This article describes the 1995 and 1996 Flatland boundary layer experiments, known as Flatland95 and Flatland96. A number of scientific and instrumental objectives were organized around the central theme of characterization of the convective boundary layer, especially the boundary layer top and entrainment zone. In this article the authors describe the objectives and physical setting of the experiments, which took place in the area near the Flatland Atmospheric Observatory, near Champaign–Urbana, Illinois, in August–September 1995 and June–August 1996. The site is interesting because it is extremely flat, has uniform land use, and is in a prime agricultural area. The instruments used and their performance are also discussed. The primary instruments were a triangle of UHF wind-profiling radars. Rawinsondes and surface meteorological and flux instruments were also included. Finally, some early results in terms of statistics and several case studies are presented.

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*CIRES, University of Colorado, and NOAA Aeronomy Laboratory, Boulder, Colorado.

+National Center for Atmospheric Research, Boulder, Colorado.