In this study the Qing weather records 'Clear and Rain Records' were used to reconstruct the 18th century summer (June-August) precipitation and monthly precipitation series of May, June, July, and August. The...In this study the Qing weather records 'Clear and Rain Records' were used to reconstruct the 18th century summer (June-August) precipitation and monthly precipitation series of May, June, July, and August. The nature of these records and the techniquc of transforming them into numerical codes are described. The procedure of converting these descriptive records into quantitative monthly precipitation and its scientific basis are given in detail. The reliability of the obtaind precipitation series is also ex- amined.展开更多
The advantage of artificial neural network and wavelet analysis are integrated through replacing the traditional S-shaped activation function with the wavelet function. One method of chaotic prediction based on wavele...The advantage of artificial neural network and wavelet analysis are integrated through replacing the traditional S-shaped activation function with the wavelet function. One method of chaotic prediction based on wavelet BP network was put forward based on the reconstruction of state space. Training data construction and networks structure are determined by chaotic phase space, and nonlinear relationship of phase points was established by BP neural networks. As an example, the new method was applied on short term forecasting of monthly precipitation time series of Sanjiang Plain with chaotic characteristics. The results showed so higher precision of the method had that the theoretical evidence would be provided for applying the chaos theory to study the variable law of monthly precipitation.展开更多
基金supported by the U.S.National Science Foundation Climate Dynamics Section Grant ATM-8511905.
文摘In this study the Qing weather records 'Clear and Rain Records' were used to reconstruct the 18th century summer (June-August) precipitation and monthly precipitation series of May, June, July, and August. The nature of these records and the techniquc of transforming them into numerical codes are described. The procedure of converting these descriptive records into quantitative monthly precipitation and its scientific basis are given in detail. The reliability of the obtaind precipitation series is also ex- amined.
基金The project is supported by National Natural Science Foundation of China （30400275） Science Found for Distinguished Young Scholars of Heilong, iiang （QC04C28）
文摘The advantage of artificial neural network and wavelet analysis are integrated through replacing the traditional S-shaped activation function with the wavelet function. One method of chaotic prediction based on wavelet BP network was put forward based on the reconstruction of state space. Training data construction and networks structure are determined by chaotic phase space, and nonlinear relationship of phase points was established by BP neural networks. As an example, the new method was applied on short term forecasting of monthly precipitation time series of Sanjiang Plain with chaotic characteristics. The results showed so higher precision of the method had that the theoretical evidence would be provided for applying the chaos theory to study the variable law of monthly precipitation.
