土壤中210Pbex背景值含量动态平衡模型

在利用土壤侵蚀模型估算侵蚀速率的过程中，背景值点选取的好坏直接关系到结论是否可靠，如果能通过科学计算得出研究区域背景值，将大大提高背景值的准确性，对研究土壤侵蚀具有重大意义。土壤未受到侵蚀和沉积的背景区，首先假设全球大气沉降量为定值，研究把²¹⁰Pb_ex沉降过程以一年为时间尺度划分为n年，经过n年以后（n=0，1，2，…，∞），土壤中²¹⁰Pb_ex沉降量和经过衰变减少量达到平衡，土壤中²¹⁰Pb_ex含量趋于稳定。假设各地年平均降水量为定值，通过研究发现²¹⁰Pb_ex的大气沉降通量与年降水量之间存在极显著相关（P < 0.01），区域年降水量是影响土壤中²¹⁰Pb_ex量的主要因素，由于年平均降水量不同，全球各地土壤中²¹⁰Pb_ex含量都会达到不同的稳定值，从而建立土壤中²¹⁰Pb_ex含量与年降水量关系模型。研究²¹⁰Pb_ex来源、沉降的连续性和稳定性，提出利用区域年平均降水量来计算该地区的²¹⁰Pb_ex背景值，建立土壤中²¹⁰Pb_ex背景值含量动态平衡模型，为准确确定²¹⁰Pb_ex背景值提供了方法，对研究土壤侵蚀具有重要的意义。

Dynamic Equilibrium Model of 210Pbex Background Value in Soil

Selection of background value point is directly related to the conclusion that is reliable or not in the process of estimating erosion rate by use of soil erosion model. If the background value can be calculated through scientific research, which will greatly improve the accuracy of the background value and is great significance of soil erosion study. In the background region, the soil is not affected by erosion and deposition, assuming that the atmospheric precipitation amount setting value. Based on the time scale of ²¹⁰Pb_ex sedimentation process for one year time scale, after n years later, the soil ²¹⁰Pb_ex settlement and the amount of ²¹⁰Pb_ex decay decrement achieve balance in this study. It is assumed that an average annual rainfall is constant in various regions. Research finds that correlation between ²¹⁰Pb_ex atmospheric subsidence flux and annual rainfall is extremely significant correlation(p<0.01). Regional annual precipitation becomes main factors affecting the amount of soil ²¹⁰Pb_ex. Because the annual rainfall is different around the world, the ²¹⁰Pb_ex content can reach the stability of the different values, so as to establish relationship model with annual precipitation ²¹⁰Pb_ex content in the soil. According to the ²¹⁰Pb_ex settlement continuity and stability, this research put forward to calculate the area of ²¹⁰Pb_ex background value through the regional average annual precipitation. According to the establishment of the soil ²¹⁰Pb_ex background value content dynamic equilibrium model, it provides a method of accurately determining ²¹⁰Pb_ex background value and has an important significance to regional soil erosion research.