Sea Ice Concentration data from NASA Goddard and NSIDC based on Bootstrap algorithm

Teaser image
Sea Ice Concentration data from NASA Goddard and NSIDC based on Bootstrap algorithm
Main content

Bootstrap sea ice refers to a well-known algorithm used to estimate sea ice concentration from passive microwave brightness temperatures. It can be applied to data from many satellite instruments, such as SMMR, SSMI, and AMSR-E. This page discusses the algorithm itself and the long-term data set ("NSIDC 0079, version 2") produced by J. Comiso and distributed by NSIDC. The latest version of the Bootstrap data set has been completely reprocessed so that SMMR and SSMI data are inter-calibrated with AMSR-E data. The Bootstrap data set provides a long-term, consistently interpreted and calibrated record for studies of climate variability and change, but users should be aware of uncertainties and possible biases.

Key Strengths

Key Strengths

Long-term (1978-almost present) record

Consistent algorithm through time

SMMR and SSMI concentrations are inter-calibrated to AMSR-E using varying tie points to account for changes in signatures of ice and open water due to changes in satellite instruments and platforms, or to physical effects

Key Limitations

Key Limitations

Influenced by temperature variability; very low temperatures can lead to underestimates

Underestimates concentration in cases of melt ponding

Please cite data sources, following the data providers' instructions
Suggested Data Citation
  1. From NSIDC: Comiso, J. 1999, updated 2012. Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS, [list dates you used]. Boulder, Colorado USA: National Snow and Ice Data Center. Digital media.

Dataset DOIs
Hosted Climate Index Files
Usage Restrictions

unrestricted; registration requested

Cite this page

Acknowledgement of any material taken from or knowledge gained from this page is appreciated:

National Center for Atmospheric Research Staff (Eds). Last modified "The Climate Data Guide: Sea Ice Concentration data from NASA Goddard and NSIDC based on Bootstrap algorithm.” Retrieved from on 2024-04-16.

Citation of datasets is separate and should be done according to the data providers' instructions. If known to us, data citation instructions are given in the Data Access section, above.

Acknowledgement of the Climate Data Guide project is also appreciated:

Schneider, D. P., C. Deser, J. Fasullo, and K. E. Trenberth, 2013: Climate Data Guide Spurs Discovery and Understanding. Eos Trans. AGU, 94, 121–122,

Key Figures

Climate Data Guide Image: Sea Ice Concentration data; Goddard Bootstrap

Average Arctic sea ice concentration for March 2003-2007 according to the Bootstrap data set. Figure by D. Schneider.

Other Information

Earth system components and main variables
Dataset collections

Years of record
Data time period extended
Yes, data set is extended
Daily, Monthly
Input Data


Vertical Levels:
Missing Data Flag
Missing data present
Ocean or Land
Ocean & Land
Spatial Resolution

25 x 25 km

Model Resolution (reanalysis)
Data Assimilation Method
Model Vintage (reanalysis)

Key Publications
  1. Cho, K., N. Sasaki, H. Shimoda, T. Sakata, and F. Nishio. 1996. Evaluation and Improvement of SSM/I Sea Ice Concentration Algorithms for the Sea of Okhotsk. Journal Remote Sensing of Japan 16(2):47-58.
  2. Comiso, J. C., and F. Nishio. 2008. Trends in the Sea Ice Cover Using Enhanced and Compatible AMSR-E, SSM/I, and SMMR Data. Journal of Geophysical Research 113, C02S07, doi:10.1029/2007JC0043257.
  3. Comiso, J. C. 1995. SSM/I Concentrations Using the Bootstrap Algorithm. NASA Reference Publication 1380. 40 pages.