A Time-Series Method to Identify and Correct Range Sidelobes in Meteorological Radar Data

Abstract

he use of pulse compression techniques to improve the sensitivity of meteorological radars has become increasingly common in recent years. An unavoidable side effect of such techniques is the formation of ?range sidelobes,? leading to the spreading of information across several range gates. These artifacts are particularly troublesome in regions where there is a sharp gradient in the power backscattered to the antenna as a function of range.In this article a simple method for identifying and correcting range sidelobe artifacts is presented. The method makes use of the fact that meteorological targets produce an echo that fluctuates at random, and that this echo, like a fingerprint, is unique to each range gate. By cross correlating the echo time series from pairs of gates, therefore, information that has spread from one gate into another can be identified, and hence regions of contamination can be flagged. In addition it is shown that the correlation coefficients contain quantitative information about the fraction of power leaked from one range gate to another, and a simple algorithm to correct the corrupted reflectivity profile is proposed.