Introduction

The WRF ARW model is a fully compressible, nonhydrostatic model (with a hydrostatic option). Its vertical coordinate is a terrain-following hydrostatic pressure coordinate. The grid staggering is the Arakawa C-grid. The model uses higher order numerics. This includes the Runge-Kutta 2nd and 3rd order time integration schemes, and 2nd to 6th order advection schemes in both horizontal and vertical directions. It uses a time-split small step for acoustic and gravity-wave modes. The dynamics conserves scalar variables.

The WRF ARW model code contains several initialization programs (ideal.exe and real.exe), a numerical integration program (wrf.exe), and a program to do one-way nesting (ndown.exe). The WRF ARW model Version 2 supports a variety of capabilities. These include:

- Real-data and idealized simulations
- Various lateral boundary condition options for both real-data and idealized simulations
- Full physics options
- Non-hydrostatic and hydrostatic (runtime option)
- One-way, two-way nesting and moving nest
- Applications ranging from meters to thousands of kilometers

 

Software requirements

- Fortran 90 or 95 and c compiler
- perl 5.04 or better
- If MPI and OpenMP compilation is desired, it requires MPI or OpenMP libraries
- WRF I/O API supports netCDF, PHD5, GriB 1 and GriB 2 formats, hence one of these libraries needs to be available on the computer where you compile and run WRF

Program Flow

• If you are only planning on running Idealized Cases, you would need:

WRF-ARW Model + PostProcessing

• If you are planning on running Real Cases, you would need:

WPS + WRF-ARW Model + PostProcessing

• If you are planning on running Real Cases with Variational Analysis, you would need:

WPS + WRF-Var + WRF-ARW Model + PostProcessing
If you plan on using WRF-Var, be sure to reference Chapter 6 in the WRF-ARW User's Guide, once you have familiarize yourself with the basic WRF ARW Model.

View the flowchart to see how the programs interact.

Documentation

Users' Guide
The OnLine Tutorial is complementary to the Users' Guide. The latest WRF and WPS code are described in this document. The Users' Guide is updated for every Bi-Annual Tutorial, and is therefore the most up-to-date guide for running the WRF ARW model. It is highly recommended to download this guide before you start running the model.

WRF ARW Technical Note
This document contain:
- Descriptions of ARW model equations, discretization, initialization, and nesting
- General description of physics options available in the model
- General description of the WRF-Var

Bi-Annual Tutorial Presentations
All the slide shows presented at the last Bi-Annual Tutorial Class

WRF-Var
Refer to Chapter 6 in the WRF-Arw User's Guide.

Also browsers the WRF ARW Users Pages for more information and documentation.

Getting Started