Runoff series of the Yangtze River presents an intricate variation tendency under the reinforced influence of human activities.The Morlet Wavelet Transform method has been applied to analyze the annual runoff data from 1950 to 2011 at the Yangtze River Estuary.It can clearly reveal the multi-time scales structure,break point,change and distribution of periodic variation in the different time scales of the runoff series.The main conclusions are that:1) Repeated periodic oscillations accompanied by an extremely large fluctuation are presented in the runoff series with an obvious difference between wet and dry years,and the major periods of the time series are about 3,8,16 and 23 years respectively.Among them,the presented maximum periodic oscillation is 23 years scale.2) In the 23-year time scale,the wet periods are 1950-1958,1969-1980 and 1992-2003,and the dry periods are 1959-1968,1981-1991 and 2004-2011.3) It can be predicted from the view of long time scales that the low annual runoff will likely occur in the near future. 相似文献
A component (s-factor) with obvious promoting effect on hydrogen evolution of hydrogenase has beenisolated and extracted from a Cell=free preparation of Spirulina platensis.The effect of the s-factor in the re-action system is similar to that of Na_2S_2O_4, but is coupled with ligh. The s-factor has the maximumabsorption peak at 620 nm in the oxidized state, at 590 nm in the reduced state. The partially purifieds-factor showed two bands by SDS-PAGE and is distinctly different from phycocyanin,which has nochange of oxidized state and reduced state absorption spectra, and also has no promoting effect onhydrogenase of Spirulina platensis under the light. 相似文献