黄土高原风水蚀交错带风力作用对流域产沙贡献的空间特征研究

Spatial characteristic research on wind erosion contribution to sediment yield in wind and water complex erosion zone of loess plateau

利用黄土高原风水蚀交错带水文站水沙资料及有关气象资料,分析了风力作用对流域产沙贡献的空间特征。结果表明:风沙区并不是风蚀贡献最大的区域,风蚀贡献率约为1/4。风沙区和黄土丘陵沟壑区交界处的风蚀贡献急剧增大。靠近风沙区并有零星片沙分布的区域,风蚀贡献率约为1/3。风蚀贡献最大的区域为穿过风沙区和黄土丘陵沟壑区的流域,约为2/5。黄土丘陵沟壑区,风蚀贡献率约为1/10～1/4。河源梁涧区的风蚀贡献率小于1/10。风蚀贡献率的大小依次为河源梁涧区<黄土丘陵沟壑区<风沙区<风沙区和黄土丘陵沟壑区交界处<穿过风沙区和黄土丘陵沟壑区的流域。整个黄土高原风水蚀复合区风力作用产生的输沙量接近流域总输沙量的1/10～1/5,风沙入河量占d>0.05 mm粗泥沙年输沙量的1/4。

Spatial characteristics of wind erosion to the sediment yield in the watershed was estimated based on the sediment and meteorological records in hydrological stations.In desert,wind erosion contribution to sediment yield is not the biggest,and the sediment yield associated with wind erosion was only about 1/4.In the margin of the loess hills and gullies which is near the deserts and covered with sporadic patches of sands,the contribution sharply increased,and the proportion is about 1/3.The highest proportion,about 2/5,of sediment yield due to wind erosion occurred in the area where the river flows between sands and loess areas.In the areas with loess hills and gullies,the contribution was about 1/10～1/4.The lowest proportion,lower than 1/10 of sediment yield occurred in the area of river source with hills.The arrange of wind erosion contribution to sediment yield from lowest to highest is the area of river source with hills,the areas with loess hills and gullies,desert,the margin of the loess hills and gullies,the area where the river flows between sands and loess areas.For the whole complex erosion zone by wind and water of the loess plateau,wind erosion contribution to sediment yield was between 1/10 and 1/5,the amount of sediment yield due to wind erosion was about 1/4 of the sediment yield whose aiameter was larger than 0.05mm.