The MRI portable X-band Doppler radar (X-POD): Status and Applications

Many important meteorological processes occur at sub kilometer-kilometer scales (fine scale) and these are difficult to observe with traditional stationary meteorological radars. The most critical limitation is that stationary radar deployment is usually relatively far from target area. This results in fine scale structures being unresolvable due to beam spreading, topography, and earth curvature between stationary radars and the targets. There is a need for fine scale observations of these phenomena in order to better understand the mechanisms involved in their formation and maintenance. A portable X-band Doppler radar (X-POD: X-band, Portable Doppler radar) has been developed as a ground-based radar observation platform to make fine-scale observations of various phenomena. It has a 60-km observation range, a 2.0 azimuth resolution, and a pulse length of 1.0 (0.5) micro-sec providing independent data points every 150 (75) m in range. It is operated in both PPI and RHI modes and the velocity dealiasing algorithm (Kusunoki et al. 1996) correctly dealiases velocities even in a complicated circulation including thunderstorm outflows, mesocyclones, and wake vortices. An important aspect of X-POD is its portability. X-POD is basically truck-mounted radar system. X-POD can travel to regions of interesting weather and approach to a range where fine scale measurements. The height of the radar antenna while running on the roads is about 3.2 m AGL, which is lower than the generally permitted value of 3.8m. After stopping, the antenna can be lifted up to 5.2m AGL by a hydraulic lift in order not to be blocked by the cab. Furthermore, X-POD can be easily dismounted from the truck and deployed on top of a tall building for studies of boundary layer circulations over an urban area. It is expected that X-POD will increase opportunities to observe more cases than would result if only stationary radars are used.