Studies on the development of model to estimate the soil moisture with AMeDAS data

利用AMeDAS数据估算土壤湿度模型的开发研究

基本信息

批准号：
63560248
负责人：
NAKAYAMA Keiichi
金额：
$ 1.09万
依托单位：
Chiba University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63560248/
关键词：
Soil moisture Evapotranspiration Capillary rise Water balance

项目摘要

The studies were conducted to develop the model to estimate the soil moisture in the root zone by using only AMeDAS data of the meteorological agency. The model is based on the water balance of the root zone and is composed by some submodels which are connected with the terms of the water balance. The outline and the experimental results on adaptability of the model are summarized as follows:Submodel to estimate the evapotranspiration was constructed by combining the Priestley Taylor method to estimate the potential evapotranspiration and the formula to calculate the net radiation from the duration of sunshine. Furthermore, to estimate the actual evapotranspiration from any surface moisture condition, the complementary relationship was available with the pan evaporation.Submodel to estimate the capillary rise was constructed by using the Darcy's law which has the unsaturated hydraulic conductivity of concerned soil and the hydraulic gradient. The hydraulic gradient was calculated by the difference of hydraulic potential between the center of the root zone and the depth of 100 cm from the center of the root zone. The hydraulic potential at the depth of 100 cm from the center of the root zone was assumed as the potential corresponded to the field capacity of the soil.Method for estimating the outflow from the root zone after the heavy rain is composed of the surface runoff and the percolation at bottom of the root zone. In this work, we could propose the method to calculate on the basis of the assumption that the soil moisture in the root zone was corresponded to the field capacity when the zero-flux layer arrived at the bottom of the root zone.Through the experiments on the adaptability of the model at the loose sloping field,the ridging field and etc., we found out that the model represented the soil moisture in the root zone fairly well.

进行了研究以开发模型，以通过仅使用气象局的AMEDAS数据来估计根部区域的土壤水分。该模型基于根部区域的水平衡，并由与水平衡项相关的某些子模型组成。概述了模型适应性的轮廓和实验结果如下：子模型通过结合Priestley Taylor方法来构建蒸发量的子模型，以估算潜在的蒸散液和公式来计算阳光持续时间的净辐射。此外，为了估算任何表面水分条件中的实际蒸散液，与PAN蒸发可用。用于估计估计毛细血管上升的估计是通过使用Darcy定律构建的，Darcy定律具有相关土壤和液压梯度的不饱和水力导电性。液压梯度是根据根部区域中心和距根区中心100 cm的深度之间的液压电势计算得出的。假定从根部区域中心的100 cm深度的液压电势被假定为电势与土壤的田间容量相对应。用于估算大雨后从根部区域流出的流出量和根部区域底部的渗透率。在这项工作中，我们可以提出一种基于以下假设计算的方法，即零升压层到达根部区域的底部时，根部区域中的土壤水分对应于田间容量。通过对模型的适应性进行实验。在宽松的倾斜场，脊场等上，模型的适应性，我们发现模型在模型中表明了土壤湿度在根区域中很好地表示。