鄂尔多斯高原生态水文指数与地下水的关系研究

发布时间：2018-01-30 06:09

本文关键词： 干旱指数植被指数降水产流植被耗水都思兔河海流兔河　出处：《中国地质大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：陆地植被生态系统如何同时受到气候梯度和地下水的影响?这是生态水文地质学研究的基本问题之一。本文以鄂尔多斯高原这个干旱-半干旱气候过渡地区为例,提出分布式生态水文指数的概念,对这一问题开展了专门的研究。生态水文指数是指能够反映陆地生态系统水分供给程度、物种生存状况、水文功能和生态耗水强度等各方面特性的定量指标。本论文建议的生态水文指数包括4种,即干旱指数、植被指数、降水产流指数和植被耗水指数。干旱指数(φ)反映气候背景。植被指数包括增强型的归一化植被指数(EVI)和叶面积指数(LAI),反映植被覆盖特征。降水产流指数(C_r)是反映大气降水在被陆面蒸散消耗之后剩余产流的能力,在干旱区反映的是地下水补给能力。植被耗水指数(Cw)反映的是植被生态区消耗水分的程度。这些指数都在遥感数据的像元尺度计算,分辨率为250 m~1 km。本论文以鄂尔多斯高原的都思兔河-无定河东西向片区为重点,以气象数据、遥感数据和地下水观测数据为基础,加工生成了以上4种生态水文指数的分布式数据和地下水埋深(d)数据。其中,降水产流指数和植被耗水指数都以实际陆面蒸散为计算基础,采用1 km分辨率的MOD16陆面蒸散和MuSyQ陆面蒸散数据,经过流域尺度水平衡校正生成。统计分析表明生态水文指数和地下水埋深都不服从正态分布。在250 m空间分辨率基础上,本论文详细分析了植被指数EVI与干旱指数和地下水埋深的关系。随着干旱指数和地下水埋深的增加,EVI总体上都存在减小趋势,但是单因素的相关分析不足以充分反映EVI的空间变化规律。本论文建立双因素(φ-d)坐标系,将双因素空间划分为网格区间统计EVI的特征值(p=50%和p=98%),绘制特征值变化曲线。这种双因素空间分布图揭示了干旱指数和地下水埋深对植被指数的联合影响,发现植被指数对地下水比较敏感的埋深段是d7 m。半干旱气候条件下,EVI随d的增加呈减小趋势;但是当φ6时,EVI随d的减小而降低,这是浅埋深地下水强烈蒸发诱发土壤盐渍化造成的。在1 km分辨率基础上,其它生态水文指数也存在复杂的相关性。地下水埋深为250 m分辨率的数据采用合理的尺度提升为1 km分辨率的有效地下水埋深(d_e)数据,用于分析生态水文指数与多个因素的相关特征。随着干旱指数的增加,基于MOD16数据的降水产流指数(C_r)和植被耗水指数(Cw)都呈现减小的趋势,但基于MuSyQ数据的C_r与干旱指数相关性并不显著。另外,叶面积指数(LAI)对降水产流指数(C_r)和植被耗水指数(Cw)都有强烈的影响:随着LAI的增加,C_r减小而Cw增大。为此,本论文又建立了LAI-d_e双因素坐标系来分析C_r和Cw对植被指数与地下水的联合响应。当LAI较低时,C_r和Cw的特征值(p=50%和p=90%)在某个地下水埋深段呈现极大值或极小值;当LAI较大时,C_r和Cw与地下水埋深的关系不显著。互相关的相关系数和协方差矩阵结果表明,C_r和Cw与LAI的相关性远大于它们与干旱指数的相关性,而地下水埋深对LAI与干旱指数的相关性以及降水产流指数与干旱指数的相关性有一定的影响。论文研究成果为鄂尔多斯高原植被生态格局及其控制因素提供了新的认识,并从统计规律的角度初步揭示了植被指数对降水产流和地下水补给的影响。
[Abstract]:How to land vegetation is also affected by the climatic gradient and groundwater? This is one of the basic problems in the study of eco hydrological geology. In this paper, the Erdos plateau arid semiarid climate transition area as an example, the concept of distributed eco hydrological index, on this problem is studied. The eco hydrological index refers to reflect the land water supply ecological system, survival status of species, quantitative indicators of hydrological function and ecological water consumption intensity and other aspects of the characteristics of eco hydrological index. The thesis proposal includes 4 kinds, namely, drought index, vegetation index, rainfall runoff index and water consumption of vegetation index. The drought index (phi) reflect the climatic background. Including enhanced vegetation index normalized vegetation type index (EVI) and leaf area index (LAI), to reflect the characteristics of vegetation. Rainfall runoff index (C_r) is a reflection of atmospheric precipitation The ability of the remaining runoff after consumption of land surface evapotranspiration, reflected in the arid area is groundwater recharge capacity. Water consumption of vegetation index (Cw) reflects the vegetation ecological district water consumption level. These indices are calculated in pixel scale of remote sensing data, a resolution of 250 m~1 km. in the Erdos plateau dusitu the rabbit River Wuding River east area as the key to meteorological data, remote sensing data and groundwater data as the basis, produced more than 4 kinds of eco hydrological index distributed data and groundwater depth (d) data. The rainfall runoff index and vegetation water consumption index in the actual land surface evapotranspiration for the basis of calculation, using the MOD16 land surface evapotranspiration and MuSyQ land surface evapotranspiration data of 1 km resolution, the basin scale water balance correction generation. Statistical analysis showed that the eco hydrological index and groundwater depth are not subject to normal distribution. 250 m spatial resolution based on the detailed analysis of the relationship between vegetation index EVI and drought index and groundwater depth. With the increase of drought index and the groundwater depth decreases, there are EVI on the whole, but the single factor correlation analysis is not sufficient to reflect the spatial variation of EVI. The two factors (-d) coordinate system, the space is divided into two factors characteristic of the grid interval statistics the value of EVI (p=50% and p=98%), draw the characteristic curve. The spatial distribution map of the two factors reveals the drought index and groundwater depth combined effects on vegetation index, vegetation index was more sensitive to the groundwater depth section of the D7 M. is a semi arid climate condition, with the increase of D EVI decreased; but when the diameter of 6 EVI, and decreased with the decrease of D, which is the shallow groundwater evaporation induced by soil salinization caused by km in 1. Resolution on the basis of other eco hydrological index are complex. The relationship between groundwater depth of 250 m resolution data using a reasonable scale to enhance effective groundwater depth of 1 km resolution (d_e) data for the analysis of characteristics of ecological hydrology index and multiple factors. With the increase of drought index, MOD16 data based on the rainfall runoff index (C_r) and water consumption of vegetation index (Cw) were decreased, but C_r and the correlation between drought index based on MuSyQ data is not significant. In addition, the leaf area index (LAI) of rainfall runoff index (C_r) and water consumption of vegetation index (Cw) have a strong effect: with the increase of LAI, C_r and Cw decrease increases. Therefore, this paper established the LAI-d_e double coordinate system to analyze the factors combined with C_r and Cw response to vegetation index and groundwater. When LAI is low, the special value of C_r and Cw syndrome (p=50% and p=90%) in a The groundwater depth section shows the maximum or minimum value; when LAI is large, the relationship between C_r and Cw and the depth of groundwater is not significant. The correlation coefficient of correlation and covariance matrix. The results show that the correlation between C_r and Cw and LAI is far greater than their correlation with drought index, and the depth of groundwater and the drought index LAI the correlation between precipitation and runoff index and drought index correlation has certain effect. The research results provide new insights into the ecological pattern and control Erdos Plateau vegetation factors, and from the angle of statistical law preliminarily reveals the influence of vegetation index on rainfall runoff and groundwater recharge.

【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：Q948;P641

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