NOAA/NMC/CAC Arctic and Antarctic Monthly Sea Ice Extent, 1973-1990

Sea ice extent data digitized from weekly operational charts produced by the Navy/NOAA Joint Ice Center. The dataset provides monthly snapshots from January 1973 to August 1990, with coverage for 36 longitudinal sectors in each hemisphere. Data were originally provided by the NOAA National Weather Service National Meteorological Center Climate Analyses Center.

Use Cases

• Analyzing decadal trends in sea ice coverage by hemisphere and 10-degree longitudinal sector.
• Correlating historical sea ice extent with atmospheric circulation patterns from the 1970s and 1980s.
• Calibrating satellite-derived sea ice records with this earlier, manually digitized baseline.
• Studying hemispheric asymmetry in sea ice retreat or advance during the specified time period.

Strengths

• Provides a consistent 17-year record (1973-1990) of monthly sea ice extent for both polar regions.
• Data is spatially detailed, aggregated into 36 longitudinal sectors per hemisphere for granular analysis.
• Digitized from authoritative operational charts produced by the Navy/NOAA Joint Ice Center.
• Cross-platform presence on Data.gov and NASA EarthData indicates recognized importance and curation.

Limitations

• Exact row count, file size, and specific column names are not provided by any source.
• Sources conflict on the last updated date: Data.gov lists a future date (2026-03-12), while NASA EarthData lists the end of the data period (1990-08 31).
• Data collection ended in 1990, limiting analysis to pre-satellite-era trends.

Provenance

Source

NOAA National Weather Service National Meteorological Center (NMC) Climate Analyses Center (CAC).

Collection Method

Weekly operational sea ice charts were manually digitized using a 1° latitude x 2.5° longitude grid, then summed into 1° latitude x 10° longitude slices.

Time Range

1973-01-01 to 1990-08-31

Freshness

1990-08-31 23:59:59.999000

Geography

Global coverage for both the Arctic and Antarctic hemispheres.