Hourly Surface Observations Suggest Stronger Solar Dimming and Brightening at Sunrise and Sunset Over China

Wang, Yawen; Zhang, Jiahua; Sánchez-Lorenzo, Arturo; Tanaka, Katsumasa; Trentmann, Jörg; Yuan, Wenping; Wild, Martin

doi:10.1029/2020gl091422

Cited by 4 publications

(5 citation statements)

References 44 publications

(68 reference statements)

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“…For all-sky conditions, the brightening effect of SDR (positive trend) increases with SZAs (Figure 4a), ranging from about 0.1%/y to about 0.7%/y for the statistically significant trends. The trends in the morning and afternoon hours are more or less consistent with small differences at small SZAs, which can be attributed to effects on clear sky SDR from systematic diurnal patterns of aerosols during the warm period of the year, consistent with the results reported for China by Wang et al [33]. Note that SZAs less than 25 • can only occur during the warm period of the year around noon when clear skies are more frequent.…”

Section: Effects Of the Solar Zenith Angle On Sdrsupporting

confidence: 89%

“…The solar zenith angle is a major factor affecting the SDR, as increases in SZA leads to enhancement of the radiation path in the atmosphere, especially in urban environments with human activities emitting aerosols [33]. In order to estimate the effect of SZA on the SDR trends, we grouped the data in bins of 1 • SZA and calculated the overall trend for each bin separately for the daily periods before noon and after noon (Figure 4).…”

Section: Effects Of the Solar Zenith Angle On Sdrmentioning

confidence: 99%

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Trends from 30-Year Observations of Downward Solar Irradiance in Thessaloniki, Greece

Natsis,

Bais,

Meleti

2023

Applied Sciences

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The shortwave downward solar irradiance (SDR) is an important factor that drives climate processes and energy production and can affect all living organisms. Observations of SDR at different locations around the world with different environmental characteristics have been used to investigate its long-term variability and trends at different time scales. Periods of positive trends are referred to as brightening periods and of negative trends as dimming periods. In this study we have used 30 years of pyranometer data in Thessaloniki, Greece, to investigate the variability of SDR under three types of sky conditions (clear-, cloudy- and all-sky). The clear-sky data were identified by applying a cloud screening algorithm. We have found a positive trend of 0.38%/year for all-sky, ∼0.1%/year for clear-sky, and 0.41%/year for cloudy conditions. The consistency of these trends, their seasonal variability, and the effect of the solar zenith angle have also been investigated. Under all three sky categories, the SDR trend is stronger in winter, with 0.7, 0.4, and 0.76%/year, respectively, for all-, clear-, and cloudy-sky conditions. The next larger seasonal trends are in autumn—0.42 and 0.19%/year, for all and cloudy skies, respectively. The rest of the seasonal trends are significant smaller, close to zero, with a negative values in summer, for clear and cloudy skies. The SDR trend is increasing with increasing solar zenith angle, except under cloudy skies, where the trend is highly variable and close to zero. Finally, we discuss shorter-term variations in SDR anomalies by examining the patterns of the cumulative sums of monthly anomalies from the climatological mean, both before and after removing the long-term trend.

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Section: Effects Of the Solar Zenith Angle On Sdrsupporting

confidence: 89%

Section: Effects Of the Solar Zenith Angle On Sdrmentioning

confidence: 99%

Trends from 30-Year Observations of Downward Solar Irradiance in Thessaloniki, Greece

Natsis,

Bais,

Meleti

2023

Applied Sciences

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“…During 1993–2014, R d % in China shows a consistent and significant dimming in the diurnal cycle, with an average magnitude of −4.4% decade −1 in the morning and afternoon (5–8 and 17–20 LT) and −1.5% decade −1 for the hours in between (9–16 LT), respectively. This is consistent with the diurnal evolution pattern in R s and sunshine duration with a maximal change near sunrise and sunset (Aksoy, 1999; Cohen & Kleiman, 2005; B. Liepert & Tegen, 2002; B. G. Liepert & Kukla, 1997; Y. Wang et al., 2021). Higher changing rates of R d % at the hours with low solar elevation angle can also be observed over the seasons (Figure 3d).…”

Section: Evidence From Hourly Rd and Rf Surface Observations Over Chinasupporting

confidence: 85%

“…Hourly solar radiation data for R s and R f were obtained from the China Meteorological Data Service Center (http://data.cma.cn/), which measured consistently since 1993 for 1–24 local time (LT) with automatic thermopile pyranometers with errors not exceeding 5% by the China Meteorological Administration (CMA) (Shi et al., 2008; K. Wang et al., 2015). This study was conducted on the same period of 1993–2014 with our previous work for hourly R s (Y. Wang et al., 2021). R d on the horizontal surface is calculated as the difference between R s and R f .…”

Section: Methodsmentioning

confidence: 99%

“…Such light extinction processes can be aggravated at lower solar elevation angle along a longer optical path (Sanchez‐Romero et al., 2014). Meanwhile, the sun's rays spread over a larger surface area, which may induce a weakened R s intensity (Y. Wang et al., 2021), but with uncertain influence on R d and R f proportions. This induces the interest to explore the effect of atmospheric transparency on the diurnal variations of R d and R f with a changing elevation of the sun.…”

Section: Introductionmentioning

confidence: 99%

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Observations and Implications of Diurnal Climatology and Trends in Direct and Diffuse Solar Radiation Over China

et al. 2022

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Solar radiation received at the Earth's surface (Rs) is comprised of two components, the direct radiation (Rd) and the diffuse radiation (Rf). Rd, the direct beam from the sun, is essential for concentrated solar power generation. Rf, scattered by atmospheric molecules, aerosols, or cloud droplets, has a fertilization effect on plant photosynthesis. But how Rd and Rf change diurnally is largely unknown owing to the lack of long‐term measurements. Taking advantage of 22 years of homogeneous hourly surface observations over China, this study documents the climatological means and evolutions in the diurnal cycles of Rd and Rf since 1993, with an emphasis on their implications for solar power and agricultural production. Over the solar energy resource region, we observe a loss of Rd which is relatively large near sunrise and sunset at low solar elevation angles when the sunrays pass through the atmosphere on a longer pathway. However, the concentrated Rd energy covering an average 10‐hr period around noon during a day is relatively unaffected. Over the agricultural crop resource region, the large amounts of clouds and aerosols scattering more of the incoming light result in Rf taking the main proportion of Rs during the whole day. Rf resources and their fertilization effect in the main crop region of China further enhances since 1993 over almost all hours of the day.

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Diurnal Variation in Surface Incident Solar Radiation Retrieved by CERES and Himawari-8

Lu,

Li,

Liang

et al. 2024

Remote Sensing

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The diurnal variation of surface incident solar radiation (Rs) has a significant impact on the Earth’s climate. Satellite-retrieved Rs datasets display good spatial and temporal continuity compared with ground-based observations and, more importantly, have higher accuracy than reanalysis datasets. Facilitated by these advantages, many scholars have evaluated satellite-retrieved Rs, especially based on monthly and annual data. However, there is a lack of evaluation on an hourly scale, which has a profound impact on sea–air interactions, climate change, agriculture, and prognostic models. This study evaluates Himawari-8 and Clouds and the Earth’s Radiant Energy System Synoptic (CERES)-retrieved hourly Rs data covering 60°S–60°N and 80°E–160°W based on ground-based observations from the Baseline Surface Radiation Network (BSRN). Hourly Rs were first standardized to remove the diurnal and seasonal cycles. Furthermore, the sensitivities of satellite-retrieved Rs products to clouds, aerosols, and land cover types were explored. It was found that Himawari-8-retrieved Rs was better than CERES-retrieved Rs at 8:00–16:00 and worse at 7:00 and 17:00. Both satellites performed better at continental sites than at island/coastal sites. The diurnal variations of statistical parameters of Himawari-8 satellite-retrieved Rs were stronger than those of CERES. Relatively larger MABs in the case of stratus and stratocumulus were exhibited for both hourly products. Smaller MAB values were found for CERES covered by deep convection and cumulus clouds and for Himawari-8 covered by deep convection and nimbostratus clouds. Larger MAB values at evergreen broadleaf forest sites and smaller MAB values at open shrubland sites were found for both products. In addition, Rs retrieved by Himawari-8 was more sensitive to AOD at 10:00–16:00, while that retrieved by CERES was more sensitive to COD at 9:00–15:00. The CERES product showed larger sensitivity to COD (at 9:00–15:00) and AOD (at 7:00–10:00) than Himawari-8. This work helps data producers know how to improve their future products and helps data users be aware of the uncertainties that exist in hourly satellite-retrieved Rs data.

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Hourly Surface Observations Suggest Stronger Solar Dimming and Brightening at Sunrise and Sunset Over China

Cited by 4 publications

References 44 publications

Trends from 30-Year Observations of Downward Solar Irradiance in Thessaloniki, Greece

Trends from 30-Year Observations of Downward Solar Irradiance in Thessaloniki, Greece

Observations and Implications of Diurnal Climatology and Trends in Direct and Diffuse Solar Radiation Over China

Diurnal Variation in Surface Incident Solar Radiation Retrieved by CERES and Himawari-8

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