Overview
ISO 16622:2002 - "Meteorology - Sonic anemometers/thermometers - Acceptance test methods for mean wind measurements" - defines standardized acceptance tests for sonic anemometers/thermometers that use the inverse time measurement of sound velocity along differently oriented sound paths. It applies to instruments measuring two- or three-component wind vectors with an unlimited (360°) azimuthal acceptance. The standard supports reliable mean wind measurements using sonic arrays (typical path lengths ~10–20 cm) and helps ensure instrument performance for meteorology, air quality, and dispersion applications.
Key topics and requirements
- Measurement principle: Inverse time measurement of the velocity of sound along transducer pairs (sound paths) to derive wind components and sonic temperature.
- Array inspection: Verify mechanical array integrity, transducer alignment and path lengths before testing.
- Minimum acceptance tests:
- Zero wind chamber test - determines zero offset (system delay asymmetry) and temperature dependence of offsets.
- Wind tunnel test - evaluates vector deviation between measured and true wind across ranges of flow speed and direction.
- Field test - assesses instrument response under real environmental conditions (adverse or complex flow) not easily simulated in the lab.
- Optional test:
- Pressure chamber test - recommended when operating above 2 000 m altitude to confirm performance at reduced air densities (sound transmission limits).
- Performance evaluation: Accuracy, repeatability and reproducibility reporting in accordance with ISO 5725 principles.
- Definitions and metrics: System delay, transit time, turbulence level, zero offset and other formal terms used for standardized reporting.
Applications
ISO 16622 is directly applicable where accurate, repeatable mean wind measurements are required:
- Routine and research meteorological monitoring
- Atmospheric dispersion and air-quality studies
- Wind resource assessment and microclimate studies
- Environmental compliance and regulatory monitoring
- Instrument manufacturing quality control and acceptance testing
Who should use this standard
- Sonic anemometer/thermometer manufacturers for factory acceptance and calibration processes
- Calibration laboratories and wind tunnel facilities conducting performance tests
- Meteorological services, environmental agencies, research institutions and consultants validating instrument suitability for deployments
- Field operators planning high-altitude or harsh-environment measurements
Related standards
Normative references cited by ISO 16622 include:
- ISO 5725-1 / ISO 5725-2 (accuracy, repeatability/reproducibility)
- ASTM D5741-96
- WMO/CIMO Guide to meteorological instruments and methods of observation
Keywords: ISO 16622, sonic anemometer, sonic thermometer, acceptance test methods, mean wind measurements, zero wind chamber, wind tunnel test, pressure chamber test, field test, inverse time measurement.