NSIDC archives and distributes daily and monthly data derived from the Special Sensor Microwave Imager/Sounder (SSMIS) and its two predecessors, the Special Sensor Microwave/Imager (SSM/I) and the Scanning Multichannel Microwave Radiometer (SMMR). Together, these passive microwave sensors offer an extensive data record which spans from 1978 through the present. The products derived from these sensors are offered in two flexible and easy-to-use projections: EASE-Grid and Polar Stereographic.
The Equal-Area Scalable Earth Grid (EASE-Grid) projection is mainly intended for users of global-scale gridded data who wish to view their data in maps with the least amount of shape and areal distortion. EASE-Grid data products are offered in three different equal-area projections: northern and southern azimuthal, and global cylindrical. For more information, refer to the EASE-Grid Web site.
The NSIDC polar stereographic projection specifies a projection plane or grid tangent to the surface of the Earth at 70 degrees northern and southern latitude. While this increases the distortion at the poles by six percent, the latitude of 70 degrees was selected so that little or no distortion would occur in the marginal ice zone. For more information, visit the Polar Stereographic Data Web site.
For a list of available SMMR and SSM/I-SSMIS data products, refer to the Data Sets page listed in the navigation on the left side of this page.