Sea Ice Concentration data from NASA Goddard and NSIDC based on Bootstrap algorithm
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.
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
Influenced by temperature variability; very low temperatures can lead to underestimates
Underestimates concentration in cases of melt ponding
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.
- binary: stand-alone gridded data set at NSIDC (ftp)
- netCDF: gridded data, distributed by NSIDC with Climate Data Record
- Area and Extent daily and monthly timeseries at NSIDC
- NSIDC pixel area grids and geocoordinate tools (needed to calculate sea ice ext…
- Extent timeseries from JAXA based on Bootstrap, multiple instruments (SMMR, SSM…
unrestricted; registration requested
SMMR, SSMI, SSMI/S, AMSR-E
25 x 25 km
- 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.
- 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.
- Comiso, J. C. 1995. SSM/I Concentrations Using the Bootstrap Algorithm. NASA Reference Publication 1380. 40 pages.