地学前缘 ›› 2009, Vol. 16 ›› Issue (4): 381-388.

• 论文 • 上一篇    下一篇

泥石流阵流序列的整体性

  

  1. 1中国科学院 山地灾害与地表过程重点实验室, 四川 成都 610041
    2中国科学院、水利部 成都山地灾害与环境研究所, 四川 成都 610041

  • 出版日期:2009-08-01 发布日期:2009-08-01
  • 作者简介:李泳(1967—),男,研究员,主要从事地理过程和泥石流的理论研究。Email:ylie@imde.ac.cn
  • 基金资助:

    国家自然科学基金项目(40771010, 40671025);中国科学院水利部成都山地灾害与环境研究所创新项目(ARP1100001062)

Integrity of debrisflow surge sequence.

  1. 1Key Laboratory of Mountain Hazards and Surface Process, Chinese Academy of Sciences, Chengdu 610041, China
    2Institute of Mountain Hazards and Environment, Chinese Academy of Sciences & Ministry of Water Conservancy, Chengdu 610041, China

  • Online:2009-08-01 Published:2009-08-01

摘要:

泥石流往往以阵流群的形式出现,不同阵流参数具有统一的统计分布,意味着阵流序列隐含着深层的系统信息。文中根据蒋家沟泥石流观测数据,揭示阵流序列的自相关性和时空变化特征,进而确立其整体性。Hurst指数是刻画序列相关性的指标。阵流的流量、速度和时间间歇序列的Hurst指数值均大于05,从而证明序列具有长程相关性;另一方面,将阵流作为其运动参数(如流速、流量、间歇时间)组所确定的点,则一个泥石流事件为参数空间的一个点集,且集中在一个狭小区域,直观表现了阵流在时空的聚集特征,这是序列整体性的又一特征。阵流序列的这些基本特征,意味着不同泥石流事件背后隐藏着同一个动力学机制,即泥石流作为流域行为(而不是流体运动)的系统动力学。

关键词:  泥石流;阵流序列;Hurst指数;时空间隔

Abstract:

Debris flow, which is usually  of high density and viscosity, is conspicuous for its composition of successive surges of various properties. A debris flow is equal to a surge sequence and thus the surge sequence is believed to convey the information about the integrated properties of a system underlying debris flow. Based on observations in Jiangjia Gully, in this paper we focus on the integrity of surge sequence by considering the autocorrelation and tempospatial interval. The Hurst exponent is employed to express the autocorrelation. Results show that the Hurst exponents are exclusively bigger than 05, the value for random series without longrun aftereffects, suggesting the longrange correlation of the surge sequences. Furthermore, an eventspace is introduced by taking each surge as a point assigned with a parameter set. Three parameters, the discharge, velocity, and time interval are chosen to define a surge point. Then a debris flow event appears as a group of points clustered in a small range in the eventspace. This visualizes the concentration of surges in temporal and spatial dimensions, and further illustrates the tempospatial correlation of the surges. The integrity and autocorrelation of the surge sequence can be taken as the sign of an underlying dynamics of debris flow.

Key words:

Key words: debris flow; surge sequence; Hurst exponent; longrange correlation

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