The NCEP’s Climatology-Calibrated Precipitation Analysis (CCPA) Upgrade and Its New Products

Through extensive collaboration efforts, the NCEP Environmental Modeling Center has developed Climatology-Calibrated Precipitation Analysis (CCPA) products at high temporal and spatial resolutions for precipitation verification, calibration and downscaling. This primary 6-hourly analysis product utilizes linear regression and spatial and temporal downscaling techniques. It is generated by combining two widely used datasets by taking advantage of the higher reliability of the NCEP CPC Unified Global Daily Gauge Analysis and the higher temporal and spatial resolution of the NCEP EMC Stage IV multi-sensor quantitative precipitation estimations (QPEs). CCPA was first implemented into operations at the National Centers for Environmental Prediction Central Operations in July 2010 and experienced three upgrades afterwards. The product is available to users at six basic grids over the Contiguous United States (CONUS) with 1 hour, 3 hour and 6 hour accumulations from 2002 to present. At EMC CCPA provides a proxy of truth for the bias correction and statistical downscaling of precipitation forecasts from the NCEP GFS Ensemble Forecast System (GEFS) and Short Range Ensemble Forecast System (SREF) products, and precipitation verifications in evaluating the performance of various forecast systems. In recent years, CCPA application is also expanded to the National Blender Models (NBM) projects led by MDL, which applies CCPA as the best analysis for precipitation calibration.

Driven by users’ needs and feedback CCPA will be continuously improved and expanded. To support the National Blender Models (NBM) projects, an upgrade to the version 5 of CCPA (CCPAv5) is planned for further development. The upgrade includes: 1) updating the regression coefficients with extended historical training data sets from 2002 to 2019, which is the most important quality enhancement to CCPA; 2) expanding the CCPA domain to cover CONUS adjacent ocean areas; 3) merging 8km/30min CMORPH and gauge quality-controlled 1km/1hour Multi-Radar Multi-Sensor (MRMS) data into CCPA; 4) adding real-time data available/missing information products to allow users to better use of CCPA products. In this presentation, an overview of the CCPA upgrades and some preliminary results from recent development will be given.