Use of intensimetric techniques for measurements of airport noise

In aeroportual surroundings a challenging issue is the determination of whether the noise level measured at the receptors is generated by airplanes, by ground services or other sources. The indication given by any quantity derived from sound pressure is not helpful for this task; this paper addresses and discusses the use of sound intensity for the source separation problem. An innovative 3D sound intensity probe has been installed on a tall pylon near Malpensa airport, at 500 meters from the runaway. The 3D probe is located in a strategic position in order to identify the macro noise sources that influence the noise exposure at the measurement point. The experimental site is surrounded by the airport terminal, the runway, major and minor roads and a helicopter school. The sound reaches the measurement point with different directions, depending on the noise source that has generated it. Results of the experimental campaign show that the use of sound intensity allows a simple classification of sound sources on the basis of the direction of the intensity vector. The use of the 3D sound intensity measurement leads to noteworthy advantages in the identification of the noise sources in aeroportual environment.