March 25, 2022 - 3:00 pm
March 25, 2022 - 4:00 pm
CategoriesConvective Meteorology (Mesoscale Dynamics)
Convective Meteorology (Mesoscale Dynamics)
Meteorological Benefits of Rapid-Scanning, Dual-Polarization Radar for Hail Producing Storms
Friday, March 25
Hailstorms continue to be one of the leading economic natural hazards in the United States, amounting to ten billion dollars in damage, on average, annually. Radar technology has continued to prove to be one of the best means of detecting hailstorms, especially from an operational standpoint, and the advent of dual-polarization radars have further supported this capability. However, most operational radar systems to date have temporal update times that are insufficient for understanding some of the rapidly evolving microphysical and dynamical processes of hailstorms, such as drop shedding, melting of hail, or variability of hailfall associated with updraft changes. As such, past studies have heavily relied on models and radar observations with update times on the order of 5-7 minutes.
Recent advances in radar technology have paved the way for a better analysis of hailstorms through the advent of rapid scanning radar systems. This study uses two radars providing rapid-scan observations: the Rapid X-band Polarimetric Radar (RaXPol) and KOUN to examine the meteorological benefits of such systems in regard to hailstorms. RaXPol, a mobile X-band radar system, provides full volumetric update times of 24 seconds and with its close proximity to the storm, also provides high spatial resolution, thus allowing for some microphysical processes to be resolved in more detail. While KOUN does not update as quickly as RaXPol, it can complete fast sector scans in 90 â€“ 120 seconds. This provides more temporal detail than a conventional NEXRAD system and its fixed-site operation can capture the full lifecycle of a hailstorm. Using vertical cross sections, RaXPolâ€™s high temporal and spatial resolution is able to capture the rapid growth of the ZDR column as well as numerous hail fallout signatures. One such fallout showed a descending hail signature that becomes stratified into distinct layers. We hypothesize these layers to be associated with 1) large, dry hail, 2) melting hail, and 3) large drops from melting hail or drop shedding with the stratification resulting from size sorting. KOUN was able to capture more variability than a conventional NEXRAD system and through the use of derived parameters, such as MESH and an HCA, was able to better capture the full lifecycle of a hailstorm and some associated features. Such examples include the ZDR column, the three-body scatter spike and the cyclic evolution of hail production. Through PPI and vertical cross sections, hail fallout was able to be resolved, though the extent of the microphysical processes ongoing was more limited, especially when compared to the RaXPol data. Understanding the benefits of using a rapid scanning radar system will be advantageous for future phased-array systems and will provide more detail on the processes affecting hail growth and production both from the research realm, as well as detecting hail and other precursor signatures in warning operations.