AIDJEX Bulletin #40 - Polar Science Center - University of Washington

It is notknownat present how to predict boundary motions accurately.
However, a parameter study (Pritchard and Thomas, 1977) shows that
errors introduced at the boundary decay in magnitude with distance
from the boundary. This is true for velocity errors that have random
variation in time about a zero mean. The effect of steadystate
errors in the boundary motion is not known; however, it is
known that they do not necessarily decay with distance.
It is shown here that the AIDJEX model provides accurate predictions
of ice behavior on time scales of one or two days. The
pressure field predictions can be inaccurate, especially if the
prediction is made for longer times; however, the errors do not
dominate the behavior of the predicted ice response.
It is felt that it will be necessary to deploy and operate a set of
data buoys to determine the drift of the ice and the barometric
pressure if reliable predictions are to be made under all conditions.
At present it is recommended that these buoys be deployed in a region
along the entire continental shelf of the Alaskan north slope, from
the shore out to approximately 800 km. These will provide accurate
data from which to predict barometric pressure, as well as important
information on the state of the ice at any instant so that predictions
can be updated.
INTRODUCTION
In this work we examine the AIDJEX air, ice, and ocean models to ascertain
their usefulness in forecasting the motion and condition of arctic sea ice
in the nearshore portions of the Beaufort and Chukchi seas. Because we are
concerned with the short-term forecasting needed to insure safe day-to-day
operation of ships and marine structures, we limit the time scale to a
maximum of two days, the longest period for which predictions of atmospheric
conditions were available when this research was performed.
In the arctic summer, the edge of the floating ice sheet that covers
the Beaufort Sea usually retreats northward from the land mass, opening a
coastal band of water about 200 km wide that is, for the brief time it
remains open, the sea route to the Alaskan north slope. During the 1975
shipping season, attempts to use this corridor for pipeline shipments
were thwarted by the worst ice conditions ever recorded. For two months
barges lay south of Point Wainwright waiting for the pack to move northward
so that they could sail past Point Barrow and on to Prudhoe Bay.
Finally, after a loss of several months and millions of dollars, most of
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