ERF Tools

A collection of Python-based modules and scripts for facilitating the usage of the Energy Research and Forecasting (ERF) model.

Examples

Some short snippets are provided below with commonly used workflows also having command line analogues to facilitate execution. These console scripts are immediately available in your environment after you install the erftools package. Note that each script includes a --help option, e.g.,

wrf_namelist_to_erf --help

Please see the notebooks folder for more detailed examples.

Converting a WRF namelist into ERF inputs

from erftools.preprocessing import WRFInputDeck

wrf = WRFInputDeck('namelist.input')
wrf.write_inputfile('inputs')

# optional: extract data from wrfinput
wrf.process_initial_conditions('wrfinput_d01',
                               write_hgt='terrain_height.txt',
                               write_z0='roughness_height.txt')

The namelist conversion may also be accomplished from the command line:

wrf_namelist_to_erf namelist.input inputs

Plotting a Nested Grid Configuration

from erftools.grids import LambertConformalGrid

now23 = LambertConformalGrid(
    ref_lat=37.100163,
    ref_lon=-122.49992,
    truelat1=37.100163, # standard parallel
    stand_lon=-122.49992, # standard longitude
    dx=[6000, 2000],
    dy=[6000, 2000],
    nx=[243, 552], # WRF staggered dim - 1
    ny=[243, 579],
    ll_ij=[(30,27)], # parent grid index
)
fig, ax = now23.plot_grids()

From the command line, the grid geometry can be read from an ERF input file and plotted:

plotgrids inputs --latlon0 35.85 -123.72 --truelat1 36.05 --standlon -65.0

Postprocessing Data Logs

Data logs are output with the erf.data_log param and can include time histories of surface conditions and planar averaged profiles (e.g., for idealized LES simulations)

from erftools.postprocessing import DataLog

log = DataLog(f'{simdir}/surf_hist.dat',
              f'{simdir}/mean_profiles.dat',
              f'{simdir}/flux_profiles.dat',
              f'{simdir}/sfs_profiles.dat')

log.calc_stress()
log.est_abl_height('max_theta_grad')

print(log.ds) # data are stored in an xarray dataset

Installation

Clone and create a conda (or mamba) environment:

git clone https://github.com/erf-model/erftools.git
cd erftools
conda create -n erftools python=3.9
conda activate erftools

Then, install with:

pip install -e . # editable install

or install with all optional dependencies:

Contributing

Some notes and recommendations:

• An aspirational goal is to contribute code that can be used as in the examples above, with clear, intuitive naming.
• To avoid duplication, model constants are defined in erftools.constants, which should replicate ERF/Source/ERF_Constants.H.
• In the same vein, equation of state evaluations are defined in erftools.utils.EOS, which should replicate ERF/Source/Utils/ERF_EOS.H.
• Other utilities for calculating/deriving/diagnosing quantities of interest are also in erftools.utils.*
• Please follow PEP-8 style--as a set of guidelines rather than gospel--to facilitate code usage and maintenance by the community.