Using Radar Measured Spectrum Width to Estimate Large Scale Background Wind Shear Intensity

It is well-known that turbulence and shear are two major meteorological contributors to radar measured spectrum width. Substantial research has focused on estimating the turbulence intensity in clouds and storms from the spectrum width. But studies on the contribution of shear to the spectrum width have been limited. Although shear can play an important role in the development and evolution of storms and squall lines, it is not easily measured directly. This study compares radar measured spectrum width fields with simulations obtained using VAD wind profiles and introduces a simple method to estimate large-scale background wind shear intensity and depth from the spectrum width field. The estimated shear intensity and depth agree well with those obtained from the VAD derived wind profile, a 6-point method, and simulations. This study provides a means to improve turbulence estimates too, since to isolate the turbulence contribution, the shear contribution must be removed from radar measured spectrum width.