Jamie Morison

Polar Science Center, University of Washington

morison@apl.washington.edu

PresentationSEARCH Open Science Meeting

Seattle, WashingtonTuesday, October 28, 2003

SEARCH Vision and Core Hypotheses

SEARCH Motivation

“Axiom”The Arctic has been characterized in

recent decades by a complex of significant, interrelated, pan-Arctic

changes (Unaami).

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 (Parkinson et al.)

Atmospheric Pressure and Ice Changes

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.

Ocean Salinity Change

From Morison, et al., , 2000, , Arctic, 53, 4.

Saltier Atlantic-Derived Water

Frontal Shift

Salinity Increase

Fresher Pacific-Derived Water

(from Brodeur et al., 1999)

Marine Ecosystem Change in 1990s

Brackish water sea-ice ecosystems

Whale migrations shifting with reduced ice extent

Barents Sea fisheries shifting north

Bering Sea jellyfish increase

Bering Sea phytoplankton blooms

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]

June Runoff Annual Runoff

Pavlov et al., 1998

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.

Terrestrial Change - Thawing of Frozen Ground

(from Osterkamp & Romanovsky, 1999)

Permafrost temperatures in the Russian Arctic and intermittent permafrost region of Alaska rising in the 90s.

Permafrost temperatures falling in eastern Canada.

1985T. Osterkamp photo1997 T. Osterkamp photo

Thermokarst formation - drainage changes

Highest Highest 1/31/3

Middle 1/3Middle 1/3 Lowest 1/3Lowest 1/3

High values in PC-1 correlated variables occur in recent years

1965 1975 1985 1995 Overland et al., Clim. Change, 2003

What’s Unaami you ask?Check out the Unaami Web site :http://www.unaami.noaa.gov and Jim’s Principal Component analysis.

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

SEARCH Hypothesis 1

Unaami is related to a spin up of the atmospheric Polar Vortex

(e.g., AO).

Connection to the Polar Vortex

Low pressure spins up Polar Vortex, brings warm air to Greenland Sea & Russian Arctic

Warm air over Greenland Sea allows warmer Atlantic Water in Arctic Ocean

Warm air advection increases SAT, warms permafrost

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

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

AO Index

1900 1920 1940 1960 1980 20001900 1920 1940 1960 1980 2000

Rising AO means lowers SAP over the Arctic.

Thompson and Wallace, 1998)

1950 1960 1970 1980 1990 2000 2010

-1.5

-1

-0.5

0

0.5

1

1.5

2AO Index (NDJFMA) 1950-2003 Relative to 1950 -88 Avg

AO update: Decreased in mid 90s but on average still high

Cyclonic Circulation

- Increases export of fresh water and sea ice- Decreases salinity and increases stratification of the sub-Arctic seas- Inhibits global ocean overturning

Does positive AO produce more cyclonic circulation?

- 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.

a) 1979 - 88

b) 1989 - 96

b) - a)

More Cyclonic

Shift in axis of front and surface current

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: YesFrom: Furevik, Chapman Conference, 2002

SEARCH Hypothesis 2

Unaami is a component of climate change.

Spin up of the Polar Vortex as part of greenhouse warming response

(Shindell et al., 1999)

AO observations

EOF 1 in GHW simulation with stratosphere

(Fyfe et al.,1999)

1950 2000 2050 2100

GHW Simulation

GHW Simulation

GHW Simulation

Control Simulation

Observed -

earlier and larger than simulated

AO Index

SEARCH Hypothesis 3

Feedbacks among the ocean, the land, and the atmosphere are critical to

Unaami.

Zhang

Zhang, Rothrock and Steele, 2000, , J. Clim., 13, 3099-3114.

-0.5

-1.00.0

2.01.0

Simulated sea ice changes by Zhang et al. (2000) show shift in drift axis, increased drift speeds, increased lateral melt

(a) 1979 - 88 mean

These lead to reduced residence time, reduced average thickness in the basin, but

increased ice export from the Basin to the North Atlantic.

Ice Budget Differences in the Basin*(89 to 96) - (79 to 88)Vert. Growth 0.0Lateral Melt - 0.6Export - 0.7Ice Production -1.3

* (1012 m3 yr-1)

(b) 1989 - 96 mean

(c) = (b) - (a) UnaamiAffects Albedo

Affects Global THC

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

Borrowing from Bob Dickson’s talk tomorrow:

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.

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

+40

-20

SEARCH Hypothesis 4

The physical changes of Unaami have large impacts on the Arctic ecosystems and society.

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)

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

Enhanced cyclonic ocean circulation raises coastal sea level (Proshutinsky and Johnson, 1997)

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)

Can the SEARCH paradigm help deal with change?

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!

http://iabp.apl.washington.edu/SeaIceAO/

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.

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.

Ocean Temperature Changes

§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.

Atlantic Water 1.5° warmer

From Morison, et al., , 2000, , Arctic, 53, 4.

Conditions at the North Pole

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

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Salinity — North Pole 1950–2001 — Temperature (°C)

EWG Climatology,1950s, 60s, 70s, 80s

Oden ‘91,SCICEX, ’93-’99

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Salinity — North Pole 1950–2001 — Temperature (°C)

200288° 30' N71° 14' E

NPEO 2000 2001 2002

2003

2003: Atlantic Water slightly fresher

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

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

…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.

… and its continued spread in 1993, 1995, 1996 & 1999,

from Karcher et al 2003.