Definition:  logarithm of the ratio of a given time integral of squared Afrequency weighted sound pressure, over a stated time interval or event such as an aircraft flyover, to the product of the squared reference sound pressure of 20 μPa and the reference duration of one second. Sound exposure level in decibels is ten times the logarithm to the base ten of that ratio. The reference
sound pressure and the frequency weighting may be different, if specifically stated with the sound exposure level
