气候变化和人类活动对科尔多凡省北部苏丹地区沙漠化影响的评估
发布时间：2021-12-23 00:09
植被沙漠化在农业生产量和生产力方面的不利影响受到广泛的关注。气候变化和人类活动通常被认为是导致植被沙漠化的两大根本原因。在本研究中,采用基于净初级生产力（NPP）的综合分析方法定量评估2000-2008年科尔多凡省北部苏丹地区气候变化和人类活动对沙漠化的影响。采用三种形式的净初级生产力（NPP）,即实际NPP,潜在NPP和HNPP（人类占用的NPP）,来描述了沙漠地区气候变化和人类活动的相对作用。结果表明,研究区63.75%的地区经历了沙漠扩张,其中受人类活动影响的占76.32%,受气候变化影响的占32.03%,受两者共同影响的占0.65%。人类活动造成的沙漠化的缩减占2.3%,气候变化占97.7%。相比之下,气候变化是沙漠化缩减的主导因素,在缩减地区并不存在气候变化和人类活动的相互作用。最大扩张区和缩减区分别分布在研究区的东北部和西部地区。通过研究,我们可得到两个主要结论:一是在研究区的北东部,中部和南部的典型区域,沙漠扩张主要是由人类活动引起的,沙漠的缩减主要是由气候变化引起的;二是在研究区的西北部,沙漠的扩张和缩减都是由气候变化引起的。因此,人类活动对荒漠化扩张的影响比气候变化更...
【文章来源】：西北师范大学甘肃省
【文章页数】：93 页
【学位级别】：博士
【文章目录】：
Abstract
摘要
CHAPTER ONE INTRODUCTION
1.1 Background and Significance
1.1.1 Research backgrounds
1.1.2 Research significant
1.2 General concepts
1.3 Aim and Objectives
1.4 Hypothesis
1.5 Research contents
CHAPTER TWO THEORETICAL BACKGROUND
2.1 Desertification
2.2 Arid and semi-arid lands
2.3 Vegetation indices
2.3.1 The calculation of vegetation indices
2.3.2 Normalized difference vegetation index (NDVI)
2.3.3 Net Primary Productivity (NPP)
2.3.4 Moderate Resolution Imaging Spectroradiometer (MODIS)
2.3.5 The MOD17 products
2.3.6 Application of MODIS for observing vegetation
2.3.7 MODIS NPP (Actual NPP)
2.3.8 Potential NPP (P NPP)
2.3.9 The impact of climate change and human activities on NPP
2.3.10 Correlations between NPP and climate variables
2.4 Desertification dynamics
2.5 Quantitative assessments the contribution of climate and human to desertification
CHAPTER THREE THE DATA AND METHODS
3.1 Sudan
3.2 Northern Kordofan province
3.2.1 Population
3.2.2 Climate
3.2.3 Topography
3.2.4 Soils
3.2.5 Geology
3.2.6 Vegetation
3.2.7 Crops Production
3.2.8 Crops Production
3.2.9 Human activities
3.3 Data
3.3.1 Data source and processing
3.4 Methods
3.4.1 Estimation of actual NPP
3.4.2 Estimation of potential NPP
3.4.3 Statistical analysis
3.4.4 Correlation analysis between NPP and climate factors
3.4.5 Desertification dynamics analysis
3.4.6 Scenario design and quantitative assessment method
CHAPTER FOUR RESULTS AND DISCUSSION
4.1 Results
4.1.1 Spatial and temporal dynamic based on actual NPP and potentialNPP
4.1.2 Temporal (mean annual) variation of NPP
4.1.3 Correlation between annual variation of climate and NPP
4.1.4 Correlation between NPP and temperature
4.1.5 Correlation between NPP and rainfall
4.1.6 Desertification dynamics analysis
4.1.7 Relative roles of inter-annual climate change and human activities in desertification expansion based on area
4.1.8 Relative roles of inter-annual climate change and human activities in desertification expansion based on NPP variation
4.2 Discussion
4.2.1 Methodology
4.2.2 The responses of annual NPP to climate variables
4.2.3 Driving factors of desertification
CHAPTER FIVE CONCLUSION AND LIMITATION
5.1 Conclusion
5.2 Limitations
5.3 Recommendations
REFERENCES
ACKNOWLEDGEMENT
本文编号：3547379
【文章来源】：西北师范大学甘肃省
【文章页数】：93 页
【学位级别】：博士
【文章目录】：
Abstract
摘要
CHAPTER ONE INTRODUCTION
1.1 Background and Significance
1.1.1 Research backgrounds
1.1.2 Research significant
1.2 General concepts
1.3 Aim and Objectives
1.4 Hypothesis
1.5 Research contents
CHAPTER TWO THEORETICAL BACKGROUND
2.1 Desertification
2.2 Arid and semi-arid lands
2.3 Vegetation indices
2.3.1 The calculation of vegetation indices
2.3.2 Normalized difference vegetation index (NDVI)
2.3.3 Net Primary Productivity (NPP)
2.3.4 Moderate Resolution Imaging Spectroradiometer (MODIS)
2.3.5 The MOD17 products
2.3.6 Application of MODIS for observing vegetation
2.3.7 MODIS NPP (Actual NPP)
2.3.8 Potential NPP (P NPP)
2.3.9 The impact of climate change and human activities on NPP
2.3.10 Correlations between NPP and climate variables
2.4 Desertification dynamics
2.5 Quantitative assessments the contribution of climate and human to desertification
CHAPTER THREE THE DATA AND METHODS
3.1 Sudan
3.2 Northern Kordofan province
3.2.1 Population
3.2.2 Climate
3.2.3 Topography
3.2.4 Soils
3.2.5 Geology
3.2.6 Vegetation
3.2.7 Crops Production
3.2.8 Crops Production
3.2.9 Human activities
3.3 Data
3.3.1 Data source and processing
3.4 Methods
3.4.1 Estimation of actual NPP
3.4.2 Estimation of potential NPP
3.4.3 Statistical analysis
3.4.4 Correlation analysis between NPP and climate factors
3.4.5 Desertification dynamics analysis
3.4.6 Scenario design and quantitative assessment method
CHAPTER FOUR RESULTS AND DISCUSSION
4.1 Results
4.1.1 Spatial and temporal dynamic based on actual NPP and potentialNPP
4.1.2 Temporal (mean annual) variation of NPP
4.1.3 Correlation between annual variation of climate and NPP
4.1.4 Correlation between NPP and temperature
4.1.5 Correlation between NPP and rainfall
4.1.6 Desertification dynamics analysis
4.1.7 Relative roles of inter-annual climate change and human activities in desertification expansion based on area
4.1.8 Relative roles of inter-annual climate change and human activities in desertification expansion based on NPP variation
4.2 Discussion
4.2.1 Methodology
4.2.2 The responses of annual NPP to climate variables
4.2.3 Driving factors of desertification
CHAPTER FIVE CONCLUSION AND LIMITATION
5.1 Conclusion
5.2 Limitations
5.3 Recommendations
REFERENCES
ACKNOWLEDGEMENT
本文编号：3547379
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