The Expedition - Overview
Overview | Objectives | Science Crew | The Ship
This cruise represents the physical oceanographic component of the
Western Arctic Shelf Basin Interactions (SBI) Experiment.
SBI is a multi-year, multi-disciplinary
program sponsored jointly by the National Science Foundations Office of
Polar Programs and the High-latitude branch of the Office of Naval
The overall goal is to understand how the Arctic shelves
communicate with the interior basin from a coupled
physical--biogeochemical standpoint. The premise is that this system
is in a delicate balance that could be upset by global change, which
in turn could have important ramifications. These include possible
melting of portions of the polar ice cover, changes in export of water to
the global ocean, and alteration of the food web with significant
consequences for native populations. From the physical oceanographic
perspective the goal is straightforward: understand how shelf water
is transferred, at the continental shelfbreak, to the interior basin
in order to help maintain the cold halocline of the Arctic
Ocean. This is the salty layer at mid-depth which shields the surface
ice cover from the warm deep water. If this shield is weakened, there
is more than enough heat contained in the underlying
Atlantic-origin water to start melting the ice from below.
SBI is divided into three phases:
Phase 1 (1999-2002) - Retrospective data analysis and
modeling to help define a new measurement program.
Phase 2 (2002-2004) - Data collection in the Chukchi and Beaufort Seas,
with continued regional modeling.
Phase 3 (2004) - Data/model synthesis to develop realistic descriptions
and predictions of Arctic climate change.
Specific questions that SBI will focus on include:
Answering these questions will help create a more general picture of Arctic
- How is the inflowing water from Bering Strait transformed
as it flows across the Chukchi shelf? How is this water subsequently
transferred into the interior Arctic upon reaching the shelf edge?
- What are the major biological and chemical processes linking the
outer shelf to the deep basin,
and to what extent are they governed by the physical exchange
- How do exchange mechanisms differ between
the wide Chukchi and narrow Beaufort shelves
and adjacent slopes?
- What are the variations in this system from season to
season and year to year?