Volume-imaging UHF radar measurement of atmospheric turbulence

The Turbulent Eddy Profiler (TEP) is a volume-imaging 915 MHz radar designed for atmospheric boundary layer turbulence studies. TEP is a pulsed, phased-array radar using digital beamforming techniques to provide four-dimensional images of refractive index fluctuations and wind vectors on grid scales comparable to those of large-eddy simulations. During October 1999, TEP was deployed during the Cooperative Atmospheric Surface Exchange Study (CASES´99) held near Wichita, KS. The authors present observations from this experiment which focused on the evolution and dynamics of the stably-stratified nocturnal boundary layer. Unlike the convective boundary layer, radar echoes are characterized by intermittent bursts of shear-induced turbulence. The scales of turbulence features are generally smaller than the resolution of the UHF radar. This is demonstrated by comparison with a co-located S-band FMCW radar. Estimation of turbulence intensity is also complicated by the presence of significant bird and insect scatter