A New Frontier for Mobile Weather Radar—The Atmospheric Imaging Radar: meteorological implications and requirements

High temporal resolution radar observations are needed to observe many quickly evolving atmospheric phenomena, but most mobile radar systems have revisit times of several minutes for full volume scans. For example, revisit times of a few seconds may be necessary to observe processes leading to tornadogenesis, so revisit times of several minutes are inadequate. To address this need, the Atmospheric Radar Research Center (ARRC) at the University of Oklahoma (OU) is currently designing and building the Atmospheric Imaging Radar (AIR), which will be the first mobile imaging radar for meteorological applications. An imaging radar transmits a wide beam (“spoiled beam”), and utilizes a set of independent receive arrays using advanced digital beamforming techniques to obtain enhanced spatial resolution and immunity to ground clutter over conventional mobile radar systems. The primary advantage of an imaging radar, however, is that the receive beams are formed in software and can be obtained simultaneously. Therefore, there is no time delay between beam positions, so extremely fast update times can be obtained. Using an advanced phased array weather radar simulator, the capabilities of the AIR to provide higher temporal resolution imaging of atmospheric phenomena will be shown, including simulations of a tornado from Advanced Research Prediction System (ARPS) model output. Exploiting the potential for extremely rapid update times using the AIR, the relationship between optimal spatial and temporal resolution will be addressed in terms of requirements for particular severe weather phenomena.