Results from an experimental implementation of multiple-frequency range imaging (RIM) are presented. The technique exploits the benefits of frequency diversity to improve range resolution of atmospheric radar systems. The theory has been described in the literature, and simulations have proven its usefulness. Nevertheless, experimental results have been extremely limited. Over a 5-day period in May 1999 we conducted experiments using RIM on the sounding system (SOUSY) radar in northern Germany to observe the layered structure in the troposphere. The experiment is referred to as the SOUSY Multifrequency Atmospheric Radar Experiment 1999 (SOMARE-99). Estimates of range brightness produced by the RIM analysis provide insight about the layered structure of the atmosphere. The RIM results show distinct similarities to previous in situ measurements, which have shown sharp refractive index discontinuities to exist throughout the troposphere and stratosphere. Examples from selected time periods show layers modulated by possible short-period gravity waves or advection of periodic structures as well as other layers with apparent downward motion possibly caused by the progression of a warm front or large-scale subsidence. ¿ 2001 American Geophysical Union