Solar Radiation Research Articles

Genetic diversity of leaf photosynthesis under fluctuating light conditions among temperate japonica rice varieties.

Under field conditions, solar radiation on a crop canopy fluctuates according to clouds, wind, and self-shading. The slower response of photosynthesis compared with the rate of irradiation changes leads to loss of photosynthetic carbon gain. Although some genetic differences in the rate of photosynthetic induction have been reported, the diversity among rice varieties is largely unknown. Here we evaluated genetic variation in the response of photosynthesis to a step increase in light intensity among 166 temperate japonica varieties including landraces and modern varieties. Large genetic variation in photosynthetic induction and less evidence of improvement across modern breeding programmes were acknowledged. In the correlation analysis between physiological traits for all varieties, the efficiency of non-stomatal processes was the major factor affecting the rate of induction. The landrace Aikokumochi, which has intermediate photosynthetic capacity, showed rapid photosynthetic induction-eight times that of the slowest variety. This was attributed to smaller non-stomatal limitation in the initial phase of induction and smaller stomatal limitation in the later phase than in reference varieties. Aikokumochi also had a greater photosynthetic CO2 gain without reduced water use efficiency under repeated fluctuating light. These findings demonstrate the importance of genetic resources to improve photosynthesis while maintaining water use efficiency under fluctuating light conditions.

Seasonal and lifelong changes in skin colour and pigmentation of Austrian farming families: an exploratory study.

Farmers are exposed chronically to solar ultraviolet radiation. Their chronically exposed skin undergoes alterations in pigmentation, but quantitative measurements have not be done yet. Therefore, we followed skin color and pigmentation in Austrian farming families (male and female farmers, their spouses, and children) for one year by objective tri-stimulus measurements on different body sites. The difference between constitutive and facultative pigmentation was quantified by the "degree-of-tan" (TAN°), which we defined as the difference in individual typology angle between constitutive and facultative pigmentation. Personal sun exposure was measured in parallel. Measurements of skin colour showed that independent of occupation, adult males had a darker red component in skin color of the forehead than adult females and children, with the highest values observed in males only. This difference develops during puberty and adolescence. Even in late winter, an obvious TAN° was found in all groups at continuously and intermittently exposed body sites. TAN° was higher in adults than in children and highest in farmers. The seasonal changes in TAN° were pronounced in all groups on intermittently exposed body sites but less so on the forehead. In conclusion, TAN° increases in farmers on average during their lifetime but not in their spouses, even though many spouses have higher TAN° than farmers of the same age. Such high TAN° is reversible if sun exposure is low in the following seasons. The highest TAN° values were found in farmers older than 50years.

Assessing aerosol effects on solar irradiance in the NEOM region with the WRF-solar model

This study demonstrates the usability of the Weather Research and Forecasting (WRF)-Solar model, in predicting solar irradiance in the NEOM region of Saudi Arabia across different sky conditions. This research aims to enhance the accuracy of solar radiation forecasting by systematically evaluating the model's responses to external time-varying two-dimensional (2-D) aerosol optical depth (AOD) data at 550 nm under scenarios with varying cloud cover and aerosol levels. Through experiments representing distinct sky conditions, this study demonstrates consistent trends, with the control experiment (CTRL) consistently producing the highest Global Horizontal Irradiance (GHI) and Direct Normal Irradiance (DNI) due to lower representation of AOD in the model. Notably, experiments incorporating time-varying 2-D AOD from the Copernicus Atmosphere Monitoring Service (CAMS) reanalysis outperform other experiments with NASA’s Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA- 2) analysis, and climatological AOD datasets, particularly on overcast days. Model validation against observations from the Tabuk University station further substantiates these findings. Furthermore, experimental results highlight the importance of dynamic aerosol data over the climatological or no-aerosol data in improving the solar energy predictions, emphasizing the need for accurate representation of aerosol-cloud-radiation interactions in numerical models for precise solar irradiance forecasting.

Elucidating the Structure of Melanin and Its Structure-Property Correlation.

ConspectusMelanin, specifically eumelanin, is a brownish-black pigment abundant in nature. It is a heterogeneous biopolymer known most commonly for its spectacular photoprotection property in humans, animals, and plants. Numerous other properties of eumelanin have recently been identified, including radical scavenging, thermal regulation, charge transport, etc. While the presence and significance of melanin have long been accepted, its exact chemical makeup remains unclear. Melanin has an inherent diversity of structure and complexity, making understanding many of its properties challenging. Therefore, there are large gaps in our understanding of the structure-property relationship in melanin. On the other hand, due to its diverse properties and biocompatibility, there is significant interest in engineering such biomimetic devices and materials with targeted properties utilizing melanin-like scaffolds. Furthermore, recent efforts toward understanding the molecular origin of its properties are also based on synthetic melanin analogs. For all these reasons, understanding the structure of melanin and its structure-property relationship remains pivotal to much of the progress in this direction.Our research has revolved around providing new insights into the structure of melanin and its structure-function correlations for properties such as absorption spectra, electron transport, and photoprotection. We have used tools based on a combination of computational chemistry and machine learning to answer these questions. Many of these methods and protocols developed in the group for solving this problem can be utilized for other problems of similar complexity.The difficulties in elucidating these aspects of melanin chemistry lie in its inherent structural and chemical diversity. It is a biopolymer with heterogeneity in monomeric units, oxidation states, polymerization site, and significant conformational degrees of freedom. Many of the attractive properties of melanin are a direct consequence of this diversity. One such property is its broadband absorption spectra, which allow it to absorb light across the UV-visible range and, therefore, function as a photoprotective agent against solar radiation. The melanin absorption spectra are unusual in their monotonic and featureless form. It is now well-accepted that both structural and chemical heterogeneity are responsible for these unusual spectra. Therefore, the problem of isolating specific chromophores responsible for different parts of the spectra becomes a daunting task. While previous computational and experimental studies have shown that diversity is central to this property, i.e., the spectrum is an ensemble or average spectrum, they have not been able to identify specific structures that are responsible. Therefore, we have used machine learning and artificial intelligence concepts to identify patterns and reconstruct particular structures. We have shown, with the help of machine learning and computational chemistry, that data-driven approaches can identify specific structures or classes of structures that are important chromophores. This provides a significant direction in answering the questions about the structure-function correlation of melanin for its absorption spectra.For charge transport properties we have shown the importance of hydrogen bond networks and, therefore, the most successful structural motifs for efficient charge transport. Furthermore, with a bottom-up approach, we have also identified nonradiative pathways for the deactivation of photoactivated melanin.

Integration of BIM and robotic fabrication for sustainable design and manufacturing of free-form building façade panels in off-site construction

The construction industry faces persistent challenges related to inefficiency, high energy consumption, and environmental impacts, necessitating innovative approaches to sustainable building practices. These challenges are further amplified in off-site construction (OSC) manufacturing of free-form components like façade panels, which demand extensive coordination, labor, and time due to their complex geometries and unique designs. This research addresses these issues by integrating Building Information Modeling (BIM) and robotic fabrication to develop a parametric methodology for optimizing façade designs in OSC. The methodology incorporates generative design to evaluate and select façade solutions based on minimizing solar radiation and façade area, while adhering to energy efficiency and sustainability criteria. A mock-up case study was used to validate the approach, utilizing BIM to generate a Building Energy Model (BEM) for energy performance analysis. The findings demonstrate significant reductions in solar radiation through the selected façade designs, highlighting the methodology’s potential to improve environmental performance. By incorporating digital fabrication and robotic manufacturing, the methodology mitigates the challenges of producing free-form components, streamlining production, reducing labor intensity, and enhancing accuracy. This research contributes a scalable framework for sustainable façade design and fabrication, advancing the efficiency and adaptability of OSC workflows.

Solar-Driven Massive Production of Dimerized Imine in Aqueous Phase via an Atomically Engineered Photocatalyst.

Photocatalytic selective oxidation of organicsrepresents a promising avenue for the sustainable production of value-added chemicals, but suffers from sluggish charge separation and difficult selectivity manipulation. In particular, the Schottky barrier-induced adsorption of expected organic products at reduction sites tends to trigger the hydrogenation side reaction, which is more pronounced in the ideal aqueous environment due to distinct polarity. Here, we report a precise cocatalyst strategy on ZnIn2S4 (ZIS) photocatalyst at the atomic level to eliminate the Schottky barrier between ZIS and cocatalyst, thus achieving exceptional activity (565 μmol h-1) and selectivity (99%) for photocatalytic dimerized imine production in aqueous media, which is five times more effective than ZIS loaded with Pt nanoparticles. The excellent performance is achieved by effectively attenuating the accumulation of photogenerated holes near the Pt sites and then suppressing the unwanted hydrogenation side reaction. We further demonstrate that our system can be directly scaled up to 0.5 m2 for scalable outdoor experiment and achieve solar-driven production of benzylimine with 125 mL yield and 97 wt% purity for two weeks under solar irradiation. This study presents an interfacial atomical design strategy for photocatalysts to efficiently produce high-value imine coupled with H2 under mild and green conditions.

Optimization of building envelope latent heat storage integration based on internal surface solar insolation profiles

Optimization of building envelope latent heat storage integration based on internal surface solar insolation profiles

A Perspective on Global Dimming and Brightening Worldwide and in China

Abstract Worldwide radiation records suggest that the amount of sunlight received at the Earth’s surface (surface solar radiation, SSR) has not been stable over the years, but underwent significant decadal variations, popularly also known as “global dimming and brightening”. These variations have been particularly evident in China, where the SSR substantially declined from the 1960s to the 1990s (dimming), with indications for a trend reversal in the 2000s and a slight recovery (brightening) in recent years. This perspective/review paper will discuss recent updates and remaining challenges regarding our knowledge of the magnitudes, causes, and implications of these variations in SSR worldwide, with a particular emphasis on the developments in China.

Corrigendum: World Climate Research Programme lighthouse activity: an assessment of major research gaps in solar radiation modification research

Corrigendum: World Climate Research Programme lighthouse activity: an assessment of major research gaps in solar radiation modification research

AI-Driven Global Solar Radiation Prediction: Harnessing Machine Learning and Satellite Imagery for Accurate Forecasting

AI-Driven Global Solar Radiation Prediction: Harnessing Machine Learning and Satellite Imagery for Accurate Forecasting

Solar ventilation wall for alleviating thermal and health risks of formaldehyde and virus infection

The solar ventilation wall is a well-established passive solar system that can mitigate indoor formaldehyde pollution and virus infections, which could significantly impact health. This study introduced and evaluated a thermal purification composite ventilation wall system that utilizes solar energy to regulate indoor thermal conditions and air quality. Steady-state experiments with simulated light sources assessed its thermal efficiency and formaldehyde degradation. After 2 h of ultraviolet (UV) exposure at 300, 500 and 800 W/m², indoor temperatures rose by 2.5°C, 1.6°C and 1.0°C, with thermal efficiencies of 32.14%, 29.65% and 26.49%. Thermal catalytic oxidation reduced formaldehyde from 600 ppb to 207.1, 166.0 and 140.9 ppb, achieving degradation rates of 50.7%, 60.1% and 66.4%. Model validation showed that the root mean square deviation for temperature, formaldehyde concentration and the clean air delivery rate was below 5%, confirming reliability. Regional analysis identified solar radiation as the primary efficiency factor. From December to April, heating capacity and clean air volume across cities varied minimally, while UV disinfection of SARS-CoV-2 achieved a 96.22%–97.09% inactivation rate, demonstrating the system's potential.

Robert Lewis Fullarton Boyd. 19 October 1922—5 February 2004

Professor Sir Robert Boyd led the development of space science in the UK from the pre-Sputnik days using sounding rockets to the intensive collaboration with NASA and the successful structuring of European efforts through ESA. He founded the Mullard Space Science Laboratory of University College London and set high engineering standards for university-supplied space instruments, winning invitations to provide sensors for most of the major international space agencies. Sir Robert’s vision extended beyond the early studies of the ionized layers of the upper atmosphere to the effect of solar radiation on the Earth and also the astronomical importance of observing the Universe at all possible wavelengths.

Grain‐size evidence of Middle Pleistocene sedimentary environmental changes in the eastern Tai‐hang Mountains, North China

ABSTRACTGrain size is a proxy for climate and environmental change, and the results of grain size analyses can be used to infer the conditions and environment under which the sediments were formed. The eastern foothills of the Tai‐hang Mountains in northern China are on the edge of the East Asian Summer Monsoon and are extremely sensitive to climate and environmental changes. Understanding the ecological changes in this region is vital for coping with future climate change and solving related climate and environmental problems. This study uses parametric grain size end‐member analysis to discuss the depositional dynamics and ecological changes in the Middle Pleistocene of the Shijiazhuang JingXing YF profile. The results indicate that: (1) The OSL dates of the YF profile vary from 274 to 0.997 ka, and sedimentation began in the Middle Pleistocene. (2) The YF profile's sediments’ grain size is separated into four end elements: EM1 is the clay fraction produced by loam‐forming action; EM2 and EM3 are long‐distance transported fine silt and short‐distance transported silt at low altitudes, representing the variation in East Asian Summer Monsoon intensity; EM4 represents the near‐surface transported coarse silt fraction driven by East Asian Winter Monsoon power. (3) The grain size index reconstructed the paleoclimate of the Middle Pleistocene in the Shijiazhuang area, and it can be divided into four stages: 274–210 ka, the climate changed from cold to warm; 210–170 ka, was a warm period; 170–80 ka, the climate changed from warm to cold; and from 80–1 ka was a cold period. Multi‐indicator comparisons show that the monsoon evolution recorded in the Middle Pleistocene YF loess‐paleosol sequence is fundamentally consistent with changes in mid‐ to high‐latitude solar radiation, and changes in solar radiation modulate that monsoon changes in East Asia.

CFD model of the heat transfer processes in an offshore photovoltaic panel

AbstractSolar energy has become increasingly important in recent years. The installed capacity has increased over the years, and today solar energy represents a significant part of the renewable energy contribution. One of the handicaps of photovoltaic panels is the cooling process. The panels are susceptible to overheating, which leads to a reduction in efficiency. One of the ways to mitigate this problem is to install the photovoltaic panels offshore, where cooling is more efficient, thus increasing power generation. Due to the lack of in‐depth analysis of numerical models for studying heat transfer in offshore photovoltaic panels in the literature, this work proposes a computational fluid dynamics model to analyse the thermal performance of an offshore photovoltaic panel. The numerical model was used to characterize the heat transfer processes. The model was validated with experimental data from an onshore panel setup, where key parameters such as solar radiation, inlet air temperature, and solar cell temperature were measured. A comparison between onshore and offshore installations was made. The model showed that the average solar cell temperature in offshore conditions is 39.11°C, compared to 45.5°C for onshore panels. Over a day analysed, the average efficiency improved from, 10.7% to 11.2%. The research also highlighted the critical role of water temperature in affecting the thermal performance of PV panels. The potential impact on the marine ecosystem due to increases in water temperature was found to be negligible, supporting the sustainability of offshore PV systems. These results demonstrate the advantages of offshore photovoltaic systems over traditional onshore ones, contributing to the advancement of sustainable energy solutions.

The study of outdoor thermal comfort in open spaces of cold climate campus

In the urbanization process, phenomena such as the urban heat island effect exacerbate climatic deteriorations, leading to environmental issues in cities. Campus areas, as significant ecological components within the urban environment, play a crucial role in environmental regulation. This paper investigates the impact of outdoor physical environments in campuses on users’ thermal comfort from the perspective of thermal comfort. Using surveys, meteorological measurements, and behavioral analysis, this study examines four distinctive spaces within a campus in Xi’an, establishing a thermal comfort baseline for the population in Xi’an’s campus spaces. The research results indicate: (1) Globe temperature (Tg), air velocity (Va), air temperature (Ta), and ground temperature (G) are the primary factors affecting students’ thermal sensations in campus open spaces. Respondents tended to improve their thermal sensations through changes in humidity and solar radiation. (2) In the campus open spaces of Xi’an, the overall NPET of the subjects was 13.9 °C, with the NPETR ranging from 9.4 to 18.4 °C. (3) The preferred warmth temperature for university students in Xi’an is 15.15 °C, which is 1.25 °C higher than the NPET (13.9 °C).

Integrated Thermoelectric Generation System for Sustainable All-Day Power Supply Based on Solar Energy and Radiative Cooling.

Thermoelectric generators have a promising application in the field of sustainable energy due to their ability to utilize low-grade waste heat and their high reliability. The sun radiates a large amount of energy to the earth, yet most of which is wasted. Efficient utilization of solar energy can be achieved by integrating a solar absorber, phase change material, and Fresnel lens with thermoelectric generators. In this work, multiwalled carbon nanotubes are mixed with polydimethylsiloxane as a solar absorber and achieve up to 99% absorption of sunlight. Meanwhile, the solar absorber as a radiative cooler also exhibits high emissivity in the atmospheric window, and a cooling effect of 7.3 K from the ambient temperature can be realized at night. Paraffin wax as a phase change material realizes heat storage during the day and release at night. The Fresnel lens realizes a high degree of convergence of sunlight over a large area, obtaining a higher output performance at a lower cost. The multienergy integrated and synergistic thermoelectric generation system achieves an output power density of 4.1 mW/cm2 during the day and a peak power density of 0.2 mW/cm2 during the night, which can meet the demand for ab uninterrupted power supply to electronic devices. This work realizes the efficient utilization of solar energy and provides an option for thermoelectric application.

Seasonal ecophysiology of two páramo species: the dominance of light over water limitations

Dry and rainy seasons in many ecosystems differ significantly in cloudiness, precipitation, and incident sunlight. These seasonal variations can influence photosynthesis by altering light availability and water stress. This study examines whether light availability or water stress is the primary limiting factor for photosynthesis in páramo plants during the dry and rainy seasons. We measured photosynthetic carbon gain per unit leaf area (An), stomatal conductance (gs), chlorophyll fluorescence (ϕPSII), and leaf water potentials, in two dominant páramo species, Espeletia grandiflora and Chusquea tessellata, across both seasons. Photosynthetic light-response curves were generated for each species, and statistical analyses assessed the relative influence of environmental factors such as light, temperature, and vapor pressure deficit on An. Contrary to our expectations, An was higher in the dry season despite increased water stress, suggesting that light availability is a stronger driver of carbon assimilation. However, light-response curves showed that Espeletia grandiflora exhibited higher potential carbon uptake during the dry season, while C. tessellata had greater uptake during the rainy season. Statistical analyses indicated that light was the primary factor influencing An in both seasons, though temperature and vapor pressure deficit also played a role for C. tessellata in the rainy season. The combination of high solar radiation and elevated leaf temperatures in the dry season facilitated greater carbon assimilation, particularly in E. grandiflora. In contrast, the cloudier conditions of the rainy season limited photosynthesis despite reduced water stress. Although C. tessellata exhibited high An during the dry season, it appeared vulnerable to high radiation and desiccation. These findings emphasize that cloud cover and light availability, rather than water stress alone, are key drivers of páramo plant carbon uptake, with important implications for predicting climate change effects in high-altitude ecosystems.

Path Analysis on the Meteorological Factors Impacting Yield of Tartary Buckwheat at Different Sowing Dates

Tartary buckwheat is an important characteristic multigrain crop, mainly planted in Sichuan, Guizhou, Yunnan and Tibet, and other alpine and remote ethnic mountainous areas. In order to clarify the effect of sowing date on the yield and quality of Tartary buckwheat and its relationship with meteorological factors The variety Jinqiao No. 2 was used for a two-year trial at Dingxiang Test Base in Shanxi Province on four sowing dates (15 June, 26 June, 6 July and 17 July 2022 and 19 June, 30 June, 10 July and 21 July 2023) starting from the bud stage. Responses to sowing date were investigated by examining the growth period structure, yield, yield component, quality, and their relationship to climatic factors. The results showed that meteorological factors during the grain grain-filling stage were different when the sowing date was different. Compared with other sowing times, the treatment with the sowing of early and mid-July had less than 13.5~27.9 h of sunshine, less than 28.8~48.5 mm of rainfall, more than 10.5~19 days of ≤15 °C days, but the most serious low-temperature stress (≤15 °C days up to 27 days). The yield of sowing in July was 69.8~77.0% and 69.9~79.1% lower than that of sowing in June in 2022 and 2023 respectively, and the later sowing had a lower yield. Delayed sowing is beneficial to the accumulation of flavonoids and protein in Tartary buckwheat grains, and the average value in 2022 and 2023 is 11.55% and 14.64% higher than that in the first sowing, but the content of fat and starch is significantly reduced. The result of path analysis showed that the low temperature (≤15 °C days up to 27 days) and less solar radiation duration were the key points for attaining high yield and quality, due to the mean daily temperature and ≤15 °C days from flowering to maturity had negative effect on 1000-seed weight, seed setting rate, starch and crude lipid content of Tartary buckwheat, and the direct effect of sunshine duration on the content of protein and flavonoid in Tartary buckwheat was the greatest. The yield of Tartary buckwheat sown in June was higher than that of other treatments, because of avoiding low-temperature stress and long rainy and sunless weather during the grain filling stage, which enabled the blossoming and grain filling normally and finally attained higher yield.

Assessing Skin Photoprotection in the Infrared Range: The Reflectance Profiles of Cold-Pressed Plant Oils

The harmful effects of solar radiation on the skin are known and scientifically proven, with recent studies indicating that not only ultraviolet (UV) radiation but also infrared (IR) radiation contributes to skin photoaging and increases the risk of carcinogenesis. Infrared radiation is also responsible for the degradation of protective carotenoids in the skin, the disruption of calcium homeostasis, and the activation of apoptosis pathways. The biological mechanisms underlying these effects include an increased level of reactive oxygen species and increased expression of metalloproteinases in the skin. The aim of this study was to evaluate the photoprotective properties of 10 cold-pressed plant oils in the infrared spectral range from 1000 nm to 2500 nm by assessing their impact on the directional–hemispherical reflectance (DHR) of human skin after their topical application. This study was conducted in vivo on the skin of 12 volunteers, with non-invasive DHR measurements taken before and directly after the application of the oil and 30 min later. Additionally, the correlation between the oil’s compounds (chlorophyll a, chlorophyll b, lycopene, and β-carotene) and antioxidant activity, expressed as the DPPH free radical scavenging capacity, was analyzed in relation to the differences in the skin’s DHR observed. An interesting result was obtained in the context of protecting the skin against IR radiation. A statistically significant increase in the skin’s reflectance after the penetration of the oil (p < 0.05) was observed in the 1700–2500 nm range for the chokeberry, fig, pomegranate, and perilla oils, suggesting their potential as photoprotective agents against IR. These findings indicate that chokeberry, fig, pomegranate, and perilla oils may serve as ingredients in cosmetic formulations designed for broad-spectrum skin photoprotection, complementing traditional UV filters with additional protection against infrared radiation. However, further research is needed to confirm these findings in a larger population.

Photovoltaic Absorber "Glues" for Efficient Bifacial Selenium Photovoltaics.

Bifacial solar cells hold great potential for achieving higher power output than conventional monofacial devices by harvesting solar irradiance from both their front and rear surfaces. However, almost all currently reported bifacial devices typically require a sputtered rear transparent conducting oxide electrode, which can damage the underlying layers due to plasma effects during the deposition process. Here, we report a glue-bonding strategy that uses a high-viscosity photovoltaic absorber slurry-in the case of molten selenium (Se)-as the adhesive to bond two charge-transport layer-deposited commercial fluorine-doped tin oxide glasses, directly creating bifacial solar cells without the use of magnetron sputtering. We find that molten Se exhibits relatively high viscosity, high stability, and Newtonian fluid characteristics, facilitating film formation using this strategy. The resulting bifacial Se solar cells exhibit a bifaciality factor of 90.1%, surpassing all types of conventional thin-film solar cells. These cells achieve efficiencies of 8.61% under 1-sun illumination with an albedo of 0.3 and 26.17% under 1000-lux indoor illumination with an albedo of 0.8, with no efficiency loss after 1000h of ambient storage.