The S/Z Relationship of Rimed Snow Particles

Abstract. Values of liquid-equivalent snowfall rate (S) at a ground site, and microwave reflectivity (Z) retrieved above the ground site using an airborne W-band radar, were acquired during overflights. Temperature at the ground site was between -6 and -15 °C. At flight level, within clouds containing ice and supercooled liquid water, the temperature was approximately 7 °C colder. Additionally, airborne measurements of snow particle imagery were acquired. The images demonstrate that most of the snow particles were rimed. The S/Z pairs are generally consistent with a published S/Z relationship. The latter was developed with airborne measurements of snow particle imagery, which were used to calculate S, and coincident airborne W-band radar measurements, for Z. Both the previous work and this contribution indicate that most S/Z relationships developed for W-band radars underestimate S in situations with rimed snow particles and with Z < 1 mm⁶ m^-3.