In order to test the validity of the global wavelet spectrum - a new period analysis method based on wavelet analysis, we carried out some simple experiments. In our experiments we used idealized time series and real ...In order to test the validity of the global wavelet spectrum - a new period analysis method based on wavelet analysis, we carried out some simple experiments. In our experiments we used idealized time series and real Ni(~n)o 3 sea surface temperature (SST) for testing purposes. First we combined different signals which have the same power but different periods into some new time series. Then we calculated the global wavelet spectra and Fourier power spectra for the testing time series. The testing results revealed that on some occasions the global wavelet spectrum tends to amplify the relative power of longer periods. By making comparisons with the results obtained by the traditional Fourier power spectrum, we demonstrated that on an occasion when the global wavelet spectrum does not work the Fourier power spectrum can be used to achieve the right results. Hence it is recommended that when making period analysis with the global wavelet spectrum one needs to do further tests to confirm their results.展开更多
Based on the 5-year length of tidal gravity observations recorded with a superconducting gravimeter at Wuhan International Tidal Gravity Ref-erence Station, the special gravity signals associated with the possible Ea...Based on the 5-year length of tidal gravity observations recorded with a superconducting gravimeter at Wuhan International Tidal Gravity Ref-erence Station, the special gravity signals associated with the possible Earth’s solid inner core translational oscillations in sub-tidal bands are detected and studied by using for the first time a wavelet transfor-mation technique. The analysis is conducted on gravity residuals after removing the synthetic tidal gravity signals and air pressure perturbation from original observations, demonstrating that there exist gravity oscillation signals at 4―6 h bands with am-plitude of nGal level. However, it is found that the frequency and amplitude of such kind of oscillation signals change with time, and the analysis shows that these oscillation signals are provoked probably by some non-continuous source with very low ampli-tude.展开更多
基金This study was suppo rted by a key program from the National Natural Science Foundation of China(NSFC)(Grant No.40233033).
文摘In order to test the validity of the global wavelet spectrum - a new period analysis method based on wavelet analysis, we carried out some simple experiments. In our experiments we used idealized time series and real Ni(~n)o 3 sea surface temperature (SST) for testing purposes. First we combined different signals which have the same power but different periods into some new time series. Then we calculated the global wavelet spectra and Fourier power spectra for the testing time series. The testing results revealed that on some occasions the global wavelet spectrum tends to amplify the relative power of longer periods. By making comparisons with the results obtained by the traditional Fourier power spectrum, we demonstrated that on an occasion when the global wavelet spectrum does not work the Fourier power spectrum can be used to achieve the right results. Hence it is recommended that when making period analysis with the global wavelet spectrum one needs to do further tests to confirm their results.
文摘Based on the 5-year length of tidal gravity observations recorded with a superconducting gravimeter at Wuhan International Tidal Gravity Ref-erence Station, the special gravity signals associated with the possible Earth’s solid inner core translational oscillations in sub-tidal bands are detected and studied by using for the first time a wavelet transfor-mation technique. The analysis is conducted on gravity residuals after removing the synthetic tidal gravity signals and air pressure perturbation from original observations, demonstrating that there exist gravity oscillation signals at 4―6 h bands with am-plitude of nGal level. However, it is found that the frequency and amplitude of such kind of oscillation signals change with time, and the analysis shows that these oscillation signals are provoked probably by some non-continuous source with very low ampli-tude.
