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Arctic Clouds and Climate Change
Steve Vavrus Center for Climatic Research University of Wisconsin Visiting Scientist, NCAR (Marika Holland, Dave Bailey) * Future time-mean Arctic cloud response (CMIP3, CCSM) * Role of Arctic clouds in abrupt change (rapid ice loss)
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Intermodel Mean Cloud Changes (CMIP3)
Global High Cloud Increase Polar Low Cloud Increase Late 21st century
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Seasonal Changes in Cloud Amount (20 GCMs)
winter spring summer autumn
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Future CCSM Present
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winter spring winter spring summer autumn summer autumn
Seasonal Changes in Cloud Amount (20 GCMs) Seasonal Changes in Cloud Amount (CCSM) winter spring winter spring summer autumn summer autumn
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Change in Annual Cloud Amount (CMIP)
r =0.84
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Change in Cloud Amount Sea Ice: 20th c and Change
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Cloud Feedback Observed: Arctic CRF = +25 W/m2
CRF/CLT Observed: Arctic CRF = +25 W/m2
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Cloud Feedback
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Rapid Changes in Central Arctic Sea Ice
Holland et al., GRL (2006)
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Rapid Changes in Central Arctic Sea Ice and Clouds
Cloud Amount Ice Concentration [Simulated by CCSM3 (80o-90oN), A1B emissions scenario]
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CCSM A1B Ensemble Simulations
June 2015 Feb 2017
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Sept Feb Pot of heated water analogy
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Conclusions Warming favors polar cloud increases, especially low and high Projected cloud increases are strongly associated with sea ice Cloud increase probably driven by enhanced local evaporation Cloud gain appears to be a positive feedback (autumn, winter) Clouds seem to contribute to abrupt ice-loss events
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