Draws wind barbs over maps.
procedure wmbarbmap ( wks  : graphic, lat : float, lon : float, u : float, v : float )
Arrays of any size and shape containing the latitudes and longitudes (in degrees) at which the wind barbs are to be drawn. These arrays must be the same size and shape as the u and v arrays.u
Arrays containing the zonal ("x") wind component and the meridional ("y") wind component.
This procedure is primarily to be used for drawing wind barbs that are defined on non-gridded data; if you are drawing wind barbs that are defined on gridded data over a map, then you could use a vector plot with vcGlyphStyle set to "WindBarb".
Wind barbs will be drawn at the specified locations using the current map transformation (i.e. on the most recently created map). The direction of the wind barbs is that which has the barbs pointing toward the wind direction (the meteorological convention). The length of the shaft of the wind barb is controlled by the value of the internal parameter WBS (see below for how to change the value of WBS). The length of the shaft has no relation to the wind speed.
The procedure wmbarbmap does not call frame.
[In version 4.3.0 and later] Wind barbs are not plotted where the input data has missing values.
See examples 3, 5, and 6 on the weather symbols application page.
The following code:
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl" begin cmap = (/(/1.,1.,1./),(/0.,0.,0./),(/1.,0.,0./) /) ; color map wks = gsn_open_wks("x11","test") ; ; Draw an orthographic map centered at lat/lon = (70.,-10.). ; Don't advance the frame, since we want to add wind barbs. ; mpres = True mpres@gsnFrame = False mpres@mpLimitMode = "LatLon" mpres@mpMinLonF = -40. mpres@mpMaxLonF = 20. mpres@mpMinLatF = 55. mpres@mpMaxLatF = 85. mpres@mpCenterLatF = 70. mpres@mpCenterLonF = -10. map = gsn_map(wks,"Orthographic",mpres) ; ; Draw an array of vertical wind barbs over the above map. ; lat = new((/3,2,5/),float) lon = new((/3,2,5/),float) u = new((/3,2,5/),float) v = new((/3,2,5/),float) lat(0,:,:) = 65 lat(1,:,:) = 70 lat(2,:,:) = 75 do i=0,4 lon(:,0,i) = -40.+i*5. lon(:,1,i) = -15.+i*5. end do u(:,:,:) = 0. v(:,:,:) = 90. wmsetp("col", 2) ; Draw in red. wmsetp("wbs", .06) ; Increase the size of the barb. wmbarbmap(wks, lat, lon, u, v) ; Plot barbs. frame(wks) ; Advance the frame. endwill draw wind barbs of the same magnitude, but at different locations.