Published: 2007-09-26 14:31:37
Updated: 2007-09-26 14:31:37
Posted September 26, 2007 2:31 p.m. EDT
By Kevin Steffen
MIKE MOSS SAYS: Kevin, For the most part, the vertically polarized portion of the Dual Doppler assists with discriminating the types of precipitation particles falling through the beam, correcting for attenuation of the beam as it passes through heavy precipitation areas that partially "block" the radar from more distant echoes, and assist with improving the fidelity of radar rainfall estimates. Note that both the vertically and horizontally vibrating portions of the beam are confined within the same very narrow (1 degree) channel and the "vertical" portion is simply interacting differently with the same scattering particles that the horizontal portion is and always has - it does not add to the vertical coverage of the beam in a macroscopic sense. For the most part, mesocyclone and tornado detection depend on analysis of the same reflectivity and radial velocity data that has been available from previous doppler radar systems. There is one possible exception to this that has turned up in research however. There are certain properties that can be uniquely measured by Polarimetric radar that can nicely identify the cloud of debris raised by strong tornadoes, if the tornado happens to be close enough to the radar that the radar beam does not pass over top of the upper bounds of the debris. The size, shape and distribution of the debris distinguishes it from nearby rain and hail, and if an otherwise suspicious echo shows a strong "non-meteorological" target signature in a nearby cell at low altitude, it's a good bet a significant tornado is on the ground and causing damage.