Nowcasting of motion and growth of precipitation with radar over a complex orography

Abstract

Motion vectors of radar echo patterns can be obtained by applying a cross-correlation method (eg, the TREC method) to radar data collected several minutes apart. Here an extension of TREC, called COTREC, is presented. Based on constraints and a variational technique, this extension is an efficient objective analysis method for smoothing the motion vectors and forcing them to fulfill the continuity equation. COTREC corrects the apparently wrong vectors that are often caused by failures of TREC. This allows us to identify regions of growth and decay of radar echoes. For different types of precipitation (convective and widespread), radar data were collected for evaluation of COTREC in complex orography. A comparison between the radial velocity components of retrieved fields of echo motion and the measured Doppler velocity has been made. -from Authors