分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2019-10-26 合作期刊: 《干旱区科学》
摘要： Water resources are critical for the existence and development of oases in endorheic basins. Thus, to enable sustainable development, it is fundamentally important to understand how to allocate and use these resources in a reasonable way. We therefore simulated and analyzed changes in water consumption pattern within the Dunhuang Oasis of China under three scenarios using a system dynamic model that corresponds to different water consumption pattern. This was done to assess the impacts of regional water resource planning (comprehensive planning of the rational use of water resource and protection of ecosystem services in the Dunhuang Basin) on water consumption pattern within the Dunhuang Oasis. The first of these, Scenario 1, is a baseline in which the status quo is maintained, while Scenario 2 incorporates the comprehensive effects of agricultural water-saving irrigation measures with an inter-basin water diversion project, and Scenario 3 focuses on ecological rehabilitation. In the baseline Scenario 1, the total water consumption within the Dunhuang Oasis increased progressively while agricultural water consumption remained extremely high and threatened overall ecological security. In contrast, Scenario 2 would decrease agricultural water consumption by almost 5.30×107 m3 following the implementation of water-saving practices. The additional water allocated from an inter-basin water diversion project would play an important role in alleviating ecological strain on the oasis. Finally, in Scenario 3, the total irrigated land must be decreased to 20.6×103 hm2 by 2025 assuming that water supply for ecosystem restoration would be at least 50% of the total consumption. Although water resource planning plays a very important role in alleviating the ecological water crisis within the oasis, it is necessary to consider the suitable scale of oasis with regard to current water consumption pattern.
分类： 地球科学 >> 大气科学 提交时间： 2024-05-15 合作期刊: 《干旱区科学》
摘要： The desert-oasis transition zone (DOTZ) serves as a buffer area between the desert and oasis. Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis. In this study, we used meteorological data during 2013–2019 from the portable meteorological stations at five sites (site A on the edge of the oasis, sites B, C, and D in the DOTZ, and site O in the desert) in Dunhuang, China to analyze the near-surface wind field characteristics and their causes, as well as to reveal the key role of the DOTZ in oasis protection. The results showed that the mean wind speed, frequency of sand-driving wind, and directional variability of wind decreased from west to east within the DOTZ, and wind speed was significantly affected by air temperature. The terrain influenced the prevailing winds in the region, mainly from northeast and southwest. Only some areas adjacent to the oasis were controlled by southeasterly wind. This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference. At site D, the annual drift potential (DP) was 24.95 vector units (VU), indicating a low wind energy environment, and the resultant drift direction (RDD) showed obvious seasonal differences. Additionally, the DOTZ played an important buffering role between the desert and oasis. Compared with the desert, the mean wind speed in the oasis decreased by 64.98%, and the prevailing wind direction was more concentrated. The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang.
分类： 地球科学 >> 地理学 提交时间： 2023-04-13 合作期刊: 《干旱区科学》
摘要：The Dunhuang–Golmud railway passes through different deserts in arid areas, especially drifting-sand desert and sandy-gravel Gobi. The near-surface wind environment and wind-sand transport process vary due to different external factors, such as topography, vegetation, and regional climate, resulting in evident spatial differences in surface erosion and deposition. Consequently, the measures for preventing wind-sand hazards will differ. However, the mechanism and control theory of sand damage remain poorly understood. In this study, we used meteorological observation, three-dimensional (3D) laser scanning, and grain-size analysis to compare and evaluate the spatial distribution of wind conditions, sand erosion and deposition patterns, and grain composition in the drifting-sand desert and sandy-gravel Gobi along the Dunhuang–Golmud railway in China. Results show that the annual mean wind speed, the frequency of sand-driving wind, and the drift potential of sandy-gravel Gobi are higher than those of drifting-sand desert, indicating a greater wind strength in the sandy-gravel Gobi, which exhibits spatial heterogeneity in wind conditions. The major sediment components in sandy-gravel Gobi are very fine sand, fine sand, and medium sand, and that in drifting-sand desert are very fine sand and fine sand. We found that the sediment in the sandy-gravel Gobi is coarser than that in the drifting-sand desert based on mean grain size and sediment component. The spatial distributions of sand erosion and deposition in the sandy-gravel Gobi and drifting-sand desert are consistent, with sand deposition mainly on the west side of the railway and sand erosion on the east side of the railway. The area of sand deposition in the drifting-sand desert accounts for 75.83% of the total area, with a mean deposition thickness of 0.032 m; while the area of sand deposition in the sandy-gravel Gobi accounts for 65.31% of the total area, with a mean deposition thickness of 0.028 m, indicating greater deposition amounts in the drifting-sand desert due to the presence of more fine sediment components. However, the sand deposition is more concentrated with a greater thickness on the embankment and track in the sandy-gravel Gobi and is dispersed with a uniform thickness in the drifting-sand desert. The sand deposition on the track of the sandy-gravel Gobi mainly comes from the east side of the railway. The results of this study are helpful in developing the preventive measures and determining appropriate selection and layout measures for sand control.
点击量
点击量
下载量
评论
通过
