Boundary-Layer Meteorology

, Volume 60, Issue 3, pp 207–234 | Cite as

Generation and atmospheric heat exchange of coastal polynyas in the Weddell Sea

  • Ch. Kottmeier
  • D. Engelbart


The forcing mechanisms for Antarctic coastal polynyas and the thermodynamic effects of existing polynyas are studied by means of an air-sea-ice interaction experiment in the Weddell Sea in October and November 1986.

Coastal polynyas develop in close relationship to the ice motion and form most rapidly with offshore ice motion. Narrow polynyas occur frequently on the lee side of headlands and with strong curvature of the coastline. From the momentum balance of drifting sea ice, a forcing diagram is constructed, which relates ice motion to the surface-layer wind vector v z and to the geostrophic ocean current vector c g . In agreement with the data, wind forcing dominates when the wind speed at a height of 3 m exceeds the geostrophic current velocity by a factor of at least 33. This condition within the ocean regime of the Antarctic coastal current usually is fulfilled for wind speeds above 5 m/s at a height of 3 m.

Based on a nonlinear parameter estimation technique, optimum parameters for free ice drift are calculated. Including a drift dependent geostrophic current in the ice/water drag yields a maximum of explained variance (91%) of ice velocity.

The turbulent heat exchange between sea ice and polynya surfaces is derived from surface-layer wind and temperature data, from temperature changes of the air mass along its trajectory and from an application of the resistance laws for the atmospheric PBL. The turbulent heat flux averaged over all randomly distributed observations in coastal polynyas is 143 W/m2. This value is significantly different over pack ice and shelf ice surfaces, where downward fluxes prevail. The large variances of turbulent fluxes can be explained by variable wind speeds and air temperatures. The heat fluxes are also affected by cloud feedback processes and vary in time due to the formation of new ice at the polynya surface.

Maximum turbulent fluxes of more than 400 W/m2 result from strong winds and low air temperatures. The heat exchange is similarly intense in a narrow zone close to the ice front, when under weak wind conditions, a local circulation develops and cold air associated with strong surface inversions over the shelf ice is heated above the open water.


Turbulent Flux Cloud Feedback Turbulent Heat Flux Coastal Polynya Weak Wind Condition 
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  1. Augstein, E.: 1986, ‘The Winter-Expedition of RV “Polarstern” to the Antarctic’, Alfred Wegener Institute for Polar and Marine Research, BremerhavenGoogle Scholar
  2. Behrens, A.: 1986, ‘Die windgetriebene ozeanische Zirkulation im Küstenbereich der östlichen Weddell-See beim Auftreten von Polynyen — eine numerische Modelluntersuchung’, Ph.D. thesis, Fachbereich Geowissenschaften, Universität Hamburg, 105 pp.Google Scholar
  3. Belitz, H.-J., Kottmeier, Ch., Hartig, R., and Stuckenberg, H.-U.: 1987, ‘Zur aerodynamischen Rauhigkeit arktischer Meereisflächen’, Meteorol. Rdsch. 40, 97–107.Google Scholar
  4. Bromwich, D. H. and Kurtz, D. D.: 1984, ‘Katabatic Wind Forcing of the Terra Nova Bay Polynya’, J. Geophys. Res. 89, 3561–3572.Google Scholar
  5. Comiso, J. C. and Gordon, A.: 1987, ‘Recurring Polynyas over the Cosmonaut Sea and the Maud Rise’, J. Geophys. Res. 92, 2819–2833.Google Scholar
  6. Engelbart, D.: 1989, ‘Der turbulente Strom fühlbarer Wärme im Einfluβbereich antarktischer Küstenpolynyen’, Meteorol. Rdsch. 41, 111–121.Google Scholar
  7. Fahrbach, E. and Rohardt, G.: 1989, ‘Moored Instrument Data’, in Meteorological and Oceanographic Data of the Winter-Weddell-Sea Project 1986 (ANT V/3); Berichte zur Polarforschung 46.Google Scholar
  8. Fahrbach, E., Rohardt, G.: 1992, ‘tSuppression of Bottom Water Formation in the Southeastern Weddell Sea Shelf Due to Melting of Glacial Ice’, Deep Sea Research, submitted.Google Scholar
  9. Fiedler, F. and Panofsky, H. A.: 1972, ‘The Geostrophic Drag Coefficient and the Effective Roughness Length’, Quart. J. R. Meteorol. Soc. 98, 213–220.Google Scholar
  10. Frieden, W.: 1989, ‘Spektrale Varianzanalyse der Klimaelemente und der Meereisdrift im antarktischen Weddellmeer’, Diploma thesis, Institut für Meteorologie und Klimatologie der Universität Hannover.Google Scholar
  11. Gordon, A. L. and Huber, B. A.: 1984, ‘Thermohaline Stratification Below the Southern Ocean Sea Ice’, J. Geophys. Res. 89, 2911–2916.Google Scholar
  12. Gube-Lenhardt, M. and Hoeber, H.: 1985, ‘The Development of the Atmospheric Boundary Layer over the Coastal Region of the Weddell Sea during Offshore Wind’, J. Rech. Atmos. 19, 47–59.Google Scholar
  13. Heinemann, G. and Rose, L.: 1990, ‘Surface Energy Balance, Parameterizations of Boundary-Layer Heights and the Application of Resistance Laws near an Antartic Ice Shelf Front’, Boundary-Layer Meteorol. 51, 123–158.Google Scholar
  14. Hibler, W. D. and Ackley, S. F.: 1983, ‘Numerical Simulation of the Weddell Sea Pack Ice’, J. Geophys. Res., 88, 2873–2887.Google Scholar
  15. Hoeber, H.: 1991, ‘Sea Ice Dynamics in the Weddell Sea in Winter’, Annals of Glaciology, 15, 9–16.Google Scholar
  16. King, J. C., Mobbs, S. D., Rees, J. M., Anderson, P. S., and Culf, A. D.: 1989, ‘The Stable Antarctic Boundary Layer Experiment at Halley Station’, Weather 44, 398–405.Google Scholar
  17. Kottmeier, Ch. and Hartig, R.: 1990, ‘Winter Observations of the Atmosphere over Antarctic Sea Ice’, J. Geophys. Res. 95, 16.551–16.560.Google Scholar
  18. Ledley, T. S.: 1988, ‘A Coupled Energy Balance Climate-Sea Ice Model: Impact of Sea Ice and Leads on Climate’, J. Geophys. Res. 95, 15.919–15.932.Google Scholar
  19. Martinson, D. and Wamser, C.: 1990, ‘Ice Drift and Momentum Exchange in Winter Antartic Pack Ice’, J. Geophys. Res. 95, 1741–1755.Google Scholar
  20. Maykut, G. A.: 1978, ‘Energy Exchange over Young Sea Ice in the Central Arctic’, J. Geophys. Res. 83, 3646–3658.Google Scholar
  21. McPhee, M. G.: 1975, ‘The Effect of the Oceanic Boundary Layer on the Mean Drift Pack Ice: Application of a Simple Model’, J. Phys. Ocean. 9, 388–400.Google Scholar
  22. McPhee, M. G.: 1980, ‘An Analysis of Pack Ice Drift in Summer’, in: R. S. Pritchard (ed.), Sea Ice Processes and Models, pp. 62–75, Univ. of Washington Press, Seattle.Google Scholar
  23. Navy-NOAA Joint Ice Center, Naval Polar Oceanography Center, Suitland. Weekly Ice Charts, published continuously.Google Scholar
  24. Pease, C. H.: 1987, ‘The Size of Wind-Driven Coastal Polynyas’, J. Geophys. Res. 92, 7049–7059.Google Scholar
  25. Shine, K. P. and Crane, R. G.: 1984, ‘The Sensitivity of a One-Dimensional Thermodynamic Sea Ice Model to Changes in Cloudiness’, J. Geophys. Res. 89, 10615–10622.Google Scholar
  26. Smith, S., Muench, R. D., and Pease, C.: 1990, ‘Polynyas and Leads: An Overview of Physical Processes and Environment’, J. Geophys. Res. 95, 9461–9479.Google Scholar
  27. Stull, R. B.: 1988, An Introduction to Boundary Layer Meteorology, Kluwer Academic Publishers, London.Google Scholar
  28. Tennekes, H.: 1973, ‘A Model for the Dynamics of the Inversion above a Convective Boundary Layer’, J. Atmos. Sci. 30, 558–567.Google Scholar
  29. Vowinckel, E. and Orvig, S.: 1973, ‘Synoptic Energy Budgets from the Beaufort Sea’, in S. Orvig (ed.), Energy Fluxes over Polar Surfaces, 299 pp, WMO.Google Scholar
  30. Zwally, H. J. and Comiso, J. C.: 1983, ‘Antarctic Offshore Leads and Polynyas and Oceanographic Effects’, Oceanology of the Antarctic Continental Shelf, Antarctic Research Series, Vol. 43.Google Scholar

Copyright information

© Kluwer Academic Publishers 1992

Authors and Affiliations

  • Ch. Kottmeier
    • 1
  • D. Engelbart
    • 2
  1. 1.Alfred Wegener Institut für Polar- und MeeresforschungBremerhavenGermany
  2. 2.Institut für Meteorologie und Klimatologie, Universität HannoverHannoverGermany

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