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German Contribution to the international ACSYS Project

German Contribution to the international ACSYS Project. ‘The ACSYS Decade and Beyond‘ 11-14 November 2003, St. Petersburg, Russia. Observations, simulations and scale interactions of the stable boundary layer over polar ice sheets Günther Heinemann

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German Contribution to the international ACSYS Project

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  1. German Contribution to the international ACSYS Project ‘The ACSYS Decade and Beyond‘ 11-14 November 2003, St. Petersburg, Russia Observations, simulations and scale interactions of the stable boundary layer over polar ice sheets Günther Heinemann Meteorological Institute University of Bonn, Germany gheinemann@uni-bonn.de http: www.meteo.uni-bonn.de A project funded by the Federal Ministry of Education and Research

  2. The katabatic wind system (KWS) Wintertime near-surface wind Antarctica RACMO simulations 55 km resolution 1980-1993 winter months JJA Van Lipzig (2003) Sample=2 Orography contour interval 1000 m

  3. (Klein, 2000) Wintertime near-surface wind Greenland NORLAM simulations 25 km resolution 10m wind Jan 1990 Heinemann and Klein (2002) Constancy 0.8-0.9 >0.9 Sample=4 Orography contour interval 500 m

  4. Katabatic wind dynamics Integrated katabatic wind layer (Ball, 1956): Pressure gradient (2D): Pressure gradient (1D): =- zs/x

  5. Monthly means January 1990 10-4 ms-2 Synoptic forcing FS 10-4 ms-2 Topographic forcing FT

  6. Case study 22 April 1997 NORLAM 22 April 06 UTC (30h) NORLAM 22 April 06 UTC (30h) 10-4 ms-2 10m wind Topographic forcing FT

  7. Topographic forcing FT 10-4 ms-2

  8. Comparison NORLAM/aircraft

  9. Tasiilaq Katabatic wind and boundary layer front experiment around Greenland April+May 1997 KABEG

  10. Polar 2 (AWI) Meteopod 120 Hz A3 A4 100 km

  11. KABEG Case study22 April 1997 Heinemann (2002)

  12. Profiles of turbulent fluxes Evaporation 1 W/m2.10 mm/a

  13. Regimes of the katabatic wind system

  14. Stable boundary layer (SBL) Similarity Surface layer (SL) scalingMonin-Obukhov (MO) similarity theory (MOST) (Monin and Obukhov, 1956) - Stationarity - Horizontal homogeneity - No radiation flux divergence Local scaling concept for the SBLNieuwstadt (1984), Holtslag and Nieuwstadt (1986) • - Stationarity • - Horizontal homogeneity • No TKE flux divergence

  15. Scaling regions KABEG L* from A4 data

  16. Local scaling for KABEG data Cabauw data, Nieuwstadt (1984) Data collected within 18 months Variances (about 250 data points, 6 flights) Heinemann (2004) KABEG

  17. German Contribution to the international ACSYS Project Outlook:German ACSYS Project Phase II (2002-2005)Katabatic wind and polynia interaction ► Prognostic two-class sea ice model: frazil ice (FI) and consolidated ice (CI) Flato and Hibler (1992), Shinohara (1990), Semtner (1976), Gallée (1997) 22h forecast ► Non-hydrostatic atmospheric model:2-12 km resolution 12h forecast 6h forecast CI concentration 15 m wind 12h forecast 12 km nested and coupled run m/s

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