An analytical model for wind-driven Arctic summer sea ice drift
Author:
Park H.-S.,Stewart A. L.
Abstract
Abstract. The authors present an approximate analytical model for wind-induced sea-ice drift that includes an ice–ocean boundary layer with an Ekman spiral in the ocean velocity. This model provides an analytically tractable solution that is most applicable to the marginal ice zone, where sea-ice concentration is substantially below 100%. The model closely reproduces the ice and upper-ocean velocities observed recently by the first ice-tethered profiler equipped with a velocity sensor (ITPV). The analytical tractability of our model allows efficient calculation of the sea-ice velocity provided that the surface wind field is known and that the ocean surface geostrophic velocity is relatively weak. The model is applied to estimate intraseasonal variations in Arctic sea ice cover due to short-timescale (around 1 week) intensification of the southerly winds. Utilizing 10 m surface winds from ERA-Interim reanalysis, the wind-induced sea-ice velocity and the associated changes in sea-ice concentration are calculated and compared with satellite observations. The analytical model captures the observed reduction of Arctic sea-ice concentration associated with the strengthening of southerlies on intraseasonal time scales. Further analysis indicates that the wind-induced surface Ekman flow in the ocean increases the sea-ice drift speed by 50% in the Arctic summer. It is proposed that the southerly wind-induced sea-ice drift, enhanced by the ocean's surface Ekman transport, can lead to substantial reduction in sea-ice concentration over a timescale of one week.
Funder
Korea Institute of Geoscience and Mineral Resources
Publisher
Copernicus GmbH
Reference36 articles.
1. Bitz, C. M. and Polvani, L. M.: Antarctic climate response to stratospheric ozone depletion in a fine resolution ocean climate model, Geophys. Res. Lett., 39, L20705, https://doi.org/10.1029/2012GL053393, 2012. 2. Bitz, C. M., Fyfe, J., and Flato, G.: Sea ice response to wind forcing from AMIP models, J. Climate, 15, 522–536, 2002. 3. Cole, S. T., Timmermans, M.-L., Toole, J. M., Krishfield, R. A., and Thwaites, F. T.: Ekman veering, internal waves, and turbulence observed under Arctic Sea Ice, J. Phys. Oceanogr., 44, 1306–1328, 2014. 4. Dee, D. P., Uppala, S. M., Simmons, A. J., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., Balmaseda, M. A., Balsamo, G., Bauer, P., Bechtold, P., Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C., Dragani, R., Fuentes, M., Geer, A. J., Haimberger, L., Healy, S. B., Hersbach, H., Hólm, E. V., Isaksen, L., Kållberg, P., Köhler, M., Matricardi, M., McNally, A. P., Monge-Sanz, B. M., Morcrette, J.-J., Park, B.-K., Peubey, C., de Rosnay, P., Tavolato, C., Thépaut, J.-N., and Vitart, F.: The ERA-Interim reanalysis: configuration and performance of the data assimilation system, Q. J. Roy. Meteorol. Soc., 137, 553–597, 2011. 5. Gray, J. M. N. T. and Morland, L. W.: A two-dimensional model for the dynamics of sea ice, Philos. T. Roy. Soc. A, 347, 219–290, 1994.
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