Introduction
Principles of operation
Data Naming Conventions and Data Format
Contact Information
The Office of the Federal Coordinator for Meteorology has a page devoted to radiosondes and rawinsonde, and it is the source for much of the following information.
The term radiosonde is a contraction for radio-sounding device. The instrument measures the ambient pressure, temperature, and moisture. When attached to a weather balloon filled with a lighter-than-air gas, radiosondes can attain heights in excess of 30 kilometers. Winds are determined from changes in the radiosonde position during the flight. The thermodynamic and wind data information are formulated into a "rawinsonde" observation.
The radiosonde transmits its data to a ground-based telemetry system (antenna and receiver). This telemetry system receives the signals and forwards them to another module (signal processing system) to be decoded into meteorological units. Data are then passed to a computer for collection of data for the entire sounding and formulation of the observation products. When the balloon reaches it elastic limit and bursts, a parachute slows the descent of the radiosonde to the ground.
The radiosondes used at Andros Island were GPS type radiosondes using full code-correlated transmission from up to 10 GPS satellites, providing accurate height and wind information allowing pressure/height correlations to be calculated.
Andros radiosonde data is archived into one composite tar file per day of the form:
c4gandros_1998_ddd.tar
Where ddd is the day of the year. When untarred, there will be files in ascii form representing the sonde data whose filenames are in the form:
2001mmdd-hhmmss.dat
where mm is month, dd is day and hhmmss is launch time in hours, minutes and seconds in UTC.
Data is in the UAIRP uniform 10-second and standard pressure level data output file format. The UAIRP format is as shown below. Note information (in black below) concerning the type of sonde used for the sounding.
CAMEX-4 PROGRAM / FINAL ANDROS ISLAND RADIOSONDE OUTPUT
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Location: Andros Island, the Bahamas
Latitude: 24 deg. 46.02 min. North
Longitude: 77 deg. 50.58 min. West Radiosonde Type: Mark II GPS(PVT) Serial No.: 02356526 Flight ID: CMX4002
Note: (1) Rel Hum removed for Temp < -35 C, (2) -999.9(...) = missing value
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Flight Date: 08/16/2001 Time: 14:56:52 UTC
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CAMEX-4 Program / 10-second Data Levels
Geop Rel Dew Mixng Spec Wind Wind Wind Wind Rise Elapsed
Height Press Temp Hum Point Ratio Hum Dir Speed E-W N-S Rate Time
meters hPa deg C pct deg C g/kg g/kg deg m/s m/s m/s m/s seconds
3.00 1018.76 31.40 68.74 24.96 19.9065 19.2892 91 4.1 -4.1 0.1 0.0 0.0
71.56 1011.00 28.81 75.85 24.12 19.0589 18.4922 133 5.1 -3.7 3.5 6.8 10.0
129.80 1004.43 28.16 83.86 25.17 20.4760 19.8234 133 5.1 -3.7 3.5 6.3 20.0
185.67 998.16 27.65 88.40 25.56 21.1006 20.4082 133 5.1 -3.7 3.5 6.0 30.0
Data can be ordered and questions addressed at http://ghrc.nsstc.nasa.gov/.
To order this data or for further information, please contact: Global Hydrology Resource Center
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Last update: Tuesday, 12-Jun-2007 16:53:33 CDT
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