###### Abstract  
The Yellow River (YR), China's second-largest river, is rich in water resources, particularly in its upper reaches, which are characterized by mountainous canyons and considerable hydropower potential. Since the 1950s, 24 reservoirs have been constructed along a 918 km stretch of the upper Yellow River (UYR), creating the highest concentration of cascade reservoirs. This development has had significant ecological impacts on the surrounding environment. This study examines the relationship between reservoir attributes and climate factors to evaluate the environmental effects of reservoirs in the UYR. (1) Following reservoir construction, the average annual temperature and precipitation increased by 3-10%, though seasonal and spatial distributions varied. Temperature increases were most pronounced in winter, while precipitation decreased in some regions during spring and summer, although the overall trend remained positive. (2) The ecosystem experienced significant post-construction changes, including reductions in arable land, grassland, and unused land, while water bodies, construction land, and forests expanded. Consequently, the ecosystem within the reservoir area now accounts for 5.2-12.5% of the total area of the region. (3) Temperature and precipitation were closely linked to reservoir attributes, with storage volume (CAP) and long-term average flow (DIS) significantly affecting precipitation, while surface area (AREA) and normal storage level (FSL) had a greater influence on temperature. In conclusion, the dual impacts of reservoir construction on local climate and land use highlight the complex environmental mechanisms involved, providing valuable insights for future reservoir development and ecological protection in the Yellow River Basin and similar regions. U  
202515281620  
Studies have shown that the construction of reservoirs influences local climate elements such as temperature and precipitation by altering water-air exchange and evapotranspiration, which, in turn, affects these climate parameters [8; 9; 10; 11]. These climatic changes alter local climate patterns and may have far-reaching consequences for regional ecosystems, species distribution, and water resource management [12]. Furthermore, the construction of reservoirs is often accompanied by land use changes, such as the conversion of croplands, forests, and grasslands into watersheds, leading to alterations in biodiversity and potentially impacting groundwater levels, agricultural productivity, and ecological restoration [13; 14; 15]. Therefore, a quantitative analysis of land use changes, climate change trends, and their interrelationships before and after reservoir construction is essential. To gain a more comprehensive understanding of the environmental impacts of reservoir construction, this study focuses on 10 reservoirs in the UYR, employing remote sensing image analysis and GIS technology to investigate how these reservoirs affect local land use changes, climate shifts, and their interactions [16]. The impact of reservoir construction on the climate system has become a significant area of research in recent years [17; 18]. Studies have shown that reservoirs can significantly influence local climate conditions by altering water-air exchange processes. The evaporative effect of reservoirs may lead to lower temperatures, resulting in a localized cooling effect, particularly in arid and semi-arid regions [19]. At the same time, reservoir construction can alter precipitation patterns, which in turn affects water cycle processes. For example, [PERSON] et al. [20] examined the evaporation characteristics of sub-arid reservoirs and revealed the effects of reservoir evaporation on temperature and precipitation. [PERSON] et al. [21] further investigated the cooling effect of reservoirs and their surrounding Greenland systems on arid regions through evaporation, which enhances precipitation and regulates the local climate.