Nimbus-7 SMMR: Passive Microwave Antenna Temperatures

Nimbus-7's Scanning Multichannel Microwave Radiometer collected orthogonally polarized antenna temperature data at five frequencies from 6.6 to 37.0 GHz. This dataset provides daily swath-format observations from October 1978 to August 1987, with the scanner operating only on alternate days due to power constraints. Major data gaps are documented for specific days in August 1982 and 1984 for both polar regions.

Use Cases

• Analyzing long-term sea ice concentration trends based on multi-frequency brightness temperature data.
• Calibrating modern satellite microwave sensors against historical SMMR antenna temperature records.
• Studying polar surface emissivity and snowpack properties using orthogonal polarization channels.
• Reconstructing historical atmospheric water vapor over oceans using the 21.0 GHz channel.

Strengths

• Covers a nearly nine-year time series from October 1978 to August 1987.
• Provides data at five specific microwave frequencies (6.6, 10.69, 18.0, 21.0, 37.0 GHz) with orthogonal polarizations.
• Documented data gaps are explicitly listed (e.g., August 1982 and 1984), aiding transparency.

Limitations

• Column names and precise data structure are not provided in the available metadata.
• The scanner operated on alternate days, resulting in incomplete daily coverage within the time range.
• There is a conflict in the 'last updated' metadata between platforms (1987 vs. 2026).

Provenance

Source

National Aeronautics and Space Administration (NASA)

Collection Method

Collected by the Scanning Multichannel Microwave Radiometer (SMMR) aboard NOAA's Nimbus-7 satellite.

Time Range

1978-10 to 1987-08

Freshness

2026-04-09 23:56:37.050561

Geography

Global, with specific documentation for polar regions.