* * *

Figure6.Sensorlocation(top)withcoherenceasafunctionofseparation at(0.044Hz)andfrequency(bottom).Notethedifferencebetweencoherenceassumedfor(a)paralleltowavefrontswithin5°azimuthrangeand(b) normaltowavefrontswithin0.01km/svelocityrange.