It should be noted that there are developing techniques to try to extract more information from doppler radar data (IIRC, much of it involves the use of Level-I NEXRAD data). For example, the Tornado Spectral Signature is currently being investigated by some researchers as OU and NSSL. We talked about it last semester in my radar class, but again IIRC, it essentially involves looking at spectrum power density for the valid +/- Nyquist range... If the returned power spectrum is high and is nearly equal across the Nyquist velocity range, that signifies that there is multiple velocity folding occurring with that range bin. This is just one technique being investigated, but there are also techniques that attempt to increase the resolution of the radar data (decreasing dwell time allows one to oversample azimuthally, etc).
As for correlating 88D data with actual tornado wind speeds... Not really that I know of. We have a hard enough time determining tornado wind speeds to begin with, so any comparative study of tornado winds and 88D would be difficult I would think. The know Dr. Wurman has worked with the DOW data in regards to tornado wind speed (and F-scale rating and damage production, which I think he did on the Spencer SD tornado). Again, however mobile doppler radars have a massive benefit in this regard as compared to the 88Ds.
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