Papers by Keyword: Rainfall Simulation

Abstract: Abstract. Rainfall simulation is a method of obtaining precipitation data on rainfall station based on precipitation data of other stations in same watershed at the same time, using a linear mathematical model constructed by Artificial Neural Network (ANN) method. The application of the simulation result is useful to provide information for the decision-makers. ANN backpropagation method is the one used in modeling the rainfall in a watershed because it can solve a complex mathematic problem. The objective of research was to find out the hydrologic model and its application to predict precipitation data at Bah Bolon watershed in the future. The input variable of research was data of rain at Bah Jambi rainfall station. The parameters used in this research were Mean Squared Error (MSE)= 0.028, epoch= 1000 iteration, hidden layer number= 2, neuron hidden layer number= 3, momentum= 0.7, learning rate: 0.9, training period= 4 years. The result of model verification shows the very strong correlation between simulated rain data and actual rain data, with score of 0.9664, and the reliability of hydrologic system model at Bah Bolon watershed is 64.48%.

Abstract: The red loam had abundant rainfall, rich in light and heat resource of Yunnan Province. But the uneven distribution of rainfall temporal during the year, it restricts the development of agriculture in this region. Thus how to use soil water resources reasonably and efficiency become the key to ensure crop and vegetation growth of needed water and improve the ecological environment. In this study, the key factor is district’s slope. Setting the runoff district’s rainfall intensity was 28.7mm/24h under rainfall simulation, selected four Yunnan Province read loam’ slop: 7.5°、10°、12.5°、15°.The results showed that at the same soil prophase water content and rainfall intensity, the higher runoff district’s slope will make it less time to product flow; At the beginning of product flow, flow of underground runoff was little, product flow was reached stable increase.

Abstract: Surface water film thickness is one of the main factors, which affect the vehicle safety on slippery roads. Water film depth is influenced by rainfall intensity, grades, cross slopes, drainage length and pavement texture. This paper reviews the research status and makes some comparative analysis of several pavement water film depth prediction models. An experimental validation has verified and calibrated the existing water film depth prediction models results. The experimental validation of the variable in the slope water flow model has been implemented by means of a small scale physical road model in a rainfall simulator, which is constructed in a laboratory. The results of comparative analysis have shown that in the existing water film depth prediction models, the regression models predict values are more closely than mathematical-physical models. Because under different experimental conditions, the regression model calibration parameters are different. In the case of specific road characteristics for prediction of water film thickness, the model parameters can be calibrated to further improve predicting accuracy.

Abstract: GIS technology and fractal theory provide a powerful tools in the soil erosion study.Based on GIS and three-dimensional laser，and under rainfall intensities of 45, 90 and 130mm/h with 20°slope gradient using simulated rainfall experiment, Amount of erosion , fractal dimensions and Hydraulic parameters were studied from different slope positions, Which was up-slope mid-slope and low-slope, The results showed that the distribution of erosion along the slope was difference in different rainfall intensity. the fractal dimensions increased along the slope，It indicated that the complexity of erosion increased with slope length. Reynolds number, Froude number, Darcy-weisbach drag coefficient and the shear stress were the important hydraulic parameters to study the soil erosion process and soil erosion mechanism. They were showed the same or the opposite trend with fractal dimensions, taking into the erosion distribution and erosion development process, Dynamics of soil erosion could be further advance.

Abstract: Soil erosion processes and erosion distribution was research focus to establish distributed mathematical equation in the soil erosion areas, GIS techniques and fractal theory provide a means to advance these studies.Slope erosion patterns of bare slope was studied under rainfall intensities of 45、90 and 130mm/h with 20°slope gradient using simulated rainfall experiment. The results showed that the time of rill appeared of lower rainfall intensity was later than that of high rainfall intensity；Within the rainfall time，the rill scale expanded increased with the increasing of rainfall intensity; The erosion distribution was studied by the three-dimensional laser scanner，The trend of rill erosion deep kept roughly consistent with that of sediment; The characteristics was analyzed of slope erosion by GIS, the fractal dimension and sediment were both increased with rainfall intensity, The fractal dimension was increasing with erosion pattern complexity. So the fractal dimension is the representative of erosion complexity.