WCRP:

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WCRP Climate and Cryosphere The way forward to
2013 and beyond
Tony Worby and Koni Steffen Co-Chairs, CliC SSG
Presentation to CLIVAR SSG, Madrid, Spain, 19th
May 2009
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The cryosphere collectively describes elements of
the earth system containing water in its frozen
state and includes sea ice, lake and river ice,
snow cover, glaciers, ice caps, ice sheets, ice
shelves, permafrost, seasonally frozen ground and
solid precipitation.
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IPCC AR4 A1B is a typical business as usual
(2090-2099) scenario Global mean warming 2.8C
Much of land area warms by 3.5CArctic warms
by 7C
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Courtesy, Tom Agnew, Climate Research
Division Environment Canada
Sea Ice Concentration () Sept 1 2007 and
anomalies
Sea ice cover in 2007 was 23 per cent lower than
the previous record low set in 2005 and 39 per
cent less than average
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Total Greenland ice sheet melt area increased on
average by 20 from 1979 to 2007. On the western
part of the ice sheet the melt area increased by
30
The increasing trend in the total area of melting
bare ice is unmistakable at 13 per year
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Trends in Permafrost Temperature
Western Arctic
High Arctic
Alert 15 m depth
Trend 1994-2004 0.07C/yr
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Rignot et al., 2008
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Rapid freshening of the deep Southern Ocean
Courtesy Steve Rintoul
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WCRPs Climate and Cryosphere Project Co-sponsored
by SCAR and IASC

• Principal Goals
• To assess and quantify the impacts of climatic
  variability and change on components of the
  cryosphere and the consequences of these impacts
  for the climate system.
• To determine the stability of the global
  cryosphere.
• To improve predictability of the cryosphere

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WCRPs Climate and Cryosphere Project Co-sponsored
by SCAR and IASC

• CliCs four theme areas
• Terrestrial Cryosphere and Hydroclimatology of
  Cold Regions (TCHM)
• - role of terrestrial processes in water,
  energy, carbon cycles of cold regions
• - interactions and feedbacks between
  terrestrial and other elements of
  cryosphere/climate
• Ice Masses and Sea Level (IMSL)
• - contribution of glaciers, ice caps and ice
  sheets to sea level rise
• - how will ice shelves respond to changes in
  ocean and atmosphere
• The Marine Cryosphere and Climate (MarC)
• - impacts and feedbacks of a reduction in sea
  ice cover
• - nature of hemispheric differences between the
  two polar regions
• Global Predictions and the Cryosphere (GPC)
• - impacts of changes on ocean and atmosphere
  circulation
• - liklihood of abrupt climate changes

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CliC Initiative 1 Improved understanding of ice
sheet and shelf dynamics and impacts on SLR
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NEED IS DRIVEN BY
Future sea level predications are uncertain
because of uncertainties in the contributions of
Greenland and Antarctica IPCC models do not
include ice sheet dynamics Current language in
the IPCC AR4 is conservative (0.28 0.58 m SLR
by 2100) A recent study suggests a range of 0.4
1.4 m by 2100 (Rahmsdorf, 2007)
Larger values cannot be excluded
Sliding ice sheets (Greenland and Antarctica)
Principally ocean warming and melting glaciers
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CliC Initiative 2 Cryospheric inputs to Arctic
and Southern Ocean Fresh Water Balance
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NEED DRIVEN BY Terrestrial supply of freshwater
to the Arctic Ocean affects Salinity/sea-ice
production and hence radiative feedbacks Intensity
of thermohaline circulation
Additionally, terrestrial water budget
impacts Source/sink relationships of major
organic stores (e.g., peatlands) Soil
moisture/vegetation succession that can affect
radiative feedbacks
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1670
2986
582
3950
713
1075
?
CHANGES IN THE FRESHWATER BUDGET COMPONENTS
e.g., from ACIA Walsh et al., 2005
melt area on Greenland ice sheet increased 16,
1979-2002
scaled from Carmack
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CliC Initiative 3 Regional Climate Modelling
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• Key modelling challenges
• Inflow of Pacific/Atlantic water into
• Arctic ocean
• Bering Strait (60 miles)
• Outflow/inflow through Fram Strait
• 10km or higher horizontal resolution is needed if
  we agree that such details are important for
  realistic modeling of sea ice conditions,
  variability, and effects on atmosphere - ocean
  exchanges
• Forcing of cryospheric models with high
  resolution atmospheric data
• Improvement and evaluation of polar RCMs
• Complement GCMs by RCMs

Maslowski and Kinney, 2009 (in revision)
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Arctic System Reanalysis

• Regional Reanalysis of the Arctic
  Atmosphere/Ocean/Land System
• High Resolution in Time (3 hours) and Space
  (15 km, 71 levels) will consider 10 km
  resolution
• Time 2000 to 2010
• Satellite Radiance Assimilation
• May Extend Grid to Cover All of the
  Continental U.S.
• Supported by NSF as an IPY Project

Courtesy Dave Bromwich
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CliC Initiative 4 Climate feedbacks from
changes in Arctic and Antarctic sea ice
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• NEED IS DRIVEN BY
• Hemispheric mismatch in sea ice extent in Arctic
  v. Antarctic
• Inability of models to correctly predict the
  observed response in either hemisphere
• Importance of albedo-feedback to climate
  processes
• Need to coordinate in situ, remote sensing and
  modelling studies

Antarctic
Arctic
Courtesy John Turner
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Change in Sea Ice Coverage and Winds between
2003-7 and 1982-6
courtesy J. Russell
Average decrease of 24 in ice extent and 34 in
total volume predicted across 15 IPCC AR4 models
(Arzel et al., 2006)
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3D ice-ocean models
See Timmermann et al. (2005) Vancoppenolle et
al. (2009a) Timmermann et al. (2009)
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CLIVAR CliC Synergies

• Modelling
• - Greater focus on seasonal to decadal
  predictability (CliC aims build capacity/profile
  of ice sheet modelling community)
• - Raise the profile of cryosphere within WGCM,
  CMIP
• - Ocean-ice modelling new CliC panel linked to
  WGOMD
• - Regionally focussed modelling experiments
  Arctic basin, Polynyas, Ice shelf/ocean
  interaction
• - SOPHOCLES
• Observations
• - Implementation of SAON (new CliC Arctic sea
  ice panel) and
• SOOS (through ASPeCt)
• - Arctic freshwater budget assessment input to
  SWIPA
• - Southern Ocean freshwater budget links to
  Southern Ocean panel
• - Knowledge of initial conditions for decadal
  predictability
• - Provision of data for Asian monsoons studies
  (Asia CliC)
• - Reanalyses
• What does CLIVAR need/expect from CliC?

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