The inverse problem in acoustic profiling
Current methods of obtaining wind profiles from SODARs generally employ ad hoc strategies for Doppler spectrum peak selection, profile smoothing, and consistency checks. This project addresses the problem of systematically obtaining vertical profiles of wind vectors from a SODAR for more reliable measurements of highly resolved wind measurements applicable to wind farm siting, urban air quality studies and others.
A new approach is to regard every spectrum frequency as a possible estimator
of the radial wind component, but to weight these Doppler estimates according
to the spectral power at each frequency. This allows the peak detection, smoothing,
and assimilation of a priori information to be combined into a constrained linear
inversion methodology. The inversion process also allows an estimation of signal-to-noise
ratio, degrees of freedom, and information content versus height. Examples are
given of profiles obtained using this new inverse method. The relationship to
the physical limitations of the SODAR instrument and the atmosphere is discussed.
Publications:Bradley, S. G. and S. von Hünerbein. A systematic algorithm for obtaining SODAR wind profiles. Met. Atmos. Phys. (2003), 85(1-3):77-84
S. von Hünerbein and S. G. Bradley. Use of inverse methods to improve acoustic profiling. 11th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans, Rome, Italy, July 2002.
For further information please contact Sabine von Hünerbein