Using hydraulic parameters is essential for describing soil detachment and developing physically based erosion prediction models. Many hydraulic parameters have been used, but the one that performs the best for describing soil detachment on steep slopes when the lateral expansion (widening) of rills is not limited has not been identified. An indoor concentrated flow scouring experiment was performed on steep loessial slopes to investigate soil detachment rates for different flow rates and slope gradients. The experiments were conducted on a slope‐adjustable plot (5 m length, 1 m width, 0.5 m depth). Sixteen combinations of 4 flow rates (10, 15, 20, and 25 L/min) and 4 slope gradients (17.6%, 26.8%, 36.4%, and 46.6%) were investigated. The individual and combined effects of slope gradient and flow hydraulic parameters on soil detachment rate were analysed. The results indicated that soil detachment rate increased with flow rate and slope gradient. Soil detachment rate varied linearly and exponentially with flow rate and slope gradient, respectively. Multivariate, nonlinear regression analysis indicated that flow depth exerted the greatest influence on the soil detachment rate, followed by unit discharge per unit width, slope gradient, and flow rate in this study. Shear stress and stream power could efficiently describe the soil detachment rate using a power equation. However, the unit stream power and unit energy of the water‐carrying section changed linearly with soil detachment rate. Stream power was an optimal hydraulic parameter for describing soil detachment. These findings improve our understanding of concentrated flow erosion on steep loessial slopes. 相似文献
基于LMDZ(Laboratoire de Météorologie Dynamique-Zoom)模型的模拟数据、NCEP/ NCAR格点气象数据和北极涛动指数(Arctic Oscillation Index,AOI),验证了LMDZ模型在蒙古高原的适用性,分析了局地大气水线(Local Meteoric Water Line,LMWL)、降水中δ18O与环境因子的关系,探索了降水中δ18O、氘盈余(d-excess)的时空变化,并结合HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model)模型对蒙古高原气团运输轨迹进行了模拟。结果表明:在LMDZ模型的2种结果中,LMDZ-nudged模拟蒙古高原降水稳定同位素效果较好;计算得到的蒙古高原LMWL为δD=7.78δ18O+3.31(R2=0.995),其斜率和截距均小于全球大气水线( Global Meteoric Water Line,GMWL)斜率和截距,表明该区域雨滴下落中受云下二次蒸发影响较大;降水中δ18O夏高冬低,与温度、北极涛动指数呈正相关,而与相对湿度呈负相关。降水中d-excess呈现夏低冬高的特点;对蒙古高原后向轨迹追踪并对其进行聚类分析发现,研究区主要有3条水汽路径:西风带水汽(约88.39%)、东亚季风水汽(约5.73%)与极地水汽(约5.88%),其中西风带水汽为主控水汽。 相似文献
During the past 50 years, many research efforts have been invested in understanding soil erosion process and development of erosion prediction models at various scales. This paper briefly introduces the erosion process and prediction model development in the USA. Especially, this paper focuses on discussing potential impacts of the erosion process on erosion model development, and future directions of the soil erosion process research and process- based model development. 1 DEVELOPMENT O… 相似文献
Accurate, high-resolution precipitation data is important for hydrological applications and water resource management, particularly within mountainous areas about which data is presently scarce. The goal of the this study was to assess the accuracy of TRMM 3B43 precipitation data from the southwest monsoon region of China between 1998 and 2011 based on the correlation coefficients, regression, and geostatistical methods. We found a strong correlation between TRMM 3B43 data and observational data obtained from meteorological stations, but the TRMM 3B43 precipitation data was consistently lower than that obtained from the weather stations. The TRMM 3B43 data was significantly different from the data obtained by weather stations located in the northwest and northeast regions of the Hengduan Mountains. The spatial distribution of precipitation obtained from TRMM 3B43 was also different from meteorological data, but the deviation was predominantly distributed along the northern longitude and southern latitude. In addition, the TRMM data more accurately reflected the regional precipitation patterns. Our results indicate that the TRMM 3B43 data should be used for hydrological applications and water resource management at meteorological stations that have a sparse and uneven distribution of observation stations in the southwest monsoon region.