PLUME-IN-GRID (PinG) NOTES - 30 September 2006 The plume-in-grid (PinG) approach is an optional component when building the CMAQ chemical transport model (CTM). The PinG module was previously released in 2005 with the CMAQ modeling system. However, this 2006 release of the CMAQ PinG module supersedes previous versions. The CMAQ PinG approach was specifically designed to provide a realistic, subgrid treatment of the dynamic and chemical processes governing concentrations in pollutant plumes emitted from isolated, major point source stacks. The PinG approach is appropriate for use in model applications with relatively coarse grid cell sizes (i.e., ~12-40 km), that are typical for regional to continental modeling domains. In order to include the PinG module in a CTM executable program, the ping module must be set with ModPinG in the model build script rather than the default "no PinG" module (i.e., ping_noop ) as given below. For the 2006 release, PinG has been updated to allow for aerosol modeling in plumes with the aero4 version of the aerosol module. #set ModPing = ( module ping_noop $release; ) set ModPing = ( module ping_smvgear_aero3 $release; ) with CB4 only set ModPing = ( module ping_smvgear_aero4 $release; ) with CB4 or CB05 The CTM/PinG module increases CPU processing time of model simulations, however, the computational increased time is dependent on the number of PinG sources and the overall dimensions of the modeling domain. Additional preprocessing steps must be undertaken prior to running the CTM/PinG model simulations. In particular, during emissions processing with the SMOKE system, a stack parameter file (i.e. stack_groups) and a point source emissions file must be generated for the selected major point sources to be treated by the PinG module. In addition, the plume dynamics model (PDM) processor program must be applied with the stack_groups file to generate a plume parameter file (PDM_PING_1) which is used to drive the PinG module in the CTM/PinG program. Information about the PDM program and applying it were described in previous release notes. CERTAIN FEATURES AND UPGRADES OF THE 2006 CMAQ PING MODULE INCLUDE: Aerosols processing with the aero4 version has also been implemented in PinG to treat aerosol formation and deposition from selected point sources. However, PinG can also be built with the aero3 version along with CB4 chemistry. Consequently, a selection of ping_smvgear_aero3 or ping_smvgear_aero4 must be made when building the CTM/PinG executable. The CTM/PinG program can be executed on a single processor platform or on a parallel computing architecture, such as a Linux cluster. A dry deposition file is generated containing plume pollutant dry deposition amounts in a 2-D gridded output file analogous to the CTM dry deposition file. Plume dry deposition amounts must be added to the CTM dry deposition values in order to compute total dry deposition. The sparse matrix Gear solver (smvgear) algorithm is the only chemical solver available with the PinG module. The default number of plume pillar cells has been set to 8 to resolve the horizontal plume width with 4 plume cells on each side of the centerline and subgrid plume concentrations are written out at 15 minute intervals to the CTM_PING_1 output file, as specified in PLUME_PARM.F KEY RUN SCRIPT INFORMATION WHEN RUNNING CTM WITH THE PING TREATMENT To perform CTM/PING simulations, additional input and output files related to the PinG module must be specified. The specific input files needed for the PinG module include; a major point source emissions data file (MEPSE_1) of specific PinG sources which was generated during SMOKE processing, and a PDM output data file. Specific settings for a CTM/PinG Unix run script are given by the following. # Set varaible for the aerosol diagnostic file [ T | Y | F | N ] # Currently, do not generate a PinG aerosol diag. file. setenv CTM_AERDIAG Y setenv PING_AERDIAG N # With aero4 only for the sea-salt emissions diagnostic file [ T | Y | F | N ] # Currently do not generate this file when running with PinG setenv CTM_SSEMDIAG N # mepse emissions file for PinG set MEPSEpath = directory path set MEPSEfile = pingts_l.${DAY} # PDM data file for PinG set PDMpath = directory path location set PDMfile = pdm.ioapi_${DAY} The output files generated by the PinG module include a plume concentration file containing species concentrations in all active subgrid plume cells, a plume dry deposition file, and an optional plume diagnostic aerosol file. set PG1file = PINGCONC.${DAY} # CTM_PING_1 plume conc file set PGWfile = PINGDRYDEP.${DAY} # CTM_PING_DDEP_1 # Currently, do not write to a plume diagnostic file. #setenv PING_AERDIAG Y # optional diagnostic output #set PGDfile = PINGDIAM".${DAY} # CTM_PING_DIAM_1 A key plume environment variable flag (INIT_PING) must also be specified to signal to the PinG module whether a PinG concentration file exists for the previous day. The INIT_PING variable in the run script must be set to T in order to begin on the first day with no active plumes. For all subsequent simulation days, INIT_PING must be set to F in order to continue and complete plumes active at the end of the previous day's simulation. Plume concentrations are initialized with the active plume concentrations from the end of the previous day's CTM_PING plume concentration file which is specified in the run script below. # PinG plume continuation flag ( previous CTM_PING file not required ) setenv INIT_PING T # Begin "fresh" on day 1 only (i.e. No continuation # or restart) setenv INIT_PING F # For all simulation days after day 1, for # continuation of active plumes from the previous day # The PinG conc file generated from the previous day's simulation # must be declared when INIT_PING is defined by F above. set PG0file = PINGCONC.${PREVDAY} # CTM_PING_0 set PINGpath = $OUTDIR # directory path of ping conc files set PINGfile = $PG0file When applying the CMAQ/CTM with PinG, a run script can be set up to sequentially execute multiple days in a particular simulation if files are available just as in a CTM run without PinG. A post-processor program is available in the TOOLS section to merge the CTM_CONC_1 and CTM_PING_1 concentration files. The merge_ping_ctm program weights the subgrid plume concentrations with the CTM grid concentration and generates a merged concentration file containing the contributions of the subgrid plume concentrations. For visualization of the plume concentration file, the PAVE graphics tool can be used to view species concentrations in plumes.