利用全球的UMD土地覆盖数据集、Global Land Cover 2000数据集、GlobCover全球陆地覆盖数据和GlobCover全球陆地覆盖数据2009这4个数据集,提取出塔吉克斯坦4个时期长达28年的土地覆盖信息。并针对这4种数据集的土地覆盖分类系统不统一的问题,将塔吉克斯坦的土地覆盖类型大致分为6类:自然林木、自然草本、农田、裸地、水体和其他,分析出塔吉克斯坦土地覆盖的变化趋势。塔吉克斯坦土地覆盖类型多样,其中草地、裸地、农田和冰雪占绝对优势。1981年~1994年至2000年农田面积的急剧下降,主要是耕地弃耕转变为草地和裸地。与此同时,草地和裸地面积有所增加。这种变化与1991年前苏联解体导致的经济政策变动有关。而1981年~2009年近30年来,草地在空间上的东移和裸地在空间上的西移则是由气候变化引起,气候变暖导致冰川融化,位于塔吉克斯坦东部高寒地区的裸地也逐渐长出草本。从这些变化中可看出,人类活动和气候变化是影响塔吉克斯坦土地覆盖分布的主要原因。
英文摘要:
The information of land use and land cover change in Tajikistan is scarce,and it is unable to meet the research demands of ecological environment change in Tajikistan. In this context, using four global land cover characteristics datasets (including UMD,GLC2000,GlobCover2005-2006,and GlobCover2009 datasets), which extracted 4 times coverage information for about 30 years, to get the information of land use and land cover change in Tajikistan. Considering the differences between classification systems for the 4 datasets, this paper divided the Tajikistan land cover types into 6 categories: natural forest, natural herb,farmland, bare land, water and the other, to analysis the change trend of land cover in Tajikistan. The results show that there are several land cover types in Tajikistan, and the bare land, grassland, farmland and snow absolutely advantage. Because of the Soviet Union collapse in 1991,large areas of farmland were abandoned and changed into bare land and grassland during 1981-1994 to 2000. At the same time,grassland and bare land area increased. The phenomenon that the grassland moved to the East of Tajikistan and the bare land moved to the west during the recent 30 years was due to climate change. Climate warming led to glacier melting,so the bare land in the eastern part of Tajikistan alpine area gradually grew. Therefore, human activity and climate change is the main factor influencing the Tajikistan land cover distribution. In this paper, the multi period datasets were used to acquire the land cover dataset in Tajikistan. Although there are differences in aspect of classification system,it still displays the situation of land cover in Tajikistan. It makes up the shortage of land cover dataset in Tajikistan to a certain extent. In addition,the land cover change trend and distribution pattern in Tajikistan can be roughly analyzed through merging the land cover type into 6 categories.