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

Super-Res Reflectivity productMaximum range = 248 nm

8-bit 1 deg azimuth Reflectivity productMaximum 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

SR Base Reflectivity Product

Legacy Base Reflectivity Product

Source: WDTB DLOC Topic 3

Example of Noisiness for Convective Rainfall

SR Base Reflectivity Product

Legacy Base Reflectivity Product

Example of Noisiness for Stratiform Rainfall

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 clearly in 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

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 kts

vs +21 kts) .• Overall storm identification is enhanced.

Source: WDTB DLOC Topic 5

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