RELEASE NOTES for CAMx v7.10, 1/5/21 The Comprehensive Air Quality Model with extensions (CAMx) is available at http://www.camx.com. Overview of Version 7.10 ------------------------ V7.10 includes new features, modifications, and bug fixes from the previous release (v7.00) * Use the chemistry parameters files specifically labeled for v7.1. * The TUV photolysis input files include some format changes; see below for details. * The CAMx control namelist file has not changed since the last 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 v7.10 New Features and Major Updates ------------------------------------ 1. CB6 revision 5 (CB6r5) incorporates recent updates to chemical reactions for inorganic and simple organic species that play important roles in ozone formation. One new reaction was added. Implications: Generally small changes in ozone concentrations within a few ppb. v7.10 Modifications ------------------- 1. Requirements to include nested grid buffer cells on gridded emission input files have been relaxed and all gridded output files no longer include buffer cells. Implication: The inclusion of buffer cells was historically required on all gridded input files, even though data in those cells are not used by the model. CAMx continues to allow for emission files that include buffer cells to maintain backward compatibility with older datasets. Nested grid buffer cells continue to be required on input meteorological files because they provide the needed space to store the staggered wind fields. No further post-processing will be necessary to remove unused buffer grid cells from the output arrays. 2. Plume depth override has been added to NCF point source files. Implications: Fortran binary point source files include an option to specify plume top/bottom heights to override the internal plume rise algorithm in CAMx. This option has been extended to the NCF point source files for consistency. 3. TUV photolysis input files have been updated to include a more specific version label on the first record. Implications: The label now specifically includes TUV version, CAMx version, and photochemical mechanism version to help ensure proper photolysis rates are provided to CAMx for the chosen mechanism. 4. The ammonia bidirectional scheme has been updated for landuse categories associated with high anthropogenic ammonia emissions. Implications: A logic error was fixed that was prohibiting both deposition and re-emission of ammonia for landuse categories that are associated with high ammonia emission rates (fertilization or animal waste). Now only deposition is allowed for these landuse categories because in such areas: explicit ammonia emissions are provided to the model, resulting ambient ammonia concentrations are high, and deposition should dominate (otherwise bidirectional NH3 emissions would double-count the explicit emissions). This restriction was extended to include grasslands. 5. Updated the wet and dry deposition treatment for the RTCMC component of RTRAC. Implication: RTCMC dry and wet deposition parameters are now defined, and deposition rates are calculated, in a manner consistent with the standard RTRAC methodology. 6. Added explicit requirement that APCA must be invoked when using NH3 bidi with SAT to ensure user supplies natural source emissions file as first SAT emission category. Implications: NH3 bidi emissions are attributed to "natural" emission category in SAT, similar to APCA for ozone source apportionment. The APCA option requires natural emissions (e.g., biogenic) to be listed as source category 1. If you are running NH3 bidi with SAT pay careful attention to the APCA option and your input list of emission files. v7.10 Bug Fixes --------------- 1. Fixed several bugs in improperly injecting emissions into nested grids. Implications: a) Under certain conditions 3D emission files for SAT were not properly injected into nested grids. b) When running >2 grids, core and Probing Tools emissions were emitted incorrectly into grids 3+. Non-fatal errors, but resulted in obviously incorrect results. 2. Fixed bug that improperly mapped point source species to model species when running SAT. Implications: Core model point source species were improperly injected affecting core model concentrations and by extension SAT concentrations. 3. Fixed bugs writing DDM output and restart files for nested grids when DDM is set to calculate sensitivities only for a specific grid. Implications: DDM output for single nested grids is now properly generated. 4. Fixed several NCF I/O bugs: a) Changed CAMx file type global attribute from "NAME" to "CAMX_NAME" to alleviate conflicts with updated C libraries introduced in NCF v4.6.2. Caused fatal model crashes. c) Fixed a source apportionment bug related to using NCF meteorological inputs with binary IC/BC files to calculate IC/BC reactivity. Led to fatal model stop. d) Fixed incorrect global attributes for grid dimensions in output files. Non-fatal. e) Fixed the VARLIST global attribute to use proper 16-character string lengths (specific to IO-API) Non-fatal but affected ability to post-process output files using I/O-API tools. f) Fix bug to expand NCF file type string lengths to avoid read errors. Avoids fatal model stop when reading certain NCF input files. 3. Fixed a bug in PiG that was rarely locating puffs in improper grid cells. Implications: Single-precision math was occasionally locating PiG puffs in neighboring cells, leading to model stop due to reaching a maximum number of iterations from crossing cell borders. 4. Fixed NH3 bidi emissions bug that was not emitting NH3 for the core model. Implications: NH3 bidi emissions were only emitted for core model when SAT or DDM was enabled.