风蚀对窟野河流域产沙贡献的时间尺度特征

风蚀在黄土高原风水蚀复合区的侵蚀产沙中扮演着重要的角色。利用窟野河流域神木水文站水沙资料及有关气象资料,分析了风蚀对窟野河神木水文站以上流域产沙贡献的时间尺度特征。结果表明,风力的侵蚀搬运对窟野河流域产沙起着重要的作用。月时间尺度上,风沙入河量存在"存储-释放"的过程;风蚀产沙贡献在3月和11-12月出现高峰值,4-9月风蚀贡献率逐渐降低;冬春季节淤积的泥沙,在夏季逐渐被冲走,到了9月,把淤积的泥沙最大限度冲走而开始新的淤积过程;月时间尺度上风蚀贡献率与风蚀气候因子分布趋势一致;7、8两月的风沙贡献量占年风蚀贡献总量的80.5%,风沙贡献量的峰值出现在7月,约7.75×10⁶ t。季尺度上,夏季风蚀贡献率最低,仅7.8%。秋、冬季逐渐升高,春季达到最高,风蚀贡献率为28.6%。年尺度上,风力作用对神木水文站以上流域的产沙贡献为17.2%,风蚀贡献量为12.7×10⁶ t/a。

Contribution Characteristics of Wind Erosion to the Sediment Yield in the Kuyehe River Watershed at Time Scales

Wind erosion plays an important role on sediment yield in complex erosion zone by wind and water of the Loess Plateau. Contribution characteristics of wind erosion to the sediment yield in the Kuyehe River watershed at time scales was estimated based on the sediment discharge records at Shenmu Hydrological Station and meteorological measurements recorded at meteorological stations in and around the watershed. The results reveal that wind erosion is a principal contributor to sediment yield of the Kuyehe River watershed. At the monthly scale, sediment yield from wind erosion had a restore-release process. Wind erosion contribution rate was the highest in March and November-December, and was lower from April to September. Alluvial sediment in winter and spring was gradually discharged in summer. The wind erosion contribution rate at the monthly scale was consistent with the wind erosion climatic factor. The amount of sediment of July and August from wind erosion occupied 80.5% of the total amount of a year. At the seasonal scale, wind erosion contribution rate in summer was the lowest of 7.8%, and gradually increased in autumn and winter, then reached the highest in spring of 28.6%. At yearly scale, wind erosion contribution rate is about 17.2% at catchments upstream of Shenmu Hydrological Station in the Kuyehe River watershed during the period 1956-1970.