GEMPAK Listing Programs: SFLIST

3.2.2| GEMPAK Listing Programs: SFLIST

Your first experience with the GEMPAK user interface will be with the program SFLIST

SFLIST lists any parameters which can be derived from the data in a GEMPAK surface data file, and can print the undecoded text information for standard and special observations if that information was stored by the decoding program.

$ sflist
 SFFILE          Surface data file               $GEMPAK/data/hrcbob.sfc
 AREA            Data area                       WV 
 DATTIM          Date/time                       LAST 
 SFPARM          Surface parameter list          SKYC;TMPF;WSYM;PMSL;;DWPF;BRBK
 OUTPUT          Output device/filename          T       
 IDNTYP          STNM or STID                    STID 
 Parameters requested: SFILE, AREA ,DATTIM, SFPARM, OUTPUT, IDNTYP. 
 GEMPAK-SFLIST>

What are looking at? HRCBOB.SFC? WV?

These are the program defaults and allow us to list/plot data immediately when starting to use GEMPAK. Try it!

 GEMPAK-SFLIST>r
 ...
    MVN    910820/0600  -9999.00    61.00 -9999.00 -9999.00    51.00     0.00
    ORD    910820/0600      6.00    65.00 -9999.00  1015.60    59.00  9020.00
    DPA    910820/0600      5.00 -9999.00 -9999.00 -9999.00 -9999.00 11000.00
    NBU    910820/0600      6.00    67.00 -9999.00  1015.40    58.00  8040.00
    DEC    910820/0600      0.00    62.00 -9999.00 -9999.00    58.00 11320.00
    MDW    910820/0600      6.00    67.00 -9999.00 -9999.00    60.00  9030.00
    MMO    910820/0600  -9999.00    58.00 -9999.00 -9999.00    51.00  8340.00
    YQG    910820/0600      8.00    64.00    80.00  1012.60    61.00  7060.00
    YXU    910820/0600      6.00    63.00 -9999.00  1013.70    59.00  7050.00
    YYZ    910820/0600      6.00    64.00 -9999.00  1014.00    52.00  8050.00

 Parameters requested: SFFILE,AREA,DATTIM,SFPARM,OUTPUT,IDNTYP.
 GEMPAK-SFLIST>

To restore the defaults file for SFLIST:

 GEMPAK-SFLIST> restore defaults/sflist.nts 
 GEMPAK-SFLIST> l

The user interface should now look like this:

 GEMPAK-SFLIST>
 SFFILE   =  
 AREA     =  
 DATTIM   =  
 SFPARM   =  
 OUTPUT   = t
 IDNTYP   = stid
 GEMPAK-SFLIST>

The restore defaults/sflist.nts command is not neccessary when running GEMPAK programs, but is used here to give us a "blank slate" to work with. OUTPUT and IDNTYP have been set to default values, so you don't need to worry about them. The rest will need to be defined (to access help type phelp sflist at the GEMPAK-SFLIST> prompt, or consult the on-line help file for SFLIST.

Additionally, you can see the GEMPAK help documentation for individual variables by typing phelp var (where var is the name of a variable, such as DATTIM).

To continue with our SFLIST erxample, we need to define the default/blank variables:

SFFILE - Data file name (be sure to include the correct path)
SFPARM - Surface Parameters
- 4-Character parameter names - For a complete list:
```
phelp sfparm
```
- Separated by a semicolon
```
sfparm = tmpc; pmsl; skyc
```
- If necessary, GEMPAK will calculate parameters
  If the requested parameter is not present in the data set, GEMPAK will attempt to calculate it from other parameters that are available.
  For example:
```
SFPARM = RELH
```
  If RELH (relative humidity) is not in the data set, GEMPAK will consult it's library of functional dependencies. GEMPAK finds: RELH=FUNC (TMPC;DWPT)
  
  Meaning, relative humidity (RELH) is a function of temperature (TMPC) and dew point (DWPT). GEMPAK can calculate RELH from the temperature and dew point as long as those parameters are in the data set. This is done automatically; all you have to do is ask for RELH.
- Arithmetic functions
  You can manipulate the values of parameters using the following arithmetic functions:
  Multiply"*", Divide"/", Add"+", Subtract"-", Greater than">", Less than"<"
  For Example:
```
SFPARM = tmpc/2         Divides all temperatures by two.

SFPARM = pmsl>1000      Only includes mean sea level
                        pressures higher than 1000 mb.
```
- Raw Hourly and Special reports (in addition to other parameters desired) if stored in the file
```
SFPARM = text
SFPARM = spcl
SFPARM = text;spcl
SFPARM = pmsl;tmpc;wthr;text
```
  Let's try it..

Exercises: Practice Exercises!!

List all measured data for the Rochester area from the last time in the Hurricane Bob surface data file.

Here's how to set the variables. Remember, you've already restored the defaults file earlier so the user interface should look like this:

 GEMPAK-SFLIST>display
 SFFILE    Surface data file                 
 AREA      Data area                         
 DATTIM    Date/time                         
 SFPARM    Surface parameter list            
 OUTPUT    Output device/filename            t
 IDNTYP    STNM or STID                      stid
 GEMPAK-SFLIST>

Now let's set the variables:

 GEMPAK-SFLIST>sffile=$GEMPAK/data/hrcbob.sfc
 GEMPAK-SFLIST>area=roc  
 GEMPAK-SFLIST>dattim=last
 GEMPAK-SFLIST>sfparm=dset

Redisplay the settings to be sure we've set everything properly:

GEMPAK-SFLIST>display
 SFFILE    Surface data file                 $GEMPAK/data/hrcbob.sfc
 AREA      Data area                         roc
 DATTIM    Date/time                         last
 SFPARM    Surface parameter list            dset
 OUTPUT    Output device (TPF)               T
 IDNTYP    STNM or STID                      STID
 GEMPAK-SFLIST>

Once all variables are defined, run the program.

GEMPAK-SFLIST>run

The list should look something like this (except quite a bit longer):

 GEMPAK-SFLIST>run
 PARM = PMSL;ALTI;TMPF;DWPF;SKNT;DRCT;GUST;WNUM;CHC1;CHC2;CHC3;VSBY;PT03;P03I;   
        HSUN;SNOW;TMPX;P24I
               
 
    STN  YYMMDD/HHMM      PMSL     ALTI     TMPF     DWPF     SKNT     DRCT
                          GUST     WNUM     CHC1     CHC2     CHC3     VSBY
                          PT03     P03I     HSUN     SNOW     TMPX     P24I
    ROC    910820/0600   1014.50    29.96    60.00    53.00     3.00    70.00
                      -9999.00     0.00   402.00 -9999.00 -9999.00    15.00
                          0.00 -9999.00 -9999.00 -9999.00    71.00 -9999.00
    ...

    YZE    910820/0600   1017.30    30.04    57.00    50.00     7.00    60.00
                      -9999.00     0.00     1.00 -9999.00 -9999.00    15.00
                      -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
    YAM    910820/0600   1017.70    30.05    54.00    52.00     0.00     0.00
                      -9999.00     0.00     1.00 -9999.00 -9999.00    15.00
                      -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
 Parameters requested: SFFILE,AREA,DATTIM,SFPARM,OUTPUT,IDNTYP.
 GEMPAK-SFLIST>

tip: Note: -9999.0 is the GEMPAK missing data value and indicates that no data was recorded.

Because this list was so overwhelmingly long, let's contract the data area. To do this we use the asterisk:

GEMPAK-SFLIST>area=roc**

This gives you a shorter list with data from only nine stations:

 GEMPAK-SFLIST>r
 PARM = PMSL;ALTI;TMPF;DWPF;SKNT;DRCT;GUST;WNUM;CHC1;CHC2;CHC3;VSBY;PT03;P03I;   
        HSUN;SNOW;TMPX;P24I                                                      
 
    STN  YYMMDD/HHMM      PMSL     ALTI     TMPF     DWPF     SKNT     DRCT
                          GUST     WNUM     CHC1     CHC2     CHC3     VSBY
                          PT03     P03I     HSUN     SNOW     TMPX     P24I
    ELM    910820/0600   1013.50    29.94    62.00    57.00     5.00    50.00
                      -9999.00     0.00   253.00   903.00  1104.00    10.00
                          0.00 -9999.00 -9999.00 -9999.00    79.00 -9999.00
    SYR    910820/0600   1013.40    29.93    61.00    56.00     6.00    10.00
                      -9999.00     0.00   302.00   802.00 -9999.00    10.00
                         -0.50 -9999.00 -9999.00 -9999.00    76.00 -9999.00
    JHW    910820/0600  -9999.00    29.92    60.00    51.00    11.00    90.00
                         14.00     0.00 -9999.00 -9999.00 -9999.00    10.00
                      -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
    BUF    910820/0600   1014.20    29.96    62.00    57.00     6.00    90.00
                      -9999.00     0.00   852.00  1104.00 -9999.00    30.00
                         -0.20 -9999.00 -9999.00 -9999.00    76.00 -9999.00
    IAG    910820/0600   1013.60    29.94    61.00    54.00     6.00    90.00
                      -9999.00     0.00   352.00   803.00  2504.00    20.00
                          0.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
    ROC    910820/0600   1014.50    29.96    60.00    53.00     3.00    70.00
                      -9999.00     0.00   402.00 -9999.00 -9999.00    15.00
                          0.00 -9999.00 -9999.00 -9999.00    71.00 -9999.00
    ART    910820/0600   1014.60    29.96    49.00    48.00     4.00   130.00
                      -9999.00     0.00     1.00 -9999.00 -9999.00    15.00
                      -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
    YTR    910820/0600   1014.70    29.96    59.00    52.00     2.00    90.00
                      -9999.00     0.00  2506.00 -9999.00 -9999.00    15.00
                      -9999.00 -9999.00 -9999.00 -9999.00 -9999.00 -9999.00
 Parameters requested: SFFILE,AREA,DATTIM,SFPARM,OUTPUT,IDNTYP.
 GEMPAK-SFLIST>

To leave the program, type exit.

GEMPAK-SFLIST>exit

Next: GEMPAK Listing Programs: SNLIST

GEMPAK Online Tutorial > GEMPAK Listing Programs