PILPS 2e Experiment Summary

The purpose of this page is to summarize the model settings used by various groups for the PILPS 2e experiment, as well as the model structure at the time of the experiment. The information can be divided into four main components:

General Model Structure

Model Components
  Lake Model? Frozen Soils? Vegetation?
  Yes No Yes No Lumped Mosaic
CHASM            
CLASS            
ECMWF            
ISBA            
MECMWF            
SEWAB            
SPONSOR            
VIC            
VISA            

Snow Model Structure
  Zero Order Implicit Composite Bulk Layer Multi-layer
CHASM          
CLASS          
ECMWF          
ISBA          
MECMWF          
SEWAB          
SPONSOR          
VIC          
VISA          

Stability Correction
  Monin-Obuhkov Flux Richardson Bulk Richardson Gradient Richardson Other
CHASM          
CLASS          
ECMWF          
ISBA          
MECMWF          
SEWAB          
SPONSOR          
VIC          
VISA          

Runoff Generation
  Surface Runoff Subsurface Runoff
CHASM None Free drainage
CLASS Exceedence of surface detention capacity Free drainage
ECMWF Infiltration limitation Free drainage
ISBA variable infiltration capacity Free drainage following Mahfouf and Noilhan (1996) and Habets et al. (1999)
MECMWF variable infiltration capacity Free drainage following Van Genuchten (1980)
SEWAB No surface runoff before upper soil layer is saturated; 'topmodel' approach Free drainage; 'topmodel' approach
SPONSOR Horton overland, direct from saturated fraction Free drainage
VIC Variable infiltration curve ARNO baseflow curve
VISA runoff generated by saturated fraction of cell; 'topmodel' approach Free drainage; 'topmodel' approach

Parameter Selection

  Calibration? Apply knowledge? Input TS? Output TS?
CHASM No No 1 hr 1 hr
CLASS No No 0.5 hr 1 hr
ECMWF No No 0.5 hr 1.0 hr
ISBA No No 1.0 hr 1.0 hr
MECMWF Yes Yes 1 hr 0.5 hr
SEWAB Yes Yes 0.5 hr 1 hr
SPONSOR No No 1 hr 1 hr
VIC Yes Yes 1 hr 1 hr
VISA Yes Yes 1 hr 1 hr

  Calibration
CHASM No calibration performed.
CLASS No calibration performed.
ECMWF No calibration performed.
ISBA No calibration performed.
MECMWF Depth of the soil over which the relative soil water content is calculated was tuned.
SEWAB Applied a logarithmic profile for the saturated conductivity of the soil (topmodel approach).
SPONSOR No calibration.
VIC
VISA Applied a logarithmic profile for the saturated conductivity of the soil (topmodel approach).

Soil Parameters
  Clapp et al Cosby et al. Rawls et al. Other
CHASM        
CLASS        
ECMWF        
ISBA        
MECMWF        
SEWAB        
SPONSOR        
VISA        
VIC        

Snow Albedo
  Visible NIR
CHASM 0.85 0.65
CLASS 0.95 (new snow) 0.72 (new snow)
ECMWF Function of snow age and temperature
ISBA 0.85 0.85
MECMWF Function of snow age and temperature
SEWAB 0.9 0.9
SPONSOR 0.85 0.65
VIC 0.85 (new snow) 0.85 (new snow)
VISA 0.95 (BATS param) 0.65 (BATS param)

ChartObject SOIL LAYER DEFINTIONS

General impressions about the experiment

General Impressions
We experienced large interception evaporation and inappropriate diurnal variation due to the treatment of hourly precipitation (equal to daily total precipitation/24).
I had the impression that the snow model suited quite well to the problem. The soil model I think had some problems in storing the large amount of water from snow and ice in the spring, which led to an unsatisfactory fitting of the discharge
The forcings show some very low winds and/or low atmospheric humidities, giving rise to strong peaks in evaporation. Validation data are lacking and the performance is somewhat uncertain.

Model References

The most recent references describing model structure, as specified by the model users, are listed below:

CHASM

Desborough, C.E., 1999. Surface energy balance complexity in GCM land surface models. Climate Dynamics, 15, 389-403.

Desborough, C.E., 2000. Surface energy balance complexity in GCM land surface models, Part II: coupled simulations. Climate Dynamics, in press.

SEWAB

Mengelkamp, H.T., K. Warrach, and E. Raschke, 1997. A land surface scheme for atmospheric and hydrologic models: SEWAB (Surface Energy and Water Balance). Externer Bericht des GKSS Forschungszentrum, GKSS 97/E/69.

Warrach, K., 2000. Gefrorener boden und schneebedeckung unter besonderer beruecksichtigung des hydrologischen verhaltens der landoberflache, Dissertation GKSS 200/21.

MECMWF

Viterbo, P. and A.C.M. Beljaars, 1995. An improved land surface parameterization scheme in the ECMWF model and its validation. Journal of Climate, 8, 2716-2748.

Viterbo, P., A. Beljaars, J.F. Mahfouf and J. Teixeira, 1999. The representation of soil moisture freezing and its impacts on the stable boundary layer. Q.J.R.Meteorol. Soc., 125, 2401-2426.

Van den Hurk, B.J.J.M., P. Viterbo, A.C.M. Beljaars and A.K. Betts, 2000. Offline validation of the ERA40 surface scheme, ECMWF TechMemo 295, Journal of Climate, to be submitted.

Van den Hurk, B.J.J.M.,, P. Graham and P. Viterbo, 2000. Evaluation of simulations of runoff to the Baltic Sea by atmospheric models; KNMI Preprints 2000-04; 31 pp. (submitted to Journal of Hydrology



Last Updated on 1/31/01
By L Bowling
Email: lxb@hydro.washintgon.edu