Recent Changes in the Arctic and the Study of Environmental Arctic Change SEARCH

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Recent Changes in the Arctic and the Study of
Environmental Arctic Change(SEARCH)
Canadian Foundation for Climate and Atmospheric
Science Workshop on Arctic Climate February
20-21, 2003
James Morison Polar Science Center Applied
Physics Laboratory University of
Washington Seattle, Washington USA morison_at_apl.was
hington.edu
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Outline

• The 1990s revealed Arctic change involving
  atmosphere, ocean, and land.
• The Arctic change appears connected to changes in
  the atmospheric circulation of the Northern
  Hemisphere.
• Ocean changes potentially affect global climate
  through
• Changing albedo
• Weakening global thermohaline circulation
• In 2000-2002 the atmosphere and Arctic Ocean were
  still in a changed state.
• The change motivates a program of observations,
  analysis, modeling, and assessment the Study of
  Environmental Arctic Change (SEARCH)
  http//psc.apl.washington.edu/search/index.html
• SEARCH requires internationalization

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Ice andAtmospheric Pressure 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

• Ice thickness decreased 42 in last 30 years
  (Rothrock et al, 1999)

• Extent negatively correlated with Arctic
  Oscillation (Rigor et al., 2002)

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Ocean ChangesSalinity Difference, Pargo 93 -
Climatology
Fresher Pacific-Derived Water
Frontal Shift
Saltier Atlantic-Derived Water
Salinity Increase
From Morison, J. H., K. Aagaard, and M. Steele,
2000, Recent Environmental Changes in the Arctic
A Review, Arctic, 53, 4.

• Shift in front between Atlantic and Pacific
  waters
• Salinity increase in the upper 200 m of the
  Makarov
• Surface salinity decrease in Beaufort Sea (SHEBA)

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• Ocean Differences From Climatology, 2000-2001

NPEO 00 01 Hydrographic Surveys
Saltier Atlantic-derived
Pacific-derived
Fresher at Coast
Morison et al., 2002, EOS, in press.

• Front still shifted counterclockwise near Pole

• Pacific-derived surface waters moving east and
  appearing off Ellesmere Island

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Ecosystem Change

• Massive Bering Sea phytoplankton blooms
• Brackish water sea ice ecosystems in Beaufort Sea
• Whale migrations shifting with reduced ice extent
• Barents Sea fisheries shifting north

• Small perturbation in physical mode can create
  nonlinear change in other parts of the system

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Human Dimension of Change

• Ice extent, thickness, and duration are reduced,
  hurting transportation and food gathering
• 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 65N 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

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Connection to Global Climate

• Increase in Polar Vortex
• - More cyclonic ocean circulation
• Shift in front and Transpolar Drift
• Russian shelf water to Beaufort

• Increase in Polar Vortex
• - Weakens Beaufort High
• Increases open water
• Decreases Albedo
• Increases radiative heating melt
• Freshens upper Beaufort Sea

• 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 and Russian Arctic
Rising AO means lowers atmospheric pressure over
the Arctic.

• Cyclonic Circulation
• - Increases export of fresh water
• Increases stratification in Greenland and
  Labrador seas
• Inhibits global ocean overturning

Thompson and Wallace, 1998)
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Does high AO cause a frontal shift?
From Furevik, Chapman Conference, 2002
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
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Simulated Sea Ice Thickness Changes
a) 1979 - 88 mean
Shift in drift axis, increase in drift speeds,
increased lateral melt
b) 1989 - 96
Ice Budget Differences (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)
Reduced residence time, production and average
thickness
c) b) - a)
Zhang, Rothrock and Steele, 2000, Recent changes
in Arctic sea ice the interplay between ice
dynamics and thermodynamics, J. Clim., 13,
3099-3114.
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Could ocean changes be due to greenhouse warming?
Simulations suggest spin up of the Polar Vortex
is part of greenhouse warming response.
(Fyfe et al.,1999)
GHW Simulation
GHW Simulation
AO Index
GHW Simulation
Control Simulation
Observed - earlier and larger than simulated
Yes, or changes may indicate whats to come.
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Update 2000 -2002

• Polar Vortex increased in strength ca 1989

• Relaxed toward climatology in mid 1990s

• However still higher than 1950-88

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Climatological Ice Extent at End of August
Ice Extent at End of August 2002
Note Ice extent negatively correlated with AO
(Rigor et al, 2002)
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Observations Motivate SEARCH

• The changes, the impacts they are having on
  northern communities, and the potential impacts
  on global climate warrant a long-term program of
  observations, analysis, and modeling to
  understand them.
• 2001 - Science Plan available at
  http//psc.apl.washington.edu/search/index.html
• SEARCH is being developed in the US as an
  interagency program.
• The focus of the SEARCH Interagency Working Group
  (IWG) has been on how to obtain funding.
• 2002 - First major SEARCH funding through the NSF
  Freshwater Initiative. See http//psc.apl.washingt
  on.edu/search/index.html.
• The focus of the SEARCH Science Steering
  Committee has been how to implement the science.
• 2003 (15/1) Draft SEARCH Implementation
  Strategy available at http//psc.apl.washington.ed
  u/search/index.html.
• NSF, NOAA, NASA, DOD, DOE, DOI

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SEARCH Organization
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SEARCH Activity Area Large-scale Atmospheric
Observations
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SEARCH Activity Area Distributed Marine
Observatories
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SEARCH Activity Area Distributed Terrestrial
Observatories
CEON
Circumarctic Environmental Observatories

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SEARCH ASR - Arctic System Reanalysis
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Critical and Timely SEARCH IssueInternational
Participation
- International membership on SSC and Panels -
International SEARCH Working Groups (e.g.,
ASOF) - Affiliation with large international
programs (e.g., IASC, IGBP, International
CLIVAR) - SEARCH-IASC International Symposium in
2005
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Examples of Existing and Potential Canadian
Participation
- Organization - Understanding - DQU, ASR and
LGC - Archipelago through flow - ASOF and FWI
DAO (e.g., CFS Alert) DTO (e.g., CEON sites)
DMO (e.g., Alert and NPEO)