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The daily composite of Synthetic Aperture Radar (SAR) Normalized Radar Cross Section (NRCS) imagery covering the Arctic and sub-Arctic maritime regions over a period of one day are available at 1-km resolution. These high-resolution, weather- and time-agnostic measurements of surface backscatter contain detailed information tailored for sea ice classification purposes. 

A composite for typical day contains around 200-400 individual scenes gathered from several C-Band SAR systems, including Sentinel-1A/B, RADARSAT-2, and RADARSAT Constellation Mission, which are calibrated with values given by the SAR data provider and are then projected and resampled onto a 1km polar stereographic grid. The files are produced in SAROPS (SAR Operational Product System) by the Water Surface Conditions/Sea Surface Roughness group within the NOAA STAR Satellite Oceanography and Climatology Division.

For further details on the individual granules that make these composites and for links to the GeoTIFF versions of these files, please see the SAR NRCS page.

Data Courtesy of the Copernicus Program, RADARSAT Constellation Mission, and the Canadian Space Agency.



Sentinel-1A/B / RADARSAT-2 / RADARSAT Constellation Mission / Synthetic Aperture Radar


NRCS Composites

Sample Filename

Source filenames begin with satellite, data source, year, month, day, hour, minute, second, Julian seconds, center latitude, center longitude, polarization, delimited with an underscore NRCS: S1A_ESA_2016_12_07_18_18_57_0534449937_178.66E_51.85N_VV_C5_GFS05 CDF_nrcs_level2.[png,nc]

CoastWatch distributed composites:  SAR_composite_2022070T0000_2022070T2359_NP06_1km_nrcs.[png,nc]

Dataset Type


Processing Level

NRCS:  Level-2, Averaged and resampled and mapped L-1

Composite: Level-4, Averaged and resampled and mapped L-1

Spatial Coverage

Arctic and sub-Arctic maritime regions (>40°N)
  Pixel width:                   1.0669 km
  Pixel height:                  1.0669 km
  Total width:                   11018.7124 km
  Total height:                  11018.7124 km
  Center:                        89.9925 N, 90.0000 W
  Upper-left (pixel center):     23.6456 N, 90.0000 W
  Upper-right (pixel center):    23.6509 N, 0.0057 W
  Lower-left (pixel center):     23.6509 N, 179.9943 W
  Lower-right (pixel center):    23.6562 N, 90.0000 E

Temporal Coverage

00:00Z-23:59Z (daily)


Generated at 14Z the following day




Polar Stereographic / WGS84

projection:grid_mapping_name = "polar_stereographic" ;
                projection:latitude_of_projection_origin = 90. ;
                projection:straight_vertical_longitude_from_pole = -45. ;
                projection:standard_parallel = 60. ;
                projection:false_easting = 0. ;
                projection:false_northing = 0. ;
                projection:semi_major_axis = 6378137. ;
                projection:inverse_flattening = 298.257223563 ;
                projection:units = "m" ;
                projection:proj4 = "+proj=stere +lat_0=90 +lat_ts=60 +lon_0=-45 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs" ;
                projection:spatial_ref = "PROJCS[\"unknown\",GEOGCS[\"unknown\",DATUM[\"WGS_1984\",SPHEROID[\"WGS 84\",6378137,298.257223563,AUTHORITY[\"EPSG\",\"7030\"]],AUTHORITY[\"EPSG\",\"6326\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]]],PROJECTION[\"Polar_Stereographic\"],PARAMETER[\"latitude_of_origin\",60],PARAMETER[\"central_meridian\",-45],PARAMETER[\"false_easting\",0],PARAMETER[\"false_northing\",0],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],AXIS[\"Easting\",SOUTH],AXIS[\"Northing\",SOUTH]]" ;


Data Provider



Creator: NOAA STAR
Release Place: Suitland, MD, USA
Data courtesy of Copernicus Program, RADARSAT Constellation Mission, and the Canadian Space Agency



Portable Network Graphic (PNG)
Network Common Data Format (NetCDF) with Climate-Forecast, ACDD, and CoastWatch attributes


OAA, SAR, Sentinel-1, RADARSAT-2, RCM, arctic, polar, ice



Synthetic Aperture Radar Marine Users Manual. Ed C.R Jackson and J.R. Apel: NOAA: Washington, DC, USA, 2004. ISBN 0-16-073214-X