An 11-CM full-matrix polarimetric radar for meteorological research

The Geophysics Directorate operates a unique 11-cm (S-band) coherent polarimetric radar. The radar can transmit signals of alternating orthogonal polarizations, with either circular or linear basis, and receive signals of polarizations identical and orthogonal to that of the transmitted signal. The received signals, comprising logarithmic power and in-phase and quadrature components of both polarizations, are sampled in 50 selectable gates and recorded for off-line analysis. The radar antenna and the polarimetric data acquisition are controlled by interactive computer programs. Measurements are underway to characterize the performance of the radar, describe microphysical attributes of clouds and precipitation, and identify the effects of changing electric fields on the orientations of hydrometeors. Examples of these measurements are shown. Related facilities are described briefly.