开都河流域积雪特征变化及其与径流的关系

本文利用MOD10A2遥感影像提取开都河流域2000年-2010年积雪覆盖数据,结合水文气象站点数据分析了开都河流域积雪时空分布特征、及气象因子-积雪面积-径流之间的关系。结果表明：开都河流域积雪面积在时间上的分布特征体现在年内和年际的变化。年内积雪变化较大,冬季积雪面积达到最大,夏季面积最小。近11a来积雪面积年际变化呈微弱的下降趋势,其中夏季和冬季下降趋势较明显,春季和秋季的变化趋势不明显。通过研究区积雪面积与气候资料的相关性表明,冬春季气温与流域积雪面积相关性最大,夏季最小;而降水在冬季和积雪面积的相关性最大。对径流和基流的影响因素进行分析表明积雪面积对春季径流和基流影响最大,在夏季的影响最小。气温与径流和基流的相关性在春秋季最大,降水量在夏季与径流和基流最相关。由此可见,气温在影响流域积雪面积变化方面起着重要作用,而气温和积雪面积在春秋季对径流和基流的影响最大,夏季降水对径流和基流的影响最大。

Snow Cover Change and Impact on Streamflow in the Kaidu River Basin

Snow plays an important role in balancing Earth’s surface heat and generating streamflow in arid areas.In Xinjiang,the Tianshan Mountain is abundant in seasonal snow.Seasonal snow melt is the primary source of water,especially for river systems over mountainous areas.There is about 9.63×109m3 snow melt and ice melt in the Tianshan Mountain contributed to streamflow every year.The Kaidu River originates from the central part of the Tianshan Mountain,and is primarily supplied by mixed water from snow melt and rain.The temporal and spatial variations of snow cover depend on many factors,such as air temperature,precipitation,local vegetation cover,wind direction,wind speed,and solar radiation.As a result,the snow cover is extremely sensitive to climate change,which could lead to changes in streamflow in spring and summer.The changes in streamflow would subsequently affect the fragile environment in arid areas.Effectively monitoring snow cover is therefore an essential requirement for water resources management over the region.MOD10A2 comprises the 8-day composite snow cover product with spatial resolution of 500 m from the Moderate Resolution Imaging Spectroradiometer(MODIS)/Terra satellite.In this study,MOD10A2 snow products during the period 2000-2010 were employed to detect variation in snow cover,impact of snow cover change on streamflow and baseflow,as well as relationships among meteorological factors,snow cover,and streamflow.Results show that there was a seasonal change in snow cover,and the maximum value occurred in winter and the minimum in summer.The total snow cover showed a slightly decreasing trend from 2000 through 2010.The snow cover decreased in summer and winter,and there was no obvious change in spring and autumn.The correlation between snow cover and meteorological variables suggests that there existed a stronger correlation between snow cover and temperature in spring and winter than in summer.Snow cover had marked correlation with precipitation in winter.In addition,both streamflow and baseflow showed appreciable correlation with snow cover in spring.Temperature had a significant effect on streamflow and baseflow in spring and autumn,but streamflow and baseflow were more sensitive to precipitation in summer than in other seasons.Temperature was the major factor affecting changes in snow cover in the Kaidu River basin.Temperature and snow cover showed the most significant influence on streamflow and baseflow in spring and autumn,whereas precipitation was the primary factor affecting streamflow and baseflow in summer.