SEARCH Vision and Core Hypotheses

2. SEARCH Vision and Core Hypotheses Presentation SEARCH Open Science Meeting Seattle, Washington Tuesday, October 28, 2003 Jamie Morison Polar Science Center, University of Washington morison@apl.washington.edu

3. SEARCH Motivation “Axiom” The Arctic has been characterized in recent decades by a complex of significant, interrelated, pan-Arctic changes (Unaami).

4. Atmospheric Pressure and Ice Changes • Beaufort High decreased and shifted east in 1990s • Transpolar Drift of ice shifted axis counterclockwise producing a more cyclonic motion in 1990s • Ice extent decreased 3%/decade (Parkinson et al.) • Ice thickness decreased 42% in last 30 years (Rothrock et al, 1999)

5. Ocean Salinity Change Fresher Pacific-Derived Water Frontal Shift Saltier Atlantic-Derived Water Salinity Increase From Morison, et al., , 2000, , Arctic, 53, 4. Comparing the 1993 SCICEX data with the EWG climatology, we see a salinity increase in the upper 200 m of the Makarov Basin, indicating a shift in front between Atlantic and Pacific waters.

6. Marine Ecosystem Change in 1990s • Bering Sea jellyfish increase • Bering Sea phytoplankton blooms • Brackish water sea-ice ecosystems • Whale migrations shifting with reduced ice extent • Barents Sea fisheries shifting north

7. Terrestrial Change - Increased Runoff Over 64 years, discharge from the 6 largest Eurasian arctic rivers has increased 7% (128 km3/y or 0.004 Sv) [Petersen et al., Science 2002] Peterson, Bruce J. , Robert M. Holmes, James W. McClelland, Charles J. Vörösmarty, Richard B. Lammers, Alexander I. Shiklomanov, Igor A. Shiklomanov, and Stefan Rahmstorf, Increasing River Discharge to the Arctic Ocean, Science, December 13; 298: 2171-2173.

8. Terrestrial Change - Thawing of Frozen Ground • Permafrost temperatures in the Russian Arctic and intermittent permafrost region of Alaska rising in the 90s. • Permafrost temperatures falling in eastern Canada. • Thermokarst formation - drainage changes

9. 1965197519851995 What’s Unaami you ask? Check out the Unaami Web site : http://www.unaami.noaa.gov and Jim’s Principal Component analysis. High values in PC-1 correlated variables occurin recent years • Highest 1/3 • Middle 1/3 • Lowest 1/3 Overland et al., Clim. Change, 2003

10. Three Types of Arctic Change (30 Years of Data) • PC-1: Regime-like – Arctic Oscillation/NAO 1989 Shift • PC-2: Interdecadal - High Arctic (P&J Index) • PC-3: Linear – Lower Arctic Land

11. SEARCH Hypothesis 1 Unaami is related to a spin up of the atmospheric Polar Vortex (e.g., AO).

12. AO update: Decreased in mid 90s but on average still high • Increase in Polar Vortex • Increases open water • Decreases Albedo • Increases radiative heating & melt • Freshens upper Beaufort Sea Connection to the Polar Vortex • Increase in Polar Vortex • More cyclonic ocean circulation • Shift in front and Transpolar Drift • Russian shelf water to Beaufort Warm air advection increases SAT, warms permafrost Warm air over Greenland Sea allows warmer Atlantic Water in Arctic Ocean Low pressure spins up Polar Vortex, brings warm air to Greenland Sea & Russian Arctic • Cyclonic Circulation • - Increases export of fresh water and sea ice • Decreases salinity and increases stratification of the sub-Arctic seas • Inhibits global ocean overturning Rising AO means lowers SAP over the Arctic. Thompson and Wallace, 1998)

13. a) 1979 - 88 Does positive AO produce more cyclonic circulation? Shift in axis of front and surface current b) 1989 - 96 b) - a) More Cyclonic - Gudkovich (1961) - Proshutinsky and Johnson (1997) - Zhang, Rothrock and Steele, 1998, Warming of the Arctic Ocean by a strengthened Atlantic inflow, GRL, 25, 1745-1748.

14. Does high AO cause a frontal shift? 1973 LOW AO Concentration of Atlantic Water tracer (%) averaged over depth of 180-560 m for repeated 1973 forcing (Maslowski et al, 2000) 1993 HIGH AO Concentration of Atlantic Water tracer (%) averaged over depth of 180-560 m for repeated 1993 forcing (Maslowski et al., 2000) Model Suggests: Yes From: Furevik, Chapman Conference, 2002

15. SEARCH Hypothesis 2 Unaami is a component of climate change.

16. AO observations (Shindell et al., 1999) EOF 1 in GHW simulation with stratosphere AO Index GHW Simulation GHW Simulation (Fyfe et al.,1999) GHW Simulation Control Simulation Observed - earlier and larger than simulated Spin up of the Polar Vortex as part of greenhouse warming response

17. SEARCH Hypothesis 3 Feedbacks among the ocean, the land, and the atmosphere are critical to Unaami.

18. (a) 1979 - 88 mean Zhang Simulated sea ice changes by Zhang et al. (2000) show shift in drift axis, increased drift speeds, increased lateral melt These lead to reduced residence time, reduced average thickness in the basin, but (b) 1989 - 96 mean increased ice export from the Basin to the North Atlantic. Ice Budget Differences in the Basin* (89 to 96) - (79 to 88) Vert. Growth 0.0 Lateral Melt - 0.6 Export - 0.7 Ice Production -1.3 * (1012 m3 yr-1) Unaami Affects Albedo (c) = (b) - (a) Affects Global THC Zhang, Rothrock and Steele, 2000, , J. Clim., 13, 3099-3114.

19. Borrowing from Bob Dickson’s talk tomorrow: entire system undergone freshening Unaami’s increased runoff, change in Pacific water circulation, and increased ice production may be manifest in a general freshening of the entire system of overflow and entrainment that ventilates the deep Atlantic. Dickson et al 2002

20. The Polar Vortex Responds to Arctic Change A simulated atmospheric response to a change in Labrador Sea ice cover from minimum to maximum produces a shift in NAOmodel of -0.7 Std. Changes in ice cover feedback on hemispheric circulation of the atmosphere & snow in Seattle, temperature in Washington D.C., etc. +40 -20 Simulated difference in long-term JFM 1000 hPa height (m) between max ice extent and minimum ice extent in the Labrador Sea Kvamtso, Skeie, and Stephenson, 2003, accepted, Int. J.of Climatology

21. SEARCH Hypothesis 4 The physical changes of Unaami have large impacts on the Arctic ecosystems and society.

22. Human Dimension of Change • Ice extent, thickness, and duration are reduced, hurting transportation and subsistence • 43% decrease in sea ice thickness (Rothrock et al. (1999) • Weather is more unpredictable affecting safety, food gathering, and transportation • Increases in cyclone activity north of 65°N since at least 1958 (Serreze et al., 2000) • Decreased ice extent & changes in storm patterns produce higher seas that accelerate coastal erosion • Enhanced cyclonic ocean circulation raises coastal sea level (Proshutinsky and Johnson, 1997) • Inland precipitation changes cause drying affecting food gathering • Increases in fire frequency in Alaska over the past 50 years (Oechel and Vourlitis, 1996) • Increase in the abundance of woody shrub species and slow northward movement of treeline have major impacts on winter snow accumulation and soil temperature (Sturm et al., 2001), • Changes in climate raises concern about native foods • From Alaska Native Science Commission and Institute of Social and Economic Research, Alaska Traditional Knowledge and Native Foods Database, http://www.native knowledge.org

23. Can the SEARCH paradigm help deal with change? http://iabp.apl.washington.edu/SeaIceAO/ Example Rigor et al. (2002) find a negative correlation between winter AO index and ice extent the following fall. This suggests that …. Six month ice condition “outlooks” are possible!

24. Can the SEARCH paradigm help deal with change? Example Griffith et al. (2002) find a negative correlation between winter AO index and growth of the Porcupine Caribou herd. This suggests … We can and should account for natural climate variations in discussions wildlife management in general and of ANWR specifically.

25. To test these hypotheses and help society deal with change… requires a program long-term, large-scale observations (including retrospective and paleo studies), analysis, and modeling —SEARCH.

27. Ocean Temperature Changes Atlantic Water 1.5° warmer From Morison, et al., , 2000, , Arctic, 53, 4. • Comparing the 1993 SCICEX data with the EWG climatology, we see warm cores over ridges indicating a shoaling and 1.5° warming of the temperature maximum where the Atlantic Water inflow subducts to spread through the Eurasian basin.

28. Conditions at the North Pole Oden ‘91, SCICEX, ’93-’99 NPEO 2000 2001 2002 2003 EWG Climatology, 1950s, 60s, 70s, 80s • EWG: 0.5° AW core at 350 m & 31 o/oo surface salinity • 1990s: 1.5° AW core @ 250 m & 32.5 o/oo surface salinity • 2000-02: AW temp slightly less than 1995 max Surface salinity < 1990’s 2003: Atlantic Water slightly fresher

29. Variations in Global Temperature and their uncertainties,1861- April 2001(land air and sea surface temperature) The context (i): during the past century, the global mean temperature has increased in two main episodes of warming

30. When we plot air temperature as a function of latitude and time, two things become clear: 1) the World is warmer. Including 2002, all ten of the warmest years since records began in 1861 have occurred since 1990; Jones and Moberg, 2003. 2) in the last two decades the distribution of warming has become global. Courtesy Tom Delworth, GFDL

31. …and Karcher et al have pieced together the spread of warming around the boundary of the Arctic Ocean ……in 1980, 1984, 1987 & 1991, from Karcher et al 2003.

32. … and its continued spread in 1993, 1995, 1996 & 1999, from Karcher et al 2003.