The National Snow and Ice Data Center (NSIDC) has released Version 5 of the NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration data set and Version 3 of the Near-Real-TimeNOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration data set. The sea ice concentration climate data record (CDR) Version 5 and near-real-time (NRT) CDR Version 3 provide daily and monthly sea ice concentration data for north and south polar regions from October 25, 1978, to the present on a 25 km × 25 km polar stereographic grid.
The main changes in these new versions include the following:
- Adds a prototype AMSR2 sea ice concentration
- Uses the NASA Team 2 land spillover correction, replacing the original NASA Team correction
- Improved the Arctic pole hole filling
- Uses a new land mask
- The concentration variable (cdr_seaice_conc) contains concentration values only (no land mask).
- Adds a separate surface type variable (surface_type_mask)
- Improved spatial interpolation of TBs
- Includes the raw NT (raw_nt_seaice_conc) and BT (raw_bt_seaice_conc), maintaining full range of values instead of clipping at 100% for provenance and transparency
- Updated the layout and names of variables, with added netCDF groups for better organization
- Sea ice concentration values below 10% in the CDR are set to 0%
- Fixed a bug in the BT tie points calculations
- Fixed a bug in the one-sided temporal interpolation calculation
For detailed information about these changes, a comprehensive overview of CDR Version 5, and comparisons with Version 4, please refer to NSIDC Special Report 26:
https://nsidc.org/sites/default/files/documents/technical-reference/nsidc-special-report-26.pdf
Access the data, documentation, and citation information at these locations:
- Version 5 CDR: https://doi.org/10.7265/rjzb-pf78
- Version 3 NRT CDR: https://doi.org/10.7265/j0z0-4h87
Note: To allow users time to transition to the new versions, the previous versions of both data sets will remain available through July 2025.
- Version 4 CDR: https://doi.org/10.7265/efmz-2t65
- Version 2 NRT CDR: https://doi.org/10.7265/tgam-yv28