Single-Doppler Radar Analysis of Banded Precipitation Structures

Abstract

A method for the analysis of single-Doppler radar data called band-velocity-processing (BVP) is presented. The BVP method was designed to exploit the two-dimensional nature of banded precipitation systems with crossband length scales of 5?50 km. The BVP method offers improved horizontal (crossband) resolution over existing volume scan methods (VAD/VVP), plus the ability to extract band-perpendicular vertical cross sections from a single volume scan. The BVP analysis yields a more complete kinematic structure than RHI analyses, providing estimates for both horizontal wind components, both horizontal divergence components, the shearing deformation, and the vertical shear vector. The bias and variance errors for the BVP method are shown to be acceptably small. The application of the BVP method to a narrow cold frontal rainband reveals several important kinematic features. The mesoscale structure of the low-level jet ahead of the narrow cold frontal rainband is examined. The band relative flow field exhibits a closed helical circulation cell at the front of the band.