German contribution to the international acsys project
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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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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

Meteorological Institute University of Bonn, Germany

[email protected]

http: www.meteo.uni-bonn.de

A project funded by the Federal Ministry of Education and Research


The katabatic wind system kws

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


German contribution to the international acsys project

(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


Katabatic wind dynamics

Katabatic wind dynamics

Integrated katabatic wind layer (Ball, 1956):

Pressure gradient (2D):

Pressure gradient (1D):

=- zs/x


German contribution to the international acsys project

Monthly means January 1990

10-4 ms-2

Synoptic forcing FS

10-4 ms-2

Topographic forcing FT


German contribution to the international acsys project

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


German contribution to the international acsys project

Topographic forcing FT

10-4 ms-2


German contribution to the international acsys project

Comparison NORLAM/aircraft


German contribution to the international acsys project

Tasiilaq

Katabatic wind and boundary layer front experiment around Greenland

April+May 1997

KABEG


German contribution to the international acsys project

Polar 2 (AWI)

Meteopod 120 Hz

A3

A4

100 km


German contribution to the international acsys project

KABEG Case study22 April 1997

Heinemann (2002)


German contribution to the international acsys project

Profiles of turbulent fluxes

Evaporation 1 W/m2.10 mm/a


German contribution to the international acsys project

Regimes of the katabatic wind system


Stable boundary layer sbl similarity

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


German contribution to the international acsys project

Scaling regions KABEG

L* from A4 data


German contribution to the international acsys project

Local scaling for KABEG data

Cabauw data, Nieuwstadt (1984)

Data collected within 18 months

Variances

(about 250 data points, 6 flights)

Heinemann (2004)

KABEG


Outlook german acsys project phase ii 2002 2005 katabatic wind and polynia interaction

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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