Doppler Velocities at Orthogonal Polarizations in Radar Echoes From Insects and Birds

The differential Doppler velocities (DDVs) measured with weather radar at horizontal and vertical polarizations in echoes from insects and birds are considered. In weather echoes, DDV is usually less than 0.5 ms^{- 1}, whereas in echoes from flying birds and insects, it can reach 5-7 ms^{- 1}. Such large difference can be used as an additional parameter in distinguishing between weather and nonmeteorological echoes. It is shown that large values of DDV pertain to multipeaked Doppler spectra with different spectral differential reflectivity values in the peaks.