About the data

Image derivation is from the Sea Ice Index data product, which relies on NASA-developed methods using passive-microwave data from the Defense Meteorological Satellite Program (DMSP) F13 Special Sensor Microwave/Imager (SSM/I). The basis for the Sea Ice Index is the data set, "Near Real-Time DMSP SSM/I Daily Polar Gridded Sea Ice Concentrations," and the NASA-produced "Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Passive Microwave Data." The Sea Ice Index was developed with financial support from NOAA NESDIS and in cooperation with NOAA NGDC.

Please note that our daily sea ice images, derived from microwave measurements, may show spurious pixels in areas where sea ice may not be present. These artifacts are generally caused by coastline effects, or less commonly by severe weather. Scientists use masks to minimize the number of "noise" pixels, based on long-term extent patterns. Noise is largely eliminated in the process of generating monthly averages, our standard measurement for analyzing interannual trends.

If you have questions about Arctic sea ice data, please see our Frequently Asked Questions about Arctic Sea Ice.