6th International Cloud Modeling Workshop Hamburg, Germany; 11-16 July 2004 Case 1:  Baltex BRIDGE Campaign case Susanne Crewell, Colin Jones, Markus Quante, KNMI Contact: Prof. Dr. Susanne Crewell Meteorological Institute University of Munich Theresienstr. 37 80333 Munich, Germany e-mail:  crewell@meteo.physik.uni-muenchen.de

Two days during the BALTEX BRIDGE Campaigns (BBC) will be used to evaluate

    the short-term cloud and precipitation forecasts of 3-dimensional models in the domain of a 100 by 100 km regional network in the center of the Netherlands with the central station Cabauw. Special focus will be on the effects of horizontal and vertical resolution

    the microphysical properties of liquid water clouds as modelled by spectral 1-D models. Advanced ground-based (at Cabauw) and airborne (tethered balloon and 3 aircraft) observations are available for validation.

Day	23 September 2001	21 May 2003
Campaign	BBC	BBC2
Synoptic situation	low-level clouds in the morning transferring into shallow cumulus in the early afternoon	two cloud layers during daytime: ower layer (Cu/Sc) with base at 2000 ft, second layer (Sc) with base at 6000 ft.
Cloud classification at Cabauw
Liquid water at Cabauw
Weather maps	RACMO forecast (+15h) 03 UTC RACMO forecast (+18h) 06 UTC RACMO forecast (+21h) 09 UTC RACMO forecast (+24h) 12 UTC RACMO forecast (+27h) 15 UTC RACMO forecast (+30h) 18 UTC RACMO forecast (+33h) 21 UTC RACMO forecast (+36h) 24 UTC	HIRLAM Analysis 00 UTC HIRLAM Analysis 06 UTC HIRLAM Analysis 12 UTC HIRLAM Analysis 18 UTC
Radio Soundings	Cabauw 3:46 UTC Cabauw 8:58 UTC Cabauw 10:01 UTC Cabauw 10:59 UTC Cabauw 10:59 UTC Cabauw 13:28 UTC Cabauw 14:43 UTC Cabauw 15:37 UTC Cabauw 21:59 UTC De Bilt 0,6,12 and 18 UTC	Cabauw 5:15, 8:30, 11:20 and 14:07 UTC Cabauw 16:00, 17:58, 19:50 and 21:53 UTC De Bilt 12:00 UTC
Aircraft observations	Partenavia 09:05 to 10:44 UTC Partenavia 13:43 to 16:06 Merlin 08:19-10:33 UTC Merlin 12:43-14:25 UTC Cessna 08:25-10:58 UTC Cessna 12:31-15:18 UTC	Partenavia 08:09 to 10:16 UTC Merlin 07:49 to 10:04 UTC Merlin 13:01 to 14:48 UTC ACTOS 9:15 to 11:45 UTC
Model comparison for 50 km grhid at Cabauw	ECMWF, RCA (SMHI), RACMO (KNMI), LM (DWD)

Publications

Crewell, S, M. Drusch, E. Van Meijgaard and A. Van Lammeren, 2002:
Cloud Observations and Modelling within the European BALTEX Cloud Liquid Water Network,
Boreal Environment Research, 7, 235-245. PDF

Crewell, S., C. Simmer, H. Bloemink, A. Feijt, S. García, D. Jolivet, O. Krasnov, A. van Lammeren, U. Löhnert, E. van Meijgaard, J. Meywerk, K. Pfeilsticker, M. Quante, S. Schmidt, M. Schröder, T. Scholl, T. Trautmann, V. Venema, M. Wendisch, U. Willén,
The BALTEX Bridge Campaign: An integrated approach for a better understanding of clouds,
submitted to to Bull. Amer. Meteor. Soc.

Löhnert, U., S. Crewell, C. Simmer, 2004:
An integrated approach towards retrieving physically consistent profiles of temperature, humidity, and cloud liquid water,
J. Appl. Met., accepted. PDF

van Meijgaard, E. and S. Crewell,
Comparison of model predicted liquid water path with ground-based measurements during CLIWA-NET,
submitted to Atmos. Res.

Simulations

Similiar to the model evaluation performed within the EU-project CLIWA-NET short-term forecasts (+12 to +36 h) will be analysed in detail. Model runs should be performed with different vertical and horizontal resolutions with fixed boundary conditions. The results from the model simulations will be compared to observations. A detailed description about the model output was prepared by Erik van Meijgaard (KNMI). Please put the results on a ftp server and mail me address.

For the evaluation of microphysical properties ground-based remote sensing observations provide profiles of temperature, humidity, liquid water content (LWC) and effective radius using the integrated profiling technique (IPT, Löhnert et al., 2004). In addition to aircraft observations of diverse microphysical and radiative properties measurements from the tethered balloon system ACTOS (IfT Leipzig) are available.