What can be said about the rho_hv values during Bragg scattering?

During Bragg scattering, rho_hv values, which represent the correlation coefficient between horizontal and vertical polarizations of radar signals, are typically near zero. This phenomenon occurs because Bragg scattering is a result of the constructive interference of radar signals scattered by small targets, such as raindrops, with dimensions comparable to the wavelength of the radar.

In such cases, the scatterers do not have a strong correlation in their scattering properties between the two polarizations. Thus, rho_hv approaches zero, indicating a lack of correlation, as the scatterers are not aligned in a way that would create a strong return signal for both polarizations. Values near zero suggest that the radar returns from these targets are not predominantly influenced by the size or shape that would create a polarization-dependent signal.

Understanding the behavior of rho_hv during Bragg scattering is crucial in radar meteorology because it helps in interpreting the signals reflected back to the radar system, particularly when analyzing precipitation and discerning details about the drop size distribution.