海西蒙古族藏族自治州沙漠化时空演变及其风险评价

发布时间：2018-03-13 00:21

本文选题：海西州　切入点：沙漠化　出处：《兰州大学》2016年硕士论文　论文类型：学位论文

【摘要】：长期以来,沙漠化是国内外学者和政府机构普遍关注的环境问题,它与人类的生存和发展息息相关。海西州位于中国西北干旱半干旱的高寒地区,是青海乃至全国沙漠化最为严重的地区之一。目前,对海西州沙漠化的研究主要集中于境内的柴达木盆地,本文首次将研究范围扩至海西全州,对其沙漠化过程进行了全面的研究。本文采用的主要研究方法为:基于Landsat遥感影像数据,以NDVI为评价沙漠化变化的指标,对海西州1975、1985、1995、2005和2014年五个年份的沙漠化的时空演变进行了遥感解译,分析了未来不同时期不同RCPs情景下的沙漠化风险状况及自然和人文两种驱动力对研究区沙漠化的影响,并对研究区的沙漠化治理提出了对策建议。研究的主要结论如下:(1)1975~2014年海西州沙漠化时空演变。地域分布上,从境内柴达木盆地向外围山区沙漠化程度由重及轻;时间尺度上,沙漠化土地面积经历了先增加后减少的变化过程,以1995年份面积最大,沙漠化也最严重,其中1975~1995年为沙漠化发展时期,而1995~2014为沙漠化逆转时期。沙漠化及不同程度沙漠化重心的地理坐标均经历了先向东后向西的迁移过程,且较轻程度沙漠化的重心地域变动范围小于较重程度沙漠化。(2)沙漠化驱动力。研究区气候、降水和大风的年际变化表明气候逐渐向暖湿方向发展。由于暖湿气候有利于沙漠化逆转,因此1975~1995年沙漠化扩展与暖湿气候对沙漠化的影响不一致,1995~2014年则一致。一方面说明在生态环境脆弱的干旱半干旱区,人类活动对沙漠化影响非常大,甚至超过气候作用;另一方面说明人类因素的可控性,由于人类活动的逐渐合理化、规范化,生态环境保护力度加大,加上气候的暖湿作用,沙漠化逐渐逆转。(3)沙漠化风险评估。从地域分布看,从柴达木盆地到外围山区,未来沙漠化风险由重及轻,与不同程度沙漠化土地的地域分布相似,其中高风险所占比例最高。从不同气候变化情景看,RCP4.5情景下,未来沙漠化风险程度最高,RCP2.6和RCP6.0情景下风险最低。(4)沙漠化治理对策。研究区早期的沙漠化治理成果不大,上世纪90年代以后,随着一系列环保政策的出台,沙漠化治理得到加强,沙漠化扩张已得到初步遏制,但治理过程中仍有不少问题出现。本文针对问题提出了三点新的建议,并提出了基于环境善治的沙漠化治理。环境善治作为新的环境治理理念,应用在沙漠化治理上,有利于地方政府、工矿企业、公民社会之间相互合作、取长补短,形成一个良性的沙漠化治理体系,促进研究区生态环境的可持续发展。
[Abstract]:For a long time, desertification has been a widespread concern of scholars and government agencies at home and abroad, which is closely related to the survival and development of human beings. Haixi Prefecture is located in the arid and semi-arid alpine region of northwest China. It is one of the most serious desertification areas in Qinghai and even in China. At present, the research on desertification in Haixi prefecture is mainly focused on the Qaidam basin in the territory. For the first time, the scope of this study has been extended to the whole state of Hercynian. The main research methods used in this paper are as follows: based on Landsat remote sensing image data, NDVI is used to evaluate desertification change. The temporal and spatial evolution of desertification in the five years of 1975 ~ 1985 and 2014 in Haixi was interpreted by remote sensing. The risk of desertification and the influence of natural and human driving forces on desertification in different RCPs scenarios in the future were analyzed. The main conclusions of the study are as follows: 1. The spatiotemporal evolution of desertification in Haixi from 1975 to 2014. In terms of regional distribution, the desertification degree from the Qaidam basin to the peripheral mountainous area is from heavy to light, and on time scale. The area of desertified land increased first and then decreased. In 1995, the area of desertification was the largest and the desertification was the most serious. The period from 1975 to 1995 was the period of desertification development. However, 1995 / 2014 is the reverse period of desertification. The geographic coordinates of the center of gravity of desertification and different degrees of desertification all experienced the process of migration from east to west. And the range of regional variation of the center of gravity of the lighter desertification is smaller than that of the heavy degree desertification. (2) the driving force of desertification. The climate of the study area, The interannual variation of precipitation and gale indicates that the climate is gradually developing in the direction of warm and wet, because warm and humid climate is conducive to the reversal of desertification, Therefore, from 1975 to 1995, the effects of desertification expansion and warm and wet climate on desertification are inconsistent. On the one hand, it shows that in the arid and semi-arid areas with fragile ecological environment, human activities have a very large impact on desertification, even exceed the climatic effect. On the other hand, it explains the controllability of human factors. Due to the gradual rationalization and standardization of human activities, the intensification of ecological environmental protection and the climate warming and humidity, desertification gradually reverses desertification risk assessment. From the Qaidam Basin to the surrounding mountainous areas, desertification risk in the future is from heavy to light, which is similar to the regional distribution of desertification land of different degrees, in which the proportion of high risk is the highest. From different climate change scenarios, we can see the RCP 4.5 scenario. The risk of desertification is the highest in the future. The risk of desertification is the lowest under RCP2.6 and RCP6.0 scenarios. The early results of desertification control in the study area are not significant. After -10s, with the introduction of a series of environmental protection policies, Desertification control has been strengthened, desertification expansion has been initially contained, but there are still many problems in the process of control. This paper puts forward three new suggestions to solve the problems. As a new concept of environmental governance, the application of environmental good governance in desertification control is beneficial to the cooperation among local governments, industrial and mining enterprises and civil society. To form a benign desertification control system to promote the sustainable development of ecological environment in the research area.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X171.1;X826

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