Satellite observations reveal a significant poleward expansion of the multiyear sea ice replenishment in the heart region of Arctic Ocean

Abstract Multiyear sea ice replenishment due to first-year ice aging at the end of the summer is a key factor in maintaining the overall Arctic sea ice mass balance. Utilizing satellite observations from 2000 to 2023, here we show that a significant poleward shift in the multiyear ice replenishment occurs in the north pole region (NPR) of the Arctic (north of 80˚N). The large-scale atmospheric circulation mode, characterized by an extensive and persistent high-pressure (low-pressure) pattern on the Siberia (North America) side, is responsible for the poleward shift of multiyear ice (MYI) replenishment. Associated with the poleward expansion of the multiyear sea ice replenishment, a significant decline in sea ice thickness over the central Arctic and reduced sea ice volume flux via the Fram Strait are identified. Moreover, a strengthened (weakened) connection between summer melting (winter freezing) conditions and MYI replenishment variability is outlined. This indicates that the Arctic sea ice is less resilient to warming than previous reports.