Creates a vector plot from ARW WRF model output.
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl" load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl" function wrf_vector ( nc_file : file, wks : graphic, data_u [*][*] : numeric, data_v [*][*] : numeric, res : logical ) return_val  : graphic
Reference to an input netCDF file opened with addfile.wks
A two-dimensional array of the U component of the wind.data_v
A two-dimensional array of the V component of the wind.res
A variable containing an optional list of plot resources, attached as attributes.
A scalar id of the plot created is returned.
This function creates a vector plot (but does not draw it). To draw the plot, see the example below.
If data has a _FillValue attribute, this value will be used as a missing value.
If data_u has a "description" attribute, this value will be used in the plot title. (See description of "FieldTitle" attribute below.)
This function recognizes some special resources that can be attached as attributes to res:
- NumVectors - this defaults to 25. If this resource is set
along with vpWidthF, then these two
values will be used to determine values
for vcMinDistanceF and
(opts@vpWidthF/opts@NumVectors). Otherwise, these two resources will
default to 0.02.
- FieldTitle - This becomes the main title of the vector
plot. If not set, then the "description" attribute of the data_u
variable will be used, if available.
- SubFieldTitle - if set, this will be appended to the
FieldTitle title with a space between the two.
- UnitLabel - if set, this will be appended to the existing
FieldTitle title in parentheses. If not set, the "units" attribute of
the data_u variable will be used, if available.
- PlotLevelID - if set, this will be appended to the existing
FieldTitle title with an " at " between the two. If not set, the
"PlotLeveID" attribute of the data_u variable will be used, if
The final main title could look something like "FieldTitle SubFieldTitle (UnitLabel) at PlotLevelID".
Other vector resources are internally set by this routine:
- vcGlyphStyle - "WindBarb"
- vcWindBarbColor - "black"
- vcRefAnnoOn - False (default is normally True)
- vcMinFracLengthF - 2.0
wrf_vector is part of a library of functions and procedures in WRFUserARW.ncl written to help users plot ARW WRF model data.
WRF-related questions should be sent to firstname.lastname@example.org.
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl" load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl" a = addfile("wrfout_d01_2000-01-24_12:00:00.nc","r") wks = gsn_open_wks("x11","test") u10 = wrf_user_getvar(a,"U10",0) ; U component of the wind at 10m v10 = wrf_user_getvar(a,"V10",0) ; V component of the wind at 10m res = True res@gsnDraw = True ; Forces the plot to be drawn res@gsnFrame = True ; Frame advance vector = wrf_vector(a,wks,u10,v10,res)You can see some other example scripts and their resultant images at: