流域生态基流是河流生态系统健康稳定的关键,以新疆尼雅河流域为研究区域,根据民丰县气象站1958—2018年的气象数据与尼雅河4个水文监测断面1978—2018年的水文数据,运用趋势拟合、Tennant法、相关性分析和回归模型等分析流域气候变化、确定生态基流并探究其时空分异与保证率变化,揭示生态基流对气候变化的响应。结果表明：61 a来流域气温以0.22 ℃·(10a)^-1的速度增加,年降水量以3.8 mm·(10a)^-1的速度增加;尼雅水库、八一八渠首、尼雅水文站和尼雅渠首的年生态基流推荐值分别为：1.989 m³·s^-1、2.188 m³·s^-1、1.755 m³·s^-1、1.702 m³·s^-1;生态基流年际最大值出现在2010年,最小值在1980年,年内最大值在7月,最小值在1月或12月;空间上表现为上游高下游低,以八一八渠首处最高,尼雅渠首处最低;各站多年平均生态基流保证率分别为：50%、45%、50%、45%,且表现出汛期明显高于非汛期;逐年、逐月生态基流与气温、降水量均在0.01水平上显著相关,但在春夏季对气温敏感,秋冬季对降水量敏感,各水文监测断面的回归模型耦合效果相似,流域整体回归方程R²=0.365,且生态基流对气候变化响应具有整体性和衰减性。研究结果可为尼雅河流域生态调水和水生态修复提供参考。

Watershed ecological base flow is crucial for the health and stability of river ecosystems. On the basis of meteorological data obtained by the meteorological station of Minfeng County, Xinjiang, China during 1958—2018 and hydrological data obtained by four hydrological monitoring sections in the Niya River from 1978—2018, we reveal the response of ecological base flow to climate change using trend fitting, Tennant method, correlation analysis, and regression model to analyze the climate change, determine the ecological base flow, and explore its spatiotemporal differentiation and guarantee rate change. Results show that air temperature and precipitation increased at a rate of 0.22 ℃·(10a)^-1 and 3.8 mm·(10a)^-1, respectively, in the past 61 a. For Niya Reservoir, 818 Canal Head, Niya hydrology station, and Niya Canal head, the recommended annual ecological base flow values are 1.989 m³·s^-1, 2.188 m³·s^-1, 1.755 m³·s^-1, and 1.702 m³·s^-1, respectively. The interannual minimum and maximum of the ecological base flow occurred in 1980 and 2010, respectively; the annual maximum occurred in July, and the minimum occurred in January or December. Spatially, it is higher in the upper reaches and lower in the lower reaches, with the highest at the head of 818 Canal and the lowest at the head of Niya Canal. The annual average ecological base current guarantee rate of each station is 50%, 45%, 50%, and 45%, respectively, and it is significantly higher during the flood season than the nonflood season. A significant correlation exists between annual and monthly ecological base flow and temperature and precipitation at the 0.01 level, but it is sensitive to temperature in spring and summer, and to precipitation in autumn and winter. The coupling effect of regression models of all hydrological sections is similar, with the basin overall regression equation obtaining R²=0.365. The response of ecological base flow to climate change has the characteristics of integrity and attenuation. These results can provide a reference for ecological water diversion and water ecological restoration in the Niya River Basin.