Infrasound warning model for debris flow in typical drainage basin of Beijing mountainous area
-
摘要: 次声是泥石流监测预警的有效手段,目前常用的阈值预警法未全面考虑次声的时频特征,这将降低预警的准确度。基于北京市草甸水村泥石流的次声监测数据,分析了该流域泥石流次声和环境次声的时频特征差异,并基于随机森林算法构建了泥石流次声识别模型。结果表明,泥石流次声的有效声压为0.4-1.0Pa,环境次声的有效声压多低于0.1Pa,但噪音会引起声压上升至0.4Pa以上;噪音次声能量多集中在低于6Hz的频段,泥石流次声在6-15Hz频段的能量明显高于噪音次声。因此,泥石流次声的甄别需综合考虑时频域的多个特征,重点是6-15Hz频段对应的能量。基于随机森林算法,以有效声压、6-15Hz有效声压、短时过零率、主频、主频振幅为特征变量构建的泥石流次声识别模型AUC值为0.99,对测试数据识别准确率为90.0%,相比传统声压阈值法提升了15.0%。研究结果说明随机森林模型能够较为精准地甄别泥石流次声信号,适用于草甸水村的泥石流次声预警,可为其他区域的泥石流次声预警研究提供参考。Abstract: [Objective] Infrasound is an effective debris flow warning approach. The threshold warning method commonly used in previous studies considered only individual infrasound characteristics, which can result in inaccuracies in debris flow warning. [Methods] Infrasound data collected in Caodianshui village, Beijing, was employed to investigate the differences between infrasound characteristics of debris flow and environment background. Based on random forest algorithm, the infrasound warning model for debris flow was established. [Results] The effective pressure of debris flow infrasound ranges from 0.4 to 1.0Pa. In contrast, the effective pressure of environmental infrasound is mostly lower than 0.1Pa, but it can exceed 0.4Pa due to noise. The energy of noise infrasound concentrated in frequency band below 6Hz. The energy of debris flow infrasound in 6-15Hz is significantly higher than that of noise infrasound. Therefore, comprehensive time-frequency characteristics, especially the energy in 6-15Hz, should be taken into consideration to identify debris flow infrasound. By taking effective infrasound pressure, effective infrasound pressure of 6-15Hz, zero crossing rate, main frequency and amplitude of main frequency as characteristic variables, the debris flow infrasound warning model based on random forest was constructed. The AUC of the model was 0.99. The test data recognition accuracy reached 90%, which is 15% higher than that of the traditional threshold method. [Conclusion] This study demonstrate that the infrasound warning model for debris flow based on random forest algorithm can significantly improve the warning accuracy and is applicable to the typical basin in Beijing mountainous area, which can also provide a reference for the debris flow infrasound warning research in other areas.
-
Key words:
- debris flow /
- infrasound /
- time-frequency characteristics /
- early warning model /
- random forest
点击查看大图
计量
- 文章访问数: 113
- PDF下载量: 13
- 被引次数: 0