Weather Research & Forecasting Model (WRF)

Stacey Pensgen

ESC 452 – Spring ’06

WRF Outline

What is it?

Timeline

The Technical Aspect

Future Work

Conclusion

What is it?

Project to develop a “next generation” mesoscale forecast model that will enhance the understanding and prediction of mesoscale systems.

Collaborative effort between– NCAR (National Center for Atmospheric Research)– NCEP (National Centers for Environmental Prediction)– FSL (Forecast Systems Laboratory)– NOAA (National Oceanic & Atmospheric Administration)– AFWA (Air Force Weather Agency)– Other institutions & organizations

What is it?

Promote closer ties and a common framework between the research and operational forecasting communities.

Will also be used in research and operational applications.

Besides forecasting work, WRF is also intended for regional climate predictions, air quality simulations, and idealized dynamical studies.

What is it?

Goal is to (based on it’s evaluations) eventually replace existing models, such as the Mesoscale Model (MM5) at NCAR, ETA at NCEP, and RUC at FSL.

Targeted for a 1-10 km grid scale.

Improved physics, especially for treatment & diagnosing convection and mesoscale precipitation.

Timeline

1st release (WRF 1.0) was November 30, 2000

Full implementation as a research model by the end of 2002.

Full implementation as an operational forecasting model at NCEP and AFWA by the end of 2004

Operational performance refinement from 2005-2008.

http://www.srh.noaa.gov/ssd/presentations/Bernard/MICsHICs/slide8.html

WRF compared to ETA, MM5, and actual observations.

http://www.mmm.ucar.edu/wrf/users/workshops/WS2005/abstracts/Session1/4-Novak.pdf

Technical Aspect

WRF is intended to be compatible – physics packages can be easily exchanged with other models.

WRF 1.0 prototype uses geometric height as vertical coordinate, but prototype also available that uses hydrostatic pressure as vertical coordinate.

Programming language: Fortran90!

Technical Aspect

Included physics package plug-ins:– Microphysics– Boundary Layer– Surface Layer– Ground Layer– Subgrid 3D Turbulence/Diffusion– Cumulus Parameterization– Radiation (shortwave & longwave)

Future Plans

Working to add other more advanced physical parameters:– Land surface processes– Baroclinic waves– Squall lines– Supercell thunderstorms

Future Plans

Development work on 3DVAR system - a joint effort by all working on WRF to improve initialization using multiple observation techniques, including satellite (in addition to traditional synoptic forms).

Conclusion

WRF Model is important because:– Provides a more advanced forecasting model for

mesoscale precipitation events.– Promotes closer ties between research &

forecasting fields.– Easily compatible with a variety of computing

architectures.– Intended for a wide range of applications.

References

http://www.mmm.ucar.edu/mm5/mpp/ecmwf01.htm

http://www-unix.mcs.anl.gov/~michalak/ecmwf98/final.html

http://www.mmm.ucar.edu/individual/skamarock/meso2001pp_wcs.pdf