A Canadian precipitation analysis (CaPA) project: Description and preliminary results

Abstract

A Canadian Precipitation Analysis (CaPA) project for producing 6 h rainfall accumulations at a resolution of 15 km over North America in real-time is described. The spatial interpolation technique is based on statistical interpolation using short-range precipitation forecasts from the Canadian Meteorological Centre's (CMC) regional model as the background field with rain-gauge measurements from the surface network and radar derived rain rates as observations. A pilot study was undertaken over the province of Québec at a resolution of 10 km using additional rain-gauge observations from a cooperative network for August 2003. This test period allowed the development of methodologies for an objective estimation of background and observation error statistics and for improving the overall quality of rain-gauge and radar data. The improved skill of the analysis with respect to the model short-range forecasts is assessed against radar precipitation. The use of additional rain gauges from the surface cooperative network in Québec significantly increased the quality of the resulting analysis. © 2007 Taylor & Francis Group, LLC.