# Changes in Meteorological Elements and Its Impacts on Yunnan Plateau Lakes
## 5 Conclusions  
In this study, ERA5 data were used to analyze variations in trends of the main meteorological factors relevant to the physical, chemical, and biological processes of nine plateau lakes in Yunnan Province during the past 40 years (1980 to 2019), including near-surface air temperature, short- and long-wave radiation, relative humidity, wind speed, and precipitation. The results revealed that the near-surface air temperature of the Yunnan Plateau lakes has shown a significant upward tendency during the past 40 years, with the largest increases occurring in winter air temperature, whereas in contrast, long-wave radiation, relative humidity, wind speed, precipitation, and other meteorological factors were all characterized by downward trends. The observed trends in climate change among the Yunnan Plateau lakes show evidence of the influence of geographical heterogeneity, with the rises in air temperature of a temperate lake (Lugu) and temperate-subtropical transitional lakes (Chenghai and Erhai) located in the northwest of Yunnan Province being significantly higher than those of subtropical lakes (Dianchi, Fuxian, Yangzonghai, Qilu, Xingyun, and Yilong) located in the central region of Yunnan Province. Conversely, the trends of decline in long-wave radiation, wind speed, and precipitation in the lakes of central Yunnan were found to be more pronounced than those recorded for the lakes of northwestern Yunnan. In addition, whereas the short-wave radiation of lakes in northwest Yunnan showed an upward trend, that of lakes in central Yunnan showed a downward trend. The abrupt change of air temperature in the highland lakes in Yunnan occurred between 2000 and 2005, among which the earliest year of abrupt air temperature change in the lakes in northwest Yunnan (Lugu, Chenghai and Erhai) was 2001, the year of abrupt air temperature change in the lakes in central Yunnan (Dianchi, Fuxian, Yangzonghai, Qilu and Xingyun) was 2002, and the year of abrupt air temperature change in Yilong Lake was 2004. We also found that these abrupt changes in air temperatures occurred earliest in the winter, followed by autumn, spring, and summer. Given that these lakes are semi-enclosed lakes of a plateau fault subsidence origin, they tend to be exposed to high air temperatures and high levels of radiation, and are characterized long water exchange cycles. In the future, climate change may further exacerbate the shortage of water resources in these plateau lakes, accompanied by increases in the biomass and growth period of algae, as well as increases in the thermal stability of deep-water lakes, which will contribute to enhancing hypoxic conditions in the lower layers of these lakes. Finally, our experiment is still flawed, as we only performed an analysis of meteorological factors, without further in-depth analysis in conjunction with the response of the lake ecosystem. In the follow-up work, we will further collect the lake water temperature and other monitoring data to explore the relationship between climate change and the response of the lake ecosystem, as well as the future impact of climate change on the lake ecosystem.  
Data curation, X.F.; writing--original draft preparation, X.F.; writing--review and editing, L.Z.; visualization, R.Y.; supervision, K.Y. All authors have read and agreed to the published version of the manuscript.  
This study was funded by the National Natural Science Foundation of China under Grant No. 41961019.  
Informed Consent Statement:Informed consent was obtained from all subjects involved in the study.  
Data Availability Statement:Not Applicable.  
The authors declare no conflict of interest.