Wind noise under a pine tree canopy

Area of Science:

• Acoustics
• Environmental Science
• Meteorology

Background:

• Infrasonic wind noise levels are significantly lower in vegetated areas compared to open spaces.
• Understanding wind noise within forests is crucial for various applications, including environmental monitoring and acoustic studies.

Purpose of the Study:

• To measure and analyze infrasonic wind noise levels, turbulence spectra, and wind velocity profiles within a pine forest.
• To develop a predictive model for wind noise spectra in forests based on meteorological parameters.
• To compare predicted wind noise spectra with measured data to validate the model.

Main Methods:

• Field measurements of wind noise, turbulence, and wind velocity were conducted in a pine forest.
• A predictive model for wind noise spectra was developed, integrating turbulence-shear and turbulence-turbulence interactions.
• The model was validated by comparing its predictions against four sets of measured data.

Main Results:

• The wind noise spectrum in the forest comprises low-frequency noise from turbulence-shear interaction above the trees and high-frequency noise from turbulence-turbulence interaction within the canopy.
• Convection velocity of low-frequency noise matched the wind speed above the trees.
• High-frequency noise was found to be near-stationary, generated by slow-moving turbulence near the ground.
• The predictive model demonstrated good agreement with the measured wind noise spectra.

Conclusions:

• The developed model accurately predicts wind noise spectra in pine forests.
• The findings contribute to a better understanding of acoustic propagation within forested environments.
• The prediction method can be utilized for meteorological estimates to forecast wind noise levels under similar forest conditions.