The Weather Research Forecast (WRF) model is the default meteorological driver for EMEP4UK. It is a numerical weather prediction system that generates atmospheric simulations based on real data. The WRF model can be downloaded from here, along with information on running the model. The initial boundary conditions for the parent (European) domain of the WRF model were determined by the NCEP FNL (Final) Operational Global Analysis data.

The model is applied using a one-way nested domain approach with the same horizontal and vertical resolution domains that are desired in EMEP4UK. The WRF model output consists of a 3-hourly (resolution only limited by available disk space) instantaneous value.

A summary of the main physical schemes used specifically for EMEP4UK is shown below.

  • Microphysics: Lin Purdue
  • Cumulus Parameterisation: Grell-3
  • Radiation Physics: Goddard Chou and Suarez
  • PBL Physics: YSU
  • Nudging: Re-analysis nudged for wind, temperature (and specific humidity 2001-2012)

The WRF model runs from the year 2013 up to the most recent year do not include specific humidity nudging. Recent studies had found that nudging the specific humidity led to a substantial underestimation of surface rainfall. The surface rainfall for the year 2001-2012, which included specific humidity nudging, has been normalised to match the UK annual average for each year to avoid bias in rainfall affecting wet deposition results.