Stationary radars are poorly suited for the study of many near-ground and finescale phenomena. 1993 Bluestein and Golden 1993 Zrnic et al. There is a need for finescale observations of these phenomena in order to better understand the mechanisms involved in their formation and maintenance ( Kaplan and Damaria 1995 Brandes 1993 Bluestein et al. Finally, these phenomena frequently occur on timescales of seconds to minutes and thus are sampled poorly by typical surveillance radar scanning strategies. Near-ground (<300 m AGL) structures are undetectable due to the masking of the transmitted beam by topography and obstructions, vertical beam spreading, and earth curvature. This results in finescale (subkilometer) structures being unresolvable due to beam spreading between stationary radars and the targets. Moreover, many interesting physical processes occur at subkilometer scales, but the ranges between the phenomena of interest and the stationary radars are almost always quite large. 1996), microburst outflows (Wakimoto and Bringi 1988), dust devils ( Snow and McClelland 1990), waterspouts ( Schwiesow 1981), landspouts ( Wakimoto and Wilson 1989), and landfalling hurricanes ( Wakimoto and Black 1994 Kaplan and Demaria 1995). Such phenomena include tornadoes (e.g., Bluestein and Golden 1993 Fujita 1978 Wakimoto et al. These are difficult to measure with traditional stationary meteorological radars. Many of the most interesting and important meteorological phenomena occur infrequently and/or very near the ground. This paper documents the design and early deployment of a mobile Doppler radar. Other applications are possible, including avian and entomological studies, pseudo-dual-Doppler, and rainfall estimation following and rapidly scanning storms in conjunction with mobile rain gauges. The sensitivity and mobility of the radar permits two-dimensional traveling vertical wind profiles to be obtained, extending the applicability of traditional one-dimensional profilers. The radar has successfully collected data in several tornadoes and tornadic storms and has been used to detect dust devils and other boundary layer structures. The radar employs a new high-powered, PC-based, digital intermediate frequency (IF) data acquisition scheme called the PIRAQ. At this range, the pencil beam of the radar is very narrow, permitting significantly higher-resolution measurements (at 3-km range, 64 m × 64 m × 75 m) than are usually possible with stationary or airborne systems. This portability allows the radar to be brought to within a kilometer of rare meteorological phenomena. The new radar, the Doppler on Wheels (DOW), has full scanning capability, a real-time display and archiving, and is mounted on a truck for easy portability and full mobility. A portable, pencil-beam, pulsed, Doppler, 3-cm wavelength radar has been constructed to study a wide variety of meteorological phenomena including tornadoes, severe storms, and boundary layer processes.
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