Weddell Polynya Modeling

Research Activities:
In this project a coupled sea-ice ocean numerical model was developed
for the purpose of studying the formation mechanism for a large,
aperiodic anomaly occurring in the sea-ice cover of the Weddell Sea,
Antarctica. That anomaly was first detected by Satellite in the
mid-1970s as a hole in the sea-ice cover that covered an area of
200,000 km2. The strategy employed for understanding how such a large
anomaly forms was to develop an idealized model of the physical
environment. Results arising from of a computer simulation of ocean
flow past an idealized seamount, configured periodic channel domain
with uniform atmospheric cooling, showed that a polynya spontaneously
develops off one of the flanks of the seamount. Analysis of the
simulation showed that a large cyclonic eddy is shed from the seamount
and this eddy imparts a divergent strain to the overlying sea-ice
cover (Holland, 2001a, 2001b, 2001c). That divergent strain creates
an opening in the sea-ice cover that atmospheric processes further
reinforce, and enlarges the opening.

Holland, D.M., 2001a: Explaining the Weddell Polynya - A large ocean
eddy shed at Maud Rise. Science, 292, 1697-1700.

Holland, D.M., 2001b: Transient sea-ice polynya forced by
environmental flow variability. Prog. Oceanogr., 48, 475-532.

Holland, D.M., 2001c: An impact of sub-grid-scale ice-ocean dynamics
on sea-ice cover. J. Climate, 14(7), 1585-1601.

Educational Activities:
The PI is involved in several educational initiatives at New York
University that allow him to contribute to the development of human
resources. A graduate course in physical oceanography and an
undergraduate course in environmental fluid mechanics is taught by the
PI each year. These courses allow the PI to share with students an
example of an active research program by incorporating aspects of
computer modeling of polynyas into the core curriculum.

Additionally, a formal Wednesday afternoon colloquium is offered each
week and an informal Friday afternoon student seminar series is run by
the PI. These educational activities bring together both science and
math students and gives them an opportunity to see cutting edge
research and to present their own research to their peers. For
example, Prof. Andrew Willmott of Keele University, an internationally
recognized expert on polynyas, was invited to present a seminar and
the students were given a chance to interact with him and learn about
polynya research.