A Refinement of the McMillen (1988) Recursive Digital Filter for the Analysis of Atmospheric Turbulence

作者：Falocchi Marco^*; Giovannini Lorenzo; de Franceschi Massimiliano; Zardi Dino

来源：Boundary-Layer Meteorology, 2018, 168(3): 517-523.

DOI：10.1007/s10546-018-0355-5

• Complex terrain
• Recursive filtering
• Signal amplification
• Surface-layer turbulence
• Zero-phase filter

We present a refinement of the recursive digital filter proposed by McMillen (Boundary-Layer Meteorol 43:231-245, 1988), for separating surface-layer turbulence from low-frequency fluctuations affecting the mean flow, especially over complex terrain. In fact, a straightforward application of the filter causes both an amplitude attenuation and a forward phase shift in the filtered signal. As a consequence turbulence fluctuations, evaluated as the difference between the original series and the filtered one, as well as higher-order moments calculated from them, may be affected by serious inaccuracies. The new algorithm (i) produces a rigorous zero-phase filter, (ii) restores the amplitude of the low-frequency signal, and (iii) corrects all filter-induced signal distortions.

• 出版日期2018-9