本文選題：粒子群算法 + 土壤水分運動參參數(shù)��； 參考：《東北農業(yè)大學》2016年碩士論文

【摘要】：黑龍江省冬季寒冷,歷史上最低的氣溫達到過零下50℃,白天和夜晚的溫差較大。冬季降雪,積雪覆蓋在廣袤農田上的時間能夠持續(xù)整個冬季,并為春季作物生長提供了一定的水源。由于積雪具有高導熱性弱、反射率高、熱容量等特性影響土壤溫度和含水率的變化。研究積雪覆蓋條件下土壤水分的傳遞規(guī)律以及土壤水分運動參數(shù)和含水率的關系對于水分在自然界中的循環(huán)轉移有重要意義。在凍結期由于室外溫度低,土壤中的水分基本不轉移同時土壤的深層基本保持恒定,所以雪的存在為春季農業(yè)生產提供了一定的水資源保證,土壤溫度的變化也為工程力學和工程凍脹研究提供了相應的研究思路。應用優(yōu)化算法通過計算機編程確定土壤的水分運動參數(shù)的方法能夠克服土壤空間變異的特性使研究模型精度得到保證。本研究即有在土壤水分運動模型和優(yōu)化算法求解土壤水分運動參數(shù)模型上具有較高的理論意義,對于農業(yè)生產和土壤特性分析等方面又有將強的實踐意義。因此本文的研究主要內容、材料方法、主要結論歸納總結如下:(1)表層土壤剖面溫度有積雪覆蓋的土壤度高于無積雪覆蓋土壤,無積雪覆蓋的土壤由于可以直接吸收太陽輻射進行能量交換所以隨著時間的推移溫度變化明顯。溫度保持不變時土壤溫度隨之恒定不變。自然降雪、積雪壓密、積雪加厚的表層土壤剖面溫度基本保持不變。自然降雪、積雪覆蓋、積雪壓密能夠保持土壤溫度,保持的深度范圍為100 cm,超過100cm后各個小區(qū)的剖面溫度基本保持一致不發(fā)生變化。(2)將粒子群算法引入到季節(jié)性凍土水分遷移規(guī)律研究中,提出了一種新的季節(jié)性凍土水分運動參數(shù)識別方法。建立了基于粒子群算法的參數(shù)識別模型,實現(xiàn)了季節(jié)性凍土水分運動參數(shù)的優(yōu)化。通過優(yōu)化模型計算的土壤導水率和擴展率與實測值總體變化趨勢一致,通過分析發(fā)現(xiàn)實測值忽略了土壤容重隨空間的變化,所以優(yōu)化模型更適合田間土壤實際應用。采用優(yōu)化后的參數(shù)模型模擬土壤體積含水率具有較高的精度,模擬值和真實值各點的最大絕對誤差僅為2.57%,最大相對誤差僅為5.53%,平均相對誤差僅為2.51%,表明建立的季節(jié)性凍土水分遷移模型可以很好的模擬水分的遷移規(guī)律[1],同時可以反映粒子群算法可以較好的優(yōu)化季節(jié)性凍土的水分運動參數(shù)。研究成果對于指導農田的灌溉與排水、土壤的蒸發(fā)、地下水補給和植物根區(qū)土壤水分運動具有重要的理論和實踐意義。(3)推導了柱坐標和球坐標中的土壤水分運動的基本方程,并且推導了零通量面與通量面、表面通量法、定位通量法的運算過程。梳理了一維土壤水分運動方程的差分求解的三種方程。對積雪覆蓋條件下的土壤水分運動方程進行差分求解,將相應方程轉化為追趕法求解的形式,利用MATLAB編程求解該方程,計算結果表明:所建的水分遷移模型可以很好的模擬有積雪覆蓋邊界條件下的土壤水分狀況。
[Abstract]:Heilongjiang province is cold in winter, the lowest temperature in history reaches 50 degrees below zero, and the temperature difference between day and night is greater. Winter snowfall, snow cover on vast farmland can continue throughout the winter, and provide a certain water source for spring crop growth. The snow has the characteristics of high thermal conductivity, high reflectance, heat capacity and so on. The change of soil temperature and water content. The study of the law of soil moisture transfer under the condition of snow cover and the relationship between soil moisture movement parameters and water content is of great significance to the circulation and transfer of water in nature. In the freezing period, the water base in the soil is not transferred and the soil is basically preserved because of the low outdoor temperature. The existence of snow provides a certain water resource for the agricultural production in spring, and the change of soil temperature also provides the corresponding research ideas for the research of Engineering Mechanics and engineering frost heave. The application of the optimization algorithm to determine the soil moisture movement parameters through computer programming can overcome the characteristics of soil spatial variation. The accuracy of the model is guaranteed. This study has a high theoretical significance on soil moisture movement model and optimization algorithm for soil moisture movement parameter model. It is of great practical significance for agricultural production and soil characteristics analysis. Therefore, the main contents, material methods and main conclusions of this paper are summarized and summarized in this paper. The following are as follows: (1) the surface soil profile with snow covered soil is higher than that of no snow covered soil. The soil without snow covered soil can exchange energy because of the direct absorption of solar radiation, so the temperature changes with time. The soil temperature keeps constant when the temperature is kept constant. The temperature of the thickened surface soil section remains unchanged. The natural snow, snow cover, and snow cover can keep the soil temperature, the depth of the depth is 100 cm, and the temperature of the section of each plot after more than 100cm does not change basically. (2) the particle swarm optimization algorithm is introduced to the study of the water migration law of seasonal frozen soil. A new method for identifying water movement parameters of seasonal frozen soil is developed. A parameter identification model based on particle swarm optimization is established to optimize the water movement parameters of seasonal frozen soil. The soil water conductivity and expansion rate calculated by the optimized model are in accordance with the overall change trend of the measured values. The soil bulk density varies with space, so the optimization model is more suitable for the practical application of soil in the field. The maximum absolute error is only 2.57%, the maximum relative error is only 5.53%, the average relative error is only 2.51%, which indicates the established season. The water migration model of the segmental frozen soil can well simulate the migration law of water [1], and it can also reflect the particle swarm optimization to optimize the water movement parameters of the seasonal frozen soil. The research results are important to guide the irrigation and drainage of the farmland, the evaporation of soil, the recharge of groundwater and the soil water movement in the plant root zone. (3) the basic equations of soil moisture movement in cylindrical coordinates and spherical coordinates are derived, and the operation process of zero flux surface and flux surface, surface flux method and location flux method are derived. The three formulas for the difference solution of one dimension soil moisture movement equation are combed. The soil moisture movement under the condition of snow cover is given. The difference solution is carried out, and the corresponding equation is transformed into the form of the pursuit method, and the MATLAB programming is used to solve the equation. The calculation results show that the water migration model can well simulate the soil moisture condition under the condition of snow covered boundary conditions.

【學位授予單位】：東北農業(yè)大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：S152
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本文編號：1862588