Measurement of Individual Hydrometeor Absorption Cross Sections Utilizing Microwave Cavity Perturbation Techniques

Abstract

A technique for measurement of individual hydrometeor absorption cross sections is presented. Cross sections are inferred by inserting the hydrometeor into a high Q resonant cavity and measuring the Q perturbation. Tests were conducted in a 10.64 GHz, TM010 cavity. Absorption cross sections were measured at room temperature for 0.5 to 2.0 mm water drops, and were found to agree with the Rayleigh theory. Cross sections were also measured as a function of temperature, and from these the dielectric loss term Im(?K) was inferred for supercooled water down to ?17°C.