Spatio−Temporal Patterns of Arctic Sea Ice Area, Concentration and Melt Onset Date During 1979–2025

The spatio−temporal variation of Arctic sea ice is one of the key indicators of polar climate change. This study used NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 5, and Modern−Era Retrospective Analysis for Research and Applications, Version 2 (MERRA−2) reanalysis data to quantitatively analyze the spatio−temporal patterns and primary drivers of changes in Arctic sea ice area (SIA), melt onset, and concentration from 1979 to 2025. The results show a significant decline in sea ice, with an annual reduction of 1.98 × 104 km2 in area and a decrease in concentration at a rate of 2.6%/decade. Edge concentrations fall below 25% from June to September. Spatial differences are pronounced: the Greenland and Barents Sea regions experience the most intense retreat, while the central Arctic remains relatively stable. The frequency of multi−year sea ice (MYI) cover has dropped from 6.7% to 3.5%, shifting the sea ice structure from ‘thick ice−dominated’ to ‘thin ice−dominated’. This research provides a scientific basis for early warning of Arctic climate change and the development of regional adaptation strategies.