Cloud Radiative Effects Slow Sea Ice Changes During Summer Arctic Dipole Anomaly

• Published in: Geophysical research letters 2024-08, Vol.51 (16), p.n/a
• Main Authors: Zhang, Haotian, Zhao, Chuanfeng, Xia, Yan, Chen, Annan, Yang, Yikun, Yang, Jie, Zhao, Xin, Chi, Yulei, Xu, Hongtao, Zhong, Shouyi
• Format: Article
• Language: English
• Subjects: Arctic clouds; Arctic dipole anomaly; Arctic sea ice; Arctic zone; Atmospheric circulation; Atmospheric circulation patterns; Climate system; cloud radiative effect; cloud variation; Clouds; Dipoles; Energy balance; Ice cover; Ice environments; Ice thickness; Meridional wind; Meteorology; Polar climates; Polar wind; Radiative forcing; Sea ice; Sea ice thickness; Sea ice variations; Spatial distribution; Summer; Surface energy; Surface energy balance; Surface properties; Thickness; Variation; Wind; Winds
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2024GL111205

Over the past 30 years, the Arctic Dipole Anomaly (DA) has repeatedly led to record lows in summer sea ice extent, with cloud radiative effects (CRE) playing a crucial regulatory role. Here, we reveal the CRE variations between positive and negative DA events and elucidate the slowing impacts of CRE on sea ice thickness (SIT) changes. The DA triggers robust meridional winds and transpolar drift, markedly reducing SIT in the Beaufort Sea (BeS), Chukchi Sea (CS), and East Siberian Sea (ESS), while increasing it in the Greenland Sea (GS). CRE significantly slow SIT changes, contributing +14.4, +4.4, +16.4, and −26.7 cm to changes from June to August, against total changes of −55.9, −29.4, −39.8, and +42.8 cm in September over BeS, CS, ESS, and GS, respectively. This study underscores the key impacts of CRE on sea ice variation, emphasizing their significance in the polar climate system. Plain Language Summary The Arctic Dipole Anomaly is one of the principal atmospheric circulation patterns in the Arctic region, significantly influencing the spatial distribution of sea ice through induced changes in polar wind directions. These wind changes also affect the fraction of Arctic clouds and, by modifying cloud‐surface radiative forcing, alter the surface energy balance. Utilizing 20 years of multi‐source observation data along with reanalysis meteorology, we observed that during the summer, a positive Arctic Dipole Anomaly significantly decreases the thickness of sea ice in the Pacific sector and increases it in the Atlantic sector. During this period, variations in cloud‐surface radiative forcing substantially slow the extent of sea ice thickness reduction/increase. In other words, without considering the impact of cloud radiative forcing, the changes in sea ice thickness would be more severe. Key Points There is a significant reduction in both the sea ice concentration and thickness across the Pacific sector of the Arctic with Arctic Dipole Anomaly phases in summer The Arctic Dipole Anomaly induces alterations in the wind and temperature fields, which subsequently influence the spatial distribution of Arctic clouds Variations in clouds and surface albedo alter the surface energy balance and slow the sea ice changes caused by the Dipole Anomaly