Studies of Turbulent Transport Processes in the Atmospheric Boundary Layr by Wavelet Analysis.

本研究的目的是建立适用于大气边界层突变现象研究的实用小波分析方法。传统的功率谱分析方法可以用于平稳时间序列的分析，但不适用于突变的分析。而小波分析可以确定突变的时间和幅度。在风暴的风速变化过程中，伴随着自由大气高速气团的下降，风速突然增大。在这种情况下，小波分析特别有效。Yamada开发了利用FFT进行离散正交小波变换的算法。Hayashi利用该算法对大气表层的风速波动和动量输运进行了研究，发现在含能频率范围内间歇性地发生较大的向下输运，并伴有扫射或抛射。

The purpose of the present study is to establish the practical method of wavelet analysis applicable for the study of abrupt phenomenon in the atmospheric boundary layr. The traditional method of power spectrum analysis can be used for the analysis of stationary time series, but it is not applicable to abrupt changes. While wavelet analysis can determine the time and magnitude of abrupt fluctuation.In the course of wind velocity changes in the storm, it increases suddenly accompanied by descending of high speed air mass from free atmosphere. In such case wavelet analysis is especially effective.Yamada has developed the algorithm for the discrete orthogonal wavelet transform using the FFT.Hayashi used this algorithm for the study of wind velocity fluctuation and momentum transport in the atmospheric surface layr, and found that large downward transports occur intermittently in the energy containing frequency range accompanied by sweep or ejection.