Improving Met Office seasonal predictions of Arctic sea ice using assimilation of CryoSat-2 thickness
<p>Interest in seasonal predictions of Arctic sea ice has been increasing in recent years owing, primarily, to the sharp reduction in Arctic sea-ice cover observed over the last few decades, a decline that is projected to continue. The prospect of increased human industrial activity in the...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-10-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/12/3419/2018/tc-12-3419-2018.pdf |
| Summary: | <p>Interest in seasonal predictions of Arctic sea ice has been increasing in
recent years owing, primarily, to the sharp reduction in Arctic sea-ice cover
observed over the last few decades, a decline that is projected to continue.
The prospect of increased human industrial activity in the region, as well as
scientific interest in the predictability of sea ice, provides important
motivation for understanding, and improving, the skill of Arctic predictions.
Several operational forecasting centres now routinely produce seasonal
predictions of sea-ice cover using coupled atmosphere–ocean–sea-ice models.
Although assimilation of sea-ice concentration into these systems is
commonplace, sea-ice thickness observations, being much less mature, are
typically not assimilated. However, many studies suggest that
initialization of
winter sea-ice thickness could lead to improved prediction of Arctic summer
sea ice. Here, for the first time, we directly assess the impact of winter
sea-ice thickness initialization on the skill of summer seasonal predictions
by assimilating CryoSat-2 thickness data into the Met Office's coupled
seasonal prediction system (GloSea). We show a significant improvement in
predictive skill of Arctic sea-ice extent and ice-edge location for forecasts
of September Arctic sea ice made from the beginning of the melt season. The
improvements in sea-ice cover lead to further improvement of near-surface air
temperature and pressure fields across the region. A clear relationship
between modelled winter thickness biases and summer extent errors is
identified which supports the theory that Arctic winter thickness provides
some predictive capability for summer ice extent, and further highlights the
importance that modelled winter thickness biases can have on the evolution of
forecast errors through the melt season.</p> |
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| ISSN: | 1994-0416 1994-0424 |