Canadian Precipitation Analysis System (CaPA)

Overview

The Canadian Precipitation Analysis System (CaPA) produces a best estimate of 6 and 24h precipitation amounts. This objective estimate integrates data from precipitation gauge measurements, radar precipitation estimates (QPE's) and a trial field generated by a numerical weather prediction system. Currently there are deterministic and ensemble configurations of CaPA systems.

Deterministic Analyses

CaPA 'deterministic' produces four analyses of 6 hour amounts valid at synoptic hours (00, 06, 12 and 18 UTC) and two 24 hour analyses valid at 00 and 12 UTC. A preliminary production is started 1 hour after valid time and a final one is launched 6 hours later. There are two deterministic versions of the analysis:

• Regional Deterministic Precipitation Analysis (RDPA)
• High Resolution Deterministic Precipitation Analysis (HRDPA)

Ensemble Analyses

CaPA ‘ensemble’ produces four sets of analyses of 6 hour amounts per day valid at synoptic hours (00, 06, 12 and 18 UTC). The production is started 1 hour after valid time and each set of analyses contains 24 members plus the control member. Currently, there is only one version of this system running at high resolution:

• High Resolution Ensemble Precipitation Analysis (HREPA)