NOAA@NSIDC

The National Snow and Ice Data Center (NSIDC) is informing users that the AMSR2 prototype sea ice concentrations in the NOAA/NSIDC Near-Real-Time Sea Ice Concentration Climate Data Record, Version 3 data set have been discontinued as of 1 September 2025.

As previously announced, this discontinuation is due to NASA ending the processing of the AMSR Unified suite of data sets, which provided input for the prototype AMSR2 sea ice concentrations in our product.

Important information:

The National Snow and Ice Data Center has learned that NASA will discontinue processing of the AMSR Unified suite of data sets. One of the products in this suite is used as input for the prototype AMSR2 sea ice concentrations in the sea ice CDR data set. As a result, the NOAA/NSIDC sea ice concentration NRT CDR Version 3 data set will no longer contain the AMSR2 prototype data after 1 September 2025. It will continue to have the SSMIS-derived sea ice concentrations. NSIDC is working to release a new version of the sea ice CDR that will include AMSR2 from a different data provider.

The National Snow and Ice Data Center has learned that the U.S. Department of Defense (DoD) will continue processing and delivering data from the Special Sensor Microwave Imager/Sounder (SSMIS) instrument through the retirement of the DMSP mission, expected in September 2026. As a result, the Near-Real-Time NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 3 data set will continue to update.

The following data sets have been retired from NSIDC as of July 31:

• NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 4
• Near-Real-Time NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 2

Data from these versions are no longer accessible, though all related documentation remains available on the data set web pages for reference:

NOAA@NSIDC is pleased to announce the release of Sea Ice Index, Version 4. This new version uses input data from the JAXA GCOM-W1 AMSR2 instrument for 1 January 2025 through forward processing. Input sea ice concentration fields from AMSR2-using NSIDC-0803 now replace those from SSMIS-using NSIDC-0081 and NSIDC-0051. 

NOAA@NSIDC is pleased to announce the upcoming release of Sea Ice Index, Version 4, available at the National Snow and Ice Data Center on August 1. This new version transitions from SSMIS to AMSR2 data due to the end of access to SSMIS data. The AMSR2 instrument provides high-quality sea ice concentration data that will ensure the continued reliability of the Sea Ice Index product.

Please note that AMSR2 typically locates the ice edge slightly inboard compared to SSMIS, resulting in somewhat smaller ice extent measurements:

The following data sets will be retired from NSIDC on July 31:

NOAA@NSIDC is pleased to announce that the Sea Ice Index, Version 3 data set, accessible through the National Snow and Ice Data Center (NSIDC), has been updated from near-real-time data to final data for the period 01 January 2023 through 31 December 2024.

The National Snow and Ice Data Center (NSIDC) is pleased to announce that the Department of Defense (DoD) has agreed to extend processing and delivery of Special Sensor Microwave Imager/Sounder (SSMIS) data through 31 July 2025.

The extension applies to NOAA products that rely on SSMIS data as input, including:

The National Snow and Ice Data Center was informed on 24 June 2025 that the Department of Defense (DoD) will cease processing and delivering the Special Sensor Microwave Imager/Sounder (SSMIS) data no later than 30 June 2025. 

Affected Data Products:

The SSMIS data serve as input for the following NOAA@NSIDC data sets, which will therefore stop processing after 30 June 2025:

Recent delivery from the US Navy of the SSMIS passive microwave data that several sea ice and brightness temperature products use has become more sporadic. The Defense Department has informed NSIDC that they will reduce the priority of processing the SSMIS data, resulting in likely daily data gaps. NSIDC will explore switching to a different sensor, the JAXA Advanced Microwave Scanning Radiometer 2 (AMSR2). However, this transition will take time. We apologize for any inconvenience and appreciate your patience during this transition.

NOAA@NSIDC is pleased to announce the release of the International Ice Patrol Annual North Atlantic Iceberg Summaries and Reports, Version 1 data set. This data set contains yearly summaries and reports of iceberg sightings from the International Ice Patrol (IIP) in the North Atlantic (40° N to 60° N, 40° W to 60° W), beginning in 2024. Each season includes two PDF files: a one-page summary and a comprehensive iceberg season report.

Effective May 5, 2025, NOAA’s National Centers for Environmental Information (NCEI) will decommission its snow and ice data products from the Coasts, Oceans, and Geophysics Science Division (COGS).

As a result, the level of services for affected products below will be reduced to Basic—meaning they will remain accessible but may not be actively maintained, updated, or fully supported.

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.

NOAA@NSIDC is pleased to announce that the Rutgers Northern Hemisphere 24 km Weekly Snow Cover Extent, September 1980 Onward, Version 1 data set, accessible through the National Snow and Ice Data Center (NSIDC), has been updated to include the 2024 water year. The data record now goes to 04 November 2024. This data set provides weekly snow cover extent for the Northern Hemisphere in NetCDF format beginning September 1980.

Data Set DOI: https://doi.org/10.7265/zzbm-2w05

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.

NOAA@NSIDC is pleased to announce that the Climate Data Record of Passive Microwave Sea Ice Concentration, Version 4 data set, accessible through the National Snow and Ice Data Center (NSIDC), has been updated to include the time period of 01 April 2024 through 30 June 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.

The Near-Real-Time NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 2 data set has been reprocessed to update the input data used in processing. For the past year, we inadvertently used data from the Special Sensor Microwave Imager/Sounder (SSMIS) F17 instrument instead of the SSMIS F18 as stated in our user guide. This discrepancy occurred due to a technical oversight during our transition to a new file format for input data.

NOAA@NSIDC is pleased to announce that the Climate Data Record of Passive Microwave Sea Ice Concentration, Version 4 data set, accessible through the National Snow and Ice Data Center (NSIDC), has been updated to include the time period of 01 January 2024 through 31 March 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. 

NOAA@NSIDC is pleased to announce that the Climate Data Record of Passive Microwave Sea Ice Concentration, Version 4 data set, accessible through the National Snow and Ice Data Center (NSIDC), has been updated to include the time period of 01 October 2023 through 31 December 2023. 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.