Recent Changes in the Arctic and the Study of Environmental Arctic Change (SEARCH) James Morison Polar Science Center Applied Physics Laboratory University of Washington Seattle, Washington USA [email protected]Canadian Foundation for Climate and Atmospheric Science Workshop on Arctic Climate February 20-21, 2003
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Recent Changes in the Arctic and the Study of Environmental Arctic Change (SEARCH) James Morison Polar Science Center Applied Physics Laboratory University.
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Canadian Foundation for Climate and Atmospheric Science
Workshop on Arctic Climate February 20-21, 2003
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
Outline
Ice andAtmospheric Pressure Changes
Ice thickness decreased 42% in last 30 years (Rothrock et al, 1999)
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
Extent negatively correlated with Arctic Oscillation (Rigor et al., 2002)
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)
Mendeleyev R.
Makarov B.
Alaska
Greenland
Siberia
0
500
Canada B.
Alpha R.
400
4 3
300
2
200
1
100
0-1-2-3
90°E
ΔS
75°N90°W
80°N
85°N
3000 m
1000 m2000 m
Eurasian B.
Lomono
Frontal Line1993
0°
180°
Frontal LinePre-1993
From Morison, J. H., K. Aagaard, and M. Steele, 2000, Recent Environmental Changes in the Arctic: A Review, Arctic, 53, 4.
Saltier Atlantic-Derived Water
Frontal Shift
Salinity Increase
Fresher Pacific-Derived Water
Ocean Differences From Climatology, 2000-2001
Pacific-derived surface waters moving east and appearing off Ellesmere Island
Front still shifted counterclockwise near Pole
0
200
400
3210
-1-2-3
Alpha R.
Eurasian B.
Canada B.
Makarov B.
Mendeleyev R.
90°E
85°N80°N
180°
0°
Canada
Greenland
90°W
Lomonosov R.
100
300
500
Hydro 2001 12
34
5
12
3
4 56
7
Hydro 2000
2000 Drift2001 Drift
ΔS
Fresher at Coast
Saltier Atlantic-derived
NPEO ’00 & ‘01 Hydrographic Surveys
Pacific-derived
Morison et al., 2002, EOS, in press.
Ecosystem Change
(from Brodeur et al., 1999)
Small perturbation in physical mode can create nonlinear change in other parts of the system
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
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)
From Alaska Native Science Commission and Institute of Social and Economic Research, Alaska Traditional Knowledge and Native Foods Database, http://www.native knowledge.org
Changes in climate raises concern about native foods
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),
Decreased ice extent & changes in storm patterns produce higher seas that accelerate coastal erosion
Rising AO means lowers atmospheric pressure over the Arctic.
Thompson and Wallace, 1998)
1973 LOW AO
Concentration of Atlantic Water tracer (%) averaged over depth of 180-560 m for repeated 1973 forcing (Maslowski et al, 2000)
Does high AO cause a frontal shift?
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
Simulated Sea Ice Thickness Changes
Zhang, Rothrock and Steele, 2000, Recent changes in Arctic sea ice: the interplay between ice dynamics and thermodynamics, J. Clim., 13, 3099-3114.
-0.5
-1.00.0
2.01.0
Shift in drift axis, increase in drift speeds, increased lateral melt
a) 1979 - 88 mean
b) 1989 - 96
c) = b) - a)Reduced residence time, production and average thickness
Ice Budget Differences*(89 to 96) - (79 to 88)
Vert. Growth 0.0Lateral Melt - 0.6Export - 0.7Ice Production -1.3
* (1012 m3 yr-1)
Could ocean changes be due to greenhouse warming?
(Fyfe et al.,1999)
1950 2000 2050 2100
GHW Simulation
GHW Simulation
GHW Simulation
Control Simulation
Observed - earlier and larger than simulated
Yes, or changes may indicate what’s to come.
Simulations suggest spin up of the Polar Vortex is part of greenhouse warming response.
AO Index
Update 2000 -2002
Polar Vortex increased in strength ca 1989
However still higher than 1950-88
Relaxed toward climatology in mid 1990’s
1950 1960 1970 1980 1990 2000 2010-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Year
NCEP Wintertime (NDJFMA) AO Index from 1950 - 2002 Minus Avg INdex 1950 - 1988
0.744
0.744 + 0.816
+ 0.577
0.744 - 0.82
- 0.577
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)
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.