县域尺度风力侵蚀栅格计算结果落地研究

Study on the Grid Calculation Results of Wind Erosion at County Scale

[目的]探讨基于栅格侵蚀数据确定风力侵蚀地块的状况,为县域尺度侵蚀计算和水土流失栅格计算结果落地等工作提供参考。[方法]以黄泛平原风沙区河南省兰考县为例,基于耕地风力侵蚀模型,采用栅格计算和软件判断方法,结合野外验证,探讨县域尺度风力侵蚀栅格计算结果落实到地块的状况。[结果](1)栅格计算的兰考县耕地风力侵蚀面积为125.91 km^(2),涉及1259128个栅格,侵蚀模数集中分布在200~400 t/(km^(2)·a)。(2)软件判断法统计的耕地风力侵蚀面积为125.08 km^(2),涉及2284个地块,侵蚀模数集中在200~400 t/(km^(2)·a);超过50%流失比例的地块占风力侵蚀地块总数的96%,100%流失比例的地块面积分布在0.00004~0.6 km^(2)。(3)在面积相对误差上,软件判断法与栅格计算法相对误差为0.66%,城关镇最大,达136.50%,张君墓镇最小,为0.56%;在空间分布上,软件判断法比栅格计算法聚集度指数高、离散程度低,空间分布集中、连续性强。(4)野外验证中,34个风力侵蚀地块强度与软件判断法相符,一致率为68%。[结论]在控制耕地地块面积的前提下,软件判断法将栅格计算风力侵蚀结果落实到地块方法可行,结果基本合理。

[Objective]This paper discusses the situation of determining wind eroded land plot based on grid erosion data,providing reference for county scale erosion calculation and soil erosion grid calculation results landing.[Methods]Lankao County,Henan Province,in the Yellow River alluvial area was taken as an example.Based on the wind erosion model of cultivated land,grid calculation and software judgment method combined with field verification were used to explore the implementation of grid calculation results of wind erosion at county scale to plots.[Results](1)The wind erosion area of cultivated land in Lankao County was 125.91 km^(2),involving 1259128 grids,and the erosion modulus concentrated in the range of 200 t/(km^(2)·a)and 400 t/(km^(2)·a).(2)The wind erosion area of cultivated land calculated by software judgment method was 125.08 km^(2),involving 2284 plots,and the erosion modulus concentrated between 200 t/(km^(2)·a)and 400 t/(km^(2)·a).The plots with more than 50%in loss proportion accounted for 96%of the total plots eroded by wind,and the plots with 100%in loss proportion ranged from 0.00004 km^(2) to 0.6 km^(2).(3)In terms of area relative error,the relative error of software judgment method and grid calculation method was 0.66%,the relative error for Chengguan Town was the largest(136.50%),and the relative error for Zhangjunmu Town was the smallest(0.56%).In the spatial distribution,the software judgment method had higher aggregation index and lower dispersion degree than the grid calculation method,and the spatial distribution was concentrated and continuous.(4)In the field validation,the intensity of 34 wind-erosion plots was consistent with the software judgment method,with an agreement rate of 68%.[Conclusion]Under the premise of controlling the land area of cultivated land,the software judgment method was feasible and reasonable to implement the results of wind erosion calculated by grid into the land area.