News Archive

2023-01-23 Service Interruption

We had server issues from 3:50 to 07:45 UTC on 21 January 2023.

Resolved: All data got reprocessed (21 Jan 2023).

2022-11-13 MODIS-AMSR2 processing stopped until further notice

Due to problems with the download of MODIS data, the processing of the MODIS-AMSR2 sea-ice concentration (SIC) has been put on hold. The latest available MODIS-AMSR2 SIC data are from November 12th, 2022. Users are referred to our ASI-AMSR2 sea-ice concentration data instead.

Update: MODIS-AMSR2 sea-ice concentration processing resumed on 1.12.2022. We are planning to reprocess the gap.

2022-10-09 Delayed processing

We have server issues and there has been a delay in processing. The data for 8 and 9 Oct should be ready on Monday, 10th October 2022.

Resolved: all data got reprocessed (10 Oct 2022).

2022-10-08 New SMOS/SMAP dataset and SMAP data outage

We released a new dataset version 300 of the SMOS/SMAP thin sea ice thickness data in our data browser. SMAP data is currently not available (since 6th of August 2022) so that our NRT product only includes SMOS data.

Changes compared to the previous version 205 are

  • updated projection information for better GIS compatibility
  • fixed slight grid shift to match official NSIDC north polar stereo grid coordinates
  • fixed issue with missing SMAP data in products after September 2021
  • updated to latest released SMAP L1B data (17000 to 18290)

2022-10 Start of Archive

2021-05-02 New version of merged MODIS-AMSR2 sea-ice concentration dataset available

As of May 02, 2021, a new and improved version of the merged MODIS-AMSR2 sea-ice concentration (SIC) dataset is provided. The changes comprise:

  • an uncertainty estimate for the merged SIC which has been added as additional field to the netCDF file.
  • a stricter MODIS cloud masking. Now, only pixels which are labeled "confident clear" are accepted, while previously all pixels which were not labeled "confident cloudy" were accepted.
  • a new threshold for the MODIS ice tie-point: Now, MODIS SIC are only retrieved for pixels with an ice tie-point beneath 266.5 K, while the previous threshold was 270 K.

The entire dataset is being updated to the new version, but as of now only data after May 2nd are available in the new version. The changes are described in more detail in Ludwig et al., 2020. The daily mean merged SIC and uncertainty are available publically. A netCDF file with the daily mean, daily mean uncertainty, daily standard deviation and daily number of measurements for each pixel is available upon request. The same holds for netCDF files of the merged, MODIS and AMSR2 SIC of single overflights. Questions can be directed to vludwig(at)

2020-11-27 Twitter

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2018-11-23 Switched to ASI Sea Ice Concentration Version 5.4

The announced switch to ASI version 5.4 for the daily sea ice concentration datal has taken  place on Nov 23, 2018. The only effect is a slight change in file names, as explained here ('v5.4' instead of 'v5').

For backwards compatibility, symbolic links of the HDF and TIFF files are being created which still have the old file name. This will only be done temporarily.

Reprocessed ASI data from 2002 to Oct 2018: Version 5.4

We have just completed reprocessing all ASI ice concentration data based on AMSR-E or AMSR2 data for the  complete period, i.e.,

  • 1 June, 2002 to 4 Oct, 2011 (AMSR-E)
  •  July, 2012 to 17 Nov, 2018 (AMSR2).

The reprocessing has been done for the hemispheric maps only. i.e., Arctic/Antarctic (6.25 km grid spacing) and Arctic3125/Antarctic3125 (3.125 km grid spacing).

The tie points of the ASI algorithm were the same (version 5). However, some other details as the version of GMT (generic mapping tools) used for gridding the data and defining land masks and coast lines have changed over the years. The reprocessed data are therefore consistent with respect to  all this, and have the version number 5.4. The full version number is also part of all file names ('v5.4'); the new files are stored alongside the files of previous versions  5.2 and 5.3 which just have 'v5' in their file names.

The new data being processed every day have been switched to version 5.4 on Nov. 23, 2018 which implies the mentioned change in the file names ('v5.4' instead of just 'v5')

All details about the ASI ice concentration data can be found in the the new ASI user guide

2018-06-19 News: CIMR

A new website is available for the Copernicus Imaging Microwave Radiometer (CIMR) proposed as EU Copernicus Sentinel-9 satellite:

CIMR will allow retrieval of global, daily sea ice concentration at 5 km resolution (as on this website) but with higher accuracy. Lower frequencies will be used that also will allow all-weather SST observations (and many more sea ice parameters). If you like to support CIMR please use the hashtag #CIMREU