SIPEX II AUVMERTZ GLACIER CALVING

SEAL OCEANOGRAPHY

Update from Guy WilliamsAUV/Sea Ice Specialist

Sea Ice ProgramCryosphere

SIPEX II AUV

• Major setback after loss of collaboration with Memorial University and long-range AUV capability for Cryosat-II Calibration/Validation

• Major comeback with new collaboration with WHOI ‘SeaBed’ vehicle for floe-scale measurements of ice draft during SIPEX-II

• Collaborative links with UK ICEBELL mission in the Weddell/Bellingshausen Sea in Nov. 2010

• Better integration with other Ice Station projects

• Floe scale survey (500 x 500 m)• 230 kHz multibeam sonar• CTD + ADCP• Hyper spectral radiometer• 4 man team• ~$250—300K• Integrated with surface

measurements and ROV program

Important collaborative links with UK ICEBELL mission in the Weddell/Bellingshausen Sea in Nov. 2010

Ice thickness maps from 4 unique ice stations

Wilkinson et al., Williams (in prep)

2011 - Timeline

• April - Visit to Scottish Association of Marine Science (SAMS), UK, to establish collaboration with the ICEBELL project.

• May - Visit to Hobart by Hanumant Singh (WHOI) to establish AUV contract for SIPEX-II. Meetings with AAD operations and Aurora Australis crew

• July - Visit to WHOI, USA, to work with AUV team and ICEBELL project leader on AUV operations for SIPEX and the processing of AUV data from the ICEBELL project.

• September - Visit to Hawaii, USA for pre-cruise mobilisation experience with the SEABED vehicle.

• Ongoing processing and analysis of ICEBELL data with SAMS and WHOI for co-authorship on upcoming publications from the UK groups.

Impacts of the Mertz Glacier Calving

Ocean-Ice Modelling

Kusahara, Hasumi and Williams, Nature Comm. 2011

Sea ice via Satellite Analyses

Tamura, Williams, Fraser and Ohshima (in review Nature Geoscience)

• 23% reduction in modelled dense shelf water export• 27-36% decrease in sea ice production• Greater than 0.05 decrease in salinity, equiv. to last 50 years of long-term freshening • Contribution to observed changes in oceanography in Rintoul et al., (in prep)

Seals as Polar Ocean Observers in the Prydz Bay/Amery Ice Shelf and Cape Darnley regions

• Over 15,000 new CTD profiles from elephants seals deployed from Davis Station and Kerguelen Island

• Amazing new observations of high salinity shelf water and dense shelf water overflows relevant to Cape Darnley/Prydz Bay Antarctic Bottom Water.

• Sea ice growth rate estimates for the McKenzie Bay and Barrier polynyas

• Unique summer-fall-winter observations on the continental shelf, across the Amery Ice Shelf and across the southern ocean.

1st author manuscripts near submission for GRL-style journal and the PLoS-ONE Special volume on ‘Trends and Change’ resulting from the Australia-

Japan Antarctic Biology workshop in Feb. 2011

with Hindell, Field, Roquet, Tamura and Herraiz-Borreguero