Solar spectral observations at high altitudes in Xizang

The high altitude area of Xizang has rich solar energy resources due to its unique geological conditions and climate environment. In order to better utilize and develop these resources, as well as study their impact on the earth's ecosystem, it is necessary to conduct in-depth observation and research on the solar spectrum. The field observation mainly conducted solar spectral observations on three areas with an altitude of more than 5000m in Xizang around the summer solstice in 2022 and 2023, and compared with the spectrum of Daxing District of Beijing (altitude 30.00m), Chengguan District of Lhasa (altitude 3664.48m) and AM0/AM1.5 spectrum. The results show that the strongest value of solar spectrum in Jiacula Pass of Everest National Nature Reserve (altitude 5248.00m) is 2.497W•m^-2•nm^-1, the strongest value of solar spectrum in Mila Pass of Lhasa-Nyingchi boundary point (altitude 5118.50m) is 2.361W•m^-2•nm^-1, and the strongest value of solar spectrum in the top of Drepung Peak of Lhasa (altitude 5352.50m) is 2.69W•m^-2•nm^-1, which exceeds the AM0 standard spectrum to varying degrees. The changes in surface, atmosphere and environment caused by changes in altitude affect the absorption of different gas molecules to the solar spectrum. It can also be inferred that the contents of O₃, O₂, H₂O and other gas molecules in various regions are different. The solar ultraviolet radiation of 287nm-300nm belonging to the UVB band even appears in high altitude areas. The overall performance of the high altitude area is closer to the AM0, but also has the spectral characteristics of AM1.5, showing the advantages of high altitude observation, which can reduce the influence of atmospheric absorption and scattering, provide more accurate solar spectral data, and highlight the importance of high altitude solar spectral observation in Xizang, which is helpful to further promote the research and development of related fields.