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A Refresher on Super-Resolution Radar Data. Audra Hennecke , Dave Beusterien. Base Data Resolution: Legacy vs. Super-Res. Base Reflectivity : Legacy Range Resolution: 1, 2, 4 km (0.54, 1.1, 2.2 nm) Azimuthal Resolution: 1.0 degree Super-Res Range Resolution: 0.25 km (0.13 nm)
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A Refresher on Super-Resolution Radar Data Audra Hennecke, Dave Beusterien
Base Data Resolution: Legacy vs. Super-Res • Base Reflectivity: • Legacy • Range Resolution: 1, 2, 4 km (0.54, 1.1, 2.2 nm) • Azimuthal Resolution: 1.0 degree • Super-Res • Range Resolution: 0.25 km (0.13 nm) • Azimuthal Resolution: 0.5 degree • Base Velocity: • Legacy • Range Resolution: 0.25, 0.50, 1km (0.13, 0.27, 0.54 nm) • Azimuthal Resolution: 1.0 degree • Super-Res • Range Resolution: 0.25 km (0.13 nm) • Azimuthal Resolution: 0.5 degree
Display Ranges • Base Reflectivity • Legacy and Super-Res: • Both available to 248 nm • Base Velocity • Legacy: • Available to 124 nm • Super-Res: • Available to 162 nm
Super-Res Characteristics • Available at lower elevation angles • Base data generated for only the Split Cut elevations of the VCPs • Retains the highest reflectivity value for display in courser resolutions; preserves important features • i.e. maximum reflectivity values in the cores of strong thunderstorms
8-bit 1 deg azimuth Reflectivity product Maximum range = 248 nm Super-Res Reflectivity product Maximum range = 248 nm Source: WDTB DLOC Topic 5
Super-Res Base Data • Super-Res Base Data, compared to all the base reflectivity/velocity products: • Highest number of data levels (256) • Greatest range resolution (250 m, 0.13 nm) • Best azimuthal resolution (0.5 degree) • Base data signatures easier to discern when viewing these higher resolution base data products
Super-Res Base Data • Two signal processing techniques used to produce Super-Res base data • Overlapping radials and windowing • Windowing process introduces more error in the base data estimate • Results in SR base products being visually noisier than legacy resolution base products • However, it supports visual detection of smaller scale features at longer ranges
Noisy Super-Res Base Data • Most apparent with reflectivity (compared to legacy resolution) • 8 SR reflectivity bins for every 1 legacy resolution reflectivity bin • More apparent in areas of stratiform precipitation and low returned power • Not as apparent in convective areas when compared to stratiform precipitation
Example of Noisiness for Convective Rainfall Legacy Base Reflectivity Product SR Base Reflectivity Product Source: WDTB DLOC Topic 3
Example of Noisiness for Stratiform Rainfall Legacy Base Reflectivity Product SR Base Reflectivity Product Source: WDTB DLOC Topic 3
Super-Res Base Velocity • Range: 162 nm • 256 data levels • Important velocity features will more readily appear and look clearer with Super-Res products • Super-Res velocity magnitudes associated with important signatures may need to be adjusted • May show stronger velocity values than those normally associated with many velocity signatures in the 1 degree data.
Super-Res: SRM • 250 m (0.25 km, 0.13 nm) x 0.5 degree • Range: 162 nm • 256 data levels • Displays the highest resolution velocity data available from the radar out to 162 nm for the split cut elevation angles.
Super-Res: SRM • High detail (spatially and in data magnitude) provides improved detection of TVSs, mesocyclones, microbursts, and boundaries. • Very useful for examining the velocity structure of fast moving storms (> 10kts) • Significant advantage compared to base velocity products of the same resolution
Super-Res: Storm-Scale Features • Storm-scale features show up more often and more clearlyin Super-Res products. • BWERs, hook echoes, TBSSs, low-level boundaries, hail cores, mesocyclones, TVSs, inflow notches
Super-Res: Mesocyclone Identification • Super-res velocity data: typically easier to identify small-scale features, i.e. mesocyclones • Velocity magnitudes associated with these features may appear stronger because of the finer resolution in the azimuthal direction
Source: WDTB DLOC Topic 5 Super-Res SRM Legacy, 1 deg. Azimuth SRM • For Super-Res, the strongest velocities associated with the mesocyclone cover a smaller area. • Super-res image has a significantly stronger outbound component of the mesocyclone (+43 ktsvs+21 kts) . • Overall storm identification is enhanced.
Super-Res: TVSs • Super-Res velocity: available on the lowest 2-3 elevation angles • Exactly where you would want to look for TVSs • Gate-to-gate shear will often have a greater magnitude in Super-Res data than indicated in the TVS definition. • Additional research is needed to understand the relationship between super-res gate-to-gate shear magnitudes and tornadic events.
TVS graphic product; Super-Res 0.5 SRM Source: WDTB DLOC Topic 5