Climate Data

Sea ice concentration data from NASA Goddard based on SSMI and NASA Team (NT2) algorithm

The NASA Team 2 (NT2) / SSMI data set of Arctic and Antarctic sea ice concentration is available at daily timesteps and 25km spatial resolution for 1992-2008. NT2, an extension of the original NASA Team algorithm, uses SSMI 85GHz channels to help resolve ambiguity between low ice concentrations and areas with strong surface effects (due to snow layering and glazing). 85GHz channels introduce more weather contamination. NT2 implements a radiative transfer model to filter for weather that simulates brightness temperatures under several idealized polar atmospheres. The algorithm searches for the best fit between the observed and modeled brightness temperature ratios to pick the final concentration. Sea ice from NT2 is more similar to Bootstrap sea ice than was the original NASA Team sea ice. Some differences are still apparent; NT2 usually shows slightly higher concentrations in the Antarctic and more sensitivity to thin ice. This data set overlaps with those using the same satellite data but different algorithms, including the Goddard/NSIDC Bootstrap and NASA Team data sets, facilitating useful comparisons that can serve as a measure of uncertainty.

Key Strengths:

  • Addresses weaknesses of the original NASA Team algorithm, especially with regards to sensitivity to emissivity variations. This leads to significant improvement in the Antarctic.

Key Limitations:

  • Potential sensitivity of NT2 to weather effects as it uses the 85GHz channel
  • Short period of record

Years of Record

1992/01 to 2008/04
temporal metadataID:




Data Time Period Extended?

no, data set not being extended


Spatial Resolution

25 x 25 km

Ocean or Land

Ocean Only

Missing Data Flag

missing data present

Vertical Levels

Input Data

SSMI: multiple channels

Earth system components and main variables

Data Access: Please Cite data sources, following the data providers' instructions.

Key Figures

Click the thumbnails to view larger sizes



Arctic sea ice: SSMI / NT2 Average sea ice concentration for March 2003-2007 according to the Goddard NT2 / SSMI data set. (Figure by D. Schneider)

Cite this page

National Center for Atmospheric Research Staff (Eds). Last modified 20 Aug 2013. "The Climate Data Guide: Sea ice concentration data from NASA Goddard based on SSMI and NASA Team (NT2) algorithm." Retrieved from

Acknowledgement of any material taken from this page is appreciated. On behalf of experts who have contributed data, advice, and/or figures, please cite their work as well.