NOAA@NSIDC is pleased to announce that both Version 4 and Version 5 of the Climate Data Record of Passive Microwave Sea Ice Concentration data set, accessible through the National Snow and Ice Data Center (NSIDC), have been updated to include the time period of 01 July 2024 through 31 December 2024. This data set provides a consistent daily and monthly time series of sea ice concentrations beginning 25 October 1978 for both the north and south polar regions on a 25 km x 25 km grid.
For Version 4, there is one day of missing data on 17 September 2024, and a day with partial missing data on 18 September 2024, due to missing input data from the satellite during that time. For Version 5, the code fills these dates with temporal interpolation that the Version 4 code does not have.
Please note that the near-real-time (NRT) data from July to December 2024 (Version 2 and Version 3 of the Near-Real-Time NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration) have been removed from public access, as they are now superseded by the final processed versions. If you are using NRT data from this period, please download and use the final processed version instead.
In addition, an NSIDC Special Report has just been published that provides a detailed analysis of the differences in sea ice extent trends from Version 4, Version 5, and the Version 5 AMSR2 prototype: NSIDC Special Report 27: A Comparison of Trends in Sea Ice Extent from the Sea Ice Concentration CDR V4, CDR V5, and the V5 AMSR2 Prototype.
Important: Version 4 will be decommissioned and removed from public access in August 2025. Please switch to Version 5 before this date.
Version 4 Data Set DOI: https://doi.org/10.7265/efmz-2t65
Version 5 Data Set DOI: https://doi.org/10.7265/rjzb-pf78