CMAQ Release Notes: Preprocessors

MCIP

Removed Superfluous Open/Close Couplet to Read WRF Files in MCIP

Tanya Spero, U.S. Environmental Protection Agency

Type of update: Efficiency

Release Version/Date: CMAQv5.5

Description: Updated rdwrfem.f90 in MCIP to remove redundant open/close of netCDF files.

Significance and Impact: This change improves efficiency and does not change the simulation results. The change reduces runtime of MCIP by ~25-30% per day for hourly WRF output in daily files on the benchmark domain. Reductions in runtime become negligible for large computational domains.

References: N/A

Internal PRs: PR#1097

Updated MCIP Metadata for WRF Physics Beyond WRFv4.1

Tanya Spero, U.S. Environmental Protection Agency

Type of update: Metadata Update

Release Version/Date: CMAQv5.5

Description: The global header information (i.e., metadata) in the MCIP output files lists the high-level WRF physics options that were used in the simulation processed by MCIP. The text interpretation of the WRF token values (collected from the WRF metadata in its output header) is based on a translation in MCIP that is performed in the subroutine wrfemopts.f90. That subroutine had not been updated since WRFv4.1 was released, and additional WRF physics options have been implemented between then and the release of WRFv4.5.2. This set of changes to MCIP updates the cross-reference listing to provide accurate metadata for newer WRF physics options.

Significance and Impact: This change to MCIP does not affect the numerical calculations. However, it improves the accuracy of the metadata in the MCIP header when newer WRF physics options (implemented after WRFv4.1) are exercised and subsequently processed through MCIP.

References: WRF Users Guide for WRFv4.5

Internal PRs: PR#1098

Additional MCIP release notes can be found under the DOCS/MCIP folder.

ICON

No changes were made to ICON in CMAQv5.4.

BCON

Improved IC/BC species mappings for CRACMM

Havala Pye and Christian Hogrefe, U.S. Environmental Protection Agency

Type of update: Bug fix

Release Version/Date: CMAQv5.5

Description: The species definition file mapping carbon bond-based mechanism species to CRACMM species located at PREP/bcon/map2mech/SpecDef_*.txt was updated to improve consistency across mechanisms and reduce unnecessary mapping. Mapping of tracers/species that do not contribute meaningfully to mass (TOLRO2, XYLRO2, AH3OP, IEPOXP) were removed. Mapping across monoterpene and isoprene systems was updated. These updates were implemented for CRACMM1 and were carried forward to CRACMM2 as part of CRACMM2 development.

Significance and Impact: Improves consistency in how species map across mechanisms. Minor changes to model predictions are expected. This file is not recommended for mapping emissions between mechanisms as the representation of fresh emissions is more variable between mechanisms than the representation of processed emissions.

References: N/A

Internal PRs: PR#958; PR#1133

Create OMI

William T. Hutzell, U.S. Environmental Protection Agency

Type of update: Bug fix and Scripts Update

Release Version/Date: CMAQv5.4

Description: A bug fix and script enhancement was made. The bug fix corrects format statements used to write the ASCII output file. The error and its fix were identified in a CMAS Forum post. When the latitude and longitude resolution is greater than 360X360 degrees, the format descriptors are too small and cause the output lines to wrap around themselves. The error causes the total ozone column to be incorrectly calculated in CCTM and produce bad values of photolysis frequencies from the inline build option. The bad values do not exist in the repositories version of the OMI data file under CCTM/src/phot/inline. The script enhancement revises create_omi's build and run scripts so they function as similar scripts for ICON and BCON tools.

Significance and Impact: If the simulation uses an OMI data file created with lat/long resolution greater than 360X360 degrees, CCTM will calculate and use bad values of photolysis frequencies.

References: N/A

Internal PRs PR#779