Converting GFS forecast files to ARL..data above 10mb

[csbfmet]

Hello,

I am a meteorologist at NASA's Columbia Scientific Balloon Facility. We have used HYSPLIT and ECMWF reanalysis data to produce stratospheric balloon trajectories for site selection. Our balloons float at 10 to 2 mb. We use the operational GFS wind forecasts above 10 mb that are present in the "full" and "part b" for trajectory forecasting. We wish to now start using HYSPLIT for this purpose I can't seem to convert the GFS files to ARL format. For a test I downloaded the 00,03,06, and 09 hour forecasts from NOMADS, southern hemisphere only, and just u,v,t, and z at 10,7, and 5mb. I then used cnvgrib to convert the files to GRIB1 format. Now I cannot figure out how to run the conversion GUI (or command line) to convert the files.

Thanks,
Robert Mullenax
CSBF Meteorology

[barbara.stunder]

Was there are file 'MESSAGE' written when you ran the conversion program? If so, I'd like to see it.

[csbfmet]

Basically just something like terminated but I will get the full message later this morning. Thanks

[csbfmet]

First of all I am not clear how to name the file. I have 00-09 hour forecast from 12Z on 6 Feb catted into one file in GRIB format. If I name it gfs0612 then it says it can't find gfs0600 if I list start day as day 6. If I rename file to gfs0600 with start day of 6 and 3 hourly intervals I get:

113
113
while executing
"exec $exec_dir/grib2arl.exe $arg1 $arg2 $arg3 $arg4 $arg5 $arg6 $arg7 >STDOUT"
(procedure "xtrct_data" line 59)
invoked from within
"xtrct_data $gdir $gbase"
invoked from within
".ecmarch.bot.save invoke"
("uplevel" body line 1)
invoked from within
"uplevel #0 [list $w invoke]"
(procedure "tk::ButtonUp" line 24)
invoked from within
"tk::ButtonUp .ecmarch.bot.save"
(command bound to event)

obviously I want all the forecast hours in one file in the output (out to 384 hours eventually). Do I need to have each forecast hour in a separate GRIB file?

[csbfmet]

Obviously NCEP converts the GFS to ARL format operationally (but not the data above 10mb). Is there a tutorial for this?

[barbara.stunder]

Sorry there is no tutorial. The program 'gfs2arl' in the HYSPLIT package converts one-degree GFS grib1 NCEP output to HYSPLIT-format. It should be relatively simple to add higher levels. The difficulty is that NCEP now outputs data in grib2 and the grib2 libraries are harder to work with. The NCEP utility cnvgrib can be used to convert grib2 to grib1.