title: Optical anemometry based on the temporal cross-correlation of angle-of-arrival fluctuations obtained from spatially separated light sources.
abstract: The temporal cross-correlation function of the angle-of-arrival (AOA) fluctuations of two optical waves propagating through atmospheric turbulence carries information regarding the average wind velocity transverse to the propagation path. We present and discuss two estimators for the retrieval of the path-averaged beam-transverse horizontal wind velocity, v(t). Both methods retrieve v(t) from the temporal cross-correlation function of AOA fluctuations obtained from two closely spaced light-emitting diodes (LEDs). The first method relies on the time delay of the peak (TDP) of the cross-correlation function, and the second method exploits its slope at zero lag (SZL). Over a 9 h period during which v(t) varied between -1.3 ms(-1) and 2.0 ms(-1), the maximum rms difference between optically retrieved and in situ measured 10 s estimates of v(t) was found to be 0.18 ms(-1) for the TDP estimator and 0.23 ms(-1) for the SZL estimator. Applicability and limitations of these two optical wind retrieval techniques are discussed.
authors.affiliation: Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA. Shiril.Tichkule@colorado.edu
authors.forename: Shiril
authors.initials: S
authors.lastname: Tichkule
authors.forename: Andreas
authors.initials: A
authors.lastname: Muschinski