Use of dipole scattering method for calculation of electromagnetic scattering from non-spherical particles of rain

The peculiarities of using dipole scattering method for calculation of radar reflectivity from non-spherical rain particles are discussed. As well the choice of raindrop shape model is considered and comparison of different approaches to calculation of electromagnetic scattering is performed. It is shown that use of dipole scattering method is validated when particles diameter does not exceed 3 mm for an ellipsoidal model of particles shape and for model of Pruppacher-Pitter when particle dimension is less than 2.5 mm. Also it was shown that the difference between rigorous and dipole scattering calculations is provided by large drops. From the other hand the probability of large drops in polydisperse medium is quite small, that is why the error between rigorous and dipole scattering calculations is not too much for polydisperse medium and for rain intensity up to 20 mm per hour. Finally, the conclusion about applicability of approximate method of dipole scattering is made for rain of large intensity.