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A collaborative test bed where NWP research and operational communities interactto test and evaluate models and other numerical techniques and systems in order to accelerate transfer of these technologies to operational users, and to test research models and techniques used as tools to provide a better scientific understanding of atmospheric physical processes

Bob Gall


Fundamental Purpose of DTC

  • To serve as a bridge between research and operations to facilitate the activities of both halves of the NWP Community in pursuit of their own objectives:
    • Research community gets a functionally equivalent operational environment to test and evaluate new NWP methods in retrospective extended period tests using advanced tools
    • Operational community benefits from DTC testing and evaluation of strengths and weaknesses of new NWP advances prior to consideration for operational implementation


Operational Codes

  • Link Research and Operational Communities
  • Speed transition of research results into operations
  • Accelerate improvement in weather forecasts
  • Evaluate and test promising new NWP techniques
  • Provide an opportunity for NWP community to perform cycled or real-time tests of model and data assimilation systems
dtc will
DTC Will:
  • Provide for a rapid and direct transfer of new NWP research results into operational forecasting
  • Evaluate strengths and weaknesses of new methods and models for NWP prior to consideration for operational implementation
  • Evaluate strengths and weaknesses of current operational systems
Evaluate codes from the community (universities, agencies, private sector) for inclusion in the WRF Contributed and Reference Codes
  • Maintain the WRF Reference Codes for use by the community
  • Maintain an archive of observations and model results
what is wrf
What is WRF
  • It is a process by which the NWP community can work together and leverage each other’s efforts to accelerate the rate at which NWP is improved
  • This is facilitated by:
    • A system of codes developed, tested and maintained by the NWP research and operational community
    • A facility where cycled and real-time testing can conducted by both the research and operational communities in a way that doesn’t interfere with operations.
the wrf community
The WRF Community
  • Research
    • Conceive and develop new NWP concepts, techniques, and systems
    • Evaluate performance of current operational systems
    • Develop and maintain the Contributed Code system
    • Use of the WRF system for basic research
  • Testbed Centers
    • Provide a facility to link the research and operations communities
    • Maintain the Reference Code
  • Operations
    • Evaluate, choose and maintain the operational codes
    • Prepare NWP guidance from the operational models
dtc concept
DTC Concept

Evaluation of Contributed Code for Reference Status

Development and Maintenance of Contributed Code

Evaluation of Reference Code for Operations

Performing Studies with Reference System

Research Model Development & Evaluation

Pre-implementation Testing


Testing New NWP Concepts

Testing New Techniques in the DTC Environment

Maintenance of Operational Codes

Maintenance of Reference Codes






Capabilities will be expanded over the coming years to incorporate new techniques

WRF DTC End-to-End System


NCL scripts








Post Processing


WRF Model


NCEP sfc & upper air





dtc visitor program
DTC Visitor Program
  • New Announcement of Opportunity each year (late Winter – early Spring)
  • Solicit proposals for projects directed at assessing where current NWP technology is deficient or testing of new NWP technologies likely to impact w/in the next 5 years
  • Funding for up to 1 month salary, travel, and per diem
  • Access to DTC computational resources
  • Proposals reviewed by DTC Advisory Board
dtc accomplishments apr 2003 oct 2004
DTC Accomplishments Apr 2003 - Oct 2004
  • NCEP, NCAR, and FSL worked with DTC staff to complete the basic WRF Reference Code (NCEP Nonhydrostatic Mesoscale Model (NMM) and NCAR Advanced Research WRF (ARW) version 1.3)
  • Ported NCEP Post and Verification codesand NMM model to FSL supercomputer and transferred them to NCAR and AFWA computers for use in the WRF Test Plan
  • NCEP and FSL adapted the Standard Initialization to be able to initialize WRF NMM model
  • Outcome of WRF Test Plan: WRF Initial Operating Capability

Impact of the WRF Test Plan on NCEP

  • DTC testing and evaluation demonstrated to NCEP that the 6 WRF members tested were qualified to run as an ensemble system
  • 21 Sept 2004: IOCimplemented with only 2 members (the two dynamical cores - ARW and NMM - without physics swapping)
  • 6 Dec 2005: Six WRF members added to NCEP Short-Range Ensemble Forecast (SREF) included physics swapping between the cores and 2 members from NCEP breeding system
  • New WRF-based SREF outperformed the current one in all ensemble aspects including mean, spread and probability distributions
dtc accomplishments since nov 2004
DTC Accomplishments since Nov 2004
  • Conducted DTC Winter Forecast Experiment (DWFE) and disseminated model products to NWS via web, FX-Net, and AWIPS
  • Added NCEP and FSL RTVS verification systems to the Reference Code supported by DTC
  • Released an announcement of opportunity for proposals initiating DTC visiting scientists program (10 of 33 funded)
  • Released NMM core code and documentation to the community and held NMM tutorials in Sep 2005, Feb 2006, & Aug 2006
  • 13-member Advisory Panel convened to help set DTC priorities
  • Completed WRF-Rapid Refresh “Core Tests”

DTC Winter Forecast Experiment

WRF DTC conducted a high-resolution NWP real-time forecast experiment during the 2005 winter season:

- 15 January – 31 March 2005 - Domain Size — CONUS

- Horizontal resolution — 5 km - Emphasis on the Eastern US

- 38 vertical levels - Forecast period – 48 hours

  • Both WRF cores - NWS & NCEP participation

*Respective physics packages




Three hour precipitation and SLP January 22-23, 2005


Verification Results



Confidence intervals (provided by Tressa Fowler) were an important extension to these standard verification measures. Also a great example of how the DTC can work with others in RAL to raise awareness of verification issues.

impact of dwfe on nws
Impact of DWFE on NWS
  • Provided valuable hands-on experience to forecasters with high-resolution (5-km) WRF model output over CONUS
  • Popular radar reflectivity product is now being used by NCEP
  • DWFE results indicating that high-resolution versions of the WRF model could be run without a cumulus parameterization helped NCEP decide to upgrade HRW domain 8-km NMM to 5.1 km and the 10-km ARW to 5.8 km on 28 June 2005
  • DTC demonstrated importance of statistical tests of significance when comparing resulting forecast skill from multiple models
  • NWS is developing a plan to transition FX-Net tool into operations

WRF-Rapid Refresh “Core Testing”

  • Key questions still remain:
    • What are the implications of choosing a single dynamic core for WRF?
    • Do the potential cost savings overcome the loss of model diversity for ensemble predictions?
  • Previous DTC experiments provided some idea of how the two WRF cores compare in terms of forecast skill, but the tests were not totally “clean”
  • – this requires each core to be run with the same physics package, initial and boundary conditions, horizontal and vertical resolution, & run over the same domain
  • This was done with the WRF-Rapid Refresh “core test”
    • WRF-RR is the first operational WRF model at NCEP for which the DTC performed such tests and evaluations prior to implementation
    • Never before has such a clean dynamic core test been performed
    • 2 tests completed: using NMM physics in both cores and RUC-like physics
    • 13-km WRF run to 24h even though RUC only extends to 12h

2-sigma = 95% CI

Red = Physics 1 = NMM set

Blue = Physics 2 = RUC-like set