WORKING GROUP 5: MODEL PHYSICS
Take me to the
WRF WG5 Forum.
Table of Contents
John M. Brown (lead)
NOAA/Forecast Systems Laboratory
NOAA/Environmental Technology Laboratory
NOAA/NCEP/Environmental Modelling Center
University of California at Davis and
Air Force Weather Agency
NCAR/Mesoscale and Microscale Meteorology Division
Yonsei University, Seoul, Korea and
NOAA/NCEP/Environmental Modeling Center
Illinois State Water Survey
Department of Natural Resources and University of Illinois at Urbana-Champaign
Pennsylvania State University
NASA/Goddard Space Flight Center/Laboratory for Atmospheres
OU/Center for the Analysis and Prediction of Storms
1. Incorporate physics packages into WRF.
Specific tasks include
2. Understand strengths, weaknesses and limitations of individual physics
selection of physics packages for WRF
design of physics modules and their interface
coding physics packages or porting them from
testing physics modules in WRF framework.
packages as well as their coupling and feedbacks.
3. Make recommendations regarding the configuration of physics
suites to be tested in idealized simulations and
in real-data simulations and
4. Encourage development of new schemes or improvements (accuracy,
consistency, efficiency) to existing physics schemes
for application in WRF.
We define model physics as code describing
those processes (Table 5.1) not
explicitly included in the basic dynamical
and thermodynamical equations
describing the earth's atmosphere. These
processes are either too complicated
to be explicitly included in the model
based on their most fundamental physics
laws (e.g. radiation and microphysics),
or finer in scale than can be
adequately represented by realizable grid
resolutions (sub-grid scale
turbulence, PBL transport). Yet,
their effects on the resolvable scale flows
and on the sensible weather (e.g., precipitation
amount) have to be properly
included for a model to accurately predict
for NWP purposes. Simplifications
are typically made and
variables (parameters) on the resolvable
scales are often used in treating
these processes; the resulting schemes
are usually referred to as physics
Table 5.1 Physical processes to be incorporated into WRF.
|Generation of PBL turbulence and related
transports (including non-local effects but essentially dry surface-based
|Surface-atmosphere exchanges (momentum,
heat,moisture, might eventually include other quantities, either land or
water surfaces) including dependencies on surface and subsurface processes.
|Generation of subgrid-scale turbulence
and related transports above the PBL (resulting in primarily local diffusion)
|Convection (non-local fluxes aided by
condensation, including "shallow" convection)
|Radiation (short and long wave, atmospheric
and surface effects)
|Cloud and precipitation physics
(local processes including fallout)
We have currently implemented and are testing the options listed below in table 5.2.
The schemes in the column "In" have already been implemented into the WRF model. The schemes in the "Under Development" column are being worked on currently. This table has been updated for release 2.0 in May 2004.
Table 5.2 WRF Version 2.0 Physics Options and Packages
- Lin (Purdue)
- WSM3 simple ice
- WSM5 mixed-phase
- Eta (Ferrier)
- WSM6 graupel
- Goddard microphysics (Tao et al.)
- Reisner graupel
- Kain-Fritsch (new)
- Grell ensemble
- Dudhia short wave
- GFDL (Eta)
- MM5 Similarity theory
- Janjic (Eta)
- 5-layer soil temperature
- Noah LSM
- RUC LSM
- Yonsei (YSU)
||Subgrid eddy diffusion
- Constant diffusion
- Stress/deformation form (with TKE)
- Stress/deformation form (Smagorinsky)
- Horizontal Smagorinsky (mesoscale)
Continue to evaluate physics performance in real-time WRF forecasts.
Continue to work on adding options for
WRF Research Version release.
Test physics in idealized settings.
Select and test physics suites in NWP testbed periods.
Finalize physics modules for Research Version release.
Design method to handle contributed physics modules within WRF.
Interaction with other
WRF Working Groups:
Dynamic Model Numerics Working Group: Interface
of physics with dynamical solver (vertical coordinates, basic variables,
Software Architecture, Standards, & Implementation
Working Group: Physics coding standards (array and loop ordering, special
variables and constants, subroutine interfaces).
Standard Initialization Procedures Working
Group: Use of real data input for NWP tests.
3D-VAR Data Assimilation System Working Group:
4D-VAR Data Assimilation System Working Group:
Adjoint codes for physics.
Post Processing Working Group: Model output
fields and visualization.
Model Testing & Verification Working Group:
Design tests of physics, use verification to identify areas for improvement.
Web Site, Workshops, and Model Support Working
Group: Interact with outside institutions to add other physics options.
Operational Implementation Working Group:
Selection of physics, optimization issues.