Changes in Arctic clouds during intervals of rapid sea ice loss

• Published in: Climate Dynamics
• Other Authors: Vavrus, Steve (author), Holland, Marika (author), Bailey, David (author)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2011
• Subjects: Arctic; Clouds; Abrupt change; Rapid change; Sea ice; CCSM; Climate change
• Online Access: http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-000-133; https://doi.org/10.1007/s00382-010-0816-0

We investigate the behavior of clouds during rapid sea ice loss events (RILEs) in the Arctic, as simulated by multiple ensemble projections of the 21st century in the Community Climate System Model (CCSM3). Trends in cloud properties and sea ice coverage during RILEs are compared with their secular trends between 2000 and 2049 during summer, autumn, and winter. The results suggest that clouds promote abrupt Arctic climate change during RILEs through increased (decreased) cloudiness in autumn (summer) relative to the changes over the first half of the 21st century. The trends in cloud characteristics (cloud amount, water content, and radiative forcing) during RILEs are most strongly and consistently an amplifying effect during autumn, the season in which RILEs account for the majority of the secular trends. The total cloud trends in every season are primarily due to low clouds, which show a more robust response than middle and high clouds across RILEs. Lead-lag correlations of monthly sea ice concentration and cloud cover during autumn reveal that the relationship between less ice and more clouds is enhanced during RILEs, but there is no evidence that either variable is leading the other. Given that Arctic cloud projections in CCSM3 are similar to those from other state-of-the-art GCMs and that observations show increased autumn cloudiness associated with the extreme 2007 and 2008 sea ice minima, this study suggests that the rapidly declining Arctic sea ice will be accentuated by changes in polar clouds. National Aeronautics and Space Administration (NASA): NNG06GB26G National Science Foundation (NSF): OPP-0327664 National Science Foundation (NSF): ARC- 0628910 National Science Foundation (NSF): OPP-0612388 National Science Foundation (NSF): ARC-0652838