黄河源区达日至玛曲段近50年径流量变化趋势分析

Analysis on variety trend of runoff between Dari and Maqu in the headwater region of Yellow River in the past 50 years

本文提出了用于长时间序列变化趋势预测分析的局部主周期分析方法，并依据黄河源区达日至玛曲段1956-2000年长时间序列径流量实测资料，对天然径流量多时间尺度变化特征及未来变化趋势作了实例分析预测。结果表明：①径流量序列具有多时间尺度变化特征，并且存在3．2a、7．5a、19．5a和36．5a左右的主周期。②径流量变化趋势为：在1956～1969年偏多、1969～1975年偏少、1975～1986年偏多、1986～2004年偏少、2004～2017年偏多、2017~2020年为平水期。1986年以来出现的枯水期，在2004年左右以后将得到改变。③径流量年际变化主要是受气候变化影响所致，人类活动作用不显著。④主周期具有时效性，只有在一定时段内才有意义。

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.