[ferret_users] Data Extraction from NWP files

["Waylon.Collins" <waylon.collins@xxxxxxxx>]

Dear List,


Does anyone have a Ferret script to perform the following tasks? I want 
to (1) input netCDF files containing archived WRF-NMM, Eta, and RUC 
numerical weather prediction (NWP) model forecast output, and 
latitude/longitude values for a particular point, then (2) output the 
interpolated values for selected variables at that latitude/longitude 
point. I will process hundreds of netCDF files (literally thousands of 
calculations) and thus will need to run the script in what I believe is 
referred to as "batch mode". I have experience running Unix shell 
scripts and placing them on the cron, but I am not certain how to 
efficiently run Ferret scripts in batch mode. I have Ferret installed on 
a x86-64 Linux box running RedHat Enterprise WS3.


Also, the foregoing files are actually GRIB files, yet I plan to convert 
to netCDF. Has anyone successfully converted WRF-NMM, Eta, and/or RUC 
GRIB files to netCDF? I know that I can retain the GRIB format and run 
Arthur Taylor's degrib program 
(http://www.weather.gov/mdl/NDFD_GRIB2Decoder), and I have done so. In 
particular, I have run degrib from within a Perl script which extracts 
selected output from Eta/WRF-NMM GRIB files. However, my data set is 
several years long and it takes 1 week to process 1 year of data -- too 
slow! My programming experience is limited to shell scripting.


Also, I was wondering if anyone has a Ferret script that will calculate 
certain thermodynamic parameters (at specific latitude/longitude 
points) not available in the aforementioned files. The parameters are 
(1) Equilibrium Level (EL) height, (2) EL temperature, and (3) CAPE in 
the -10C to -20C layer. To clarify, the source data are Eta, WRF-NMM, 
and RUC files containing NWP forecast output, not "sounding" data. 


Waylon

--
Waylon Collins (Senior Forecaster)
NOAA/National Weather Service
300 Pinson Drive
Corpus Christi, TX 78406
(United States)
Telephone: (361) 289-0959