applied. A "NOEVAP" option is available to revert back to SOAP2 with no POA evaporation. 2. SVOC can be emitted and produced by POA evaporation, and can further oxidize and partition to SOA. SOAP3 continues to support IVOC emissions that similarly oxidize and partition to SOA. To take full advantage of SOAP3 updates, emission inputs should include estimates of anthropogenic IVOC and SVOC. 3. VOC reaction yields generating condensable gases and non-volatile SOA have been updated based on recent research. This update is referred to as the "complex" option. A "simple" option is also available that yields only non-volatile SOA from VOC oxidation reactions. 4. SOAP3 includes the production of non-volatile SOA from heterogeneous glyoxal/methylglyoxal oxidation on aerosols. Reactions have been added to all supported gas phase mechanisms to support this update. 5. DDM has been extended to include the Chemical Sensitivity Analysis (CSA) option that calculates the sensitivity of species concentrations to rate constants and reaction stoichiometric coefficients defined in the gas-phase chemical mechanism. CSA is configured with a separate control file namelist module. Implications: Unlike the standard DDM, chemical sensitivities are determined within a set of user-defined grid cells, providing computational efficiency comparable to box models while maintaining a complete sensitivity integration within CAMx. CSA operates only for gas-phase chemistry and cannot be invoked if aerosols are run. CSA is currently not allowed with MPI parallelization but can be used with OMP parallelization. 6. DDM has been extended to include sensitivity to dry deposition. New DDM namelist variables have been added for this feature. Implications: Concentration sensitivities to dry deposition velocities can be calculated from either the Wesely or Zhang schemes. Deposition sensitivities track how a given species concentration responds to a change in the deposition velocity for that same species or any other influencing species. 7. Removed the CMU multi-section PM size option. Implications: Now the only aerosol size option is the static 2-mode CF. v7.30 Modifications ------------------- 1. The heterogeneous chemistry rate routine has been updated to ensure consistent use of the gas-phase rate for N2O5 hydrolysis. Implications: In gas-only chemistry mode, the N2O5 hydrolysis rate was reset to a higher value than provided in the chemistry parameters file. It is now consistent with the input rate. Expect negligible to minor impacts to some gases when running in gas-only mode. No impact to heterogeneous N2O5 hydrolysis. 2. Updated chemistry parameters for certain compounds. Implications: Molecular weights, Henry's Law solubility, and deposition parameters have been updated for some compounds based on current information, especially for SOAP species. Negligible to minor effects are expected. 3. The setting of temperature and pressure intervals for the internal reaction rate lookup table has been automated. Implications: This update removes the need for the user to adjust the number of T and P intervals when max/min T and P values need to be changed (i.e., as directed by a CAMx error message). v7.30 Bug Fixes --------------- 1. Fixed vertical advection codes to properly and consistently dimension DDM sensitivity arrays. Implications: Inconsistent array dimensions between calling and receiving routines led to accessing memory out of bounds. This bug occurred under certain model memory configurations and resulted in confusing or obviously incorrect DDM results. 2. Fixed a bug that was modifying lat/lon grid spacing from namelist input. Implications: This fix alleviates a model stop with error message when comparing user-defined lat/lon grid spacing against those read from gridded input files. 3. Fixed a bug that was incorrectly writing RTRAC deposition variable names to output file headers. Implications: Names in RTRAC header records were inconsistent with variable names written to hourly binary I/O records and inconsistent with other model deposition variables. 4. Added check that users supply 4-digit years in the CAMx control namelist file. Implications: Entering 2-digit years carried over to NCF output files, which are incompatible with Models-3 software. 5. Added check that users supply ozone column and photolysis rates files with correct Dobson Units and within expected ranges. Implications: This check helps to ensure users are supplying modern O3MAP and photolysis files with correct DU units, as opposed to older files carrying DU/1000. 6. Fixed a few incorrect CPA variable unit attributes on NCF output files. Implications: No effect on CAMx results, simply correcting units attributes (e.g., "ppb hr-1") to more correctly reflect contents of each variable. 7. Improved the memory allocation of point source emission array shape. Implications: Certain portions of CAMx code were allocating point source memory using actual number of point sources read, while other portions were allocating based on a max parameter. This could lead to inconsistent memory shapes for the point array, which was discovered for DDM and led to inexplainable results. 8. Fixed mass tracking bug in SA wet deposition. Implications: The bug led to SA wet deposited mass that was inconsistent with core model deposition, leading to minor differences in reporting SA wet deposited mass. 9. Fixed bug to include molecular weight when re-ordering species in READCHM.F Implications: The model re-orders the incoming species list defined in the chemistry parameters input file for purposes of setting up the chemical solvers. All species-related parameters were reordered except molecular weight, which could affect the conversion of output gas concentrations from ppm to ug/m3 when that option is invoked. 10. Fixed code reading NCF RTRAC BC files. Implications: RTRAC was not reading NCF BC files, but was properly reading Fortran binary BC files. 11. Fixed bugs in surface model and added read of NCF surface model restart files. Implications: Several issues were found and fixed in the surface model code, including I/O files. The surface model was lacking code to read surface model NCF output files for model restarts. 12. Bug fix reading SA NCF point source plume bottom variable. Implications: This fix results in a consistent treatment of plume rise between the core model and SA point source treatments. 13. Fix bug to allow >99 MPI nodes in the names of node-specific .OUT and .DIAG output files. Implications: Previously only two digits were written to the filenames, resulting in hash marks (#) when nodes>99. Now up to 999 nodes are accommodated.