Abstract
Original language  English 

Qualification  Doctor Degree 
Awarding Institution 

Supervisors/Advisors 

Award date  3 Jan 2014 
Place of Publication  Espoo 
Publisher  
Print ISBNs  9789513881092 
Electronic ISBNs  9789513881108 
Publication status  Published  2013 
MoE publication type  G4 Doctoral dissertation (monograph) 
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Keywords
 acoustic wave propagation
 aeroacoustics
 atmospheric acoustics
 environmental acoustics
 environmental noise
 noise assessments
 uncertainty
 statistical model
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A measurementbased statistical model to evaluate uncertainty in longrange noise assessments : Dissertation. / Maijala, Panu.
Espoo : VTT Technical Research Centre of Finland, 2013. 196 p.Research output: Thesis › Dissertation › Monograph
TY  THES
T1  A measurementbased statistical model to evaluate uncertainty in longrange noise assessments
T2  Dissertation
AU  Maijala, Panu
PY  2013
Y1  2013
N2  Carefully validated longrange sound propagation measurements with extensive meteorological instrumentation were continued for 612 days without interruption, around the clock, resulting in a database with millions of files, terabytes of sound and environmental data, and hundreds of pages of documentation. More than 100 environmental variables were analysed by statistical means, and many statistically highly significant dependencies linked to excess attenuation were found. At a distance of 3 km from the source, excess attenuation was spread over a dynamic range of 80 dB, with differences of 10 dB between individual quarters of the year; also, negative excess attenuation at frequencies below 400 Hz existed. The low frequencies were affected mainly by the stability characteristics of the atmosphere and the lapse rate. Humidity; lapse rate; sensible heat flux; and longitudinal, transverse, and vertical turbulence intensities explain excess attenuation at higher frequencies to a statistically highly significant extent. Through application of a wide range of regression analyses, a set of criteria for frequencydependent uncertainty in sound propagation was created. These criteria were incorporated into a software module, which, together with a stateoftheart physical sound propagation calculation module, makes it possible to perform environmental noise assessments with known uncertainty. This approach can be applied to the shortterm measurements too and it was shown that some of the most complex meteorological variables, among them atmospheric turbulence, can be taken into account. Comparison with two standardised noise modelling methods showed that the statistical model covers well a range of uncertainty notmatched with the standardisedmethods and themeasured excess attenuation fit within the limits of predicted uncertainty.
AB  Carefully validated longrange sound propagation measurements with extensive meteorological instrumentation were continued for 612 days without interruption, around the clock, resulting in a database with millions of files, terabytes of sound and environmental data, and hundreds of pages of documentation. More than 100 environmental variables were analysed by statistical means, and many statistically highly significant dependencies linked to excess attenuation were found. At a distance of 3 km from the source, excess attenuation was spread over a dynamic range of 80 dB, with differences of 10 dB between individual quarters of the year; also, negative excess attenuation at frequencies below 400 Hz existed. The low frequencies were affected mainly by the stability characteristics of the atmosphere and the lapse rate. Humidity; lapse rate; sensible heat flux; and longitudinal, transverse, and vertical turbulence intensities explain excess attenuation at higher frequencies to a statistically highly significant extent. Through application of a wide range of regression analyses, a set of criteria for frequencydependent uncertainty in sound propagation was created. These criteria were incorporated into a software module, which, together with a stateoftheart physical sound propagation calculation module, makes it possible to perform environmental noise assessments with known uncertainty. This approach can be applied to the shortterm measurements too and it was shown that some of the most complex meteorological variables, among them atmospheric turbulence, can be taken into account. Comparison with two standardised noise modelling methods showed that the statistical model covers well a range of uncertainty notmatched with the standardisedmethods and themeasured excess attenuation fit within the limits of predicted uncertainty.
KW  acoustic wave propagation
KW  aeroacoustics
KW  atmospheric acoustics
KW  environmental acoustics
KW  environmental noise
KW  noise assessments
KW  uncertainty
KW  statistical model
M3  Dissertation
SN  9789513881092
T3  VTT Science
PB  VTT Technical Research Centre of Finland
CY  Espoo
ER 