Weather Research & Forecasting: A General Overview

HPC Symposium 2014, IIT Madras

Tabish U AnsariMS – Environmental Engineering

Department of Civil Engineering, IIT Madras

The WRF Model• State of the art atmospheric simulation system- portable and

efficient on available parallel computing platforms• Broad range of applications across scales: Idealized

simulations (LES, baroclinic waves)• Parameterization research• Data Assimilation research• Forecast research/ Realtime NWP• Hurricane research• Regional climate research• Coupled model applications• Teaching

Components of the WRF modelling system

• The WRF preprocessing system• WRF-Var• ARW solver• Post-processing & vizualization tools

WPS

• Defining simulation domains• Interpolating terrestrial data (terrain, landuse,

soil categories etc.)• Degribbing and interpolating meteorological

data from another model to this simulation domain

WRF Solver• Several initialization programs for idealized and real data

simulations and the numerical integration program• Fully compressible non hydrostatic equations• Regional and global applications• Map projection terms• Arakawa C-grid staggering• Runge kutta 2nd and 3rd order time integration options• Scalar conserving flux form for prognostic variables• 2nd to 6th order advection options (horizontal and vertical)• Lateral boundary conditions• Full Physics options for Land surface, PBL, radiation,

microphysics and cumulus convection• A single layer ocean mixed model

Post Processing

Supported combinations of hardware and software

The WRF model may be built to run on:• A single-processor machine• A shared-memory machine (that uses the

OpenMP API)• A distributed memory machine (with the

appropriate MPI libraries), or on a distributed cluster (utilizing both OpenMP and MPI)

• The WRFDA and WPS packages run on the above-listed systems

Required compilers and scripting languages

• The majority of the WRF model, WPS, and WRFDA codes are written in Fortran90

• The software layer, RSL, which sits between WRF and WRFDA, and the MPI interface is written in C

• WPS makes direct calls to the MPI libraries for distributed memory message passing

• There are also ancillary programs that are written in C to perform file parsing and file construction, which are required for default building of the WRF modeling code

• Additionally, the WRF build mechanism uses several scripting languages: including perl, Cshell and Bourne shell

• The traditional UNIX text/file processing utilities are used: make, m4, sed, and awk

It’s free, check it out today!

http://www.mmm.ucar.edu/wrf/users/downloads.html