1. Snow modelling using Surfex with the Crocus snow scheme for Norway Dagrun Vikhamar-Schuler 1 and Karsten Müller 2 1 MET.NO, 2 NVE

2. Data sources Weather forecasts Weather stations Gridded 1 km maps: snow depth, temp, prec. Snow observations Physical snow models seNorge.no

3. CROCUS snow scheme: -Up to 50 layers -Temp -Grain size, type -Liquid Water cont. -Density -.. SURFEX: land-surface model from HARMONIE atm. model. Ref: Eric Brun and Samuel Morin, MeteoFrance Date Snow depth Snow temperature

4. 1D model run for weather stations in Norway

5. Driving data? Short- and longwave radiation Precipitation (+prec. phase) Air temperature Wind dir. + speed Surface pressure Air humidity Too few parameters are observed at the weather stations to drive SURFEX. Can forecasts replace observations without reducing the quality of the modeled snow depth?

6. Grotli (872 masl): 2009-2010 - forcing data: observations except …: Observed Snow Depth Modelled Snow Depth UM: Radiation UM: Radiation, Surface pressure UM: Radiation, Wind UM: Radiation, Air humidity UM: Radiation, Temperature UM: Radiation, Precipitation

7. Sensitivity study   For all Stations (Grotli, Filefjell, Beitostølen, Mannen, NGI- fonnbu):   BEST results using OBSERVATIONS of precipitation and temperature.   Other parameters seems ok to derive from MetUM (NWP) forecasts.

8. We have evaluated the snow depth. What about the snow pack layers?

9. Liquid water content (%) Filefjell winter 2011-2012 Snow density(kg/m3) 1 Sept 2011 17 April 2012

10. Snow Temperatures FILEFJELL Weather Station  Snow temperatures are measured hourly  0, 5, 15, 30 og 55 cm snow height 20102011 ºC Ground surface temperature

11. Summary  CROCUS reproduces well the observed snow depth using observations.  Results are most sensitive to precipitation and temperature Other parameters ok to derive from NWP data Other parameters ok to derive from NWP data  Ongoing work: comparing driving data: NWP models (Harmonie 2.5 km) NWP models (Harmonie 2.5 km) Observations Observations  Future: 2D simulations