Abstract: In this paper, wavelet analysis methods, mainly including wavelet basis function, continuous and discrete wavelet transform and wavelet threshold de-noising, were introduced first. Then, current researches and applications of the wavelet analysis methods to various aspects of hydrology were summarized and reviewed from three points of view: research significance, current researches and applications, and key and difficult problems and the inadequate applications to hydrology. The six aspects of wavelet-based hydrologic analysis include: continuous wavelet-based analysis of hydrologic time series' characteristics under multi-temporal scales, discrete wavelet decomposition and reconstruction different sub-signals of hydrologic time series, quantification of complicated variability of hydrologic processes, wavelet de-noising in hydrologic time series, wavelet cross-correlation analysis of hydrologic time series, and wavelet-based hydrologic time series simulation and forecasting. Finally, several suggestions and opinions on the future researches and applications of wavelet analysis methods in hydrology were discussed. They focus on selection of wavelet basis function, wavelet threshold de-noising, wavelet decomposition, wavelet cross-correlation analysis, and wavelet aided forecasting.

Key words: hydrologic forecasting, hydrologic time series analysis, hydrology and water resources, uncertainty, wavelet analysis