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Creates a background chart for Skew T, Log P plotting.


load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"   ; These two libraries are automatically
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"    ; loaded from NCL V6.2.0 onward.
                                                           ; No need for user to explicitly load.

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/skewt_func.ncl" ; Still need to load this library.

	function skewT_BackGround (
		wks  : graphic,  
		res  : graphic   

	return_val  :  graphic



A Workstation identifier. The identifier is one returned either from calling gsn_open_wks or calling create to create a Workstation object.


A variable containing an optional list of plot resources, attached as attributes. Set to True if you want the attached attributes to be applied, and False if you either don't have any resources to set, or you don't want the resources applied.

Return value

A plot identifier of the Skew T background chart created is returned.


This function creates a Skew T background in conformance with the weather prediction chart (WPC) described in DOD-WPC 9-16-1. For an overview of the information on a Skew T chart, see:

skewT_BackGround takes a workstation ID and a resource list as arguments. By default skewT_BackGround produces no graphical output; it sets the special resources gsnDraw and gsnFrame to False. The user must use the draw procedure to render the background and invoke the frame procedure to advance the plot.

The primary use of this procedure is to create a background for use with skewT_PlotData.

Note: in versions NCL 6.1.0 and later, the colors produced by this function may appear slightly different. This is because the code is using named colors to draw certain elements, like "PaleGreen" for the background, and "Tan" for the lines. In NCL 6.1.0, named colors no longer need to be added to a color map in order to be recognized, so you will start to see the correct colors in this release. If you don't like these colors, you can restore the old ones by setting the "UseMyColorMap" resource to True. You may also need to set the color map to "default":


There are a number of resources the user can set to alter the default Skew T background. For more information about how to use these resources, see the examples section below.

Resource name Default value
DrawIsotherm True
DrawIsobar True
DrawMixRatio True
DrawDryAdiabat True
DrawMoistAdiabat True (aka: saturation or pseudo adiabat)
DrawWind True
DrawStandardAtm True
DrawColLine True
DrawColAreaFill False
DrawFahrenheit True (Fahrenheit "x" axis)
DrawHeightScale False
DrawHeightScaleFt True (default is feet [otherwise km])
DrawStandardAtmThk 2.0
UseMyColorMap False
PrintOpts False
Font "helvetica"

See Also



Several examples illustrating the use of skewT_BackGround and selected resources may be seen in the Skew T examples page.