Thicker Clouds and Accelerated Arctic Sea Ice Decline: The Atmosphere‐Sea Ice Interactions in Spring

• Published in: Geophysical research letters Vol. 46; no. 12; pp. 6980 - 6989
• Main Authors: Huang, Yiyi, Dong, Xiquan, Bailey, David A., Holland, Marika M., Xi, Baike, DuVivier, Alice K., Kay, Jennifer E., Landrum, Laura L., Deng, Yi
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.06.2019
• Subjects: Arctic clouds; Arctic radiation; Arctic sea ice; Arctic sea ice retreat; Atmosphere; atmosphere‐sea ice coupling; Atmospheric models; atmospheric physical processes; cloud and radiation impact; Cloud cover; Cloud formation; Clouds; Computer simulation; Coupling; Earth; Evaporation; Ice; Ice cover; Ice environments; Ice melting; Radiation; Sea ice; Sea ice forecasting; Spring; Spring (season); Temperature; Wildlife; Arctic region
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2019GL082791

Observations show that increased Arctic cloud cover in the spring is linked with sea ice decline. As the atmosphere and sea ice can influence each other, which one plays the leading role in spring remains unclear. Here we demonstrate, through observational data diagnosis and numerical modeling, that there is active coupling between the atmosphere and sea ice in early spring. Sea ice melting and thus the presence of more open water lead to stronger evaporation and promote cloud formation that increases downward longwave flux, leading to even more ice melt. Spring clouds are a driving force in the disappearance of sea ice and displacing the mechanism of atmosphere‐sea ice coupling from April to June. These results suggest the need to accurately model interactions of Arctic clouds and radiation in Earth System Models in order to improve projections of the future of the Arctic. Plain Language Summary Arctic summer sea ice has declined by nearly 50%, leading to a larger exposed area of open water that persists longer than before. Clouds have large influences on Arctic sea ice long‐term trends and variability. Atmosphere and sea ice are believed to actively interact with each other in spring. But attributing cause and effect is difficult. Therefore, this study seeks to answer the following question: does the atmosphere primarily drive the sea ice changes or does the sea ice dominate changes in the atmosphere in spring? In this study, we isolated the atmospheric response to Arctic sea ice changes from coupled system through both observations and model simulations. It suggests that this relationship is initiated with active coupling in March. Spring clouds then become a driving force in the disappearance of sea ice from April to June. Overall, identifying the two‐way interactions between Arctic sea ice and atmosphere is a critical step to improve seasonal sea ice forecasts and future sea ice prediction. The sea ice coverage and length of the open water season is important for human activities and wildlife. The long‐term time series will inform future planning of military, civilian, and commercial infrastructure. Key Points Active coupling is found between the atmosphere and sea ice in early spring Clouds are one of important drivers for sea ice melting from April to June