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20001202: Gempak

>From: Diana DeRubertis <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200012022321.eB2NLvo18500

>Hi,
>       I'm a grad student in climatology at UC Berkeley and will be
>calculating stablility indices from archived radiosonde data for a VERY
>LARGE selection stations and observation times over the last 50 years.  I
>basically need to create my own dataset of daily stability indices for each
>station.
>       I'd like to use Gempak, but will only need to use the program
>SNLIST.  Is it possible to download part of the package, since I won't need
>most of the other applications?  Second, can gempak handle the task I am
>looking to complete?  Meaning, can it calculate stabilty indices in a loop,
>for a very large set of soundings?
>
>Thanks for your time,
>Diana DeRubertis
>
>******************************************************************************
>
>Diana DeRubertis
>Dept of Geography
>University of California, Berkeley
>Office:  199 McCone Hall
>Email:  address@hidden
>
>

Diana,

GEMPAK consists of a very comprehensive library of functions, and most programs
are very simple calls to the library to read data, calculate quantities, etc.
As a result, it isn't possible to build just snlist without the rest of
the library code.

However, it is possible for you to download binary distributions for
some platforms (I already have distributions built for Linux, Solaris, 
Solaris X86). So, you could download the binaries and delete some parts of the 
distribution. For snlist, you don't need the map databases which are the biggest
users of disk space. You would still need the parameter, help and error tables
that the program uses.

The number of soundings that can be handled in a single file is a function of
the compile time settings for varying array sizes. The default configuration
allows 29,700 different stations at 300 times in a file (29,700 + 300 = 30,000
database records).

Typically, you could put 1 month of soundings in a file (31 days * up to 8
sounding times per day = 248 sounding times).
Looping through files is easily done through a shell script which can run
snlist for each month of each year. I did something similar for 50 years
of sounding data from NCDC's upper air archive on CDROM (Journal of
Atmospheric and Oceanic Technology, Vol 11, No 5 (1994), 1253-1261).

Before you start down this path, do you already know that snlist does compute 
the indicies that you need?

Steve Chiswell