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Processed Dropwindsonde Observations in FRD Format

Expanded explanation of FRD, CAT, and Skew-T Diagram files

HRD's Full-Resolution Data (FRD) files are the output from the data received from the ASPEN program as used either on our onboard computer during a flight or, more likely, in post-flight quality control processing. It is in a standardized ASCII format. Each file begins with a header identifying the sonde, the date and time the sonde was processed. There follows several lines identifying the processing parameters, such as filters and bias corrections that have been applied as well as processor comments. The next block contains the launch information, such as time and location of launch and flight level temperature, pressure and geopential altitude at the aircraft at time of launch. The main body of data follows begining with a header line listing each column parameter and units. Each line of data will contain the observation sequential number, elapsed time, the meteorological observations, as well as the latitude, longitude, and altitude as determined by the sonde's GPS navigation chip. The usual time interval between observations is one half second.


Please contact Sim Aberson or Kathryn Sellwood if you have any questions about FRD format.

Last modified: 13 June 2018.
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