Snow Melt Onset Over Arctic Sea Ice, 1979-2025

Yearly snow melt onset dates over Arctic sea ice derived from SMMR, SSM/I, and SSMIS satellite brightness temperature measurements. The data are gridded to a 25 km Northern Hemisphere Polar Stereographic projection and include value-added statistics for each grid cell, such as mean, earliest, latest, range, and standard deviation of melt onset dates. One browse image is provided for each yearly file and statistical field.

Use Cases

• Tracking interannual variability in Arctic snow melt timing based on the yearly gridded data.
• Analyzing spatial patterns of melt onset extremes using the earliest and latest onset date statistics.
• Assessing melt season consistency across grid cells using the standard deviation and range of onset dates.
• Validating climate models with long-term satellite-derived melt onset records spanning over four decades.

Strengths

• Provides a long-term, consistent record from 1979 through at least 2025, enabling analysis of multi-decadal trends.
• Includes derived statistical fields (mean, min, max, range, standard deviation) for each 25 km grid cell, adding analytical value.
• Data is derived from established satellite microwave radiometer instruments (SMMR, SSM/I, SSMIS), ensuring a standardized methodology.

Limitations

• Column names and specific data formats are not detailed in the provided metadata, limiting understanding of the exact file structure.
• There is a conflict in the stated temporal coverage: one source indicates data through 2025, while another indicates through 2022.
• The license is specified only as 'other-license-specified', requiring users to seek out specific terms and conditions.

Provenance

Source

National Aeronautics and Space Administration (NASA)

Collection Method

Derived from Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave/Imager (SSM/I), and Special Sensor Microwave Imager/Sounder (SSMIS) brightness temperature measurements.

Time Range

1979 through 2025 (conflicting source suggests 2022).

Freshness

Most recent platform update was 2026-04-09, though the underlying data time range may end in 2025.

Geography

Arctic sea ice, gridded to the Northern Hemisphere Polar Stereographic projection.