NASA Distributed Active Archive Center (DAAC) at NSIDC

Supporting scientific study of the cryosphere

See Also

Passive Microwave Sea Ice Products at NSIDC

The most popular sea ice products available from NSIDC.

NOAA/NASA Polar Pathfinder Data

This product page contains tools for ordering and working with SMMR data, information regarding the availability of data products, how to obtain guide documentation, FAQs, and other related information.

Related Resources

National Space Science Data Center (NSSDC): Nimbus-7

The NSSDC Web page for the Nimbus-7 satellite.

National Space Science Data Center (NSSDC): SMMR

The NSSDC Web page for the SMMR instrument.

DAAC Data Projects: Passive Microwave


The Scanning Multichannel Microwave Radiometer (SMMR) operated on NASA's Nimbus-7 satellite for more than eight years, from 26 October 1978 to 20 August 1987, transmitting data every other day as part of NASA's Pathfinder Program. The SMMR was a ten channel instrument capable of receiving both horizontally and vertically polarized radiation, and delivered orthogonally polarized antenna temperature data. A combination of oval Instantaneous Fields of View (IFOVs) and the integration times of the radiometers yields roughly circular beam spots with the following diameters: 6.6 GHz at 148 km, 10.7 GHz at 91 km, 18 GHz at 55 km, 21 GHz at 46 km, and 37 GHz at 27 km.

The primary purpose of SMMR was to measure sea surface temperature and near-surface winds under all weather conditions for developing and testing global ocean circulation models and other aspects of ocean dynamics. Additional parameters were also measured using SMMR, such as winds, water vapor, liquid-water content, mean cloud droplet size, rainfall rate, and sea ice.

The National Snow and Ice Data Center (NSIDC) archives and distributes daily data products from SMMR. To obtain SMMR data, please refer to the Passive Microwave Sea Ice Products Web page.

Sample Image


SMMR Northern Hemisphere Brightness Temperatures.
Sample browse image: 25-km EASE-Grid; 37 GHz; horizontally polarized for ascending passes acquired on 01 January 1980; derived from Nimbus-7 SMMR Pathfinder Daily EASE-Grid Brightness Temperatures