艾比湖流域土壤盐渍化地区生态环境遥感监测研究

发布时间：2018-06-01 00:20

本文选题：艾比湖地区 + 土壤盐渍化　；参考：《新疆大学》2017年硕士论文

【摘要】：土壤盐渍化及次生盐渍化严重制约着社会经济的不断发展,威胁生态系统的稳定,是世界各国所面临的主要生态环境问题之一。艾比湖流域处于极端干旱的荒漠地带,气候干燥,生态系统极为脆弱。近年来,由于水资源及土地资源不合理利用致使湖水减少,湖面萎缩,水盐运移发生变化。艾比湖地区地下水位不断升高,裸露干涸湖底盐漠化,盐尘暴活动频繁,对该地区乃至北疆造成了严重的影响。土壤盐渍化问题已成为艾比湖地区重要的生态环境问题之一,盐渍化监测治理刻不容缓。因此准确、科学、迅速获取盐渍化变化的程度、空间分布特征、水盐运移规律等信息,给定量化监测和预报区域盐渍化的动态变化提供重要依据,对艾比湖地区土壤盐渍化的治理利用、统筹规划具有重要意义。本文以实测数据为基础,利用统计学和地统计学分析,分析当前艾比湖地区土壤盐渍化特征和空间分布;以遥感影像为数据源,结合实测电导率数据,研究不同指数对土壤盐度的敏感性;选取对土壤盐度最敏感的指数,构建艾比湖地区土壤盐渍化生态环境指数,对土壤盐渍化影响区域的生态环境进行快速、定量、客观的监测,以期为艾比湖地区土壤盐渍化治理提供一个新的思路。研究结论如下:(1)利用描述性统计方法对土壤样品的理化性质进行统计分析,得到艾比湖地区土壤盐分有明显的表聚现象,表层(0-10 cm)土壤含盐量最高,电导率值最大,土壤盐分离子含量按阳离子由高到低为Na~+Ca~(2+)K~+Mg~（2+）,按照阴离子SO_4~(2-)Cl-HCO_3~-。表层土壤盐分的组成类型按阴离子分类主要以硫酸盐、氯化物盐为主,按阳离子分类主要以钠盐、钙镁盐为主。各土层pH的平均值在8.16-8.49之间土壤偏碱性。土壤剖面主要分为三种类型:表聚型土壤盐分剖面、中聚型土壤盐分剖面和底聚型土壤盐分剖面。通过冗余分析及相关分析得出,土壤电导率和土壤含盐量极显著的正相关关系,表层土壤含盐量和七个盐分离子都通过了显著性检验。pH相比于其他盐分离子与HCO_3~-、Na~+相关性更强。(2)利用半方差函数进行分析,得出pH、EC、HCO_3~-、SO_4~(2-)、Na~+和Mg~(2+)的块金值和基台值之比小于0.25,具有非常强的空间相关性。K~+、Ca~(2+)的块金值和基台值分别为0.342、0.478,受随机因素和结构性因素影响,属于中等空间相关性。Cl-是弱空间变异强度。pH、SO_4~(2-)、Na~+和Ca~(2+)拟合最好的理论模型是指数模型(Exponential),EC、HCO_3~-、K~+、Mg~(2+)最优拟合理论模型是球状模型(Spherical),CI-最优拟合模型是线性模型(Linear)。从克里金插值图中可以看出艾比湖地区表层土壤含盐量与EC的分布规律大体相同,在湖区的东北、西南方向含盐量较高。pH属于弱空间变异,分布较均匀。各离子含量的分布规律总体上呈现出由湖滨向外围递减。(3)基于Landsat8 OLI影像提取了5种盐分指数、4种植被指数、地表反照率以及湿度指数,结合实测土壤电导率数据,利用曲线估计的方法,分析了不同指数对土壤盐度的响应程度。研究发现,5种指数与土壤电导率通过了显著性检验,对盐渍化程度敏感性程度高。其中盐分指数中基于Cubic模型的SI3指数表现最好,R2=0.713,EVI指数相比于其他植被指数在艾比湖地区对土壤盐渍化响应最敏感,R2=0.784。地表反照率中表现最好的模型是Cubic模型,R2=0.665,相关性最好。基于WI指数的Cubic模型拟合效果相对较好,R2=0.735。(4)利用主成分分析,耦合植被指数、盐分指数、土壤湿度和地表反照率,构建SSEI指数。结果表明:土壤含盐量与土壤盐渍化生态指数SSEI表现出负相关性,R2=0.7512,这表明SSEI指数可以用于该区域由土壤盐渍化主导引起的生态环境评价。四期遥感影像第一主成分的贡献率分别为75.61%、75.22%、78.82%、82.20%,均在75%以上,盐分指数与植被指标对主成分PC1的贡献量最大,植被指数呈正值,盐度指数呈负值,说明植被与盐度指标对生态环境的影响相反,这与一般生态意义上的结果相一致。(5)将SSEI指数分成差、较差、中等、良、优5个等级。统计得出1990-2015年,生态级别为优、良等级所占的面积下降了8.78%,盐渍化生态指数为差-中级所占的面积升高了8.78%,说明艾比湖地区盐渍化区域整体生态环境质量在下降。从检测图中可以看出绿洲区域的生态环境质量上得到显著的改善,非人类影响的荒漠地区,生态环境质量较差,土壤盐渍化引起的生态问题仍然十分严峻。
[Abstract]:Soil salinization and secondary salinization seriously restrict the continuous development of social economy and threaten the stability of the ecosystem. It is one of the main ecological environment problems facing all the countries of the world. The Ebinur Lake Basin is in the extreme arid desert area, the climate is dry and the ecosystem is extremely fragile. In recent years, because of the unreasonable water resources and land resources, the water resources and the land resources are not reasonable. With the reduction of lake water, the lake surface atrophy and the change of water and salt movement. The water level of the lake area is increasing, the salt desertification of the bare bottom of the lake and the frequent salt dust storm have caused serious influence on the area and the northern Xinjiang. The soil salinization has become one of the important ecological environmental problems in the Ebinur Lake area, and the salinization is monitored and treated. Therefore, it is of great importance to accurately, scientifically and quickly obtain the degree of changes in salinization, spatial distribution characteristics, and water and salt migration rules, which provide important basis for quantitative monitoring and prediction of dynamic changes in regional salinization. It is of great significance to the control and utilization of soil salinization in the Ebinur Lake area and the overall planning of the soil salinization. On the basis of statistics and Geostatistics Analysis, the characteristics and spatial distribution of soil salinization in the current Ebinur Lake area are analyzed. The sensitivity of different indices to soil salinity is studied with remote sensing image as the data source and measured electrical conductivity data, and the most sensitive index of soil salinity is selected to construct the ecological ring of soil salinization in Ebinur Lake area. The boundary index, which provides a new idea for the treatment of soil salinization in the Ebinur Lake area, provides a new idea for the soil salinization control in the area of Ebinur Lake. The conclusions are as follows: (1) the physical and chemical properties of soil samples are statistically analyzed by the descriptive statistics method, and the soil salinity of the Ebinur Lake area is clear. The surface (0-10 cm) soil has the highest salt content and the highest electrical conductivity. The content of soil salt ions is Na~+Ca~ (2+) K~+Mg~ (2+) from high to low. According to the composition type of the surface soil salt of the anion SO_4~ (2-) Cl-HCO_3~-., the main contents of the anion are sulfate and chloride salt, mainly by cation classification. The average value of pH in each soil layer is alkaline between 8.16-8.49 and soil. The soil profile is mainly divided into three types: the surface soil salt section, the medium type soil salt section and the bottom soil salt section. By the redundancy analysis and the correlation analysis, the soil soil conductivity and the soil salt content are very significant positive correlation. The relationship, the salt content of the surface soil and the seven salt ions have passed the significance test. Compared with other salt ions,.PH has a stronger correlation with HCO_3~- and Na~+. (2) the semi variance function is used to analyze pH, EC, HCO_3~-, SO_4~ (2-), Na~+ and Mg~ (2+), and the ratio of the base value is less than 0.25, and has a very strong spatial correlation.K~+. The value and base value of ~ (2+) are 0.342,0.478 respectively, which are influenced by random factors and structural factors, and the middle spatial correlation.Cl- is the weak spatial variation intensity.PH, SO_4~ (2-), Na~+ and Ca~ (2+) fitting the best theoretical model is the exponential model (Exponential), EC, HCO_3~-, which is a spherical model. L), the optimal fitting model of CI- is linear model (Linear). From Kriging interpolation, it can be seen that the distribution of salt content in the surface soil of Ebinur Lake area is the same as that of EC. In the northeast of the lake area, the salt content of the southwest of the lake area is relatively high,.PH belongs to the weak spatial variation and the distribution is more uniform. The distribution of each ion content is generally presented by the lakeside. (3) 5 kinds of salt index, 4 planting index, surface albedo and humidity index were extracted based on Landsat8 OLI image. According to the measured soil conductivity data, the response degree of different index to soil salinity was analyzed by the method of curve estimation. The study found that the 5 indices and soil conductivity passed the significant test. The degree of sensitivity to salinization degree is high. The SI3 index based on Cubic model in salt index is the best, R2=0.713, EVI index is the most sensitive to soil salinization in Ebinur Lake area compared with other vegetation index, and the best model of R2=0.784. surface albedo is Cubic model, R2=0.665, and the best correlation is based on WI. The fitting effect of Cubic model is relatively good. R2=0.735. (4) uses principal component analysis, coupling vegetation index, salt index, soil moisture and surface albedo, and constructs SSEI index. The results show that soil salt content and soil salinization ecological index SSEI show negative correlation, R2=0.7512, which indicates that SSEI index can be used in this region by soil. The contribution rate of the first principal component of the four phase remote sensing image is 75.61%, 75.22%, 78.82% and 82.20%, respectively, which are above 75%. The contribution of the salt index and the vegetation index to the principal component PC1 is the largest, the vegetation index is positive, and the salinity index is negative, indicating the effect of vegetation and salinity on the ecological environment. On the contrary, it is consistent with the general ecological results. (5) the SSEI index is divided into poor, poor, medium, good, and excellent 5 grades. The statistics show that 1990-2015 years, the ecological grade is excellent, the area of good grade is 8.78%, the salinization index is 8.78%, which indicates that the salinization area of the Ebinur region is whole. The quality of the ecological environment is declining. It can be seen from the test map that the ecological environment quality of the oasis area has been greatly improved, the non human affected desert areas, the ecological environment quality is poor, the ecological problems caused by soil salinization are still very severe.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S156.41;S127

【参考文献】