RRTMGP uses a k-distribution to provide an optical description (absorption and possibly Rayleigh optical depth) of the gaseous atmosphere, along with the relevant source functions, on a pre-determined spectral grid given temperatures, pressures, and gas concentration. The k-distribution currently distributed with this package is applicable to the Earth's atmosphere under present-day, pre-industrial, and 4xCO2 conditions.
RTE computes fluxes given spectrally-resolved optical descriptions and source functions. The fluxes are normally summarized or reduced via a user extensible class.
Example programs and documentation are evolving - please see examples/ in the repo and Wiki on the project's Github page. Suggestions are welcome. Meanwhile for questions please contact Robert Pincus and Eli Mlawer at firstname.lastname@example.org.
- The default method for solution for longwave problems that include scattering has been changed from 2-stream methods to a re-scaled and refined no-scattering calculation following Tang et al. 2018.
- In RRTMGP gas optics, the spectrally-resolved solar source function in can be adjusted by specifying the total solar irradiance (
gas_optics%set_tsi(tsi)) and/or the facular and sunspot indicies (
gas_optics%set_solar_variability(mg_index, sb_index, tsi))from the NRLSSI2 model of solar variability.
rte_lw()now includes optional arguments for computing the Jacobian (derivative) of broadband flux with respect to changes in surface temperature. In calculations neglecting scattering only the Jacobian of upwelling flux is computed. When using re-scaling to account for scattering the Jacobians of both up- and downwelling flux are computed.
- A new module,
mo_rte_config, contains two logical variables that indicate whether arguments to routines are to be checked for correct extents and/or valid values. These variables can be changed via calls to
rte_config_checks(). Setting the values to
.false.removes the checks. Invalid values may cause incorrect results, crashes, or other mayhem
Relative to commit
master on Apr 20, 2020, the required arguments to both the longwave and shortwave versions of
Building the libraries, examples, and unit-testing codes.
- Set environment variables
FC(the Fortran 2003 compiler) and
FCFLAGS(compiler flags). Examples are provided in the
- Set environment variables
RRTMGP_ROOTto the top-level RTE+RRTMGP directory and
openaccif you want the OpenACC/OpenMP kernels rather than the default.
make libsin the top-level directory will make the RTE and RRTMGP libraries.
- The examples and testing codes use netCDF. Set the variables
NFHOMEto the roots of the C and Fortran netCDF installations, then
make teststo build and run these. (A few files need to be downloaded for
examples/rfmip-clear-sky. The default is to download these with
wgetbut a Python script is also available.)
- Evaluating the results of the tests requires
xarraypackage and its dependencies installed. Comparisons can be made with
make checkin the top level directory.
makeinvoked without a target in the top level attempts all three steps.
Two examples are provided in
examples/, one for clear skies and one including clouds. Directory
tests/ contains regression testing (e.g. to ensure that answers are independent of orientation) and unit testing (to be sure all the code paths are tested). See the README file and codes in each directory for further information.