Spectrum width patterns in precipitation

One of the difficulties in relating spectrum width features to weather phenomena is that the spectral width is a sum of contributions from different mechanisms (e.g., wind shear, turbulence, drop fall speed, etc.). Furthermore, spectrum width fields are more susceptible to errors due to improper radar set up. Nevertheless, in properly adjusted radars, and under certain conditions, meteorological features associated with each of the principal contributors (shear, turbulence, and fall speed) to spectrum width can be seen as distinctive patterns of spectrum in RHI and PPI displays. Spectrum width patterns for layers of turbulence, apparently in early stages of development, show as two semicircles of enhanced width at constant range, and for fully developed turbulence, as a complete circle of enhanced width. When wind changes its direction with height, a spiral pattern of enhanced width appears in the PPI display. Theoretical models confirm this interpretation of observed spectrum width patterns. Spectrum width fields in convective clouds show distinctive patterns for storms in their various stages of development.