A synergetic radar-lidar technique for the LWC retrieval in water clouds

The parameterization of the microphysical characteristics for low-level stratiformwater clouds can be developed in terms, among others, of the effective radaius of droplets and the liquid water content (LWC). These parameters can be directly measured using aircraft mounted in-situ probes observations. The instruments used to perform these measurements, however, have an extremely small sample volume. The remote sensing methods are less direct but give much better coverage and are less expensive. As it was noted in many studies, there are some problems in applicability of the radar measurements alone for the retrieval of the mentioned above parameters. Small number of big particles (so-called drizzle) can produce the major part of the cloud's reflectivity Z without strong contribution in the LWC and effective radius. A few Z-LWC relations were published in literature, but all of them are noted as applicable only in absence of drizzle. From other point of view, in many studies were noted that the presence of the drizzle fraction in water clouds is more usual than its abscence. All these facts give the motivation for the efforts to find the combination of the remotely measurable parameters, which can be used for the detection of drizzle, its parameterization and taking into account in cloud's microphysics retrieval algortihm.