When monthly processing for the July 2013 update to the Sea Ice Index took place, the baseline climatological period for it and for the Arctic Sea Ice News and Analysis (ASINA) site changed from 22 years (1979-2000, inclusive) to 30 years (1981-2010, inclusive). Below is a summary of what changed and what did not change.
Changes to the data:
- Position of the median line (pink) on the monthly extent images
- Monthly Sea Ice Concentration Anomaly Images
- Monthly Sea Ice Concentration Trend Images
- The slope of the monthly extent anomalies graph
- The median line (orange) on the daily extent images
- The average line on the daily graph
- The values in the daily climatology data file
Data that did not change:
- Sea ice extent values
- Sea ice concentration values
- Sea ice area values
The Sea Ice Index is a largely NOAA-supported data product, while ASINA is a largely NASA-supported effort.