西北干旱区植被净初级生产力的遥感估算及时空格局研究
文献类型：学位论文
| 作者 | 焦伟 |
| 答辩日期 | 2017-05-01 |
| 文献子类 | 硕士 |
| 授予单位 | 中国科学院大学 |
| 授予地点 | 新疆乌鲁木齐 |
| 导师 | 陈亚宁 |
| 关键词 | 净初级生产力 西北干旱区 CASA 模型 时空分布格局 土地利用/覆被 net primary productivity the Arid Region of Northwest China the model of CASA temp-spatial distribution patter land use / cover |
| 学位专业 | 理学硕士 |
| 英文摘要 | Over the past half-century, almost all parts of the world have experienced warming process, resulting in a series of ecological and environmental problems. Different forms of climate change have different effects on the carbon cycle of terrestrial ecosystems. As an important part of the carbon cycle, vegetation has a profound response to climate change. The vegetation fixed CO2 and synthesized the organic material through photosynthesis. Through respiration and other disturbances in different time scales, the carbon can be returned to the atmosphere. Thus, the carbon cycle is a dynamic equilibrium process, and the whole process must have the participation of plants. Net primary productivity (NPP) represents the carbon sequestration capacity of vegetation. The NPP is an integral part of understanding the carbon cycle process, an important ecological index to monitor the changes of natural resources and ecological environment. The ecological environment in arid area of Northwest China is fragile and sensitive, and the smaller climate fluctuation may cause the change of ecological environment, so the arid region of Northwest China has been widely concerned by scholars Arid continental climate, landforms of mountains and basins and the special characteristics of the soil and vegetation have made significant different vegetation types and ecosystems between these areas with other regions in our country. Climate change has further aggravated the unbalanced distribution of the water resources in the study area. The contradiction of water resources is more prominent, and the vulnerability of ecosystem is more serious. Therefore, it has a profound and far reaching significance for select vegetation NPP as a representative index to monitor and evaluate the ecological environment in this area. Based on MODIS NDVI data and Meteorological station data from 2000-2014 in arid region of Northwest China, this paper improved CASA model with land cover type, and then estimated and quantitative analyzed the changes of NPP in different vegetation types by using the ARCGIS, MATLAB, ENVI and other software. Under the background of climate change, this paper trying to answer some question of what are the distribution of vegetation, the trend of the vegetation, the difference of the biomass in different land cover types, the difference of the effects of climate change on vegetation NPP and the effects of different land use / land cover on vegetation NPP. Results show: 1. In this paper, the remote sensing statistical models, including multi-stepwise regression model, principal components regression model, partial least-squares regression model and ridge regression model, and the CASA model were constructed. The vegetation NPP was estimated by these models. Through the comparison and analysis of the two kinds of estimation models, it is found that the simulation results of the CASA model are closer to the measured data and the simulation results of the CASA model are better than the remote sensing statistical model when the model parameters are easily obtained. 2. The mean annual vegetation NPP of this area is 191.63gC/m2 , There is an obvious regional difference in NPP distribution in arid area in Northwest China, basically high in the northwest and southeast and low in the center. In the Altai Mountains, Ili River Valley, Tianshan Mountains, west of Kunlun Mountains and some areas in Hexi Corridor, the biomass is high; in the Central of desert, the vegetation NPP is very low, generally less than 30gC/m2 . 3. There is increasing trend in annual NPP with an annual rate at 2.98 gC/m2 (p<0.01).The trend is relatively stable from 2000 to 2009 with the annual rate at 2.30 g C m-2 . After 2009, the annual NPP increased rapidly with the rate at 6.60 g C m-2 a -1 . The trend differs for vegetation types with largest increase in cropland(6.34gC/m2·a), followed by shrub(4.40 gC/m2·a), and least increase in woodland(0.53 gC/m2·a). In the seasonal changes, the vegetation NPP is high in July, and then shows s downward trend. By calculation, the NPP from June to August accounted for 64.9% of the whole growth season in the acid region of Northwest China from 2000 to 2014. 4. On the spatial distribution of NPP in the study area, overall vegetation NPP has showed a tendency to improve. The vegetation NPP in 82.84% areas was appeared an increased tendency, 3.05% areas remained relatively stable, and 14.11% areas appeared slightly decreased since 2000. Vegetation NPP has a significant correlation with precipitation (r=0.538) and not so significant correlation with temperature (r=0.394), indicating vegetation NPP is more highly correlated with precipitation than temperature, and the correlation coefficient differs for different vegetation types. 5. By analyzing the characteristics of land use/land cover and the effects between the land use/land cover with the vegetation NPP, The change of land use / land cover in the arid area of Northwest China was characterized by the decrease of unused land area and the increase of forest land, cultivated land, shrub and grassland from 2000 to 2014. The trend differs for vegetation types with largest increase in cropland (6.34gC/m2·a), followed by shrub (4.40 g C/m2·a), and least increase in woodland (0.53 gC/m2·a). The total amount of vegetation NPP increased from 2.89 × 105G g C / a to 3.26 × 105G g C /a from 2000 to 2014. The increase was 3.69 × 104 G g C / a and the rate of change was 13%. |
| 学科主题 | 自然地理学 |
| 语种 | 中文 |
| 源URL | [http://ir.xjlas.org/handle/365004/14878]  |
| 专题 | 新疆生态与地理研究所_研究系统_荒漠环境研究室 |
| 作者单位 | 中国科学院新疆生态与地理研究所 |
| 推荐引用方式 GB/T 7714 | 焦伟. 西北干旱区植被净初级生产力的遥感估算及时空格局研究[D]. 新疆乌鲁木齐. 中国科学院大学. 2017. |
入库方式： OAI收割
来源：新疆生态与地理研究所
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