Introduction The accelerated
decline of
arctic sea ice in recent years presents both challenges and
opportunities.
There will be enhanced fishing, resource extraction, and
marine
transportation
in the Arctic Ocean but there also will be challenges for
the local
Native
subsistence communities who use the ice cover as a hunting
platform. To
assist
in the planning and management of economic and subsistence
activities
in the
north polar regions, it is important to develop capabilities
for
seasonal
forecasts of arctic sea ice. We plan to improve our
existing seasonal ensemble forecasting system
and use the system
to predict sea
ice conditions in the arctic and subarctic seas with lead
times ranging
from one month to three seasons. The ensemble
forecasting
system is based on a synthesis of
a
model, NCEP/NCAR reanalysis data, and satellite
observations of ice concentration. The model is the Pan-Arctic Ice-Ocean
Modeling and Assimilation System (PIOMAS, Zhang and
Rothrock, 2003).
The ensemble predictions are
constructed by using the NCEP/NCAR atmospheric forcing
from the previous 7 years (corresponding to 7 ensemble members)
and the
PIOMAS
retrospectively
estimated,
with assimilation of satellite
ice
concentration
data, ice
and
ocean conditions at a
given date at which ensemble
predictions start. Details about the ensemble prediction
procedure may
be found in Zhang
et
al.,
2008.
The September
2012 arctic sea ice
extent is predicted to be 4.3 +/- 0.3 million
square kilometers(forecast
starts
on
7/1/2012). Movie:
hindcast/forecast of 2012 arctic sea ice (forecast starts on
7/1/2012) (To view
the movie
frame by frame, download it and use the free QuickTime
Player
to open
it)
Movie:
Zooming
of
the
Chukchi
and
Beaufort
seas (To view
the movie
frame by frame, download it and use the free QuickTime
Player
to open
it)
Movie:
Zooming
of
the
Northwest
Passage
region (To view
the movie
frame by frame, download it and use the free QuickTime
Player
to open
it)
Ensemble
forecast
of
9/2012
ice
thickness
and
standard
deviation
(SD)
(white line is satellite
observed ice edge for 9/2011 and black line is model predicted
ice edge for
9/2012)
Compared
to
6/2011,
the Pacific sector of the Arctic
Ocean was generally warmer in 6/2012,
according
to
the
NCEP/NCAR
surface
air
temperature
(SAT).
Hindcast of September sea ice without data assimilation
-- white (black) line is satellite
(model)
observed (simulated) ice edge --
Links
to
some
other
activities
for
seasonal
outlook
of
arctic
sea
ice
The purpose
of
the seasonal predictions of arctic sea
ice is for
scientific research and education only. There
are many uncertainties with the predictions and the results must
be
viewed with caution. The work is conducted at
the Polar
Science Center, Applied Physics Laboratory, University of
Washington. Support is provided by NSF.
Neither the Government nor the University of Washington nor any
individual person makes any warranty, expressed or implied, or
assumes
any responsibility or liability for the use of the prediction
results
or any other results in this web site.
