The IPY Synoptic Antarctic Shelf-Slope Interactions Study (SASSI)Alejandro H. OrsiTexas A&M University

Synoptic Antarctic Shelf-Slope Interactions Study

Understand and quantify the observed freshwater variability at Antarctic shelf-slope regime

Asses the impact on global climate through its influence on both the shallow and deep meridional circulations of the Southern OceanLong Term GoalsSynoptic Antarctic Shelf-Slope Interactions StudyThrough the implementation of an observing system over the Antarctic continental margins to monitor global climate change

Theme 1: SASSI will provide a unique synoptic snapshot of the Antarctic continental shelf and slope environment, including physical (iAnZone), biogeochemical (GEOTRACES, SOLAS, IMBER) and biodiversity (CoML, GLOBEC) measurements: a legacy against which to measure future change.

Theme 2: SASSI aims to understand and parameterise the continental shelf/slope processes that are currently absent from climate models, yet are critical to understanding global climate variability.

Synoptic Antarctic Shelf-Slope Interactions Study

Assessment of funding statusPartly funded: 20 to 50% of resources needed to meet the science objectives

Expected to be upgraded to the Mostly funded category (50 to 80%) by the end of 2006

Most certain contributions are from Australia, China, Germany, Japan, Norway, Russia and Spain

Pending funding for Brazil, France, Italy, UK and US contributions

Hydrographic work most likely to be completed as planned, but mooring arrays poorly subscribedSynoptic Antarctic Shelf-Slope Interactions Study

UK: 5 moorings (HOMER, ADCP, T,S,P, CMs) no section at 15W ADELIE (20 stas, 40 surface drifters, 4 ARGOs)Norway/UKFilchner sill 5 moorings at 35W (BIAC)Norway3 moorings at 0E (Fimbul Ice Shelf)Germany1 south of Joinsvile/3 center/2 cape Norvegia mooringsUS/UKARCHES 2 mooringsOrkney Passage 4 mooringsUSACROSS five mooringsJAPANone mooring at 65E, 3 moorings at 140EFRANCE2 to 5 moorings ALBION Adelie Depression10 moorings across Drake PassageKerguelen Plateau moorings at gapsSASSI MOORINGS

Massive freshening of all Ross Sea watersRoss Sea Bottom Water production with evolving properties? varying source strengths? new sites or mechanisms?slopeouter shelfinner shelf

iAnZone 10th Biennial Meeting and SASSI WorkshopScheduled for 27-28 August 2007 in Bergen, Norway to be collated with the Open Science Conference of the Polar Dynamics Meeting

ACROSS: Antarctic Cross-Road Of Slope Streamflows CTD, CFCs, isotopes

ADCP surveys

Moored Current Meter Array

Turbulence Measurements

Modeling

Components:CTD, CFC Tracer, and ADCP surveysMoored Current Meter ArrayTurbulence MeasurementsModelingACROSS: Antarctic Cross-Road Of Slope Streamflows

Goal: comprehend physical processes governing the northward outflow of ventilated slope waters from the Weddell Sea across the Philip Ridge, and their contribution to the conspicuous cooling and freshening of Circumpolar Deep Water (CDW) as it transits the deep Scotia Sea.

Research questions: Where and how does the Antarctic Slope Current contribute directly to the Antarctic Circumpolar Current (ACC) with ventilated deep waters, and; How large is this contribution? Working hypothesis: Ventilation of the ACC via this mechanism is much more efficient than by the more commonly cited upward diffusion of relatively denser bottom water outflows from the deep boundary current in the NW Weddell Sea.

ACROSS: Antarctic Cross-Road Of Slope Streamflows

International Polar Year 2007-2008The Role of Antarctica and the Southern Ocean in Past, Present and Future Climate: A Strategy for the International Polar Year

This project was planned and coordinated by the International Antarctic Zone Program (iAnZone) as a multinational effort during IPY by Dr. Karen Heywood, while Chair of iAnZoneduring 2003-2005.