On Radio Wave Forward Scattering on Rain Drops

In this contribution critical size parameter (x
crit
) was defined and its values were found. It is limitation for utilisation of Rayleigh approximation for forward scattering functions (for x>x
crit
Mie theory is required for calculation. It is possible only in case of spherical particles shape assumption. For meteoradar frequencies 5.5, 10 and 35 GHz the critical values of size parameter (x
crit
) were calculated, its values are: 0.0168, 0.0199 and 0.0403, respectively. If size parameter is lower than these critical values, the simple Rayleigh approximation to compute complex forward scattering function is possible.