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Ultrasonic Anemometers/Thermometers with Increased Spatial Resolution


Summary:  Ultrasonic anemometers/thermometers are commercially produced, robust instruments for measurements of temperature and velocity. Much of a progress in the boundary layer meteorology over the last few decades can be attributed to the wide use of these instruments. Due to concerns about wind distortion, the transducers of an ultrasonic anemometer are located at some distance from each other. As a result, the anemometer enables only path-averaged measurements of temperature and velocity, with a spatial resolution larger than about 15 cm. There are, however, several important applications/concerns in the boundary layer meteorology and theories of turbulence which require analysis of turbulent fields at smaller scales. Among these are: (i) studies of the inertial subrange at small scales which are important for analysis of the dissipation rate and the turbulent kinetic energy budget, (ii) studies of turbulence closure models, (iii) studies of energy transfer in the atmospheric boundary layer which are important, for example, for wind energy, (iv) measurements of turbulence, particularly momentum and heat fluxes, when the energy-containing range extends to spatial scales smaller than those resolved by currently used ultrasonic anemometers, e.g., near the surface or within canopies, (v) studies of small scale turbulence for the Ameriflux CO2 flux network. In principle, hot-wire and cold-wire anemometers enable one to make measurements of small-scale turbulence. However, these anemometers are not reliable instruments and often break down. Furthermore, they might disturb the flow around them. Therefore, there is a need for a new generation of ultrasonic anemometers/thermometers with increased spatial resolution.


Project Goals:  The main goals of the project are to develop a concept and a prototype of a new generation of ultrasonic anemometers/thermometers with increased spatial resolution, with a final goal to produce them commercially. Different approaches for achieving these goals can be considered including but not limited to acoustic tomography. A new generation of ultrasonic anemometers should be reliable, robust instruments designed to work in harsh conditions ranging from tropical marine environments to Polar Regions. The spatial resolution of such instruments should be increased to about 1-2 cm, with a potential to resolve even smaller scales.


Phase I Activities and Expected Deliverables:

  • Develop a concept of an ultrasonic anemometer/thermometer with increased spatial resolution.
  • Build a preliminary prototype of a new ultrasonic anemometer.
  • Determine a feasibility of a new generation of reliable ultrasonic anemometers with increased spatial resolution.


Phase II Activities and Expected Deliverables:

  • Design a commercial prototype of a new generation of robust ultrasonic anemometers/thermometers with increased spatial resolution.
  • Build and test a commercial prototype of such ultrasonic anemometers.
  • Develop a plan to commercialize a new generation of ultrasonic anemometers.
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