RONNE POLYNYA EXPERIMENT

Project Description
[from ROPEX Background page,
http://www.esr.org/ropex/ronice.html#bac]

The Ronne Polynya Experiment (ROPEX) was carried out in the southern
Weddell Sea in January and February 1998, using the Royal Navy
ice-strengthened hydrographic vessel HMS Endurance. The experiment
focused on the southern shelf of the Weddell Sea.

The ship departed from the Falkland Islands on January 14 and returned
on February 20, operating in the southern Weddell Sea for the period
January 21 to February 12. Over one hundred
conductivity-temperature-depth ("CTD") stations were collected in the
region of the Filchner overflow, and near and north of the Ronne ice
front. Bathymetry data were obtained over the southwestern continental
shelf, a region for which no prior data existed. Five European current
meter moorings were recovered, three from the Ronne ice front and two
from the Filchner Depression. Four new European/US moorings were
deployed in a region where dense water modified by the inclusion of
potentially supercooled Ice Shelf Water first flows down the
continental slope after leaving the Filchner Depression.

The primary goal of the program was to obtain oceanographic, sea-ice,
and atmospheric measurements to improve our understanding of the
physical processes coupling the southern Weddell Sea to the
circulation and properties of the global ocean and atmosphere. In the
southern Weddell Sea, four elements strongly interact with each other:
the ocean over the continental shelf; the polar atmosphere; sea-ice
(when it is present); and the massive floating glacial ice shelves,
which are the oceanic termination of continental ice as it flows off
the Antarctic continent.

Therefore, the primary research tasks for the cruise were:
- Atmospheric measurements over sea ice and boundary layer
development near ice shelves;
- Sea ice observations and sampling;
- Conductivity-temperature-depth (CTD) ocean profiling;
- Oceanographic mooring deployment and recovery; and
Bathymetry.

Sea ice conditions during the cruise were very favourable, allowing
the ship to survey a large area north of the Ronne Ice Front. No
previous oceanographic or even bathymetric data have been obtained
from this region.

Our data will be integrated with other programs in the region,
including measurements obtained under the Ronne Ice Shelf (Nicholls,
1996). This study will improve our ability to model the Weddell Sea's
role in such processes as the global fresh water budget and the
generation of Antarctic Bottom Water, the latter being a fundamental
component of the Global Ocean Conveyor Belt (Broecker, 1991).

The primary institution responsible for the ROPEX cruise is the
British Antarctic Survey (BAS). Other participating institutions are:

- Southampton Oceanography Center (Southampton, UK);
- Proudman Oceanographic Laboratory (Liverpool, UK);
- Alfred-Wegener Institute (Bremerhaven, Germany);
- Cold Regions Research and Engineering Laboratory (Hanover, New
Hampshire);
- Los Alamos National Laboratory (Los Alamos, New Mexico); and
- Earth & Space Research (Seattle, Washington).

The US component of this research was supported by the National
Science Foundation grant OPP-9615525.