Remote sensing of tropospheric clouds with a dual polarization radar

Abstract

Circularly polarized radiation propagating through regions of tropospheric clouds are depolarized by the constituents of the clouds in two ways: through backscattering and propagation effects. The propagation effects are in turn composed of two components: differential phase and differential attenuation. Tropospheric clouds can consist of water droplets, ice crystals, and liquid and solid precipitation. By coherently correlating the simultaneous signals received in the right-hand and left-hand polarization channels of a circular polarization radar the presence of aligned particles can be detected and this can be used distinguish different components of the cloud. For instance, vertical alignment of ice crystals in the upper portions of the cloud are indicative of strong electrification. The degree of the ice crystal alignment is related to the strength of the electric field. Strong alignment of these ice crystals indicates that the storm has the potential to produce lightning.<>