West Antarctic Peninsula sea ice in 2005: Extreme ice compaction and ice edge retreat due to strong anomaly with respect to climate
Massom, R.A.; Stammerjohn, S.E.; Lefebvre, W.; Harangozo, S.A.; Adams, N.; Scambos, T.A.; Pook, M.J.; Fowler, C. (2008). West Antarctic Peninsula sea ice in 2005: Extreme ice compaction and ice edge retreat due to strong anomaly with respect to climate. J. Geophys. Res. 113(C2). dx.doi.org/10.1029/2007JC004239 In: Journal of Geophysical Research. American Geophysical Union: Richmond. ISSN 0148-0227; e-ISSN 2156-2202, more |  |
| Authors | | Top | - Massom, R.A.
- Stammerjohn, S.E.
- Lefebvre, W., more
- Harangozo, S.A.
| - Adams, N.
- Scambos, T.A.
- Pook, M.J.
- Fowler, C.
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| Abstract | In September-October 2005, the juxtaposition of low-and high-pressure anomalies at 130°W and 60°W, respectively, created strong and persistent northerly airflow across the West Antarctic Peninsula (WAP). This had a major impact on regional sea ice conditions, with extreme ice compaction in the Bellingshausen and East Amundsen seas (60°W-130°W) but divergence in the West Amundsen and East Ross seas. This resulted in the former in a highly compact marginal ice zone and ice cover, mean modeled ice thicknesses of >5 m, and an earlier-than-average maximum extent (mid-August). While rapid ice retreat in late winter-spring created a major negative ice extent anomaly, compact ice persisted in the subsequent summer. Other effects were anomalies in air temperature (of +1°C to +5°C) and precipitation rates (to >2.5 mm/d). The patterns in late 2005 are consistent with the occurrence of a weak La Nina and a near-neutral Southern Annular Mode, with a quasi-stationary zonal wave three pattern dominating hemispheric atmospheric circulation. Once a compact ice edge was created, it took only one additional week of strong winds to "solidify'' the pack in place. Conditions in 2005 are analyzed in the context of 1979-2005 and compared with the springs of 1993, 1997, 1999, 2001, and 2004. A statistically significant increase of the northerly 10-m wind component between 110°W and 125°W occurred in the Septembers of 1979-2005. No clear trends occur in other spring months. This work underlines the key importance of ice dynamics in recent changes in the WAP sea ice regime. |
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