Chemistry model parameters

Steering

String2

String3

Since Version 5.0 a chemistry model is available in PALM which computes chemical conversion and tranport of reactive trace gases. In addition this module permits also the simulation of passive compounds in the gas phase and particulate matter.

The main routines and the Driver of the chemistry module is included in chemistry_model_mod.f90.

The module chem_gasphase_mod.f90, where the gas phase chemistry rate equations are solved within PALM4U depends on the chosen chemical mechanism. chem_gasphase_mod.f90 is generated by a preprocessor that is based on the Kinetic Pre-Processor KPP (Damian et al., 2002, Sandu et al., 2006), Release 2.2.3 from November 2012 (​http://people.cs.vt.edu/asandu/Software/Kpp/, kpp-2.2.3.tar.gz) and an adapted version of the KPP postprocessor KP4 (Jöckel et al, 2010, ​https://www.geosci-model-dev.net/3/717/2010/). This adapted Version of kp4 which converts the KPP-generated code to a PALM4U module is named kpp4palm.

Currently PALM-4U includes the following sample of chemistry mechanisms:
CBM4: Carbon Bond Mechanism (Gery et al. 1989, 32 compounds, 81 reactions)
SMOG: Photochemical smog mechanism (13 compounds, 12 reactions)
SIMPLE: Simplified versio of SMOG (9 compounds, 7 reactions)
PHSTAT: Photo-stationary state (3 compounds, 2 reactions)

Additionally 'mechanisms' are availble that describes the transport of one and two passive tracers
PASSIVE1: Passive tracers (1 compound, 0 reactions)
PASSIVE: Passive tracers (2 compounds, 0 reactions)
and the mechanisms mentiones above plus one passive Tracer (e.g SIMPLE: Simplified of SMOG plus one Tracer named PM10 (10 compounds, 7 reactions)

For details about preparing a chem_gasphase_mod.f90 for different chemical mechanism than the one that comes with checkout of PALM4U (currently PASSIVE) see Readme_KPP4PALM.odt in the PALM4U subdirectory UTIL/chemistry/gasphase_preproc.

Chemistry is automatically activated when a chemistry_parameters namelist is set in the parameter file (_p3d).

A brief description of the chemistry model will follow here (see LSM description as an example).

NAMELIST group name: chemistry_parameters

NAMELIST /chemistry_parameters/

bc_cs_b, &
bc_cs_t, &
call_chem_at_all_substeps, &
chem_debug0, &
chem_debug1, &
chem_debug2, &
chem_gasphase_on, &
cs_heights, &
cs_name, &
cs_profile, &
cs_profile_name, &
cs_surface, &
cs_surface_initial_change, &
cs_vertical_gradient_level, &
daytype_mdh, &
decycle_chem_lr, &
decycle_chem_ns, &
decycle_method, &
do_emis &
emiss_factor_main, &
emiss_factor_side, &
icntrl, &
main_street_id, &
max_street_id, &
mode_emis, &
my_steps, &
nest_chemistry, &
rcntrl, &
side_street_id, &
photolysis_scheme, &
wall_csflux, &
cs_vertical_gradient, &
top_csflux, &
surface_csflux, &
surface_csflux_name, &
time_fac_type, &

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Steering:

Parameter Name	FORTRAN Type	Default Value	Explanation
cs_surface	R	0.0	Concentration value for chemical species at the surface. Here, a detailed description follows...Maybe also link to an example input file.