Filling the Vertical Gap in Severe Local Storms Research: New Opportunities using Vertically Continuous Radar Imaging

Severe local storms and tornadoes evolve quickly and can be highly localized.  Advancements in radar engineering have pushed the envelope of our ability to detect and analyze these storms, with specific foci on speed, resolution, and accuracy.  Of the existing rapid-scanning mobile systems, the majority take the form of a phased array antenna, allowing for new scanning modes and techniques.  One such technique, known as digital beamforming, is utilized by the Atmospheric Imaging Radar (AIR), allowing for instantaneous range-height indicator (RHI) data by transmitting a vertical fan beam and forming individual pencil beams using a receiver array.  The AIR is capable of scanning 180-deg by 20-deg volumetric sectors in 10 s, allowing for analysis of standard plan position indicator (PPI), volumetric, and RHI data types without having to change scanning modes.  The 20 vertical pencil beams formed by the AIR are aligned adjacent to each other with no gaps, and can be arbitrarily oversampled, resulting in vertically continuous data that truly fills the entire volume.  Examples of the ability to combine RHI data with volumetric data are presented in a series of severe local storms and tornadoes spanning from 2013-2015.  RHIs through tornadoes are presented in rapid succession, and PPIs from nearly identical times are shown in order to provide the reader with a full understanding of the storm under analysis.  RHIs are also shown through mesocyclones, gust fronts, and rear flank downdraft regions of supercells, while storm-scale volumetric data are presented for perspective.  Focus is given to situations where a single scanning mode would have traditionally been chosen, resulting in the loss of data analysis opportunities.  A discussion of what the AIR brings to the existing rapid-scanning mobile radar landscape is presented, and specific attention is given to how close vertical spacing can enhance data analysis capabilities and open new doors for unique studies in future field campaigns.