Receiver Bandwidth Effect on Reflectivity and Doppler Velocity Estimates

Abstract

Probert-Jones' radar equation assumes receiver bandwidth large compared to the reciprocal of the transmitted pulse width τ. The advent of coherent radars with precise transmitter frequencies allows consideration of receiver bandwidth ?matched? to and sometimes smaller than τ?1 in order to enhance measurement signal-to-noise ratio. An extension to the radar equation has been made to show explicitly the dependence of echo power on the product of transmitter pulse width and receiver bandwidth. When receiver bandwidth is less than twice τ?1, there is significant loss in echo power. This should be accounted for when estimating reflectivities. Considerable improvement in Doppler velocity estimation can often be obtained by matching range resolution to the angular one and this has implications of practical importance when moderately sensitive dual-Doppler radars are used to map the mesoscale wind in clear air.