Comparisons between two wavelet functions in extracting coherent structures from solar wind time series
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| Natura: | Artículo científico |
| Lingua: | en |
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Sociedade Brasileira de Física
2009
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| _version_ | 1876453696533954560 |
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| author | M. J. A. Bolzan |
| author_facet | M. J. A. Bolzan |
| contents | Comparisons between two wavelet functions in extracting coherent structures from solar wind time series M. J. A. Bolzan F. L. Guarnieri Paulo Cesar Vieira Física, Astronomía y Matemáticas Turbulence Solar Variables Wavelet Analysis Coherent Structures Nowadays, wavelet analysis of turbulent flows have become increasingly popular. However, the study of geometric characteristics from wavelet functions is still poorly explored. In this work we compare the performance of two wavelet functions in extracting the coherent structures from solar wind velocity time series. The data series are from years 1996 to 2002 (except 1998 and 1999). The wavelet algorithm decomposes the annual time-series in two components: the coherent part and non-coherent one, using the daubechies-4 and haar wavelet function. The threshold assumed is based on a percentage of maximum variance found in each dyadic scale. After the extracting procedure, we applied the power spectral density on the original time series and coherent time series to obtain spectral indices. The results from spectral indices show higher values for the coherent part obtained by daubechies-4 than those obtained by the haar wavelet function. Using the kurtosis statistical parameter, on coherent and non-coherent time series, it was possible to conjecture that the differences found between two wavelet functions may be associated with their geometric forms. 2009 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46413555002 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.1 Vol.39 |
| format | Artículo científico |
| id | redalyc_46413555002 |
| institution | Redalyc |
| language | en |
| publishDate | 2009 |
| publisher | Sociedade Brasileira de Física |
| spellingShingle | Comparisons between two wavelet functions in extracting coherent structures from solar wind time series M. J. A. Bolzan Física, Astronomía y Matemáticas Turbulence Solar Variables Wavelet Analysis Coherent Structures Comparisons between two wavelet functions in extracting coherent structures from solar wind time series M. J. A. Bolzan F. L. Guarnieri Paulo Cesar Vieira Física, Astronomía y Matemáticas Turbulence Solar Variables Wavelet Analysis Coherent Structures Nowadays, wavelet analysis of turbulent flows have become increasingly popular. However, the study of geometric characteristics from wavelet functions is still poorly explored. In this work we compare the performance of two wavelet functions in extracting the coherent structures from solar wind velocity time series. The data series are from years 1996 to 2002 (except 1998 and 1999). The wavelet algorithm decomposes the annual time-series in two components: the coherent part and non-coherent one, using the daubechies-4 and haar wavelet function. The threshold assumed is based on a percentage of maximum variance found in each dyadic scale. After the extracting procedure, we applied the power spectral density on the original time series and coherent time series to obtain spectral indices. The results from spectral indices show higher values for the coherent part obtained by daubechies-4 than those obtained by the haar wavelet function. Using the kurtosis statistical parameter, on coherent and non-coherent time series, it was possible to conjecture that the differences found between two wavelet functions may be associated with their geometric forms. 2009 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46413555002 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.1 Vol.39 |
| title | Comparisons between two wavelet functions in extracting coherent structures from solar wind time series |
| topic | Física, Astronomía y Matemáticas Turbulence Solar Variables Wavelet Analysis Coherent Structures |
| url | https://www.redalyc.org/articulo.oa?id=46413555002 |