SNCROSS draws cross sections through sounding data. INPUT PARAMETERS CXSTNS *Cross-section station line SNPARM *Sounding parameter list SNFILE *Sounding data file DATTIM *Date/time VCOORD *Vertical coordinate type PTYPE *Plot type/h:w ratio/margins YAXIS *Ystrt/ystop/yinc/lbl;gln;tck TAXIS *Time1-time2-tinc;lbl;gln;tck LINE *Line color/type/width/label BORDER *Background color/dash/width CINT *Contour interval/min/max WIND *Wind symbol/siz/wdth/typ/hdsz TITLE *Title color/line/title PANEL *Panel location/color/dash/width DEVICE *Graphics device CLEAR *Clear screen flag FILTER *Filter data factor TEXT *Text size/font/width/hw flag CURVE *Curve fit type CONTUR *Contour attributes FINT *Fill interval/min/max FLINE *Fill colors CTYPE *Contour type: C/F PROGRAM DESCRIPTION SNCROSS draws cross sections using upper-air sounding data. The cross-section line, CXSTNS, must be specified as a list of stations separated with semicolons. Alternatively, a single station may be entered in CXSTNS and a list of times in DATTIM. In this case, a time section will be drawn. Any parameter that can be computed from the data set parameters can be displayed. The parameter to be displayed is specified in SNPARM. If the value of SNPARM is ISEN, isentropes will be drawn. Note that SNPARM may also be THTA, in which case, potential temperature will be gridded and contoured. ISEN will fit splines to the station data in plot space and then check for tangled lines and untangle them if necessary. When SNPARM = ISEN, the results should be the same as in the GEMPAK4 version of SNCROSS. Contours may be displayed as lines or as a color fill. CTYPE must be set to C for lines. If CTYPE = F, a color fill is produced. If CTYPE = F/L, the color fill is produced and labelled contour lines are drawn using the input for CINT and LINE. Filling is not available when SNPARM = ISEN. The attributes of the contour lines, including the color, line type, line width, and label frequency are specified in LINE. The four attributes are separated with slashes; semicolons separate the values for each attribute. If the line type is set to a single negative number, negative contour values will have the absolute value of the line type and positive values will be solid. If the label type is set to a single number, n, then every nth value will be labeled. The attributes of the color fill are specified in FLINE. FINT specifies the interval or levels for the color fill. The first color specified in FLINE fills values less than the first level; while the last color fills values greater than the last level. Hence, n levels requires n+1 colors. The plot background consists of a pressure axis, a horizontal axis with the station names, a hatched region indicating the part of the plot below the earth surface, and vertical lines at each station. The station lines are solid up to the level at which wind data stop, and are dashed from there to the level at which temperature data stop. The color for the entire background is given in BORDER. The horizontal axis represents a straight line between the first and last stations. The positions of intervening stations are proportional to the perpendicular projections of the actual positions onto the section line. All of these calculations are done in lat/lon coordinates. If the plot is a time section, the times will be displayed on the x axis with the earliest time at the left. If the first character in TAXIS is an R, the earliest time will appear on the right. The vertical coordinate may be specified as LIN, LOG, or STUVE; SKEWT is not valid in this program. The bottom and top limits for the y axis are specified in YAXIS, but the axis labelling specifications are ignored. EXAMPLES 1. Draw isentropes in color 5, line type 2, labelling every line. Plot the background in color 1. Use a logarithmic scale for the y axis and a 4 Kelvin interval for the isentropes. Draw wind barbs in color number 2 at the stations. CXSTNS = sep;ggg;jan;ckl;ahn;chs SNPARM = isen SNFILE = sound.snd DATTIM = last VCOORD = pres PTYPE = log YAXIS = TAXIS = LINE = 5/2/1 BORDER = 1 CINT = 4 WIND = bm2 TITLE = PANEL = 0 DEVICE = xw CLEAR = yes FILTER = yes CURVE = 2 TEXT = 2. Draw a time section using all the data in the file for IAD. CXSTNS = iad DATTIM = all ERROR MESSAGES [SNCROSS -1] Fatal error initializing TAE. [SNCROSS -2] Fatal error reading TAE parameters. [SNCROSS -3] GEMPLT initialization error. [SNCROSS -4] Vertical coordinate for isentropes must be PRES. [SNCROSS -5] There are no times in the file. [SNCROSS -6] Fewer than four stations/times were selected. [SNCROSS -7] Data buffer is too small. [SNCROSS -8] Temperature or pressure data not available. [SNCROSS -9] The station ... cannot be found in the data set. [SNCROSS -10] Error setting up graph; check invalid LOG axis. [SNCROSS -11] Input ... for PTYPE is invalid. [SNCROSS -12] Either input ... for YAXIS or input for VCOORD is invalid. [SNCROSS -13] Parameter ... is not computable. [SNCROSS -14] Parameter ... is a character. [SNCROSS -15] The grid coordinates cannot be defined. [SNCROSS -16] Multiple station entry is invalid for time sections. [SNCROSS -17] Data at time ... is not in the file. [SNCROSS -18] Wind data cannot be computed.