Subjects: Geosciences >> Geography submitted time 2024-07-04 Cooperative journals: 《干旱区研究》
Abstract： In order to study the characteristics of hydrochemistry and groundwater recharge in Hotan River Basin, this study analyzed the characteristics of water chemical composition, main recharge sources and mutual transformation of water bodies (well, pond and river) in different geomorphic units by using SPSS statistical analysis, Piper diagram, Gibbs diagram and isotope tracing methods(D, 18O and 14C). The results showed that: (1) The water bodies mainly originated from the ice and snow meltwater and atmospheric precipitation in the middle and high mountainous areas above 2000m in the south. From the mountains to the desert, the groundwater chemical type and salinity had obvious zonal characteristics. The pH value of different water bodies were weakly alkaline, and the ion composition and TDS value were different, with the overall order of pond > well > river. The NO3- content of some groundwater samples were significantly abnormal. (2) The groundwater in the gravel plain area mainly received vertical and disconnected recharge from surface river water. The groundwater had a fast renewal rate, low salinity and main water-rock interaction, mostly SO4•Cl–Ca•Mg type. (3) The TDS value of groundwater in the fine soil plain area had a large range, mostly as the Cl•SO4–Na type. In the inter-river block, the groundwater near the upstream received surface water and lateral runoff from adjacent areas, and the 14C age was small. “Drift Oxygen” of δD and δ18O isotope in the groundwater of the middle and lower reaches was generally appeared. The 14C age of groundwater in the watershed was large, and the age was small near the riverbank. The relation between the groundwater and river was close. On both sides of the inter-river block, the groundwater runoff flowed along the northeast and northwest directions respectively, and finally discharged into the peripheral desert area.The research results can provide theoretical basis for reasonable development and utilization of water resources and ecological environment protection in Hotan River Basin.
Subjects: Geosciences >> Geography submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： As an essential hub of the Silk Road Economic Belt, the coordinated development of landscapedemographic urbanization in Central Asia not only affects the sustainable socio-economic development of Central Asia but also promotes the implementation of the Belt and Road Initiative. We explored the spatiotemporal coupling characteristics of five Central Asian capitals from 2000 to 2019 using the urban expansion mode index, population concentration index, equal fan analysis method, and spatial coupling coordination model. The results are as follows: (1) From the spatial evolutionary characteristics, the expansion type of urban land in five Central Asian capitals is mainly sprawl type, and overall, the expansion mode index tends to increase and then decrease. Regarding population concentration characteristics, the population concentration index in Ashkhabad exhibits an upward trend, whereas that in Dushanbe and Nur Sultan exhibit a downward trend, and those of Tashkent and Bishkek fluctuate between 0.6 and 0.7. (2) In terms of spatial growth trends, the expansion directions of landscape urbanization and demographic urbanization are identical in Bishkek, Ashkhabad, and Nur Sultan, with a slight deviation in Tashkent and a significant difference in Dushanbe. (3) From the coupling coordination characteristics, the landscape-demographic urbanization coupling situation is poorly coordinated in Tashkent, and the coordinated urbanization development is at the initial stage. The coupling coordination situations are better in Dushanbe and Bishkek, but their coordination levels vary widely and are at the fluctuating stage. Ashkhabad and Nur Sultan exhibit high coordination levels and are at the stable stage
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