Full
WEI Erhu, PhD, professor, PhD supervisor, majors in space geodesy and navigation, E-mail: ehwei@sgg.whu.edu.cn
Outline
This paper uses the time series of the geocentric motion provided by the Center for Space Research at the University of Texas at Austin as experimental data. First, empirical mode decomposition (EMD) is applied to the data for noise reduction. Then, fast Fourier transform (FFT) and continuous wavelet transform (CWT) are utilized to perform frequency domain transformation, power spectrum analysis, and extraction of periodic terms. Finally, an autoregressive integrated moving average (ARIMA) model and exponential smoothing method are employed to forecast the geocentric motion for the next 20 months. The results indicate that the amplitude and phase of the annual term extracted using FFT are quite close to previous studies on the geocentric motion. The ARIMA model provides better predictions for the Y-direction motion of the geocentric motion over the next 20 months, while exponential smoothing method offers more accurate predictions for the X and Z directions.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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