Southern Ocean Panel Southern Ocean CLIVAR/CliC/SCAR Report Kevin Speer, Ian Renfrew (chairs), Doug Martinson, Mike Sparrow (ICPO)

Southern Ocean Panel 2.Contributions to CLIVAR's 4 Major Themes (covered last; workshop) 3.–5.Annual workshops; ocean's role in climate; wider areas of climate science 6.New Activities 7.Cross Panel and Working Group links 8.Cross WCRP links 9.Data management 10.Review ToRs (next panel meeting) 11.Issues for SSG Topics

Southern Ocean Panel 5. Highlights of contributions to wider areas of climate science oWorkshop on Modes of Southern Hemisphere climate variability oJune, 2005, Scott Polar Research Institute, Cambridge oS.O. Panel meeting held following workshop oOrganized papers for CLIVAR Exchanges 35 on "Antarctic circumpolar ice-ocean modeling" oPanel members attended relevant meetings such as CliC SSG and WGOMD oObservations kept updated (online) for use by community Wider areas

Southern Ocean Panel A change of direction Half of panel were due to rotate off Replaced to reflect more climate system and less physical oceanography Aiming to become more relevant to: –Climate of southern hemisphere –IPCC process –Coupled models New activities

Southern Ocean Panel Panel members 1. Ian Renfrew, co-chairUK atmospheric processes 2. Kevin Speer, co-chairUSA ocean obs and processes 3. Steve RintouAus ocean obs and processes 4. Doug MartinsonUSA ocean-ice interaction 5. Aike BeckmannFinland ocean-ice modelling New members: 6. Christian Haas Germany sea ice and remote sensing 7. Alberto Naveirra-Garabato UK ocean circulation 8. Dave Thompson USA large-scale atmospheric dynamics 9. Yasu Fukamachi Japan ocean/ice observations 10. Sabrina Speich France ocean modelling 11. Hughes Goosse Belgium coupled modelling, incl. paleoclimate 12. Michiel Van den Broeke Holland atmospheric dynamics & processes 13. Niki GruberSwitzerlandecosystems, geochemistry, carbon Ex Officio:Alex Orsi (iAnZone) Eberhard Fahrbach (SCAR/SCOR Expert Group ) ICPO:Mike Sparrow New activities

Southern Ocean Panel Activities oCo-sponsorship with SCAR. oPresentations to JSC, CLIVAR and CliC SSGs, 8 th International Conference on S. H. Meteorology and Oceanography, etc. oWorkshop on Modes of Variability, Cambridge, June oNumerical models of the Southern Ocean workshop held in Tasmania, Nov oIPY input via CASO oUpgraded web site including: oThe Observing System in the SO Region oESA Google consumer portal: visualisations of sea ice drift, concentration, icebergs, etc. oNext meeting: Buenos Aires, Nov Activities

Southern Ocean Panel Planned oReview/assessment of IPCC models, GCM coupled models, etc. in S.O. region oFocus on S.O. region indices for OOPC/GSOP: oIdentify role of subsurface ocean (e.g., upwelling, dense water formation, polynyas, etc.) from atmos/ocean/ice observations oDiscuss role of eddies and storms oExpose surface and deep circulation anomalies oFocus on observational themes: oMeteorological observations oSustained time series, etc. oEffect of S.O. on regional climate in Latin America may be a theme of our next panel meeting (in B.A.) oCo-chair will attend IPY-Thorpex meeting in Oslo in June Activities

Southern Ocean Panel oContributions to CLIVAR'S 4 Major Themes oSpecific science contributions clear through June 2005 workshop on Modes of Southern Hemisphere climate variability oScott Polar Research Institute, Cambridge, UK oHave not developed S.O. connection to monsoons oOcean's role in climate no separate coverage 4 Major themes

Southern Ocean Panel Focus on Modes of Southern Hemisphere Variability, building on June workshop 34 articles The following shows just a few of examples highlighting the 4 CLIVAR themes CLIVAR Exchanges 35

Southern Ocean Panel 40% of total oceanic accumulation of anthropogenic CO 2 is located south of 35 S. Sabine et al., 2002 Ocean carbon models suggest SO uptake is sensitive to climate change. Ocean carbon models show greatest discrepancy in SO, largely due to differences in circulation + mixing. New observations support lower range of model estimates. ACC

Southern Ocean Panel SAM and Seasonal timescales (left) Monthly trends in the SAM index during the 1990s (plotted inverted and with mean removed for comparison with bottom pressure data) (left) Monthly trends in the SAM index during the 1990s (plotted inverted and with mean removed for comparison with bottom pressure data) (right) Monthly trends in bottom pressure data from southern Drake Passage during the 1990s (right) Monthly trends in bottom pressure data from southern Drake Passage during the 1990s => suggests changes in the seasonality of the SAM are inducing small (few Sv) changes in the oceanic circumpolar transport. (Anthropogenic?) => suggests changes in the seasonality of the SAM are inducing small (few Sv) changes in the oceanic circumpolar transport. (Anthropogenic?) ACC

Southern Ocean Panel IPY climate studies Ex: Yuan LDEO ENSO & other modes

Southern Ocean Panel r[Climate Modes, Sea Ice Concentration anomalies] Correlation coefficients between Antarctic sea ice concentration anomalies (lag of 2 months) and time series of the Pacific South American Pattern (PSA), Wave-3 pattern, Southern Annular Mode (SAM) and Semi-Annual Oscillation (SAO). The impacts of different climate modes on sea ice extent are examined by correlations shown in this figure. Apparently, PSA and Wave-3 patterns are strongly correlated with the Antarctic Dipole in sea ice in the western Hemisphere and generally have higher correlations than SAM and SAO. The influences of SAM and SAO on sea ice are more evenly distributed around Antarctica. Since all climate indices and sea ice concentration anomalies were filtered prior to the correlation by a Gaussian filter with filter length of 13 months, these correlations represent shared variance on interannual and longer time scales. ENSO & other modes

Southern Ocean Panel 0.107˚ C/year Significant at 0.05 ~5.4x global average Perennial Ice Western Antarctic Peninsula Most rapid recent regional winter warming on Earth Major loss of perennial sea ice 83% of glaciers are in retreat Decadal variability

Southern Ocean Panel Ocean heat flux (F T ) to atmosphere over wAP shelf shows considerable change in latter part of 1900s (coinciding with increased T air and glacial melt): Large step increase in 1990 (+4 Wm -2 ) Q shelf & Q slope are proxies for F T F T jumps in 1998 by 3 Wm -2 followed by same jump each year thereafter Decadal variability

Southern Ocean Panel Southern Ocean Panel Research Themes shallow overturning circulation deep overturning circulation interbasin exchange variability of the coupled atmosphere-ice-ocean system Process studies

Southern Ocean Panel Implementation IPY: CASO, an International Polar Year program Development of Southern Ocean Argo web site. Implementation of Southern Ocean Argo has grown strongly, but still lack broad coverage due to sea-ice. WECCON mooring, float and CTD programme in the Weddell Sea continued; Ross Sea underway… Mooring array recovered Kerguelen deep western boundary current in Repeat XBT lines at 30S Atlantic, Indian, Africa-AA. Most repeat hydrography/carbon/tracer sections are committed, but ice-breaker problems limit access.

Southern Ocean Panel Argo status Successful under- ice deployments in Weddell (Germany) and acoustic tracking of drifting RAFOS floats. Need to recover profiles from under ice. SO deployments planned in next year Deployment opportunities still can be problematic

Southern Ocean Panel The International Polar Year CASO (Climate of Antarctica and the Southern Ocean) Project Panel-led project Lead project in the Southern Ocean (SO) Circulation cluster Main aims: - To obtain a synoptic circumpolar snapshot of the physical environment of the SO (with SASSI) - To enhance understanding of the role of the SO in past, present and future climate, including connections between the zonal and meridional circulation of the Southern Ocean, water mass transformation, atmospheric variability, ocean-cryosphere interactions, physical-biogeochemical-ecological linkages, and teleconnections between polar and lower latitudes.

Southern Ocean Panel Ex: CLIVAR Repeat Hydro Lower branch of the global convection cell

Southern Ocean Panel Ex: WECCON Weddell Sea I/O Vertical section along the meridian of Greenwich with the moored instruments. Mooring 227 to 239 are the moorings which have been replaced. In addition sound sources were attached in mooring 229, 231, and in 240 which is a newly deployed one at 10° E

Southern Ocean Panel Issues and Challenges Need to maintain push for SO Argo, Met, ice buoys, and other sustained observations in southern hemisphere Resources and champions for time series sites (some progress on subsurface physics – biogeochemistry sites; unclear progress on SO air-sea flux sites - ORION?) Need to push for enhanced air-sea flux observations from resupply and other ships. Coordination of atmospheric and oceanographic communities improving; new panel reflects this. Concept of Climate Process Teams in US may hold promise as approach to enhancing model-obs interaction.

Southern Ocean Panel Issues for the SSG Role of the Panel for climate model evaluation, anything to offer regarding a framework ? Panel needs to continue to work to identify CLIVAR/CliC relevant data sets and interact with GSOP on ocean model evaluation. Biggest holes are sustained obs in the seasonal sea-ice zone and meteorological initiatives.

Southern Ocean Panel Ex: Kerguelen Plateau Deep Western Boundary Current Australia, USA, Japan 8 tall moorings; CTD/LADCP - recovered in 2005 Goal: quantify transport of a major AABW pathway Plateau ADCP data

Southern Ocean Panel Ex: AnSlope - the Ross Sea AABW source Relatively salty shelf water plume, 150 to 250-m thick, Froude numbers range from 0.7 to 1.2, speeds m/sec

Southern Ocean Panel CLIVAR Process Studies o18 studies: /process.htm18 studies: /process.htm Examples: oGOODHOPE : Interbasin exchange south of Africa ( France, South Africa, Germany, Russia, USA ) - elements underway oOISO ( France ) - ongoing program oDiapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES). - proposed J Ledwell (for US), A N-Garabato (for UK); 2007 to 2012

Southern Ocean Panel Goodhope Objectives 1. Variability in the Indo-Atlantic interocean exchanges and impact on the global thermohaline circulation and present day climate. OISO Objectives 1.Observational network to observe air-sea exchange of CO2 and hydrography 2.2+ occupations per year.

Southern Ocean Panel Diapycnal and Isopycnal Mixing Experiment in the Southern OceanDIMES oA proposed US+UK experiment odiapycnal diffusivity and isopycnal mixing ostirring and eddy fluxes of potential vorticity and heat in a large sector of the Southern Ocean in the region of the ACC oparameterizations of how these fluxes depend on variables accessible to numerical models will be tested and refined

Southern Ocean Panel DIMES