Data Set ID:
NSIDC-0037

Nimbus-7 SMMR Antenna Temperatures, Version 1

The SMMR Antenna Temperatures (Nimbus-7) data set consists of antenna temperatures from passive microwave radiometers aboard NOAA's Nimbus-7 satellite. The instrument is the Scanning Multichannel Microwave Radiometer (SMMR). Each file consists of one days worth of data in swath format, i.e. the portion of the Earth's surface viewed by the scanning radiometer. Antenna temperature data are available from NSIDC from October 1978 to August 1987. SMMR was a ten channel passive microwave instrument using six conventional Dicke-type radiometers. It delivered orthogonally polarized antenna temperature data at five frequencies: 6.6, 10.69, 18.0 21.0 and 37.0 GHz. The two 37.0 GHz radiometers operated
continuously for each polarization. The other radiometers alternated polarizations on alternate scans. The size of each daily file is 35 MBytes. The data are distributed on FTP. Copies of the data format description are available upon request from NSIDC.

The scanner operated only on alternate days, due to spacecraft power limitations. There are typically at least 14 days of coverage per month, although major data gaps occur in August: in August, 1982, the 4th, 8th, and 16th are missing for both polar regions; in August,
1984, the 13th through the 23rd are missing for both polar regions.

This is the most recent version of these data.

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Parameter(s):
  • Microwave > Antenna Temperature
Data Format(s):
  • HDF
Spatial Coverage:
N: 84, 
S: -84, 
E: 180, 
W: -180
Platform(s):Nimbus-7
Spatial Resolution:Not SpecifiedSensor(s):SMMR
Temporal Coverage:
  • 25 October 1978 to 20 August 1987
Version(s):V1
Temporal ResolutionNot specifiedMetadata XML:View Metadata Record
Data Contributor(s):Gloersen, P. and E. A. Francis.

Geographic Coverage

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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.

Gloersen, P. and E. A. Francis. 2003. Nimbus-7 SMMR Antenna Temperatures, 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/C8ZJDDHZAS59. [Date Accessed].
Created: 
17 January 2019
Last modified: 
23 January 2019

Data Description

Parameters

The main parameter for this data set is raw antenna temperatures. These temperatures are presented in swath format, showing only the portion of the Earth's surface viewed by the scanning radiometer.

File Size

The size of each daily file is 35 MB. 

Spatial Information

Coverage

Northern Latitude: 84° N
Southern Latitude: 84° S
Eastern Longitude: 180° E
Western Longitude: 180° W

Temporal Information

Coverage

Antenna temperature data are available from NSIDC for October 25 1978 to August 20 1987.

Data are missing for both polar regions on August 4, 8, and 16 1982; data are also missing for both polar regions between August 13 and August 23 1984.

Resolution

Because of spacecraft power limitations, the scanner operated only on alternate days. There are typically 14 days of coverage per month.

Data Acquisition and Processing

Background

The Nimbus-7 Scanning Multichannel microwave Radiometer (SWMM) Antenna Temperatures (TA) data set consists of raw antenna temperatures from passive microwave radiometers. Each file in the data set consists of daily antenna temperature data in swath format, i.e. the portion of the Earth's surface viewed by the scanning radiometer.

Acquisition

SMMR was a ten channel passive microwave instrument using six conventional Dicke-type radiometers. It delivered orthogonally polarized antenna temperature data at 6.6, 10.69, 18.0, 21.0, and 37.0 GHz. The two 37.0 GHz radiometers operated continuously for each polarization. The other radiometers alternated polarizations on alternate scans.

Processing

No processing was performed. This data is raw.

References

Francis, E. A. 1987. Calibration of the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR), 1979-1984. Oregon State University, M.S. thesis, 248p.

Gloersen, P., and F. T. Barath. 1977. A scanning multichannel microwave radiometer for Nimbus-G and Seasat-A. IEEE J. Oceanic Eng. OE-2:172-178.

Gloersen, P., and L. Hardis. 1978. Scanning Multichannel Microwave Radiometer (SMMR) Experiment. Nimbus-7 User's Guide. NASA/Goddard Space Flight Center, Greenbelt, MD.

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