[关键词]
[摘要]
利用 1986—2020 年 Landsat 系列遥感数据和水资源数据,基于趋势分析、相关分析和灰色关联分析等方法, 研究民勤绿洲植被变化与水资源结构变化的响应关系。结果表明:民勤绿洲平均植被覆盖度和绿洲面积总体呈 增加趋势,总可用水资源量呈持续减少趋势;民勤绿洲的发展可划分为 1986—2000 年、2001—2009 年、 2010—2020 年 3 个阶段,分别对应于绿洲面积快速扩张、高位维持、趋于稳定和总可用水资源量缓慢减少、迅速 减少、趋于稳定的 3 个阶段;绿洲面积变化受水资源和人为因素共同影响,绿洲面积和水资源量在第一、第二阶 段响应关系很弱,对应于绿洲发展粗放扩张和剧烈调整的时期,二者在第三阶段表现出较好的响应关系,是绿洲 发展进入良性阶段的反映;根据民勤绿洲现状水平估计,每 1 亿 m 3供水量可支撑绿洲面积 277?km 2。系统分析其 植被变化与水资源的关系对未来西北地区绿洲的建设和发展具有重要参考价值。
[Key word]
[Abstract]
Minqin oasis is a typical desert oasis in arid area with strong independence. A systematic analysis of the relationship between vegetation change and water resources in Minqin oasis has important reference value for the future construction and development of oasis in the Northwest China. The above key issue is analyzed using the Landsat multispectral remote sensing data and water resource data from 1986 to 2020. These results are as follows.The average vegetation coverage of Minqin oasis is low and its spatial distribution is generally high in the oasis and sparse at the edge of the oasis. Its vegetation coverage was generally stable from 1986 to 2020 with some improvements, and the areas with slight improvement were the largest. The oasis area and vegetation coverage showed a strong linear correlation, which demonstrated the technical rationality of defining oasis by vegetation coverage. For the period of 1986-2020, the area of oasis showed an overall increasing trend, which can be divided into three stages, rapid expansion, maintained in an oversized position, and stabilization.From 1986 to 2020, the total amount of available water resources continued to decrease on the whole, and the process is embodied in three stages, slow decrease, rapid decrease and stabilization. Among them, before 2000, groundwater was mainly exploited for water use, and surface runoff continued to decrease and remained at a low level. From 2000 to 2009, the study area began to gradually reduce groundwater exploitation in a large amount, and at the same time constructed some projects to transfer water from other basins. Therefore, water resources show a trend of rapid reduction of groundwater consumption, gradual increase of surface water, and steady reduction of total water consumption. After 2010, the amount of surface water and groundwater exploitation has gradually stabilized, which is the result of great efforts in governance in recent years. The precipitation shows a fluctuating and slowly increasing trend, which is generally stable, but there will be violent fluctuations in different years, which will have a certain impact on the oasis area.By analyzing the situation in different periods,the basic reasons are found for the different response relationship between oasis area and water resources and the indication function of this response relationship on the development status of oasis is put forward. Specifically, the change of the area of Minqin oasis from 1986 to 2020 was affected by the comprehensive influence of water resources and human factors. In the extensive expansion stage before 2000 and the drastic adjustment stage from 2001 to 2009, the relationship between oasis area and water resources showed high disorder, which was the result of man-made forced intervention. After 2010, the amount of water resources and the area of the oasis showed a good response relationship, which is also a reflection of the good development status of the oasis. In addition, the response relationship between precipitation and oasis area can also be verified at a reliable level. The data analysis of the benign development stage of Minqin oasis since 2010 shows that, with the current conditions and level of Minqin oasis, every additional 100 million m 3 of water resources can maintain an oasis area of 277 km 2 and a certain amount of attached ecological restoration areas. Compared with other current research results, the conclusions of this paper are more valuable. This is a preliminary quantitative reference for the bearing capacity of water resources to the scale of oasis when large-scale water transfer to Northwest China and then large-scale development of oases are carried out in the future.
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