随机模拟畦面微地形分布及其差异性对畦灌性能的影响

畦面微地形对畦灌性能具有较大影响，该文针对畦面相对高程分布具有随机性和空间相关性的特点，基于Monte-Carlo随机模拟方法和半方差分析方法建立了随机模拟畦面微地形分布状况的方法，并借助二维地面灌溉模型评价随机模拟的畦面微地形分布状况及其差异性对畦灌性能的影响。研究结果表明：同一畦面相对高程标准偏差值下随机模拟的畦面微地形分布间存在的差异性对畦灌性能的影响取决于该值大小，等于或大于3 cm以上的畦面微地形分布间存在的较大差异对畦灌性能影响显著，而小于3 cm的畦面微地形间存在的分布差异对畦灌性能影响相对较小，此条件下随机模拟的任一组畦面微地形分布状况均具有典型代表性，可直接作为二维地面灌溉模型的输入数据用于评价畦面微地形分布状况对畦灌性能的影响。

Impacts of stochastic modeling microtopograpy distribution and its discrepancy on basin irrigation performance

Microtopography has an important impact on basin irrigation performance. Considering both stochastic characteristic and spatial correlation of the surface relative elevation, a method used to stochastic modeling microtopography distribution was based on the Monte-Carlo technique and the semi-variance approaches, and a two-dimensional surface irrigation simulation model was used to evaluate impacts of stochastic modeling microtopography distribution and its discrepancy on the basin irrigation performance. Research results show that for the same standard deviation(S_d) of surface relative elevation, the effect of discrepancy on microtopography distribution on the basin irrigation performance is dependent directly upon the size of S_d. When the S_d is no less than 3 cm, the discrepancy on microtopography distribution makes a significant impact on the basin irrigation performance, while the S_d is less than 3 cm, the effect is relatively small. It suggests that any one-set of stochastic modeling microtopography distribution under the condition of S_d<3 cm is representative of whole, which can be used as the input data of the two-dimensional surface irrigation simulation model for evaluating the impacts of microtopography distribution on the basin irrigation performance.