The purpose of the Convert to Station utility menu is to list concentrations at specific latitude-longitude locations by extracting that information to a text file. The menu also has an option to produce a time series plot at one or more stations. An illustration of the menu is shown below.
Similar to the other menus in the utility section, the input concentration file must be defined by the Concentration Setup menu. The menu options correspond to the command line options of the con2stn extraction program. There are two options that can be used to define the extraction location. A station location can be defined directly as an entry in the menu, or a list of stations can be defined in an input file. In this example illustration, a file has been defined with three locations that are within the plume of the example simulation. The file consists of three records, one for each station:
The extraction program is called con2stn and for these three stations produces the output file shown below, called by default con2stn.txt. In contrast to the simulation shown in all the previous examples, in this case the output averaging time was decreased from 12 hours to one hour, to generate a smoother looking graphic.
The output file shows the Julian day, month, day, and hour of the sample start; day and hour of sample ending time, and the concentrations for each station (location selected by latitude-longitude). The format of each output record is as follows:
F8.3, 6I4 - Starting: Julian day, year, month, day, hour; Ending: day, hour
XF10 - Concentration value at X stations
The lower section of the GUI is used to create a simple time series concentration plot of the concentration time series. One or more stations may be plotted and the option is also available through the command line. The option is selected from the Display Postscript Time Series checkbox. The program, timeplot, reads the data file produced by the con2stn conversion program and plots the concentration values to the timeplot.ps output file. The illustration for the previous text file is shown below.
There are only two plot options supported through the GUI: linear or logarithmic ordinate scaling. In the linear scaling case, as shown above, the ordinate units must be integer whole numbers, and the minimum value will always be zero. Therefore it may be necessary to specify a units conversion factor, in this case 1015, to create data in the text file that can be plotted. With the log scaling option, the conversion factor can be set to 1.0, and the ordinate scale will cover the appropriate order-of-magnitude range to plot all the data.
Command Line Options - con2stn
The program can be run from the command line, through interactive prompts from the keyboard. The command line argument syntax is that there should be no space between the switch and options. The command line arguments can appear in any order.
con2stn -[option {value}]
Unspecified file names will result in a standard input prompt. The default interpolation method (-xn) is to use the value at nearest grid point to each latitude-longitude position. The station positions can be read from a file (space or comma delimited) with the first field being an integer that represents the location identification, followed by the location latitude and longitude. Level and pollutant index values can be selected for files with multiple levels and species.
Examples:
1) con2stn ... Results in prompts -->
Enter input concentration file name...
[name of hysplit output file]
Enter sampler ID#, latitude, longitude ...
[integer sample ID, real latitude, real longitude]
0 0 0 (to terminate input)
2) Read the model output file 'cdump' and write text output to file 'clist.txt' for station #517 at 53N 85W.
con2stn -icdump -oclist.txt
517 53.0 -85.0
0 0 0
3) As in 1) but multiply all concentrations by 1000.0
con2stn -icdump -oclist.txt -c1000.0
517 53.0 -85.0
0 0 0
4) As in 1) but linear interpolate concentration to station rather than using the nearest grid point
con2stn -icdump -oclist.txt -xi
517 53.0 -85.0
0 0 0
5) As in 1) but read the station lat-lon from a file "stns.txt".
con2stn -icdump -oclist.txt -sstns.txt
Command Line Options - timeplot [option {value}]