Analysis of Streamflow Change and Its Drought-flood Characteristics at Datong Station of Yangtze River
Under the influence of changing environment and upstream reservoir regulation and storage,it is very im-portant for the safety of flood control and the utilization of water resources in Jiangsu Province to analyze the evolution law of flow and the characteristics of drought and flood in the middle and lower reaches of Yangtze River.The trend,change point,period and annual distribution characteristics of streamflow at Datong station in Yangtze River from 1971 to 2020 were investigated by using the Mann-Kendall test and Morlet wavelet transform.Meanwhile,the characteristics of droughts and floods was analyzed using standardized streamflow index(SSI).The results show that the annual average streamflow of Datong hydrological station has shown a non-significant increasing trend,with relatively stable inter-annual changes in the past 50 years.However,there is a sudden change point in 2003,with a significant increase after the muta-tion;The annual average flow series mainly has a period of 12 years and is mainly occurred before the year of 1995,with three alternating oscillations between high and low flow;The annual distribution of streamflow at Datong station is une-ven,mainly concentrated in the flood season,with the highest flow in July and August.However,the flow sequence changes in each month of the flood season are not significant,while the monthly flow in the dry season,such as from De-cember to March of the following year,shows a significant increasing trend;The SSI index at different time scales reflects relatively consistent changes in drought and flood conditions.After 2003,the probability of droughts was higher with an annual drought frequency of 44.4%;While the probability of floods decreased from 37.5%to 16.7%.From a seasonal perspective,the incidence of drought in autumn and summer was relatively high,while the incidence in spring and winter decreased.According to the MK trend test of the SSI3,it decreased in Autumn,but its increased in other seasons,espe-cially in winter.
Datong hydrological stationstreamflowwavelet transformMann-Kendall teststandardized stream-flow index
万方数据
维普
