Spectral observation of the 24 solar terms on the Qinghai–Tibet Plateau: A case study of Lhasa, Tibet.
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| Title: | Spectral observation of the 24 solar terms on the Qinghai–Tibet Plateau: A case study of Lhasa, Tibet. |
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| Authors: | Zhou, Yi1 (AUTHOR) zyx9208@utibet.edu.cn, Zhou, Yanxia1 (AUTHOR), Li, Linjiang1 (AUTHOR), Sang, Nuo1 (AUTHOR) |
| Source: | Journal of Atmospheric & Solar-Terrestrial Physics. Aug2025, Vol. 273, pN.PAG-N.PAG. 1p. |
| Subjects: | Atmospheric water vapor, Solar oscillations, Sun observations, Earth's orbit, Monochromatic light |
| Geographic Terms: | Qinghai Sheng (China) |
| Abstract: | Twenty-four solar terms, which were created by farmers in ancient China, are based on the Earth's orbit around the Sun and reflect the changes in climate, natural phenomena, agricultural production and other aspects of human life. In this study, we conducted observations and analysed the solar spectrum of the 24 solar terms in Lhasa, Qinghai–Tibet Plateau using a high-precision solar irradiance metre. The objective was to investigate the relationship between solar radiation variations and geophysical processes in the Qinghai–Tibet Plateau region. The results showed that during the period from the Autumnal Equinox on September 23, 2022 to the Qingming Festival on April 5, 2023, the lowest environmental humidity was only 4.7 %. The impact of the atmospheric water vapor and clouds on solar radiation was relatively small, and the solar spectrum exhibited good regularity. However, during the remaining solar terms, the solar spectrum exhibited fluctuations caused by temperature, humidity and other factors. Among the 24 solar terms in Lhasa during the Summer Solstice in 2022 and 2023, the peak values of monochromatic light were 2.53 W m−2·nm−1 and 2.71 W m−2·nm−1, respectively, considering the combined effects of sunlight reflection and scattering caused by discrete clouds. These values exceed the peak value of the AM0 monochromatic light. By comparing the Fraunhofer lines during the 'Two Equinoxes and Two Solstices' in Lhasa, the absorption peaks of the Fe, Ca, H, Mg, Na and O elements were observed at wavelengths of 358 nm, 431 nm, 486 nm, 517 nm, 589 nm and 687 nm, respectively. These results provide a foundation for further investigation of solar radiation variations on the Qinghai–Tibet Plateau and their impact on the Earth and can be used as a reference for sustainable research in the Qinghai–Tibet Plateau region of China. • Solar Terms Observation on Qinghai-Tibet Plateau : A study analysed the solar spectrum of the 24 solar terms in Lhasa, Qinghai-Tibet Plateau, using a high-precision solar irradiance meter. • Low Humidity and Solar Spectrum Regularity: From the Autumnal Equinox (Sep 23, 2022) to Qingming Festival (Apr 5, 2023), low humidity (4.7 %) resulted in minimal impact from atmospheric water vapor and clouds, yielding a regular solar spectrum. • Spectral Fluctuations : During other solar terms, the solar spectrum showed fluctuations due to varying temperature, humidity, and other factors. • Monochromatic Light Peaks : Peak values of monochromatic light during the Summer Solstice in 2022 and 2023 were 2.53 W m−2·nm−1 and 2.71 W m−2·nm−1, respectively, exceeding the AM0 peak, considering sunlight reflection and scattering by clouds. • Fraunhofer Line Analysis : During the 'Two Equinoxes and Two Solstices', absorption peaks of Fe, Ca, H, Mg, Na, and O elements were observed at specific wavelengths (358 nm, 431 nm, 486 nm, 517 nm, 589 nm, 687 nm). • Foundation for Further Research : The results provide a basis for studying solar radiation variations on the Qinghai-Tibet Plateau and their potential impacts on Earth, serving as a reference for sustainable research in the region. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
| Abstract: | Twenty-four solar terms, which were created by farmers in ancient China, are based on the Earth's orbit around the Sun and reflect the changes in climate, natural phenomena, agricultural production and other aspects of human life. In this study, we conducted observations and analysed the solar spectrum of the 24 solar terms in Lhasa, Qinghai–Tibet Plateau using a high-precision solar irradiance metre. The objective was to investigate the relationship between solar radiation variations and geophysical processes in the Qinghai–Tibet Plateau region. The results showed that during the period from the Autumnal Equinox on September 23, 2022 to the Qingming Festival on April 5, 2023, the lowest environmental humidity was only 4.7 %. The impact of the atmospheric water vapor and clouds on solar radiation was relatively small, and the solar spectrum exhibited good regularity. However, during the remaining solar terms, the solar spectrum exhibited fluctuations caused by temperature, humidity and other factors. Among the 24 solar terms in Lhasa during the Summer Solstice in 2022 and 2023, the peak values of monochromatic light were 2.53 W m−2·nm−1 and 2.71 W m−2·nm−1, respectively, considering the combined effects of sunlight reflection and scattering caused by discrete clouds. These values exceed the peak value of the AM0 monochromatic light. By comparing the Fraunhofer lines during the 'Two Equinoxes and Two Solstices' in Lhasa, the absorption peaks of the Fe, Ca, H, Mg, Na and O elements were observed at wavelengths of 358 nm, 431 nm, 486 nm, 517 nm, 589 nm and 687 nm, respectively. These results provide a foundation for further investigation of solar radiation variations on the Qinghai–Tibet Plateau and their impact on the Earth and can be used as a reference for sustainable research in the Qinghai–Tibet Plateau region of China. • Solar Terms Observation on Qinghai-Tibet Plateau : A study analysed the solar spectrum of the 24 solar terms in Lhasa, Qinghai-Tibet Plateau, using a high-precision solar irradiance meter. • Low Humidity and Solar Spectrum Regularity: From the Autumnal Equinox (Sep 23, 2022) to Qingming Festival (Apr 5, 2023), low humidity (4.7 %) resulted in minimal impact from atmospheric water vapor and clouds, yielding a regular solar spectrum. • Spectral Fluctuations : During other solar terms, the solar spectrum showed fluctuations due to varying temperature, humidity, and other factors. • Monochromatic Light Peaks : Peak values of monochromatic light during the Summer Solstice in 2022 and 2023 were 2.53 W m−2·nm−1 and 2.71 W m−2·nm−1, respectively, exceeding the AM0 peak, considering sunlight reflection and scattering by clouds. • Fraunhofer Line Analysis : During the 'Two Equinoxes and Two Solstices', absorption peaks of Fe, Ca, H, Mg, Na, and O elements were observed at specific wavelengths (358 nm, 431 nm, 486 nm, 517 nm, 589 nm, 687 nm). • Foundation for Further Research : The results provide a basis for studying solar radiation variations on the Qinghai-Tibet Plateau and their potential impacts on Earth, serving as a reference for sustainable research in the region. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 13646826 |
| DOI: | 10.1016/j.jastp.2025.106543 |
