Linkages Between Arctic Warming and Mid-Latitude Weather Patterns Summary of a Workshop (2014) / Chapter Skim
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Appendix A: Speaker Abstracts
Appendix A: Speaker Abstracts
Pages 45-58
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From page 45... ...
We started with the idea that Arctic sea ice loss is in a sense the middle of a story that really begins with amplified Arctic change forced by greenhouse warming. In this bigger picture, Arctic sea ice, atmosphere, and ocean processes are strongly coupled and are all relevant controls on midlatitude weather.
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From page 46... ...
Thus, a degree of caution is required when linking sea ice loss to recent extreme weather events and possible trends therein. In short, the science behind Arctic-mid-latitude linkages is still in its infancy and more research is required to make more confident statements.
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From page 47... ...
Conjectures from the same paper were also provided: °observed integrated 1000-500mb Arctic warming is due to Arctic sea ice loss," and "observed weaker poleward thickness gradients are due to Arctic sea ice loss." A model was run both with and without sea ice to find the net effect of the ice. The estimated observed 1000-500hPa Arctic warming found was inconsistent with model internal atmospheric variability alone, was largely forced, but inconsistent with effects of sea ice loss alone, and thus could be largely due to natural decadal sea surface temperature (SST)
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From page 48... ...
and September Arctic sea ice extent and the winter Arctic Oscillation, the dominant mode of variability for the extratopical Northern Hemisphere, shows that the SAI is much more highly correlated with the winter AO than sea ice. An operational statistical model, which uses the SAI as its main predictor, correctly predicted the cold winter in 2013 across Northern Eurasia and the United States (pattern correlation between predicted and observed temperatures of 0.65)
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From page 49... ...
Observational Evidence of Arctic Weather Linkages James E Overland, NOAA/Pacific Marine Environmental Laboratory Loss of Arctic sea ice, record negative values of the winter Arctic Oscillation atmospheric circulation index, earlier summer snow melt, and increasing extreme weather events at mid- latitudes -- both heat waves and cold snowstorms -- have been observed over the last decade.
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From page 50... ...
Upper level atmospheric circulation in north-central Asia in winter responds to the recent large scale reduction the north-south temperature gradients, as noted by Francis and Vavrus (2012) , reducing jet-stream zonal velocities and the penetration of storms into northern Asia from the west, increasing the strength and persistence of the Siberian High, and thus increasing the intra-seasonal probability of multiple cold air events over eastern Asia.
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From page 51... ...
Drought Sam Higuchi, NASA There are two approaches to examining the relationship between an increase in flash floods (Intensity-Duration-Frequency Curves) and Arctic amplification, as a leading indicator of change and as a lagging indicator of change.
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From page 52... ...
Regression of September 2012 sea ice extent anomalies onto the PCH from October 2012 through March 2013, further suggests that the dramatic decrease in sea ice contributed to extreme weather events observed during that period. Pacific Arctic Sea Ice Loss Kathleen Crane, NOAA Pacific Arctic sea ice loss from advection of heat from the Pacific and Atlantic Gateways is shown.
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From page 53... ...
The past six Junes have seen record minimum SCEs over NH and Eur, with five of these six the lowest over NA. The recent early timing of arctic snowmelt appears to be occurring at an equivalent if not greater pace than the loss of summer Arctic sea ice extent.
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From page 54... ...
Response of the Wintertime Atmospheric Circulation to Current and Projected Arctic Sea Ice Decline Gudrun Magnusdottir, University of California, Irvine Motivated by the rapid September decrease in sea-ice concentrations over the years 2007 2012 (inclusive) , Yannick Peings and I recently planned and ran some idealized CAM5 experiments using sea-ice forcing from those 6 years (compared to average sea ice conditions over 1979-2000)
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From page 55... ...
surface change can be attributed to summer sea ice loss. 3-Minute Open Session Presentations: Modeling The Role of Global Climate Change in the Extreme Low Summer Arctic Sea Ice Extent in 2012 Rong Zhang and Thomas R
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From page 56... ...
The Influence of Sea Ice Albedo on the Global Hydrological Cycle Aneesh Subramanian, Ian Eisenman, and Simona Bordoni, Scripps Institution of Oceanography, University of California, SanDiego The idea that Arctic sea ice retreat could influence precipitation outside the polar region has garnered considerable interest in recent years. As sea ice recedes, it alters the climate system due to factors including a change in surface albedo, which has been suggested to affect the hydrological cycle in the mid-latitudes and tropics.
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From page 57... ...
Our analysis indicates that at a given time, it is impossible to distinguish a RILE from a continuously accelerating rate of loss because the difference depends on the future: A RILE necessarily ends with a period of weaker sea ice loss, while a continuously accelerating loss has increasingly greater loss with each year. Open Session Talk Clara Deser, NCAR We investigated the role of oceanic feedbacks in the atmospheric response to GHGinduced Arctic sea ice loss.
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From page 58... ...
58 Appendix A latitude ocean feedbacks in Arctic Amplification. The near-surface atmospheric circulation response did not appear to be sensitive to ocean coupling.
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