KPP Standalone

The GEOS-Chem KPP Standalone takes a given set of initial conditions to replicate grid cell chemistry of 3D GEOS-Chem, GCHP, or GEOS-CF runs. It reads an input file generated by the KPP Standalone Interface that generates model output of the full chemical state of the grid cell. The full GEOS-Chem mechanism is run to replicate the chemistry of the specified grid cell.

With contributions from: Obin Sturm (psturm@usc.edu), Michael S Long, Christoph Keller

The KPP Standalone is adapted from a box model used in the following publication: Lin, H., Long, M. S., Sander, R., Sandu, A., Yantosca, R. M., Estrada, L. A., et al. (2023). An adaptive auto-reduction solver for speeding up integration of chemical kinetics in atmospheric chemistry models: Implementation and evaluation in the Kinetic Pre-Processor (KPP) version 3.0.0. Journal of Advances in Modeling Earth Systems, 15, e2022MS003293. https://doi.org/10.1029/2022MS003293

The Kinetic PreProcessor (KPP) files can be modified and the mechanism rebuilt with KPP (see below). Then, the KPP Standalone can be rebuilt with make.

User-modifiable KPP files (taken from KPP/fullchem -- folder for the default GEOS-Chem mechanism)

This folder contains the files that define the full-chemistry mechanism (NOx-Ox-VOCs-Br-Cl-I) for GEOS-Chem.

1. fullchem.kpp: Master KPP specification file.

2. fullchem.eqn: KPP equation file, contains reaction definitoins.

3. fullchem_HetStateFuncs.F90: This module contains functions that initialize the HetChem state object.

4. fullchem_SulfurChemFuncs.F90: This module contains routines that compute rates for SO2 reactions in cloud.

5. fullchem_RateLawFuncs.F90: This module contains functions that compute rates for heterogenous chemistry reactions. This is the so-called "rate law library" for the fullchem mechanism.

6. rateLawUtilFuncs.F90: This module contains several utility functions for heterogeneous chemistry reactions.

7, commonIncludeVars.H: Global variables that are used for all KPP mechanisms. These will be inlined into the KPP-generated gckpp_Global.F90 file.

The following files link to the KPP/stubs folder. These include stub subroutines that are used by other chemical mechanisms. The stubs are needed in order to avoid compilation errors.

1. stub_aciduptake_DustChemFuncs.F90 Stub routines corresponding to the KPP/aciduptake/aciduptake_DustChemFuncs.F90 module,

2. stub_Hg_HetStateFuncs.F90: Stub routines corresponding to the KPP/Hg/Hg_HetStateFuncs.F90 module.

Files generated by KPP

With the exception of the symbolic link gckpp.kpp, and the map file gckpp.map, all files starting with the prefix gckpp_ are generated by KPP. These contain the specifications of the chemical mechanism in efficient source code.

For more information, please see:

1. KPP documentation at: https://kpp.readthedocs.io

2. Guide to Using KPP with GEOS-Chem