The IDL procedure pr_and_geo_match_x_sections.pro provides the capability to interactively select locations for, and display, vertical cross sections of PR and GV reflectivity from geometry-matched data produced by the GPM Validation Network prototype. These data are contained in a set of netCDF data files, one per “rainy” site overpass (a TRMM PR overpass of a GV radar site, with precipitation echoes present). By default, the procedure also displays a vertical cross section of the difference (PR-GV) between the PR and GV reflectivity from the geo-matched data. By default, the cross sections are along the PR cross-track scan line through the point selected by the user (i.e., perpendicular to the orbit track). Random cross section alignments are not supported.

The procedure has a feature allowing a calibration offset to be applied to the GV reflectivity data. If a GV site or GV data for a particular event is known to have an error in calibration relative to the PR, the calibration of the GV reflectivity data may be adjusted up or down in 1 dBZ increments on the currently displayed cross sections, so that the relative vertical structures of the PR and GV reflectivity fields can be evaluated with the calibration bias removed.