以民勤地区4种地表条件的3次风蚀实测数据为依据,应用WEPS风蚀子模型对风蚀量进行了预测计算。结果表明:WEPS模型预测的土壤风蚀量与实测结果存在很大差异,不能直接用于我国土壤风蚀预报工作。对没有植被覆盖的流沙地表,模型模拟结果与实际测量结果比较接近,计算值最大为模拟值的2.2倍,最小为0.47倍;当有植被覆盖时,模型预测风蚀量偏大,最大值为实测结果的41倍,最小为6.7倍。要引入WEPS模型在我国进行土壤风蚀预报,还需对模型的各项参数和计算公式进行修正,以提高WEPS的预测精度,更好地为我国风蚀预报及沙尘治理工作服务。
Wind erosion results in degradation of the land resources and destroys the ecological environment,which had stimulated a great deal research work in this region.How to predict the soil erosion and the changes of ecological environment aroused by the wind erosion has become an important problem,and it is necessary in the wind erosion control and sustainable use of the land.Based on the field observation of three sand storms in Minqin Desert,the paper investigated the application of Wind Erosion Prediction System(WEPS)in this area.The sand storms occurred on April 19,April 22 and April 23,April 30 of 2009,respectivly.Because there was a continuous wind on April 22 and April 23,the Aeolian sediments after the storm on April 23 was adopted and the two days’storm was accounted as a sand storm.The paper applied the wind erosion submodel of WEPS to calculate the aeolian discharge in Minqin desert,aiming at exploring the adaptability of WEPS in China,or rather in this region.The results showed that there is a big difference between the practical measured aeolian discharge and the predicted wind-blown mass transport.For fields without natural vegetation and any other plant,WEPS gave a relative good estimation of Aeolian discharge,the maximum calculated value is about 2.2 times as the measured soil discharge mass,and the minimal value is just 0.47.For fields with natural vegetation at and around the research plot,WEPS overestimated the aeolian discharge mass.The maximum calculated value by WEPS is about 41 times as the measured,and the minimal ratio is about 6.7.So,if this model is used without any amendment,it will give a wrong aerolian discharge.Input parameters for WEPS such as wind speed,roughness length,vegetation cover,soil crust and soil diameter were measured to determine friction velocity and threshold friction velocity.Therefore,to want a good prediction of WEPS in China,a great deal of experiments should be conducted to measure these parameters under different means of land use and cultivation in areas whe