准噶尔盆地表生生态环境演化及驱动力分析

发布时间：2018-11-24 10:18

【摘要】：准噶尔盆地地处我国西北旱区内陆盆地,降雨稀少、蒸发强烈,属于典型的生态环境脆弱区,其中天山北麓平原绿洲区是新疆经济文化发展的关键地域。21世纪以来,在西部大开发过程中西部旱区生态环境建设虽然取得了一定的成果,但局部改善、整体恶化是当前生态环境的现状,生态环境问题依然严峻。随着气候变化和人类活动的不断增强,特别是对水资源的不合理开发利用,准噶尔盆地出现了天然植被退化、土壤盐渍化、土地沙化、湖泊湿地萎缩等生态环境退化现象,此类生态环境问题严重威胁区域生态安全和经济社会的可持续发展。因此,开展生态环境演化及驱动机制研究,探究区域水循环与生态环境的关系,为实现水资源开发利用与生态环境的协调发展具有重要的理论价值和现实意义。论文以旱区水资源形成转化与表生生态环境关系为主线,基于LUCC理论、RS与GIS技术,深入分析了准噶尔盆地水循环与生态系统间的相互作用机理,系统研究了准噶尔盆地表生生态环境演化及生态环境问题,定量分析了表生生态环境演化的驱动机制,构建了基于地下水的表生生态环境评价体系。主要研究成果如下:(1)通过研究地下水循环演化与表生生态环境的关系,得出地下水状态对典型流域平原区表生生态环境具有控制作用,不同类型的植被生长指标与地下水位埋深、包气带土壤含水量、包气带土壤含盐量均呈对数关系,地下水位埋深对包气带土壤含水量和含盐量具有控制作用,由此构建了以地下水状态变量为基础的面向表生生态环境安全的多维临界标识指标体系。(2)基于旱区特征和水资源形成演化规律,以地下水循环演化与表生生态环境的关系为主线,将研究区划分为山地、人工绿洲、天然绿洲、天然水域和荒漠五大生态系统类型。基于遥感解译和LUCC理论系统分析了准噶尔盆地表生态环境格局—动态—演化特征:荒漠和山地生态系统是盆地的背景和基质,盆地生态环境总体极为脆弱。近40年来,荒漠生态系统的面积逐渐减少,人工绿洲生态系统的面积逐渐增加,天然绿洲生态系统的面积呈弱减少趋势,天然水域生态系统的面积略有减少。通过土地利用程度、土地利用动态度和土地利用转移矩阵分析可知:研究区土地利用程度总体增大,耕地和建设用地的面积增加,在人类活动影响下水资源利用量增加;永久性冰川雪地、山区林草地面积均呈减少趋势,说明准噶尔盆地水资源总量减少,水资源涵养能力呈下降趋势。(3)基于AVHRR-NDVI和MODIS-NDVI数据,利用最大值合成和时间序列数据重建技术获得研究区不同尺度的植被指数时间序列数据,采用均值、标准差和线性趋势法对准噶尔盆地和天山北麓植被覆盖变化进行不同时空尺度的研究,其总体特征为:(1)盆地尺度上:NDVI均值为0.158,NDVI小于0.2的面积占研究区总面积的43.8%,盆地整体植被覆盖度低,生态环境脆弱。1982-2006年植被指数年际变化幅度为0.0004/a,呈弱增加趋势。由NDVI空间变化分析可知,天山北麓平原区和戈壁带多年NDVI标准差均较大,属于生态环境强和较强敏感区,平原区多年植被指数呈显著增加趋势;山前戈壁带多年植被指数呈显著较少趋势,天山高山区植被指数呈增加趋势。(2)2001-2010年准噶尔盆地重点地段,即生态环境敏感区NDVI年际变化幅度为29.336/a,植被覆盖整体上是逐年增加的;植被极度增加的地区主要集中在农田植被区;植被减少区主要集中在中低山区的戈壁等稀疏植被地区;植被极度减少主要集中在湿地及水体边缘区。(4)基于天山北麓DEM数据、气象数据、地下水位埋深数据、土地利用类型、人口及GDP数据,采用空间分析和统计分析方法,对天山北麓植被覆盖变化的驱动力进行系统分析,天山北麓植被覆盖及其变化存在着明显的垂直分异特性。地质地貌因素控制着天山北麓表生生态环境的基本格局,气候变化、地下水状态和人类活动是天山北麓表生态环境在时间尺度上变化的主要驱动因素。在海拔大于700m的区域植被覆盖变化受坡度、坡向、降水和气温等自然因素的影响较大,而在海拔小于700m的平原绿洲区植被覆盖受土地利用类型、地下水位埋深、人口及经济因素的共同影响较大,而此类因素的变化来源于人类对水土资源的开发利用。(5)基于地下水的生态功能,构建了基于地下水动态的天山北麓表生生态环境评价指标体系,采用层次分析法对天山北麓平原区表生生态环境进行评价与预测,结果表明以现状条件开采地下水,研究区生态环境呈严重恶化趋势。基于生态环境约束条件,设计现状水利工程条件下的调控方案(A)和跨流域引水条件下的调控方案(B),经预测结果对比分析可知:方案B有助于维持天然河道的生态环境和地下水系统的动态平衡,优于方案A。
[Abstract]:The Quasi-Err Basin is located in the inland basin of the dry land in the northwest of China. The rainfall is rare and the evaporation is strong. It is a typical ecological environment fragile area, in which the oasis area of the northern foot of the Tianshan is the key region of the economic and cultural development of Xinjiang. Since the 21st century, Although the construction of the ecological environment in the arid region of the western part of the western region has achieved some achievements, the local improvement and the overall deterioration are the present situation of the present ecological environment, and the ecological environment problem is still serious. With the continuous enhancement of climate change and human activities, especially the irrational exploitation and utilization of water resources, the quasi-Niger basin has the phenomena of natural vegetation degradation, soil salinization, land desertification, and lake wetland atrophy. Such ecological environment problems are a serious threat to the regional ecological security and the sustainable development of the economy and society. Therefore, the research of the ecological environment evolution and the driving mechanism is carried out, and the relationship between the regional water circulation and the ecological environment is explored, which is of great theoretical value and practical significance in order to realize the harmonious development of the development and utilization of the water resources and the ecological environment. Based on the LUCC theory, RS and GIS, the mechanism of the interaction between the water circulation and the ecosystem of the Zhilerian basin is analyzed, and the ecological environment and the ecological environment are studied. The driving mechanism of the ecological environment evolution of the table was quantitatively analyzed, and the evaluation system of the ecological environment based on the groundwater was constructed. The main research results are as follows: (1) Through the study of the relationship between the groundwater circulation evolution and the ecological environment of the water table, it is concluded that the groundwater status has the control effect on the ecological environment of the normal plain area of the typical river basin, and the different types of vegetation growth indexes and the groundwater level are buried deep, and the water content of the soil water in the bag gas zone, The soil salt content of the bag gas zone is in a logarithmic relation, and the buried depth of the groundwater level has a controlling effect on the water content and the salt content of the soil in the bag gas zone, thereby constructing a multi-dimensional critical identification index system which is based on the underground water state variable as the safe environment-oriented ecological environment. (2) Based on the characteristics of the dry area and the law of the evolution of the water resources, the relationship between the groundwater circulation evolution and the ecological environment of the table is the main line, and the research area is divided into five types of ecosystem types in the mountain, the artificial oasis, the natural oasis, the natural water area and the desert. Based on the remote sensing interpretation and the LUCC theory, the dynamic and dynamic evolution of the basin's ecological environment pattern is analyzed systematically: the desert and the mountain ecosystem are the background and the matrix of the basin, and the ecological environment of the basin is extremely fragile. In the last 40 years, the area of the desert ecosystem is gradually reduced, the area of the artificial oasis ecosystem is gradually increased, the area of the natural oasis ecosystem is slightly reduced, and the area of the natural water area ecosystem is slightly reduced. Through the analysis of the land use degree, the land use dynamic attitude and the land use transfer matrix, the land use degree of the research area is increased, the area of the cultivated land and the construction land is increased, the utilization amount of the water resources is increased under the influence of the human activity, and the permanent glacier snow, The area of grassland in the mountain area is decreasing, which indicates that the total amount of water resources in the quasi-Err Basin is reduced, and the water resource conservation ability is decreasing. and (3) based on the AVHRR-NDVI and the MODIS-NDVI data, obtaining the vegetation index time series data of different scales of the research area by using the maximum synthesis and time sequence data reconstruction technology, and adopting a mean value, The standard deviation and the linear trend method are used to study the changes of vegetation cover in the quasi-Err basin and the northern part of the Tianshan Mountains. The overall characteristics are: (1) basin scale: the mean NDVI is 0.158, and the NDVI is less than 0.2, the area of the total area of the study area is 43.8%, and the overall vegetation coverage of the basin is low. The index of vegetation index in 1982-2006 was 0. 0004/ a. The NDVI spatial variation analysis shows that the standard deviation of the NDVI of the plain and the Gobi in the northern piedmont of the Tianshan Mountains is large, and it is the strong and sensitive area of the ecological environment. The vegetation index in the plain area has a significant increase in the multi-year vegetation index. The vegetation index of the high mountain area in the Tianshan Mountains is increasing. (2) In 2001-2010, the key section of the Zhilerian basin, that is, the inter-annual change of the NDVI in the sensitive area of the ecological environment is 293.336/ a, and the vegetation cover is increasing year by year; the area with the extreme increase of the vegetation is mainly concentrated in the field vegetation area; The vegetation reduction area is mainly concentrated in the sparse vegetation areas such as the Gobi and the like in the middle and low mountain areas; the vegetation is extremely reduced mainly in the wetland and the water body edge area. (4) Based on the DEM data, the meteorological data, the buried depth data of the groundwater level, the type of land use, the data of the population and the GDP, the spatial analysis and the statistical analysis method are adopted to analyze the driving force of the vegetation cover change of the northern foot of the Tianshan, The vegetation cover and its change in the northern part of the Tianshan Mountains have obvious vertical and different characteristics. The geological and geomorphological factors control the basic pattern of the ecological environment in the northern piedmont of the Tianshan. The main driving factors of the change of the ecological environment on the time scale are the climate change, the groundwater status and the human activity. In the area with the elevation greater than 700m, the vegetation cover change is affected by the natural factors such as the slope, the slope, the precipitation and the air temperature, while the vegetation cover of the plain oasis area with the elevation of less than 700m is affected by the land use type, the buried depth of the groundwater level, the population and the economic factors, The change of these factors is derived from the development and utilization of human resources. (5) Based on the ecological function of the groundwater, the evaluation index system of the ecological environment of the northern piedmont of the Tianshan mountain is constructed based on the groundwater dynamic, and the ecological environment of the Pingyuan area of the northern part of the Tianshan Mountains is evaluated and predicted by the analytic hierarchy process. The results show that the groundwater is mined in the condition of the present condition. The ecological environment in the study area is a serious trend. Based on the ecological environment constraint conditions, the control scheme (A) under the condition of the current water conservancy project and the control scheme (B) under the water diversion condition of the river basin are designed, and the comparison and analysis of the predicted results shows that the scheme B can help to maintain the dynamic balance of the ecological environment and the underground water system of the natural river channel, is superior to scheme a.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：X171

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