Highline-Forum-191120-Shepherd GROUND Noise Study

• Sound level decreases by 6 dB per doubling of distance • Additional losses due to atmospheric absorption  Ground Effect • Sound levels are lower when reflected off of soft ground vs. hard ground Sound Propagation  Refraction due to Temperature • Gradients in temperature cause the bending of sound paths • Sound bends upward during a temperature lapse (cool air over warm) • Sound bends downward during a temperature inversion (warm air over cool) Sound Propagation  Refraction due to Wind • Gradients in wind speed cause the bending of sound paths • Sound bends upward causing sound shadows in the upwind direction • Sound bends downward increasing sound levels in the downwind direction • Differences between upwind and downwind directions can be 20 dB Ground Noise Study Scope  Ground Noise Data Research • Meet with StART • Identify ground noise sources and locations • Identify atmospheric conditions that may increase ground noise  Noise Monitoring • Obtain and analyze data from permanent monitors • Collect and analyze additional temporary noise monitoring data  Identify Mitigation Options • Present findings on ground noise sources and levels and solicit input on mitigation measures • May include changes in aircraft operating procedures or utilization of new or existing structures to reduce community noise exposure  Report Project Results Aircraft Ground Noise Sources Discussion  Taxi/Idle  Auxiliary Power Units (APUs)  Engine Maintenance Run-ups  Ground Service Equipment  Reverse Thrust Noise Monitoring Discussion  Locations  Times of…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]