An enhanced algorithm for the retrieval of liquid water cloud properties from simultaneous radar and lidar measurements. Part II: Validation using ground based radar, lidar, and microwave radiometer data

The possibilities to use ratio between simul- taneously measured radar reflectivity and optical extinction profiles for detection of drizzle fraction in water clouds and estimation of its influence on remote sensing mea- surements are studied. This parameter is used for classi- fication of clouds type into three classes - the cloud with- out drizzle fraction, the cloud with light drizzle, and the clouds with heavy drizzle. The subsequent application for every resulting type of cloud specific Z-LWC relation- ship allows to minimize influence of drizzle fraction in clouds on results of LWC retrieval. Such enhanced algorithm has been applied for real radar and lidar data and retrieval results were then validated using liquid water path that was measured simultaneously with microwave ra- diometer. In this paper we present some results of application an enhanced algorithm for retrieval of liquid water cloud properties to data that were simultaneously measured with ground based radar and lidar. This algorithm was derived from study particle size spectra that were measured with aircraft-mounted in-situ probes during a few field cam- paigns, in different geographical regions, and inside different types of water clouds (Krasnov and Russchenberg, 2002). It uses possibilities to detect and characterize drizzle fraction in water clouds using ratio between si- multaneously measured radar reflectivity and optical extinc- tion profiles. The features of this ratio allow to use it values for classification of cloud's type into three classes - the cloud without drizzle fraction, the cloud with light drizzle, and the clouds with heavy drizzle. The subse- quent application for every resulting type of cloud's cells specific Z-LWC relationship allows to retrieve LWC of water clouds. In this study we have applied this enhanced algorithm for real remote sensing data that were measured during BBC campaign. We have used radar and lidar data for re- trieval of liquid water content in water cloud, and radiometer data about liquid water path (LWP) for vali- dation of retrieval results.