ASTM D7145-22
(Guide)Standard Guide for Measurement of Atmospheric Wind and Turbulence Profiles by Acoustic Means
Standard Guide for Measurement of Atmospheric Wind and Turbulence Profiles by Acoustic Means
SIGNIFICANCE AND USE
5.1 Sodars have found wide applications for the remote measurement of wind and turbulence profiles in the atmosphere, particularly in the gap between meteorological towers and the lower range gates of wind profiling radars. The sodar’s far field acoustic power is also used for refractive index calculations and to estimate atmospheric stability, heat flux, and mixed layer depth (1-5).3 Sodars are useful for these purposes because of strong interaction between sound waves and the atmosphere’s thermal and velocity micro-structure that produce acoustic returns with substantial signal-to-noise ratios (SNR). The returned echoes are Doppler-shifted in frequency. This frequency shift, proportional to the radial velocity of the scattering surface, provides the basis for wind measurement. Advantages offered by sodar wind sounding technology include reasonably low procurement, operating, and maintenance costs, no emissions of eye-damaging light beams or electromagnetic radiation requiring frequency clearances, and adjustable frequencies and pulse lengths that can be used to optimize data quality at desired ranges and range resolutions. When properly sited and used with adequate sampling methods, sodars can provide continuous wind and turbulence profile information at height ranges from a few tens of meters to over a kilometer for typical averaging periods of 1 to 60 minutes.
SCOPE
1.1 This guide describes the application of acoustic remote sensing for measuring atmospheric wind and turbulence profiles. It includes a summary of the fundamentals of atmospheric sound detection and ranging (sodar), a description of the methodology and equipment used for sodar applications, factors to consider during site selection and equipment installation, and recommended procedures for acquiring valid and relevant data.
1.2 This guide applies principally to pulsed monostatic sodar techniques as applied to wind and turbulence measurement in the open atmosphere, although many of the definitions and principles are also applicable to bistatic configurations. This guide is not directly applicable to radio-acoustic sounding systems (RASS), or tomographic methods.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this guide.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D7145 −22
Standard Guide for
Measurement of Atmospheric Wind and Turbulence Profiles
1
by Acoustic Means
This standard is issued under the fixed designation D7145; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1356 Terminology Relating to Sampling and Analysis of
Atmospheres
1.1 This guide describes the application of acoustic remote
sensing for measuring atmospheric wind and turbulence pro-
3. Terminology
files.Itincludesasummaryofthefundamentalsofatmospheric
sound detection and ranging (sodar), a description of the
3.1 Definitions—Refer to Terminology D1356 for general
methodology and equipment used for sodar applications, fac-
terms and their definitions.
tors to consider during site selection and equipment
3.2 Definitions of Terms Specific to This Standard:
installation, and recommended procedures for acquiring valid
Note: The definitions below are presented in simplified,
and relevant data.
common, qualitative terms. Refer to noted references for more
1.2 This guide applies principally to pulsed monostatic
detailed information.
sodar techniques as applied to wind and turbulence measure-
3.2.1 acoustic beam, n—focused or directed acoustic pulse
ment in the open atmosphere, although many of the definitions
(compression wave) propagating in a radial direction from its
and principles are also applicable to bistatic configurations.
point of origin.
This guide is not directly applicable to radio-acoustic sounding
3.2.2 acoustic power, n—relative amplitude or intensity
systems (RASS), or tomographic methods.
(dB) of an atmospheric compression wave.
1.3 The values stated in SI units are to be regarded as
3.2.3 acoustic refractive index, n—ratio of reference (at a
standard. No other units of measurement are included in this
standard temperature of 293.15 K and 1013.25 hPa pressure)
guide.
speed of sound value to its actual value.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.2.4 acoustic scatter, n—the dispersal by reflection,
responsibility of the user of this standard to establish appro-
refraction, or diffraction of acoustic energy in the atmosphere.
priate safety, health, and environmental practices and deter-
3.2.5 acoustic scattering Cross-section Per Unit Volume (σ,
mine the applicability of regulatory limitations prior to use.
–1
m ), n—fraction of incident power at the transmit frequency
1.5 This international standard was developed in accor-
that is backscattered per unit distance into a unit solid angle.
dance with internationally recognized principles on standard-
3.2.6 acoustic attenuation (φ, dB/100m ), n—loss of acous-
ization established in the Decision on Principles for the
tic power (acoustic wave amplitude) by beam spreading,
Development of International Standards, Guides and Recom-
scattering, and absorption as the transmitted wavefront propa-
mendations issued by the World Trade Organization Technical
gates through the atmosphere.
Barriers to Trade (TBT) Committee.
3.2.7 backscatter, n—power returned towards a receiving
2. Referenced Documents
antenna.
2
2.1 ASTM Standards:
3.2.8 beamwidth (degrees), n—one way angular width (half
angle at –3dB) of an acoustic beam from its centerline
maximum to the point at the beam periphery where the power
1
This guide is under the jurisdiction of ASTM Committee D22 on Air Quality
level is half (3 decibels below) centerline beam power.
and is the direct responsibility of Subcommittee D22.11 on Meteorology.
Current edition approved March 1, 2022. Published May 2022. Originally
3.2.9 bistatic, adj—sodar configuration that uses spatially
approved in 2005. Last previous edition approved in 2015 as D7145 – 05 (2015).
separated antennas for signal transmission and reception.
DOI: 10.1520/D7145-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.2.10 clutter, n—undesirable returns, particularly from
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
sidelobes, that increase background noise and obscure desired
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. signals.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7145−22
3.2.11 decibel (dB), n—logarithmic (base 10) ratio of power 3.2.29 sig
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7145 − 05 (Reapproved 2015) D7145 − 22
Standard Guide for
Measurement of Atmospheric Wind and Turbulence Profiles
1
by Acoustic Means
This standard is issued under the fixed designation D7145; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This guide describes the application of acoustic remote sensing for measuring atmospheric wind and turbulence profiles. It
includes a summary of the fundamentals of atmospheric sound detection and ranging (sodar), a description of the methodology and
equipment used for sodar applications, factors to consider during site selection and equipment installation, and recommended
procedures for acquiring valid and relevant data.
1.2 This guide applies principally to pulsed monostatic sodar techniques as applied to wind and turbulence measurement in the
open atmosphere, although many of the definitions and principles are also applicable to bistatic configurations. This guide is not
directly applicable to radio-acoustic sounding systems (RASS), or tomographic methods.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this guide.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
3. Terminology
3.1 Definitions—Refer to Terminology D1356 for general terms and their definitions.
3.2 Definitions of Terms Specific to This Standard:
Note: The definitions below are presented in simplified, common, qualitative terms. Refer to noted references for more detailed
information.
1
This guide is under the jurisdiction of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.11 on Meteorology.
Current edition approved April 1, 2015March 1, 2022. Published April 2015May 2022. Originally approved in 2005. Last previous edition approved in 20102015 as
ε1
D7145 – 05 (2010)(2015). . DOI: 10.1520/D7145-05R15.10.1520/D7145-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7145 − 22
3.2.1 acoustic beam, n—focused or directed acoustic pulse (compression wave) propagating in a radial direction from its point of
origin.
3.2.2 acoustic power, n—relative amplitude or intensity (dB) of an atmospheric compression wave.
3.2.3 acoustic refractive index, n—ratio of reference (at a standard temperature of 293.15 K and 1013.25 hPa pressure) speed of
sound value to its actual value.
3.2.4 acoustic scatter, n—the dispersal by reflection, refraction, or diffraction of acoustic energy in the atmosphere.
–1
3.2.5 acoustic scattering Cross-section Per Unit Volume (σ, m ), n—fraction of incident power at the transmit frequency that is
backscattered per unit distance into a unit solid angle.
3.2.6 acoustic attenuation (φ, dB/100m ), n—loss of acoustic power (acoustic wave amplitude) by beam spreading, scattering, and
absorption as the transmitted wavefront propagates through the atmosphere.
3.2.7 backscatter, n—power returned towards a receiving antenna.
3.2.8 beamwidth (degrees), n—one way angular width (half angle at –3dB) of an acoustic beam from its centerline maximum to
the point at the beam periphery where the power level is half (3 decibels below) centerline beam power.
3.2.9 bistatic, adj—sodar configuration that uses spatially separated antennas for signal transmission and recepti
...
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