2. Getting Started¶
This chapter is an introduction to setting up and running ParFlow. In ParFlow Solvers we describe the solver options available for use with ParFlow applications.
The ParFlow source code can be found on the ParFlow GitHub. Instructions for building ParFlow and Frequently-Asked Questions can be found on the ParFlow Wiki.
2.1. ParFlow Solvers¶
ParFlow can operate using a number of different solvers. Two of these solvers, IMPES (running in single-phase, fully-saturated mode, not multiphase) and RICHARDS (running in variably-saturated mode, not multiphase, with the options of land surface processes and coupled overland flow) are detailed below. This is a brief summary of solver settings used to simulate under three sets of conditions, fully-saturated, variably-saturated and variably-saturated with overland flow. A complete, detailed explanation of the solver parameters for ParFlow may be found later in this manual. To simulate fully saturated, steady-state conditions set the solver to IMPES, an example is given below. This is also the default solver in ParFlow, so if no solver is specified the code solves using IMPES.
pfset Solver Impes
To simulate variably-saturated, transient conditions, using Richards’ equation, variably/fully saturated, transient with compressible storage set the solver to RICHARDS. An example is below. This is also the solver used to simulate surface flow or coupled surface-subsurface flow.
pfset Solver Richards
To simulate overland flow, using the kinematic wave approximation to the shallow-wave equations, set the solver to RICHARDS and set the upper patch boundary condition for the domain geometry to OverlandFlow, an example is below. This simulates overland flow, independently or coupled to Richards’ Equation as detailed in [KM06]. The overland flow boundary condition can simulate both uniform and spatially-distributed sources, reading a distribution of fluxes from a binary file in the latter case.
pfset Patch.z-upper.BCPressure.Type OverlandFlow
For this case, the solver needs to be set to RICHARDS:
pfset Solver Richards
ParFlow may also be coupled with the land surface model
This version of
CLM has been extensively modified to be called
from within ParFlow as a subroutine, to support parallel infrastructure including I/O and most importantly with modified physics
to support coupled operation to best utilize the integrated hydrology in ParFlow [KM08a, MM05].
CLM into ParFlow first the
option is needed in the
./configure command as indicated in Installing ParFlow. Second, the
CLM module needs
to be called from within ParFlow, this is done using the following solver key:
pfset Solver.LSM CLM
Note that this key is used to call
CLM from within the nonlinear solver time loop and requires that the solver bet set to RICHARDS to work.
Note also that this key defaults to not call
CLM so if this line is omitted
CLM will not be called from within
ParFlow even if compiled and linked. Currently,
CLM gets some of it’s information from ParFlow such as grid,
topology and discretization, but also has some of it’s own input files for land cover, land cover types and atmospheric forcing.