Characteristics of Climate Change in the Dianchi Lake Basin and Its Relationship with the Water Environment

Based on meteorological data from six national meteorological observation stations (Kunming, Chenggong, Jinning, Anning, Taihua Mountain, and Songming) in and around the Dianchi Lake Basin from 1961 to 2024, alongside data from 151 automatic weather stations and water environment monitoring records, this study analyzes the variation trends and spatial distribution characteristics of temperature and precipitation in the Dianchi Lake Basin over the past 64 years, as well as the relationship between meteorological elements and the water environment. The results indicate that the annual average temperature in the Dianchi Lake Basin has exhibited an upward trend over the past 64 years, with a significant warming trend observed since the 1990s. Winter (December to February of the following year) contributed the most to this warming, while summer (June to August) experienced the smallest temperature fluctuations. Annual precipitation shows a slight decreasing trend, characterized by a significant reduction during the rainy season (May to October) and minor changes during the dry season (November to April of the following year). Spatially, the annual average temperature generally decreases from the Dianchi Lake area towards the northern and southern regions, with the highest temperature zone located in the main urban area; meanwhile, the spatial distribution of annual precipitation is characterized by higher amounts in the north and lower amounts in the south. Air temperature is significantly and positively correlated with water temperature. Furthermore, water temperature, air temperature, and precipitation are strongly correlated with the permanganate index, chlorophyll-a, and the comprehensive trophic state index, exerting a substantial impact. Changes in air temperature and precipitation will directly or indirectly affect the water quality of Dianchi Lake.