蒋家沟泥石流阵流的时空特征

Spatiotemporal characteristics of debris flow in Jiangjia Gully

间歇性阵流是黏性泥石流的基本活动形式,普遍发生于世界各地,而以云南昆明东川的蒋家沟表现最为典型,观测数据也最为系统。每场泥石流表现为一个阵流序列,序列呈现出整体性和非线性特征。阵流流量涨落达3个数量级,均值随时间衰减;序列Hurst指数大于0.5,说明具有一定的长程关联性;阵流间歇时间呈负幂函数分布,阵流有时空聚集性。在参数空间中,阵流点成团聚集,点之间的欧氏距离呈一定形式的标度分布。这些特征意味着阵流序列蕴含着泥石流发生的系统动力学背景。

Debris flow over the world always moves in manner of intermittent surges, which is the most conspicuous appearance in Jiangjia Gully（JJG）, Yunnan. More than fifty years of real-time observations of living debris flows in JJG have achieved a huge dataset of parameters concerning more than 10 000 surges, from which derive several fundamental features of the surge sequences： probability distribution of the interval, fluctuation and distribution of discharge, decay of the sequence, Hurst index and surge concentration in space and time. All these characteristics suggest that the surge sequence is a systemic behavior of some underlying dynamics and hints at some nonlinear dynamical mechanism of debris flow formation and evolution.