Search vision and core hypotheses
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SEARCH Vision and Core Hypotheses. Presentation SEARCH Open Science Meeting Seattle, Washington Tuesday, October 28, 2003. Jamie Morison Polar Science Center, University of Washington [email protected] SEARCH Motivation. “Axiom”

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SEARCH Vision and Core Hypotheses

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Search vision and core hypotheses

SEARCH Vision and Core Hypotheses

Presentation

SEARCH Open Science Meeting

Seattle, Washington

Tuesday, October 28, 2003

Jamie Morison

Polar Science Center, University of Washington

[email protected]


Search motivation

SEARCH Motivation

“Axiom”

The Arctic has been characterized in recent decades by a complex of significant, interrelated, pan-Arctic changes (Unaami).


Atmospheric pressure and ice changes

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)


Ocean salinity change

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.


Marine ecosystem change in 1990s

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


Terrestrial change increased runoff

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.


Terrestrial change thawing of frozen ground

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


Search vision and core hypotheses

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


Three types of arctic change 30 years of data

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

SEARCH Hypothesis 1

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


Connection to the polar vortex

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)


Does positive ao produce more cyclonic circulation

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.


Does high ao cause a frontal shift

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


Search hypothesis 2

SEARCH Hypothesis 2

Unaami is a component of climate change.


Spin up of the polar vortex as part of greenhouse warming response

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


Search hypothesis 3

SEARCH Hypothesis 3

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


Zhang

(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.


Entire system undergone freshening

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


The polar vortex responds to arctic change

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


Search hypothesis 4

SEARCH Hypothesis 4

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


Human dimension of change

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


Can the search paradigm help deal with change

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!


Can the search paradigm help deal with change1

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

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

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.


Conditions at the north pole

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


Search vision and core hypotheses

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


Search vision and core hypotheses

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


Search vision and core hypotheses

…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.


Search vision and core hypotheses

… and its continued spread in

1993, 1995, 1996 & 1999,

from Karcher et al 2003.


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