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This data set includes radiosonde measurements of upper air temperature and pressure, relative humidity, and wind direction and speed during the balloons' ascent to the upper atmosphere.
Data Set ID:
NSIDC-0231
SMEX02 Balloon-borne Radiosonde Data, Iowa, Version 1
This is the most recent version of these data.
Overview
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Citing These Data
As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.
Eichinger, W. 2004. SMEX02 Balloon-borne Radiosonde Data, Iowa, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/UKOUWG8EP6N3. [Date Accessed].Documentation
Detailed Data Description
The radiosonde data launches normally coincided with satellite overpasses, and in some cases multiple launches were made to characterize atmospheric boundary layer growth. The figure below shows the frequency of launches.
Format
Data are provided in ASCII text files.
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File Naming Convention
File names consist of the prefix "rad" for radiosonde, followed by numbers representing the month, day, hour, minute, and year. For example, the file "rad_062615022002.txt" was collected 26 June 2002 at 15:02 GMT.
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File Size
File sizes range from 1.59 KB to 7.9 KB.
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Volume
Total volume of data files is 324 KB.
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Spatial Coverage
Measurements were taken from the geographical coordinates 41.00°N, 93.61°W. Elevation is approximately 310 m above sea level.
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Temporal Coverage
Measurements were taken from 15 June through 9 July 2002. (Not all days were covered. Data are missing for 18, 19, and 20 June and 4, 5, and 7 July.)
Temporal Resolution
Launches took place between one and four times daily.
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Parameter or Variable
Parameter Description
Parameters are pressure, air temperature, relative humidity, dew point temperature, wind direction and speed.
The following table shows the data table elements and the units of measurement for the parameters. These data have been quality controlled; suspect or missing data has been flagged with a value of -999.
| Header information (first line) | Includes start time in time, day, month, and year. | |
| Site information (second line) | Includes station number, name of city, latitude, longitude, and elevation. | |
| Data Columns | Description | Unit of Measurement |
|---|---|---|
| Time min | Time after starting the measurements | minutes |
| s | Time after starting the measurements | seconds |
| AscRate m/s | Balloon ascent rate | meters per second |
| Hgt/agl m | Height above ground level | meters |
| Pressure hPa | Air pressure | hectopascals |
| Temp degC | Air Temperature | degrees Celsius |
| RH % | relative humidity | percentage |
| Dewp degC | Dew point temperature | degrees Celsius |
| Dir deg | Wind direction | degree |
| Speed m/s | Wind speed | meters per second |
Sample Data Record
The following sample was taken from the file "rad_062411532002.txt."
11:53 24 JUNE 2002 GMT 02313 Kelley 42.00N 93.61W 310 m Time AscRate Hgt/agl PressureTemp RH Dewp Dir Speed min s m/s m hPa degC % degC deg m/s 0 0 0.00 0 980.70 19.90 76 15.60 198 7.10 0 2 4.00 8 979.70 19.80 69 14.00 197 6.30 0 4 2.70 11 979.40 19.80 69 14.00 197 6.30 0 6 2.80 17 978.70 19.80 69 14.00 197 6.30 0 8 2.90 23 978.00 19.70 69 13.90 197 6.40 0 10 2.90 29 977.30 19.60 70 14.00 197 6.40 0 12 2.80 34 976.80 19.60 70 14.00 198 6.40
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Data Access and Tools
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Data Acquisition and Processing
Data Acquisition Methods
Measurements are based on use of the free-flying radiosonde, which transmitted data to the ground station over a 403 MHz radio link. Pressure, temperature and humidity were measured by sensors in the radiosonde. The location of the sonde was obtained by navigation networks (Navaids) via a receiver module on the sonde. The Navaid signals were relayed to the ground station for processing and computation of the wind profile.
The precision for atmospheric pressure is better than 1 hPa for pressures between 1060 hPa and 100 hPa, and better than 0.5 hPa for pressures between 100 hPa and 3 hPa.
The precision for air temperature is better than 0.2° C from -90° C to 60° C.
The precision for relative humidity of the air is 3%.
The precision for wind speed and direction is 0.5 m/s regardless of balloon distance from the ground system.
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Sensor or Instrument Description
The instrument used for the radiosonde was a DigiCORA MV11. This automatic rawinsonde set designed for accurate measurement of upper air pressure, temperature, relative humidity, and winds up to altitudes of 30 km. The measured data are processed automatically and given in standard meteorological formats.
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References and Related Publications
Contacts and Acknowledgments
Contributor(s) / Investigator(s):
William Eichinger
IIHR-Hydroscience and Engineering
University of Iowa
Acknowledgments:
William P. Kustas and Fuquin Li of the USDA ARS Hydrology Lab.
Document Information
DOCUMENT CREATION DATE
April 2004
