Liquid water content estimates using simultaneous S and Ka band radar measurements

A technique for the estimation of total liquid water content (LWC; the sum of cloud water and rainwater contents) using simultaneous S and K
a
band scanning radar observations is proposed and tested using the National Center for Atmospheric Research simultaneous S band and K
a
band dual-polarimetric (S-PolKa) radar system. The sources of error for this wavelength pair are evaluated, and the methods to mitigate them are discussed. The results are LWC estimates at each radar volume that are equivalent to specifying a reflectivity (Z) – LWC relation constrained by the measured attenuation over 2 km radar ray segments. Because the radars are scanning, the LWC can be mapped out over the spatial volume and temporal evolution of the clouds. The method produces reasonable results that qualitatively compare well to in situ aircraft observations.