SOMARE-99: A demonstrational field campaign for ultrahigh-resolution VHF atmospheric profiling using frequency diversity

During May of 1999 the sounding system (SOUSY) VHF radar was operated in a demonstrational field campaign specially designed to test the applicability of range imaging (RIM) to radar studies of the atmosphere. The RIM technique utilizes frequency diversity to offer a novel method of improving radar range resolution over that which can be obtained with a conventional pulsed radar with the same bandwidth. During the field campaign, which is being called SOUSY Multifrequency Atmospheric Radar Experiment 1999 (SOMARE-99), the application of RIM on a VHF radar has been demonstrated. The data from SOMARE-99 are intended for investigating the dynamics and morphology of fine-scale vertical structures in the troposphere. This paper gives an overview of SOMARE-99 and provides some initial scientific results. A central and important result was obtained by comparing RIM-processed radar observations and data from radiosondes. Profiles of the vertical gradient of the generalized refractive index and the so-called RIM- enhanced echo power are found to bear similarities during one particular case, for which the radiosonde was located directly over the radar. Furthermore, a spectral analysis of these two parameters has provided evidence that RIM is successfully identifying multiple structures within the radar sampling volume with scales smaller than the conventional range resolution.