关键词: 黄河源区, 若尔盖高原, 局部主周期, 径流, 趋势, 小波分析

Abstract:

The paper puts forward an analytical method of part time period to predict and analyze the long time series variation trend, and analyzes and predicts the multi-time scale variation features of natural runoff as well as the future variation trend, based on long time series data measured with instruments about the long time series runoff volume from the headwaters of the Yellow River in the Dari to Maqu section during 1956-2000, through field tests. The study area, located in the northeast of the Qinghai-Tibet Plateau and being one of the most sensitive areas to global climate change, is an important water conservation area in the upper Yellow River. With sustainable development of the regional economy the requirement for the exploreation of the river's hydrologic features in the study area is becoming increasingly important. The results indicate that: ①the runoff series has the characteristic of multi-time series changes, with the existence of major periods of 3.2a, 7.5a, 19.5a and 36.5a; ②the variation trend of runoff volume is as follows: it was relatively insufficient in 1969~1975, 1986~2004 , relatively excessive in 1956~1969, 1975~1986, 2004~2017, and will come to a normal period in 2017~2020. The low-flow period appeared since 1986 was supposed to be improved around 2004; ③the annual change of runoff is mainly caused by changes of climate, and has little to do with human activities; and ④the major period has time limitation, that only takes effects in certain periods of time.

Key words: headwater of the Yellow River, Zoige plateau, part major period, runoff, trend, wavelet analysis