Title: Update on the Antarctica and the Global Climate System (AGCS) Programme
1Update on the Antarctica and the Global Climate
System (AGCS) Programme
- John Turner
- British Antarctic Survey
2The Goals of AGCS
- To understand the mechanisms controlling the
climate of the Antarctic its cycles and
variability - To explain why the climate has changed in the
past roughly the last 20K years since the Last
Glacial Maximum - To predict how the climate of the Antarctic might
change over the next century under various
greenhouse gas emission scenarios
3The Four Themes of AGCS
- Theme 1 Decadal time scale variability (Dave
Bromwich) - Theme 2 - Global Regional Signals in Ice Cores
(Paul Mayewski) - Theme 3 - Natural Anthropogenic Forcing on the
Antarctic Climate System (John Turner) - Theme 4 - The Export of Antarctic Climate Signals
(Mike Meredith)
4The 500 hPa Temperature Trends (deg C/decade)
Over 1979-2001 from ECMWF 40 Year Re-analysis
Project
5Temperature trends with Depth, 1955-1998
- Much greater than rate of warming of global ocean
global change 0.31 C since 1950s - Strongly surface-intensified.
- Decays to around zero by 100m depth.
- Warming of surf T greater than 0.3 deg per decade.
6Ice core isotope proxy for temperature
(AD1800-2002)indicates all sites within range
of natural variability
Schneider et al. (2006)
7Annual Precipitation Trends 1985-2001
PMM5 E40
There are no widespread trends of either sign.
( decade-1)
Monaghan et al. (2006)
8Loss of ice Shelves Around the Antarctic
Peninsula
Strengthening of the westerlies in recent decades
9Targets for 2007 and 2008
- Assessment of the Antarctic element of the IPCC
Assessment Round 4 model predictions for the next
century - Investigation of the mechanisms responsible for
changes in the SAM - Research into mechanisms behind the
mid-tropospheric warming above the Antarctic that
occurred over the last 50 years. - Investigation of the current state of the
Antarctic climate in the context of the last
several hundred years for purposes of assessing
natural vs anthropogenic impact. - Interference between SAM and ENSO signals in
Antarctica. Teleconnections between Austral -
Midlatitudes and the Antarctic (Southern
S-America, Southern ocean islands, and New
Zealand)
10Targets for 2007 and 2008
- A 200 year array of coastal cores from Antarctica
including sea-ice extent - Marine productivity to understand sea-ice extent
in proxy record (MS) - Quantification of oceanic heat, volume, and fresh
water fluxes in the southern ocean (Quantifying
the current mean state) - Interaction of the ocean on the ice sheet, ice
shelves, and the atmosphere at the Antarctic
margin - Understanding the driving mechanisms in the
Southern Ocean overturning - Drifting buoy deployment
- Contribute to Reanalysis efforts
- Sea ice thickness
- Developments of data bases, such as READER
11The new AGCS newsletter NOTUS
12AGCS session at EGU, Vienna15-20 April 2007
13The AGCS White Paper
- State of the Antarctic and Southern Ocean Climate
System (SASOCS) - Akin to the Arctic Climate Impact Assessment
- Deals with ice core data, met, climatology,
oceanography, model projections, but not biology. - Covers the last 10,000 years and projections for
the next 100 years - How does it link to the Nature paper and the
Antarctic Climate Change and the Environment
work? - Publish Exec Summary in EOS?
- Have a draft ready.
14The New OCEAN-READER Web Site
15Science Highlight Meredith Hogg
Links the stronger westerlies and Eddy Kinetic
Energy in the ACC. Increased poleward heat
flux may have played a significant role in the
observed warming of the Southern Ocean
16Science Highlight John Fyfe
He shows that the latest series of climate models
reproduce the observed mid-depth Southern Ocean
warming since the 1950s if they include
time-varying changes in anthropogenic greenhouse
gases, sulphate aerosols and volcanic aerosols in
the Earths atmosphere. The full effect of
human-induced warming of the Southern Ocean may
not yet to be realized because of volcanic
aerosols
17Current Work on the 5 KM Warming
Two areas of work - The role of Polar
Stratospheric Clouds (PSCs)- Greater poleward
advection of heat by the atmosphere
18The Proposed Southern ice ocean model
intercomparison project (SIOMIP)
- Put forward by Siobhan OFarrell (CSIRO) and Todd
Arbetter (BAS) - Scope - a detailed examination of the sea ice
components in coupled climate models through a
comparison with observational data sets. - Relevant to AGCS, CliC, ASPECT, The Southern
Ocean Implementation panel, IPY CASO and SASSI - Links with interests in water mass formation
- But many errors come from the atmospheric forcing
19The Next 100 Years the Mean of 19 Different
Models
Annual mean surface air temperature changes (deg
per decade) CO2 levels doubled over the next 100
years
20Thank You