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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

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slide1

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@apl.washington.edu

slide2

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
slide3

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)
slide4

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)
slide5

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
slide6

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
human dimension of change
Human Dimension of Change
  • 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)
  • Ice extent, thickness, and duration are reduced, hurting transportation and food gathering
  • 43% decrease in sea ice thickness (Rothrock et al. (1999)
  • 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
slide8

Connection to Global Climate

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

slide9

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

slide10

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.

slide11

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 what’s to come.

slide12

Update 2000 -2002

  • Polar Vortex increased in strength ca 1989
  • Relaxed toward climatology in mid 1990’s
  • However still higher than 1950-88
slide13

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)

slide14

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.washington.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.edu/search/index.html.
  • * NSF, NOAA, NASA, DOD, DOE, DOI
slide16

SEARCH Activity Area

Large-scale Atmospheric Observations

slide17

SEARCH Activity Area

Distributed Marine Observatories

slide18

SEARCH Activity Area

Distributed Terrestrial Observatories

CEON*

*Circumarctic Environmental Observatories

slide19

SEARCH

ASR - Arctic System Reanalysis

critical and timely search issue international participation
Critical and Timely SEARCH Issue:International 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

examples of existing and potential canadian participation
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)