Aircraft Noise Propagation over Water

1
Aircraft Noise Propagation over Water

• by
• Micah Downing
• Wyle Laboratories, Inc.
• International Military Noise Conference
• Baltimore, MD
• 24-26 April 2001

2
Background

• NATO CCMS Working Group
• topography effects on noise propagation
• new algorithms developed
• water surface acoustically hard
• NoiseMap airfield noise exposure model
• Verison 6 flat earth grassy ground cover
• Version 7 topography effects

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Noise Propagation over Water
hard
soft
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Atmospheric Effects
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Noise Propagation over Water

• Objective Determine influence of surface water
  on long-term noise exposures near airfields
• Initial Study
• Long-term monitoring
• NAS Jacksonville
• NAS North Island
• Compare with NoiseMap 6.5 algorithms

6
Data Comparison

• Measured data
• Hourly Leq
• SEL based on exceedance events
• Radar tracking data
• FAA air traffic control
• gt20 of flights
• Low resolution
• Calculated data
• SEL based on Closest Point of Approach
• Omega10 algorithms (NOISEMAP 6.5)
• Difference between Measured and Calculated SEL

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NAS Jacksonville

• Primary Aircraft P-3C
• Arrivals and Departures directly over St. Johns
  River
• Dates on Monitoring November 1996 to March 1997
• Larson Davis LD820 Sound Level Meters
• Limited radar tracking data
• 3 weeks only
• Floor of 1,000 feet AGL

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(No Transcript)
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NAS Jacksonville P-3C Runway 9 Departures
38
68
71
29
18
97
14
data inclusion
10
NAS Jacksonville P-3C Runway 27 Arrivals
data inclusion
11
NAS Jacksonville Other Runway 27 Arrivals
data inclusion
65
33
31
56
46
77
44
15
12
NAS Jacksonville Time of Day
13
NAS North Island

• Primary Aircraft S-3 Viking
• Arrivals and Departures directly over San Diego
  Bay
• Dates on Monitoring May to September 1997
• Larson Davis LD820 Sound Level Meters
• Limited radar tracking data
• 6 weeks only
• Large scatter near airfield

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(No Transcript)
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NAS North Island Runway 18 Departures
data inclusion
8
2
16
NAS North Island Runway 29 Arrivals
data inclusion
61
94
87
10
10
17
NAS North Island Runway 29 Departures
data inclusion
5
42
92
92
22
18
NAS North Island Time of Day
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Summary Findings

• Effect of over water propagation effect observed
• Received noise levels enhanced
• Water surface as hard is good first
  approximation
• Data insufficient to quantify effect
• Lack of resolution on aircraft tracking data
• Aircraft performance variations
• Atmospheric effects

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Follow-on Study

• Summer 2001
• Higher resolution tracking data
• Detailed weather data
• 1/3 octave band recordings
• Compare with NoiseMap 7 propagation algorithms
• Goal Quantify and validate new algorithms