Our glossary contains frequently used terms and acronyms together with their explanations.


NIROS simulates the departure of aircraft that use a flight management system (FMS) on a standard departure route. The speeds in individual flight phases are used to calculate how much time the aircraft requires to cross a certain spot on the ground. This information is then used to calculate the duration of the noise at this spot. When calculating sound transmission and the resulting noise immission level, variable atmospheric phenomena may also be considered.

The noise immissions calculated by NIROS (equivalent continuous sound level, or Leq for short) are later weighted against the population density of the surface that the aircraft flies over. This leads to a noise exposure parameter for each surface element. The surface elements or raster cells have a size of 100 x 100 m. The integration of the noise exposure parameters results in a nuisance factor for the entire area considered, known as the nuisance indicator.

Results of the noise exposure modelling
Each NIROS calculation results in a nuisance indicator and three maps:

  • Distribution of population
  • Distribution of sound levels
  • Distribution of weighting (distribution of noise exposure parameters)

For more detailed analyses, it is also possible to print the NIROS results on topographic maps.