Combined Dual-Doppler and Polarimetric Analysis of Precipitating Cells from 2 X-Band Polarimetric Radars

Understanding the life cycle of precipitating systems is important for better nowcasting of significant weather and for improving weather prediction models. Doppler and Polarimetric weather radars have the ability to look simultaneously into the microphysics and dynamics of precipitation systems. The goal of this study is to make use of these powerful tools to perform combined analysis of dynamics and microphysics of precipitation systems, in order to better understand storm development.

Using the Doppler capability of the Bonn and Jülich weather radars, spaced about 50km apart, the 3D wind fields are retrieved through available techniques (MultiDop, Py-art). Simultaneously the polarimetric capability of the radars allows the retrieval of microphysical processes. Polarimetric moments depend on the size, shape, phase and number concentration of precipitating particles and have been proven useful in the identification of microphysical processes (melting, evaporation, aggregation, freezing, riming, etc). Hydrometeor classification schemes can be applied to the polarimetric data in order to get a complete view of the precipitation particles in the system, as well as their evolution through time. The interaction between these two fields is complex and not fully understood at the moment. This research aims at highlighting the processes through which precipitation systems evolve by revealing the interdependence between the storm dynamics and microphysics. The influence of the storm dynamics in the generation of certain hydrometeor types, like graupel, hail, heavy rain, will be addressed, as well as the effect of certain microphysical processes on the circulation within the storm. A better understanding of these interactions is crucial for improving nowcasting of certain weather types that have a great economical or social impact.