Unified Post Processor (UPP) | System Architecture

Unified Post Processor Description 

UPP interpolates output from the model's native grids to National Weather Service (NWS) standard levels (pressure, height, etc.) and standard output grids (AWIPS, Lambert Conformal, polar-stereographic, etc.) in NWS and World Meteorological Organization (WMO) GRIB2 format. There is also an option to output fields on the model's native vertical levels. 


  • Produces products like those used operationally on the same operational grids
  • Can read and process GFS and LAM (Limited Area Model) data from FV3 dynamical core
  • Generates output in GRIB2 format
  • Enables product generation on any user define grid
  • MPI parallel code
  • Produces hundreds of products such as:
    • T, Z, humidity, wind, cloud water, cloud ice, rain, and snow on isobaric levels
    • SLP + shelter level T, humidity, and wind fields
    • Precipitation-related fields
    • PBL-related fields
    • Diagnostic products (i.e. RH, CAPE, Vorticity)
    • Radiative/Surface fluxes
    • Cloud related fields
    • Aviation products
    • Satellite look-alike products

Synthetic Satellite Products

UPP incorporates the Joint Center for Satellite Data Assimilation (JCSDA) Community Radiative Transfer Model (CRTM) to compute model derived brightness temperature (TB) for various instruments and channels. This additional feature enables the generation of simulated satellite products such as:

  • Geostationary Operational Environmental Satellite (GOES)
  • Advanced Microwave Scanning Radiometer (AMSRE)
  • Special Sensor Microwave Imager/Sounder (SSMIS)
  • Special Sensor Microwave Imager (SSMI)
  • Multi-functional Transport Satellite (MTSAT2 and MTSAT1R)
  • Spinning Enhanced Visible and Infrared Imager (SEVIRI)
  • Indian Satellite Image (INSAT3D)

For CRTM documentation, refer to CRTM User Guide


The basic components of the UPP are shown in the schematic below.  

UPP Schematic


This component performs the bulk of the post processing. Its functions include:

  • Vertical interpolation from model levels/surfaces to isobaric, height, and other levels/surfaces
  • Computing diagnostics from model data such as CAPE, relative humidity, radar reflectivities, etc.