Sea Ice Index Processing Suspended

The Sea Ice Index is typically updated every day to display yesterday’s ice extent for both hemispheres. The Index relies on data that come from the DMSP F17 satellite. However, these data have not been reliable since early April; so the NOAA@NSIDC team has not been able to update the Sea Ice Index since 31 March 2016.

Sea Ice Index processing uses an NSIDC NASA DAAC product, Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations (NSIDC-0081), as input. The NSIDC DAAC has started the work needed to move to a new source for NSIDC-0081. This involves retrieving F18 and F16 satellite brightness temperatures from our data providers and then implementing parallel processing for ice concentration. The F18 satellite will be the primary replacement for F17, but should that satellite fail, we will be able to switch to F16 without a service interruption.

An interim version of the NSIDC-0081 data stream will be used for the ASINA product, which is based on the Sea Ice Index, to continue to report on sea ice conditions. However, the Sea Ice Index processing itself will not resume until a version of NSIDC-0081 is available that is vetted by the science team. It is not known how long this will take, but we expect it will be a minimum of two months before NSIDC-0081 is updating regularly again with a new vetted source and the Sea Ice Index is processing that new input. Users can see the latest F18 provisional daily data on the ASINA site for both the Arctic and Antarctic, or users can plot the Arctic data and compare it to other years on Charctic, NSIDC’s interactive Arctic sea ice graphing tool.

Users may also want to explore daily arctic-wide ice extent from the NIC/NSIDC MASIE product as an alternative product for the Northern Hemisphere. The MASIE ice extent record is not consistent with that from the Sea Ice Index, however, nor is it necessarily internally consistent. See the MASIE documentation in order to gain a better understanding of how the product is created.

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