Practical calculation methods for ground noise correction factors in airport noise prediction model

This paper describes the results of a study to improve the calculation method for predicting aircraft noise around Japanese airports using our prediction model. The model limited the calculation frequency for the insertion loss caused by noise barriers and buildings to a single 250 Hz, which does not reflect the actual frequency spectrum of aircraft. Therefore, to simulate more realistic conditions, we calculated a synthetic attenuation chart from the frequency spectra of several representative aircraft models and included the chart in our model. We then compared the calculated values with the measured values to verify the validity and discussed the influence of this change on the airport noise contours. In addition, for noise propagation of engines and auxiliary power units on the ground, an improved calculation formula for ground surface attenuation, taking into account the ground condition, has already been reported. In this paper, we report on the implementation of this calculation formula in our model and discussion of the calculation results.