Delay in Arctic Sea Ice Freeze-Up Linked to Early Summer Sea Ice Loss: Evidence from Satellite Observations

• Published in: Remote Sensing
• Main Authors: Lei Zheng, Xiao Cheng, Zhuoqi Chen, Qi Liang
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: Arctic; remote sensing; sea ice loss; melt timing; ice-albedo feedback; Science; Q; albedo; Chukchi; laptev; Sea ice
• Online Access: https://doi.org/10.3390/rs13112162; https://doaj.org/article/79dd556484ca4d8c957485e079fa4299

The past decades have witnessed a rapid loss of the Arctic sea ice and a significant lengthening of the melt season. The years with the lowest summertime sea ice minimum were found to be accompanied by the latest freeze-up onset on record. Here, a synthetic approach is taken to examine the connections between sea ice melt timing and summer sea ice evolution from the remote sensing perspective. A 40-year (1979–2018) satellite-based time-series analysis shows that the date of autumn sea ice freeze-up is significantly correlated with the sea ice extent in early summer (r = −0.90, p < 0.01), while the spring melt onset is not a promising predictor of summer sea ice evolution. The delay in Arctic sea ice freeze-up (0.61 days year −1 ) in the Arctic was accompanied by a decline in surface albedo (absolute change of −0.13% year −1 ), an increase in net short-wave radiation (0.21 W m −2 year −1 ), and an increase in skin temperature (0.08 °C year −1 ) in summer. Sea ice loss would be the key reason for the delay in autumn freeze-up, especially in the Laptev, East-Siberian, Chukchi and Beaufort Seas, where sea ice has significantly declined throughout the summer, and strong correlations were found between the freeze-up onset and the solar radiation budget since early summer. This study highlights a connection between the summer sea ice melting and the autumn refreezing process through the ice-albedo feedback based on multisource satellite-based observations.