wrf.getvar¶
-
wrf.
getvar
(wrfin, varname, timeidx=0, method='cat', squeeze=True, cache=None, meta=True, **kwargs)¶ Returns basic diagnostics from the WRF ARW model output.
A table of all available diagnostics is below.
Variable Name Description Available Units Additional Keyword Arguments avo Absolute Vorticity 10-5 s-1 eth/theta_e Equivalent Potential Temperature K
degC
degF
units (str) : Set to desired units. Default is ‘K’. cape_2d 2D CAPE (MCAPE/MCIN/LCL/LFC) J kg-1 ; J kg-1 ; m ; m missing (float): Fill value for output only cape_3d 3D CAPE and CIN J kg-1 missing (float): Fill value for output only ctt Cloud Top Temperature degC
K
degF
fill_nocloud (boolean): Set to True to use fill values for cloud free regions rather than surface temperature. Default is False.
missing (float): The fill value to use when fill_nocloud is True.
opt_thresh (float): The optical depth required to trigger the cloud top temperature calculation. Default is 1.0.
units (str) : Set to desired units. Default is ‘degC’.
cloudfrac Cloud Fraction % vert_type (str): The vertical coordinate type for the cloud thresholds. Must be ‘height_agl’, ‘height_msl’, or ‘pres’. Default is ‘height_agl’.
low_thresh (float): The low cloud threshold (meters for ‘height_agl’ and ‘height_msl’, pascals for ‘pres’). Default is 300 m (97000 Pa)
mid_thresh (float): The mid cloud threshold (meters for ‘height_agl’ and ‘height_msl’, pascals for ‘pres’). Default is 2000 m (80000 Pa)
high_thresh (float): The high cloud threshold (meters for ‘height_agl’ and ‘height_msl’, pascals for ‘pres’). Default is 6000 m (45000 Pa)
dbz Reflectivity dBZ do_variant (boolean): Set to True to enable variant calculation. Default is False.
do_liqskin (boolean): Set to True to enable liquid skin calculation. Default is False.
mdbz Maximum Reflectivity dBZ do_variant (boolean): Set to True to enable variant calculation. Default is False.
do_liqskin (boolean): Set to True to enable liquid skin calculation. Default is False.
geopt/geopotential Geopotential for the Mass Grid m2 s-2 geopt_stag Geopotential for the Vertically Staggered Grid m2 s-2 helicity Storm Relative Helicity m2 s-2 top (float): The top level for the calculation in meters. Default is 3000.0. lat Latitude decimal degrees lon Longitude decimal degrees omg/omega Omega Pa s-1 p/pres Full Model Pressure
(in specified units)
Pa
hPa
mb
torr
mmhg
atm
units (str) : Set to desired units. Default is ‘Pa’. pressure Full Model Pressure (hPa) hPa pvo Potential Vorticity PVU pw Precipitable Water kg m-2 rh Relative Humidity % rh2 2m Relative Humidity % slp Sea Level Pressure hPa
hPa
mb
torr
mmhg
atm
units (str) : Set to desired units. Default is ‘hPa’. T2 2m Temperature K ter Model Terrain Height m
km
dm
ft
mi
units (str) : Set to desired units. Default is ‘m’. td2 2m Dew Point Temperature degC
K
degF
units (str) : Set to desired units. Default is ‘degC’. td Dew Point Temperature degC
K
degF
units (str) : Set to desired units. Default is ‘degC’. tc Temperature in Celsius degC th/theta Potential Temperature K
degC
degF
units (str) : Set to desired units. Default is ‘K’. temp Temperature (in specified units) K
degC
degF
units (str) : Set to desired units. Default is ‘K’. tk Temperature in Kelvin K times Times in the File or Sequence xtimes XTIME Coordinate
(if applicable)
minutes since
start of
model run
tv Virtual Temperature K
degC
degF
units (str) : Set to desired units. Default is ‘K’. twb Wet Bulb Temperature K
degC
degF
units (str) : Set to desired units. Default is ‘K’. updraft_helicity Updraft Helicity m2 s-2 bottom (float): The bottom level for the calculation in meters. Default is 2000.0.
top (float): The top level for the calculation in meters. Default is 5000.0.
ua U-component of Wind on Mass Points m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. va V-component of Wind on Mass Points m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. wa W-component of Wind on Mass Points m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. uvmet10 10 m U and V Components of Wind
Rotated to Earth Coordinates
m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. uvmet U and V Components of Wind
Rotated to Earth Coordinates
m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. wspd_wdir Wind Speed and Direction (wind_from_direction)
in Grid Coordinates
m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. wspd_wdir10 10m Wind Speed and Direction (wind_from_direction)
in Grid Coordinates
m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. uvmet_wspd_wdir Wind Speed and Direction (wind_from_direction)
Rotated to Earth Coordinates
m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. uvmet10_wspd_wdir 10m Wind Speed and Direction (wind_from_direction)
Rotated to Earth Coordinates
m s-1
km h-1
mi h-1
kt
ft s-1
units (str) : Set to desired units. Default is ‘m s-1’. z/height Model Height for Mass Grid m
km
dm
ft
mi
msl (boolean): Set to False to return AGL values. True is for MSL. Default is True.
units (str) : Set to desired units. Default is ‘m’.
height_agl Model Height for Mass Grid (AGL) m
km
dm
ft
mi
units (str) : Set to desired units. Default is ‘m’. zstag Model Height for Vertically Staggered Grid m
km
dm
ft
mi
msl (boolean): Set to False to return AGL values. True is for MSL. Default is True.
units (str) : Set to desired units. Default is ‘m’.
Parameters: - wrfin (
netCDF4.Dataset
,Nio.NioFile
, or an iterable) – WRF-ARW NetCDF data as anetCDF4.Dataset
,Nio.NioFile
or an iterable sequence of the aforementioned types. - varname (
str
) – The variable name. - timeidx (
int
orwrf.ALL_TIMES
, optional) – The desired time index. This value can be a positive integer, negative integer, orwrf.ALL_TIMES
(an alias for None) to return all times in the file or sequence. The default is 0. - method (
str
, optional) – The aggregation method to use for sequences. Must be either ‘cat’ or ‘join’. ‘cat’ combines the data along the Time dimension. ‘join’ creates a new dimension for the file index. The default is ‘cat’. - squeeze (
bool
, optional) – Set to False to prevent dimensions with a size of 1 from being automatically removed from the shape of the output. Default is True. - cache (
dict
, optional) – A dictionary of (varname, ndarray) that can be used to supply pre-extracted NetCDF variables to the computational routines. It is primarily used for internal purposes, but can also be used to improve performance by eliminating the need to repeatedly extract the same variables used in multiple diagnostics calculations, particularly when using large sequences of files. Default is None. - meta (
bool
, optional) – Set to False to disable metadata and returnnumpy.ndarray
instead ofxarray.DataArray
. Default is True. - **kwargs – Optional keyword arguments for certain diagnostics. See table above.
Returns: If xarray is enabled and the meta parameter is True, then the result will be a
xarray.DataArray
object. Otherwise, the result will be anumpy.ndarray
object with no metadata.Return type: Raises: ValueError
– Raised when an invalid diagnostic type or keyword argument is passed to the routine.FortranError
– Raised when a problem occurs during a Fortran calculation.
See also
Examples
Using netCDF4
from netCDF4 import Dataset from wrf import getvar wrfnc = Dataset("wrfout_d02_2010-06-13_21:00:00") slp = getvar(wrfnc, "slp")
Using PyNIO
from Nio import open_file from wrf import getvar wrfnc = open_file("wrfout_d02_2010-06-13_21:00:00"+".nc", "r") slp = getvar(wrfnc, "slp")
Using Iterables:
import os from netCDF4 import Dataset from wrf import getvar filedir = "/path/to/wrf/files" wrfin = [Dataset(f) for f in os.listdir(filedir) if f.startswith("wrfout_d02_")] uvmet = getvar(wrfin, "uvmet", timeidx=3, units="kt")
- wrfin (