Scripts for processing WRF and CAMx files to PALM dynamic driver.

Usage

The set of Python scripts in directory WRF_interface serves for processing of WRF and CAMx output files to the PALM dynamic driver. The processing is launched by the Python script palm_dynamic.py from the subdirectory "dynamic". This script requires name of the configuration as a parameter on the command line:

palm_dynamic.py -c <config_name> [-w]

The corresponding configuration files are placed in the subdirectory "configuration" and they are named <config_name>.conf. Examples of the config files are supplied with the scripts, all configuration options are described in the README file as well as at the end of this page. The values which agree with defaults need not to be present in the config file. The file palm_dynamic_init.py contains setting and calculation of standard initialization values for particular system and can be adjusted. The optional parameter -w allows to skip horizontal and vertical interpolation in case it has been already done in previous run of this script for the same domain and resolution.

These scripts were implemented with regard to good portability and they depend only on standard and well-known Python libraries. Needed modules are:

• numpy (​https://pypi.org/project/numpy)
• scipy (​https://pypi.org/project/scipy)
• pyproj (​https://pypi.org/project/pyproj)
• netCDF4 (​https://pypi.org/project/netCDF4)
• metpy (​https://unidata.github.io/MetPy)

First four modules are included in all major linux distributions. In other cases, they can be installed via pip (e.g. "pip3 install netCDF4").

The MetPy module is a well-known and widely used module for meteorological calculations in Python maintained by Unidata. It can also be installed using pip ("pip3 install MetPy").

In the current version, the only supported projection in WRF is Lambert conformal conic, which is WRF default and recommended projection for mid-latitudes. The CAMx output files, which are used optionally for the chemical initial and boundary conditions, are expected to be the result of a coupled CAMx simulation using the same horizontal grid as WRF, although this is not strictly required.

The scripts support both variants of WRF vertical levels - the sigma levels (default until WRF version 3.*) and the hybrid levels (default since WRF 4.*). However, it is necessary to correctly configure this option via the setting "wrf_hybrid_levs = True/False".

Configuration

Configuration files have syntax:

# Comment line
<parameter1> = <value1>
<parameter2> = <value2>
...

Parameters can be string, integer, float, logical or list of these values. The <value> terms have Python syntax, the config file needs to contain only parameters which differ from default.

Description of the particular configuration options are:

Domain and case related configurations

Option	Default value	Description
domain	""	Name of the simulation case.
scenario	""	Name of the scenario in the case.
resolution	""	Name of the domain resolution.
nested_domain	False	False indicates parent and True nested domain.
dynamic_driver_file	""	File name of output dynamic driver. The default value "" means the standard name assigned in the palm_dynamic_init.
grid_from_static	True	True means the horizontal grid parameters are imported from the static driver, in case of False, they are to be prescribed in the config (see below).
static_driver_file	""	File name of the static driver in case of grid_from_static = True. The default value "" means the standard name is assigned in init.
proj_palm	"EPSG:32633"	Reference coordinate system of the PALM simulation.
proj_wgs84	"EPSG:4326"	Reference coordinate system of lon-lat projection.
dz	0.0	Height of the PALM vertical grid layer. The default value dz = 0.0 means dz is assigned from dx.
nz	200	Number of vertical layers of PALM domain.
dz_stretch_level	5000.0	Height in meters from which stretching of vertical levels starts in PALM.
dz_stretch_factor	1.0	Coefficient of the stretching of the vertical layers in PALM.
dz_max	100.0	Maximal height of the stretched vertical layers.
origin_time	""	Origin time of the PALM simulation in the format YYYY-MM-DD hh:mm:ss. The default value "" means that the value is set from the global attribute "origin_time" of the static driver.
simulation_hours	24	Extent of the simulation in hours.

WRF and CAMx related configurations

Option	Default value	Description
wrf_hybrid_levs	True	True means hybrid levels in WRF files, False sigma levels.
vinterp_terrain_smoothing	None	The standard deviation for Gaussian kernel of smoothing method of the PALM terrain for WRF vertical interpolation to avoid sharp horizontal gradients. Value None disables the smoothing.
wrf_dir_name	""	Path of the directory containing the wrf and camx files. The default value "" means that the standard path will be calculated in the init.
wrf_file_mask	"wrfout_*.e000"	File mask of the wrf input files.
radiation_from_wrf	True	Enable or disable processing of radiation from WRF files.
wrf_rad_file_mask	"auxhist6_*"	File mask of the wrf radiation input files. The default setting reads radiation from WRF auxiliary history files. This setting allows to use finer time step for WRF radiation outputs than for other WRF values.
radiation_smoothing_distance	10000.0	Smoothing distance for radiation values in m.
camx_file_mask	"CAMx.*.nc"	File mask of the CAMx input files.
species_names	['NO','NO2','O3','PM10','PM25']	PALM names of the chemical species. The default value can be used for phstatp and phstatp2 chemical mechanisms in PALM. The mapping and recalculation from the CAMx species to PALM species is defined in the variable camx_conversions (see palm_dynamic_init.py). The default mapping is configured for CAMx v6.50 with CB05 + PM (CF,SOAP2.1,ISORROPIA) chemistry mechanisms. In case of other combinations, it may be necessary to adjust this mapping.

Horizontal parameters of the PALM domain in case of grid_from_static = False

Option	Description
nx, ny	Number of horizontal grids of the domain in x and y directions.
dx, dy	Grid cell size of the domain in x and y directions.
origin_x, origin_y	Origin of the domain in the x and y directions.
origin_z	Origin of the domain in the vertical direction.

Credits

Version: 3.1, License: GPL v3, Authors: Krystof Eben, Jaroslav Resler, Pavel Krc, Institute of Computer Science of the Czech Academy of Sciences, Prague.

For an example of utilization see e.g. ​https://doi.org/10.5194/gmd-2020-175.