Ice Thickness and Subglacial Topography Results
from the joint UTIG-BAS campaign of 2004-05 are now available
HERE!
The Ross Sea and Weddell Sea embayments have been the
primary focus of attention within the West Antarctic Ice Sheet (WAIS)
since the potential for ice sheet collapse and its resulting impact
on sea level was first recognized. The third major drainage basin of
the WAIS, the Amundsen Sea Embayment (ASE), has been comparatively unstudied
primarily due to its remoteness from logistical centers. However, satellite
remote sensing studies, combined with limited ice thickness data, indicate
that the ASE discharges the largest ice flux in West Antarctica; furthermore,
of all the major drainage basins in Antarctica, it is the only one to
exhibit significant elevation change over the period of recent satellite
observations.
Our present knowledge of the ice thickness and subglacial boundary conditions
in the ASE are insufficient to understand its evolution or sensitivity
to climatic change. Stimulated by observations of its non-steady behavior
and its dominant role in WAIS net mass balance, the glaciers of the
ASE have become a focus for future integrated studies by both the U.S.
and European scientific communities with the overarching objectives
of assessing the present and predicting the future behavior of the ice
sheet in the ASE. Through a series of meetings held by the WAIS science
community, an ASE
Science Plan has been generated to achieve these objectives through
coordinated satellite, airborne, marine and surface-based observations.
|
|
|
Context
maps of West Antarctica showing its three major ice drainages:
the Amundsen Sea Embayment (ASE), the Ross Sea Embayment (RSE)
and Weddell Sea Embayment (WSE). The balance velocity map (a)
gives an estimate of the ice flow required to maintan the modern
surface topography given the modern accumulation rate (from Babmer,
2000). The outlines of drainage basins feeding Pine Island Glcaier
(PIG) and Thwaites Glacier (TG) are shown in yellow. (b) BEDMAP
bedrock topography (Lythe et al., 2000) showing elevations below
-1000 m in yellow (e.g. the Bryd Subglacial Basin - BSB), and
elevations above 1000 m in violet. Major crustal blocks Marie
Byrd Land (MBL), Thurston Island (TI), Antarctic Peninsula (AP),
Ellsworth-Whitmore Mountains (EWB) and Transantarctic Mountains
(TAM) are defined by their bed relief. Hypothesized flanks of
the West Antarctic Rift System (WARS) are shown in white. |
In order to accomplish the airborne phase of this plan,
The University of Texas (UT) and the British
Antarctic Survey (BAS) have been funded to conduct a comprehensive
aerogeophysical survey encompassing the two major drainage basins within
the Amundsen Sea Embayment - Pine Island and Thwaites glaciers. We will
conduct these surveys during the 2004/05 austral summer, operating from
two remote field camps and using two survey aircraft. In response to
logistical constraints, we have revised the survey plan from our original
proposal on order to accomplish these surveys in a single field season,
rather than in two. Additionally, the recent CECS/NASA reconnaissance/survey
flights in the ASE have provided new insights to the dynamics of the
grounding line regions. Over the coming year, we as a community have
the opportunity to optimize the survey design and refine our detailed
target priorities in order to best achieve the objectives of the Science
and Implementation Plan as the evolving logistical constraints. Geophysical
maps resulting from these surveys will be central to achieving fundamental
objectives of the ASE Science Plan and will guide future surface-based
research. Providing these geophysical results to the ASE science community
is our primary objective.
