Near-Field Measurements Versus Far-Field Estimations of Air Gun Array Sound Pressure Levels

Comparison of Sound Pressure Levels (SPL) estimated from modeled far-field air gun array signatures versus measurements from near-field hydrophones.

The near-field hydrophone SPL measurements are significantly lower than predicted by far-field signature simulations.

Since survey permits usually require an estimate of SPL for the indicated air gun array, the near-field measured values should be used instead of the far-field predictions.