in situ data, remote sensing data, and numerical modeling, extensive research has revealed a consistent trend of increasing lake water temperatures [16], heightened evaporation rates [12], diminished lake ice coverage and shortened ice duration [17], and expansions in water levels [18] with spatial heterogeneity. These alterations in lake processes consequently impact local climate patterns and ecosystems [19].  
In addition to their thermal and dynamic aspects, the ecological status of lakes plays a significant role [20; 21; 22]. Lake ecological processes have garnered increasing attention, particularly for lakes in low-altitude and plain areas, where observation monitoring is easily carried out [23; 24; 25; 26]. The rapidly warming climate has triggered widespread changes in lake ecological processes, as demonstrated by ecological indicators such as water clarity [27], methane production [28], lake water gross primary production [29], and lake thermal habitat [30]. However, due to the TP's harsh environmental conditions and high altitude of the TP, studies focusing on long-term lake ecological processes are scarce. In situ water ecological observations within lake interiors are insufficient to support long-term research on lake ecological processes. Additionally, remote sensing observations suffer from discontinuity and require validation. Consequently, the current variations in key water ecological indicators for TP lakes, especially those with minimal human activities, remain unclear.  
Lake water ecology models serve as valuable tools for investigating lake ecosystems. Presently, there are several lake water ecological models available, each with distinct advantages [31; 32; 33]. These models help assess changes in water nutrients and pollutants [34], eutrophication and risk assessments [35], and the identification of direct or indirect impact factors on lake ecology [36]. Among these models, AQUATOX, which was developed by the United States Environmental Protection Agency (US EPA), stands out as highly effective and features a flexible structure and user-friendly interface [37]. The AQUATOX model has been widely utilized for nutrient content analysis [38], studying the effects of climate change on water ecosystems [39], and conducting natural resource damage assessments [40].  
In this study, we employed this lake ecological model, AQUATOX, to simulate long-term variations in the lake water ecology in Tibetan Plateau (TP) lakes, focusing on Lake Namco, a representative alpine lake in this cold region. We extracted water nutrient data, including total nitrogen (WTN) and total phosphorus (WTP), as well as chlorophyll-a content (Chl-a), and water gross and net primary production (WGPP and WNPP) for analysis. Our objective was to examine variations in these water ecological indicators and identify the main influencing factors, particularly those related to local climate and hydrology, over the past 40 years, i.e., from 1980 to 2020. This paper is structured as follows: Section 2 introduces Lake Namco, the lake ecological model, and the data sources used in this study. Section 3 presents the simulation results and analysis. The discussion and conclusions are provided in Sections 4 and 5, respectively.