WRF Details

WRF Details

In this page are listed some details regarding how the British Isles/Scotland WRF (Weather Research and Forecast) Model is structured to operate.

The raw data, in the format of GFS (Global Forecast System) 0.25° grib2 files, is acquired by the NOMADS NOAA Server, which delivers national and global weather, water, climate and space weather guidance, forecasts, warnings and analyses to its Partners and External User Communities.

The horizontal resolution of the raw grib2 files is approximately of 27.75 km (17.24 mi), and the WRF elaboration enhances it for the following domains:

  • British Isles 9 km (5.59 mi) – Available here – 1350×1350 km (839×839 mi) nest
  • Scotland 3 km (1.86 mi) – Available here – 730×730 km (454×454 mi) nest

with a timestep of 60 minutes (1 hour). An example of the final output product is given below:


The elaboration process greatly increases the capability of the weather forecast model to capture local phenomena and details, often generated by geographic features of the terrain, like orography (rain shadows, foehn wind effects, local sea influence, etc.).

Following, a list of the operational parameters:

  • WPS 4.2 alongside WRF 4.2.2
  • Vertical Levels: 60
  • TimeStep: 60 seconds
  • Geographic resolution: 30 arcseconds
  • Daily elaborations: 2 – runs 00z and 12z
  • Total Forecast Run timeframe: 72 h (3 days)
  • Applied Mycrophisics Parametrisation: Eta (Ferrier) Scheme – Goddard Scheme (in test)
  • Longwave Radiation: RRTM Scheme
  • Shortwave Radiation: Dudhia Scheme
  • Land Surface Option: Unified Noah Land Model
  • Surface Layer Option: Revised MM5 Scheme
  • Cumulus Parametrisation: Kain-Fritsch Scheme
  • Post-Processing: NCL-NCAR 6.6.2
  • Elaboration is cron-automated on a Linux (Ubuntu) based infrastructure

The source code for the WRF Model can be found here:

With a User Guide here: https://github.com/wrf-model/Users_Guide

 

The WRF Model setup and parameterisation are objects of continuous research and study. Over time, more detailed charts will be added, covering more weather variables, and the parameters will be constantly monitored and adjusted to better reflect actual weather conditions.

Giuseppe Petricca

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