2000-2014年若尔盖湿地变化监测及驱动因子分析

发布时间：2018-05-17 06:32

本文选题：湿地 + 若尔盖　；参考：《成都理工大学》2016年硕士论文

【摘要】：本文以若尔盖地区为研究区,选用MODIS系列数据的归一化植被指数NDVI和增强型植被指数EVI,结合高程数据DEM,建立了提取该区湿地信息的决策树;选用最大值最小值分类后处理方法对提取的湿地信息进行后处理,经过精度评价研究,效果较好;对提取的各类湿地进行景观格局分析,研究其景观格局演变特征和空间分布特征;从自然因素和人为因素两方面对若尔盖地区湿地的变化做驱动分析;以期为若尔盖地区湿地的治理和保护提供依据。取得的主要研究成果如下:(1)确定了若尔盖地区的湿地类型。根据湿地分类准则,结合现有遥感数据特点,本次研究将该区的湿地类型划分为湖泊/河流湿地、草原/草甸湿地、沼泽化草甸湿地、沼泽湿地及其他。(2)获得若尔盖地区15年夏季(6-9月份)的湿地分布图。对MODIS/NDVI和MODIS/EVI数据进行预处理,采用HANTS分析对其进行降噪重构,获得质量较好的MODIS/NDVI和MODIS/EVI的数据,采用随机采样的方法统计各类湿地的MODIS/NDVI和MODIS/EVI值,结合DEM和SLOPE数据,确定阈值,构建决策树,获得湿地分类图,进行分类后处理,对其结果进行精度检验,用该方法提取若尔盖地区2000-2014年夏季的湿地分类图。(3)对15期的湿地提取结果进行景观格局分析。本次研究从斑块类型面积变化、景观破碎度、景观优势度以及景观多样性和均匀度四个方面进行景观分析。结果表明,若尔盖地区的湿地面积总体上呈缩减的趋势,且破碎度增加,草原/草甸湿地的退化速度大于其他类型的湿地,各景观类型的优势度差距增大,景观的多样性和均匀度都在减小。(4)分析若尔盖地区湿地变化的驱动因子。结合该区气候数据、四川省统计年鉴、甘肃省的统计年鉴数据和社会经济发展报告及前人的研究成果,得出若尔盖地区湿地变化的因素大致有5个:特殊的地理位置决定该区生态环境的敏感性,在全球气候变暖的大背景下,若尔盖地区的气候变化比较明显,气温呈升高的趋势,降雨也在增加,所以当地的气候处于暖湿化的状态,气候变化是该区湿地变化的背景因素;人口的猛增、超载放牧和不合理的人类活动是导致该区湿地退化的关键因素;鼠虫害的影响加剧了当地湿地退化的速率;旅游业的发展虽然带来了经济利益,但是同时也对湿地环境、水资源等带来了一定的污染;若尔盖地区湿地自然保护区的建立,一系列保护措施的实施,对该区的湿地退化在一定程度上起到了减缓的作用。
[Abstract]:In this paper, a decision tree for extracting wetland information is established by using normalized vegetation index (NDVI) of MODIS series data and enhanced vegetation index (EVI), combined with elevation data (DEM). The maximum and minimum values are selected to post-process the extracted wetland information, and the accuracy evaluation results are good. The landscape pattern of the extracted wetland is analyzed. The characteristics of landscape pattern evolution and spatial distribution are studied, and the driving analysis of wetland changes in Ruoergai area from natural and human factors is made, in order to provide the basis for wetland management and protection in Ruoergai area. The main research results are as follows: 1) the wetland types in the Joergai area are determined. According to the criteria of wetland classification and the characteristics of existing remote sensing data, the wetland types in this area are divided into lake / river wetland, grassland / meadow wetland and marsh meadow wetland. Marsh wetland and other. 2) Wetland distribution map was obtained for 15 years summer and June-September in Zoergai area. The data of MODIS/NDVI and MODIS/EVI were preprocessed and reconstructed by HANTS analysis to obtain the data of MODIS/NDVI and MODIS/EVI of good quality. The MODIS/NDVI and MODIS/EVI values of all kinds of wetlands were calculated by random sampling method, and the threshold value was determined by combining the data of DEM and SLOPE. The decision tree was constructed, the wetland classification map was obtained, the classification post-processing was carried out, the accuracy of the results was tested, and the wetland classification map from 2000 to 2014 in Ruoergai area was extracted by this method. 3) the landscape pattern of 15 periods of wetland extraction results was analyzed. In this study, landscape analysis was carried out from four aspects: patch area change, landscape fragmentation, landscape dominance, landscape diversity and evenness. The results showed that the wetland area in Ruoergai area decreased and the fragmentation increased, the degradation rate of grassland / meadow wetland was higher than that of other types of wetland, and the difference of dominance of each landscape type increased. The diversity and evenness of landscape are decreasing. 4) the driving factors of wetland change in Ruoergai area are analyzed. Combining the climate data of the region, the Statistical Yearbook of Sichuan Province, the Statistical Yearbook data of Gansu Province and the report on Social and Economic Development, and the previous research results, It is concluded that there are about five factors for wetland change in Ruoergai area: the special geographical location determines the sensitivity of ecological environment in this area. Under the background of global warming, the climate change is obvious in Ruoergai area, and the temperature tends to increase. Rainfall is also increasing, so the local climate is in a warm and humid state, climate change is the background factor of wetland change in this area, the population surge, overloading grazing and unreasonable human activities are the key factors leading to wetland degradation in this area. The impact of rodent and insect pests has aggravated the rate of wetland degradation; although the development of tourism has brought economic benefits, it has also brought about certain pollution to the wetland environment and water resources; and the establishment of wetland nature reserves in the Ruoergai area. The implementation of a series of protection measures has played a role in slowing down the wetland degradation in this area.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P942;P237

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