Expressions of Intent for International Polar Year 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Sea Ice Mass Balance in Antarctica  (SIMBAs Ice Thickness Surveys)

Outline
We plan on coordinating two emerging technologies, Autonomous Underwater Vehicles and Satellite Altimeters, to obtain the sea ice thickness distribution of circumpolar Antarctic sea ice. Unlike the Arctic, there are no under ice surveys of ice thickness using nuclear submarines in the Antarctic. Recently, however, a UK program, Autosub Under Ice (AUI), has successfully conducted ice draft measurements of sea ice using an AUV. As well, satellite altimetric measurements have provided useful measurements of ice thickness in the Arctic. Sea ice thickness measurements in the Arctic are currently widely used to denote changes there attributable to both circulation and warming changes recently observed. It is therefore an opportune convergence of the new technology, IPY intensive measurements and documented change in the Arctic to investigate the state of Antarctic sea ice thickness. These measurements may also be a harbinger of global change signals in the Antarctic, as well as providing validation for coupled ice-ocean-atmosphere models and satellite estimates of ice thickness. While the satellite altimetric measurements show high promise of regional characterization of mean thickness, coupling with AUV measurements will be both necessary and advantageous. The necessity arises from the unknown role on altimetric ice thickness measurements of the thicker snow cover and more extensive flooding on sea ice in the Antarctic compared to the Arctic. Regional validation is therefore necessary to confirm the appropriate ice thickness algorithm for the altimetric data on Antarctic sea ice. While the satellite covers extensive regions, it only provides mean thicknesses. AUV measurements are more spatially limited than the satellite, but can provide the ice thickness distribution from which the roles of dynamics and thermodynamics can be deconvolved. A total of four 60-day cruises conducted sequentially (using the same or several icebreakers and two autosubs) conducted over the winter/spring seasons of IPY can obtain a circumpolar ice thickness survey at approximately twenty degree longitude spacing. Concurrent satellite observing periods with the cruises by CryoSat and satellite laser altimeter (if available) will provide coordinated measurements between the AUVs and satellite. Satellite measurements in future can then provide the comparisons with this ice thickness baseline derived during IPY. Ship-based ice observations have been used to derive ice thickness distributions from data obtained by ASPeCt. These observation protocols can also be improved by coincident AUV missions with an observation program and used to improve the confidence level of thicknesses obtained both from earlier cruises and from ships that do not carry the AUVs.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
By characterizing Antarctic sea ice thickness on a circumpolar quantitative basis, a baseline data set for future changes will be established for the first time. Because of the coupling between AUV and satellite measurements, future changes can also be better monitored by satellite and correlations between ice thickness, ice area, and ice extents better established. The ice thickness is also a quantitative measure of the ocean-atmosphere exchanges and therefore is the gold standard for validation of air-ice-ocean coupled models of the present environment, enhancing their confidence for future predictions.

What international collaboration is involved in this project?
The present ice thickness information derived from ice observations is the product of SCAR-ASPeCt, including collaboration from Australia, USA, Germany, Russia, and UK. The UK AUV, Autosub, will be available for international collaboration during the IPY period and the vessels and programs of USA, UK, Germany and Australia are currently considering sea ice cruises using Autosub. EU sponsorship of CryoSat involves investigators throughout Europe as well as elsewhere.

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
Longitudinal sections of the circumpolar Antarctic sea ice zone at twenty degree spacing, from a minimum latitude of ~55 S to the Antarctic coast are the field locations.

Approximate timeframe(s) for proposed field activities:
Arctic: n/a
Antarctic: 03/2007 -03/2009            

Significant facilities will be required for this project:
Four 60 day icebreaker cruises using, e.g. NB Palmer, Aurora Australis and JC Ross will be necessary,each carrying an Autosub class AUV (under ice navigation and ~200km endurance). Designated observing periods for satellite altimetric observations concurrent with the cruises will be necessary.

Will the project leave a legacy of infrastructure?
Longrange autonomous underwater vehicles capable of navigating under drifting sea ice , fast ice, icebergs and ice shelves will provide enhanced marine polar measurement capability that does not presently exist.

How is it envisaged that the required logistic support will be secured?
Consortium
Own national polar operator
Another national polar operator
National agency
Commercial operator

Has the project been "endorsed" at a national or international level?

PROJECT MANAGEMENT AND STRUCTURE

Is the project a short-term expansion (over the IPY 2007-2008 timeframe) of an existing plan, programme or initiative or is it a new autonomous proposal?
New

How will the project be organised and managed?
If IPY approved, an international steering group will be formed. Through investigators in each participating nation, commitments will be sought to provide research cruise, AUV and satellite support. Research cruises will be coordinated with AUV availability and satellite observing periods and to achieve appropriate spatial coverage of the sea ice zone.

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
The plans will focus on graduate student training, educational outreach activities and disseminating results beyond the Antarctic research community. Joint meetings with Arctic scientists will be attended and/or arranged to compare and contrast the mass balance issues of the Arctic and Antarctic sea ice zones. As well as the graduate students, the efforts will include participation by undergraduate students, direct contact of investigators with secondary and elementary school students, and lectures, news media, and website contacts to the general public.

What are the initial plans of the project to address data management issues (as outlined in the Framework document?
Currently SCAR-ASPeCt has established a sea ice thickness data base derived from ship observations. This data is continuously updated with additional cruise information. A system of data quality control, archiving and website dissemination of the new data from AUVs and satellites will built on this ongoing system using GIS technology.

How is it proposed to fund the project?

Is there additional information you wish to provide?
None

PROPOSER DETAILS

Pro Stephen Ackley
118 W Castle Ln, San Antonio, TX


78213
USA

Tel: (1) 210 341 6556
Mobile: (1) 210 286 9225
Fax: no
Email:

Other project members and their affiliation