3. Introduction¶
A single-column model (SCM) can be a valuable tool for diagnosing the performance of a physics suite, from validating that schemes have been integrated into a suite correctly to deep dives into how physical processes are being represented by the approximating code. This SCM has the advantage of working with and being developed alongside the Common Community Physics Package (CCPP), a library of physical parameterizations for atmospheric numerical models (CCPP physics) and the associated framework for connecting potentially any atmospheric model to physics suites constructed from its member parameterizations (CCPP framework). In fact, this SCM serves as perhaps the simplest example for using the CCPP and its framework in an atmospheric model. This version contains all parameterizations of NOAA’s evolved operational GFS v16 suite (implemented in 2021), plus additional developmental schemes. The schemes are grouped in six supported suites described in detail in the CCPP Scientific Documentation (GFS_v16, GFS_v17p8, RAP, HRRR, and RRFS_v1beta, and WoFS_v0).
This document serves as both the User and Technical Guides for this model. It contains a Quick Start Guide with instructions for obtaining the code, compiling, and running a sample test case; an explanation for what is included in the repository; a brief description of the operation of the model; a description of how cases are set up and run, and finally, an explanation for how the model interfaces with physics through the CCPP infrastructure.
3.1. Version Notes¶
The CCPP SCM v6.0.0 contains the following major and minor changes since v5.0.
Major
Inclusion of regression testing functionality
Combine single- and multi-run capabilities into one script
Minor
Add RUC LSM support
Add the GFS_v17p8, HRRR, RRFS_v1beta, and WoFS_v0 suites
Update the vertical coordinate code to better match latest FV3 vertical coordinate code
Simplify the case configuration namelists
Add greater flexibility for output location (outside of bin directory)
3.1.1. Limitations¶
This release bundle has some known limitations:
In the output file, temperature tendency variables all mistakenly have the same description, although their variable names are correct. This has been fixed in the development code.
Using the RRFS_v1beta, HRRR, and WoFS_v0 suites for cases where deep convection is expected to be active will likely produce strange/unreliable results, unless the forcing has been modified to account for the deep convection. This is because forcing for existing cases assumes a horizontal scale for which deep convection is subgrid-scale and is expected to be parameterized. The suites without convection are intended for use with regional UFS simulations with horizontal scale small enough not to need a deep convection parameterization active, and it does not contain a deep convective scheme. Nevertheless, these suites are included with the SCM as-is for research purposes.
The provided cases over land points cannot use an LSM at this time due to the lack of initialization data for the LSMs. Therefore, for the provided cases over land points (ARM_SGP_summer_1997_* and LASSO_*, where sfc_type = 1 is set in the case configuration file), prescribed surface fluxes must be used:
surface sensible and latent heat fluxes must be provided in the case data file
sfc_flux_spec must be set to true in the case configuration file
the surface roughness length in cm must be set in the case configuration file
the suite defintion file used (physics_suite variable in the case configuration file) must have been modified to use prescribed surface fluxes rather than an LSM.
NOTE: If one can develop appropriate initial conditions for the LSMs for the supplied cases over land points, there should be no technical reason why they cannot be used with LSMs, however.
As of this release, using the SCM over a land point with an LSM is possible through the use of UFS initial conditions (see Section 7.5). However, advective forcing terms are unavailable as of this release, so only short integrations using this configuration should be employed. Using dynamical tendencies (advective forcing terms) from the UFS will be part of a future release.
There are several capabilities of the developmental code that have not been tested sufficiently to be considered part of the supported release. Those include additional parameterizations. Users that want to use experimental capabilities should refer to Subsection 4.1.2.