Simultaneous observations of the troposphere and lower stratosphere by the Flatland and Urbana ST radars

Simultaneous VHF radar observations of the troposphere and lower stratosphere were carried out on August 17–19, 1988, near Urbana, Illinois, using the Flatland radar and the Urbana stratosphere‐troposphere (ST) radar, which are operated by the Aeronomy Laboratory of the National Oceanic and Atmospheric Administration and the University of Illinois Department of Electrical and Computer Engineering, respectively. The two radar sites are located on the vast plain area of central Illinois, separated by approximately 25 km. The geographical and observational configuration is considered most suitable for investigating mesoscale structures in the troposphere‐stratosphere region. One horizontally stratified layer at about 15.5 km related to the tropopause, and another in the troposphere at about 8 km were observed at both radar sites for a long period of time. Velocity fluctuations with periods of 100 min < T < 200 min were observed to be well correlated during a period of quiet horizontal wind. A convective thunderstorm on the evening of August 18 coincided with the dissipation of the tropospheric layer observed at 8 km. We present here a qualitative comparison of low‐pass and band‐pass filtered echo power and radial velocities, and a comparison of vertical power profiles from the two radars.