Quasi-vertical profiles — a new concept of examining polarimetric radar data

A novel methodology for processing and representing polarimetric data collected by weather surveillance radars is introduced. It involves azimuthal averaging of radar reflectivity Z, differential reflectivity ZDR, cross-correlation coefficient ρhv, differential phase ΦDP, and specific differential phase KDP at high antenna elevation and presenting resulting “quasi-vertical profiles (QVPs)” in a height vs time format. Multiple examples of QVPs retrieved from the data collected by S-, C-, and X-band dual-polarization radars at elevations ranging from 4° to 28° illustrate advantages of the QVP technique. The benefits include an ability to examine temporal evolution of microphysical processes governing precipitation production and integrate polarimetric data obtained from the scanning surveillance weather radars with the observations made by vertically looking remote sensors, such as wind profilers, lidars, radiometers, cloud radars, and radars operating on spaceborne and airborne platforms. Continuous monitoring of the melting layer and the layer of dendritic growth with high vertical resolution as well as the capability to discriminate between the processes of snow aggregation and riming constitute other potential benefits of the suggested methodology. The signatures in the QVP profiles of the backscatter differential phase within the melting layer and the layer of dendritic growth in the temperature interval between -10 and -15°C are particularly interesting and revealing.