Description of the file "sonden.tar.Z":

To get the compressed and archived data file
of radiosonde data switch your ftp to binary mode
and copy the file to your local computer.

After having recieved it uncompress it by using
the "uncompress" command in UNIX.
Then you have to extract the file from archive
with the command "tar xvf sonden.tar.Z .".

Now there are two types of files. 
That one with the extension ".dat" is the corrected
radiosonde data. The extension ".apa" a the corresponding
text-file.

First two numerals of the file name is the year of launch,
2nd and 3rd numerals are the month, the next two  are the
day and the last two numerals are the rounded start-time
in full hours in GMT.

The text file contains some usefull information such as 
the position of start in [degrees.minutes], the start-date
and time, the number of the Vaisala radiosonde, information
about the ground-check and about the wind measurment.

The data file contains following parameters:

1)  time after launch in minutes

2)  time after launch in seconds
 
3)  computed height of the radiosonde in m

4)  pressure in hPa

5)  temperature in C.

6)  relative humidity in %.

7)  computed dewpoint temperature over water in C.

8)  wind direction in degrees.

9)  wind speed in m/s.

If you have any question about the data please contact me:

                  jem@sop.dkrz.d400.de