Philippe Steiner & Francis SchubigerMeteoSwiss

SRNWP/EWGLAM meeting, LjubljanaOctober 2005

Poster Session:

Numerical Weather Prediction

at MeteoSwiss

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aLMo domain

Alpine Model aLMoOperational since 2001

IFS/ECMWF, 40km

4 daily updates

Swiss version of COSMO LMnon-hydrostatic, fully compressible

Prognostic variablespressure, 3 wind components, temperature, specific humidity, precipitation (snow, rain), cloud water, cloud ice

regular, 7km mesh size, 45 levels385 x 325 x 45 gridpoints

3-hourly assimilation cycle (nudging)2 daily 72h forecasts

98% reliability (i.e. 1 problem/month)

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aLMo 7km, regional scale

Own assimilation cycle

2 daily 72h forecast

New aLMo/2 configuration In test, operational in 2008

IFS/ECMWF, 25km, synoptic scale

4 daily updates

aLMo 2.2km, local scale

Own assimilation cycle

8 daily 18h forecast

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spectral/temporal

white : snowdark gray : cloudslight gray : snow-free landblack : sea

spectral/temporal

24-hour period:

9-3-2004 12:00 UTC - 10-3-2004 12:00 UTC1 image:

10-3-2004, 10:57 UTC

Snow cover map based on Meteosat 8 Eumetsat fellowship

Improved spectral + new temporal classification snow map at 5-6 km resolution

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Snow cover map based on Meteosat 8 Eumetsat fellowship

Use also high resolution visible channel with temporal classification snow map at 1.5-2 km resolution

Composite snow map, March 10th, 2004, 07:00 - 12:00 UTC

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Parameterization of topographic effects on radiationAnalysis of slope effect on radiation fluxes at the earth’s surface

slope aspect, slope angle or slope inclination, sky view, shadowing

Example: Surface temperature difference, 2004-12-11 00 UTC +12

7 km 2.2 km

Substantial impact at high resolution Higher impact during winter time (sun elevation, snow conditions)Secondary effects on cloud cover and thermal circulation induced