Data Set ID:
NSIDC-0231

SMEX02 Balloon-borne Radiosonde Data, Iowa, Version 1

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.

This is the most recent version of these data.

BASIC Level of Service

Data: Data integrity verified

Documentation: Key metadata and links to supporting documentation available

User Support: Assistance with data access and basic data usage

See All Level of Service Details

Parameter(s):
  • ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > AIR TEMPERATURE
  • ATMOSPHERIC PRESSURE > ATMOSPHERIC PRESSURE MEASUREMENTS
  • ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > DEW POINT TEMPERATURE
  • ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > HUMIDITY
  • ALTITUDE > STATION HEIGHT
  • ATMOSPHERIC WINDS > UPPER LEVEL WINDS
  • OCEAN WINDS > VERTICAL WIND MOTION
  • ATMOSPHERIC WINDS > WIND PROFILES
Data Format(s):
  • ASCII Text
Spatial Coverage:
N: 41, 
S: 41, 
E: -93.61, 
W: -93.61
Platform(s):BALLOONS
Spatial Resolution:Not SpecifiedSensor(s):RADIOSONDES
Temporal Coverage:
  • 15 June 2002 to 9 July 2002
Version(s):V1
Temporal ResolutionNot specifiedMetadata XML:View Metadata Record
Data Contributor(s):William Eichinger

Geographic Coverage

Once you have logged in, you will be able to click and download files via a Web browser. There are also options for downloading via a command line or client. For more detailed instructions, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login.

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].

Back to Top

Collapse All / Open All

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.

Launch frequency chart

Format

Data are provided in ASCII text files.

Background color on
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.

Background color on
File Size

File sizes range from 1.59 KB to 7.9 KB.

Background color on
Volume

Total volume of data files is 324 KB.

Background color on
Spatial Coverage

Measurements were taken from the geographical coordinates 41.00°N, 93.61°W. Elevation is approximately 310 m above sea level.

Background color on
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.

Background color on
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
Background color on

Software and Tools

Background color on

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.

Background color on
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.

Background color on

References and Related Publications

Contacts and Acknowledgments

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

No technical references available for this data set.

How To

V0 Programmatic Data Access Guide
Data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) can be accessed directly from our HTTPS file system. We provide basic command line Wget and curl instructions for HTTPS file system downloads below. For questions about programmatic access to NSIDC... read more