1 引言
2 资料选取与方法介绍
2.1 资料选取及处理
2.2 方法介绍
3 结果分析
3.1 基于CEEMD算法与EMD算法的HHT对比分析
图3 2021年5月7日12:00 -12:30水平 风的CEEMD分解Fig.3 EMD decomposition of horizontal u-wind from 12:00 to 12:30 on May 7, 2021 |
表1 EMD分解与CEEMD分解各模态能量占比Table 1 Energy proportion of each mode in emd decomposition and CEEMD decomposition |
IMF阶数 | EMD分解能量占比/% | CEEEMD分解能量占比/% |
---|---|---|
1 | 0.87 | 1.11 |
2 | 0.90 | 1.17 |
3 | 1.16 | 2.08 |
4 | 1.46 | 4.26 |
5 | 2.13 | 5.93 |
6 | 5.28 | 12.08 |
7 | 8.12 | 16.16 |
8 | 13.89 | 20.51 |
9 | 12.27 | 20.75 |
10 | 26.89 | 15.29 |
11 | 17.82 | 0.59 |
12 | 9.21 | 0.03 |
13 | - | 0.03 |
3.2 基于CEEMD的HHT方法的边界层湍流个例分析
图8 2021年5月16日00:00 -00:30夜晚稳定条件下, 20 m(a)、 38 m(b)、 56 m(c) 风的CEEMD分解各IMF纵坐标范围与IMF1保持一致 Fig.8 CEEMD decomposition of 20-metre (a), 38-metre (b), 56-metre (c) u-wind under stable conditions at night from 00:00 to 00:30 on May 16, 2021.The vertical coordinate range of each IMF is consistent with IMF1 |
图9 2021年5月16日00:00 -00:30夜晚稳定条件下, 20 m(a)、 38 m(b)、 56 m(c)温度 的CEEMD分解各IMF纵坐标范围与IMF1保持一致 Fig.9 CEEMD decomposition of 20-metre (a), 38-metre (b), 56-metre (c) temperature under stable conditions at night from 00:00 to 00:30 on May 16, 2021.The vertical coordinate range of each IMF is consistent with IMF1 |
图10 2021年5月16日12:00 -12:30正午不稳定条件下, 20 m(a)、 38 m(b)、 56 m(c) 风的CEEMD分解各IMF纵坐标范围与IMF1保持一致 Fig.10 CEEMD decomposition of U-winds at 20-metre (a), 38-metre (b), and 56-metre (c) under unstable conditions at noon from 12:00 to 12:30 on May 16, 2021.The vertical coordinate range of each IMF is consistent with IMF1 |
图11 2021年5月16日12:00 -12:30正午不稳定条件下, 20 m(a)、 38 m(b)、 56 m(c)温度 的CEEMD分解各IMF纵坐标范围与IMF1保持一致 Fig.11 CEEMD decomposition of temperature T at 20-metre (a), 38-metre (b), and 56-metre (c) under unstable conditions at noon from 12:00 to 12:30 on May 16, 2021.The vertical coordinate range of each IMF is consistent with IMF1 |
表3 不同稳定条件下三个高度各IMF平均周期Table 3 Mean period of each IMF at three altitudes under different stable conditions |
IMF编号 | 稳定层结下平均周期/s | 不稳定层结下平均周期/s | |||||
---|---|---|---|---|---|---|---|
20 m | 38 m | 56 m | 20 m | 38 m | 56 m | ||
1 | 0.295 | 0.284 | 0.293 | 0.297 | 0.296 | 0.297 | |
2 | 0.701 | 0.661 | 0.686 | 0.713 | 0.704 | 0.701 | |
3 | 1.58 | 1.45 | 1.524 | 1.651 | 1.544 | 1.567 | |
4 | 3.482 | 3.333 | 3.285 | 3.742 | 3.607 | 3.543 | |
5 | 8.612 | 7.692 | 7.513 | 8.955 | 8.411 | 8.451 | |
6 | 18.750 | 17.822 | 17.143 | 22.785 | 21.176 | 20 | |
7 | 46.154 | 42.857 | 37.5 | 51.429 | 51.429 | 56.25 | |
8 | 105.882 | 100 | 105.882 | 150 | 138.462 | 138.462 | |
9 | 225 | 300 | 225 | 360 | 300 | 360 | |
10 | 600 | 450 | 900 | 900 | 900 | 900 | |
11 | 1800 | 1800 | 1800 | 1800 | 900 | 900 | |
12 | 1800 | 1800 | 1800 | 1800 | 1800 | 1800 | |
13 | 1800 | 1800 | 1800 | 1800 | 1800 | 1800 |
图13 夜晚和正午时刻, 稳定条件下20 m (a)、 38 m (b)、 56 m (c)和不稳定条件下20 m (d)、 38 m (e)、 56 m (f) 风三维希尔伯特谱Fig.13 At night and noon, under stable conditions, the three-dimensional Hilbert spectra of u-winds at 20-metre (a), 38-metre (b), 56-metre (c), and 20-metre (d), 38-metre (e), 56-metre (f) under unstable condition |
图14 夜晚和正午时刻, 稳定条件下20 m (a)、 38 m (b)、 56 m (c)和不稳定条件下20 m (d)、 38 m (e)、 5 6 m (f)温度 三维希尔伯特谱Fig.14 At night and noon, three-dimensional Hilbert spectra of temperature T at 20-metre (a), 38-metre (b), 56-metre (c) under stable conditions and 20-metre (d), 38-metre (e), 56-metre (f) under unstable conditions |