The retrieval of the LWC in water clouds: the comparison of Frisch and Radar-Lidar techniques O. A. Krasnov and H. W. J. Russchenberg International Research Centre for Telecommunications-transmission and Radar, Faculty of Information Technology and Systems, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands. Ph , Fax: : Third Progress Meeting April 2003, Reading

The Radar, Lidar, and Radiometer dataset from the Baltex Bridge Cloud (BBC) campaign August 1- September 30, 2001, Cabauw, NL Radar Reflectivity from the 95 GHz Radar MIRACLE (GKSS) Lidar Backscattering Coefficient from the CT75K Lidar Ceilometer (KNMI) Liquid Water Path from the 22 channel MICCY (UBonn) All data were presented in equal time-height grid with time interval 30 sec and height interval 30 m.

The relation between “in-situ” Effective Radius and Radar Reflectivity to Lidar Extinction Ratio for different field campaigns.

Application of the relation for the identification of the Z-LWC relationship Application of the relation for the identification of the Z-LWC relationship

Case study: August 28, 2001, Cabauw, NL, The profiles of measured variables

Case study: August 28, 2001, Cabauw, NL, The profiles of Optical Extinction and Radar-Lidar Ratio

Case study: August 28, 2001, Cabauw, NL, The Resulting Classification Map (radar and lidar data)

Case study: August 28, 2001, Cabauw, NL, Retrieval Results (classification using radar and lidar data)

Frisch’s algorithm log-normal drop size distribution concentration and distribution width are constant in the cloud From radiometer’s LWP and radar reflectivity profile:

Case study: August 28, 2001, Cabauw, NL, Retrieval Results for Frisch’s algorithm

Case study: August 28, 2001, Cabauw, NL, Histogram of Differences in Retrieval Results for the Frisch’s and the Radar-Lidar algorithm

Difference between LWC that retrieved using Frisch method and retrieved from radar-to-lidar ratio

Frisch’s fittings Log-Normal DSD N= cm -3,  = 0.8 N= cm -3,  = 0.1 Case study: August 28, 2001, Cabauw, NL, Representation results on the Z-LWC plane

Case: cloud without drizzle

Case study: September 23, 2001, Cabauw, NL, The profiles of measured variables

Case study: September 23, 2001, Cabauw, NL, The profiles of optical extinction and Radar-Liadr Ratio

Case study: September 23, 2001, Cabauw, NL, The Classification Map (Radar-Lidar, threshold -35 and -25 dB)

Case study: September 23, 2001, Cabauw, NL, The Resulting Classification Map (radar and lidar data)

Atlas Z-LWC relationship

Frisch’s fittings Case study: September 23, 2001, Cabauw, NL, The results of Frisch’s algorithm application Log-Normal DSD N= cm -3,  = 0.8 N= cm -3,  = 0.1

Conclusions The Frisch’s technique produce much more water It does not recognize the presence of in-cloud drizzle For the log-normal model Frisch’s fitting of Z-LWC relationships shows huge, non-realistic concentrations