Studies On Wavelet Characteristics Of Runoff In The Middle And Lower Reaches Of Jinsha River

Based on experimental data of runoff in the middle and lower reaches of Jinsha river during 1956～1985, respectively for Huatan hydro-entrance station and Pingshan hydro-exit station, using wavelet analysis, Long time sequence of the study area periodic changes are discussed by month and predicting future runoff changes. The results are as follows:The middle and lower of Jinsha river lies in the Hengduanshanqu Mountains, The inter-annual distribution of the runoff was extremely uneven based on typical dry-hot valley. The runoff long time series exists 7a quasi-prime period and about 16.5a in the spring; In the summer, the runoff long time series period is not clear,May and June exists 3a,5a,14.5a quasi-prime period ,but in July exists 4a and 9a; and the runoff long time series exists 5a ,13.5a quasi-prime period in fall; and the runoff long time series exists 5a quasi-prime period in winter; and the runoff long time series exists 5a,14.5a quasi-prime period in year.The annual runoff is relatively excessive in 1992～1999, and relatively insufficient in 2000～2005. The spring runoff is relatively excessive in 1996～1999 and 2003～2005, and relatively insufficient in 1991～1995 and 2000～2002; the summer runoff is relatively excessive in 1991～1993, 1997～1999 and 2002～2004, and relatively insufficient in 1994～1996 and 2000～2001; the autumn runoff is relatively excessive in 1990～1994 and 1999～2003, and relatively insufficient in 1995～1998; the winter runoff is relatively excessive in 1998～2005, and relatively insufficient in 1989～1997.