The Largest Lyapunov Exponent and the Maximum Predictable Time Scale of Hourly Series in Urban Water Consumption
时用水量观测序列的最大Lyapunov指数及其预测时间尺度

Based on conventional Wolf's algorithm for largest Lyapunov exponent, an improved calculation method was put forward in which the search for new vector length and its evolution angle weights. The chaotic characteristics and maximum predictable time scale of the observed series of hourly water consumption in Hangzhou were discussed using the advanced algorithm. For comparison, the largest Lyapunov exponents of water consumption series of one-hour and 24-hour intervals were calculated respectively. The results indicate the followings: first, chaotic characteristic obviously exists in the hourly water consumption system; second, 24-hour interval series has the maximum predictable scale longer than hourly series. The above two properties have practical significance for better prediction of urban hourly water consumption.