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Articles published on Solar spectra

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1626 Search results
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  • New
  • Research Article
  • 10.1016/j.solener.2025.114242
An efficient genetic algorithm method to extend and upscale direct solar irradiance spectra measured with spectroradiometers
  • Feb 1, 2026
  • Solar Energy
  • Gabriel López + 3 more

An efficient genetic algorithm method to extend and upscale direct solar irradiance spectra measured with spectroradiometers

  • New
  • Research Article
  • 10.5194/amt-19-565-2026
Extension of the Total Carbon Column Observing Network (TCCON) over the Eastern Mediterranean and Middle East: the Nicosia site in Cyprus
  • Jan 22, 2026
  • Atmospheric Measurement Techniques
  • Constantina Rousogenous + 14 more

Abstract. Long-term greenhouse gas (GHG) measurements are essential for understanding the carbon cycle, detecting trends in atmospheric composition, and assessing the efficiency of climate change mitigation strategies. However, observational gaps over large geographic areas such as the Eastern Mediterranean and Middle East (EMME), a well-known regional GHG hotspot, are likely to increase uncertainties in estimations of their sources and sinks. Here, we describe a new Total Carbon Column Observing Network (TCCON) observatory for solar absorption spectroscopy measurements that has been operating in Nicosia, Cyprus, since September 2019. The site helps bridge a regional observational gap in the EMME, a strategic location at the crossroads of air masses from Europe, Asia, and Africa. Using near-infrared (NIR, InGaAs detector) solar absorption spectra, TCCON-Nicosia measures total column average dry-air mole fractions (Xgas) of key trace gases, including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), hydrogen fluoride (HF), water vapor (H2O), and semi-heavy water (HDO). These continuous observations, spanning more than 4 years, are presented along with a description of the quality control procedures, compliant with the TCCON standards, to ensure total column atmospheric data with minimal errors. In 2023, observations were extended into the mid-infrared (MIR) spectral region with the addition of a liquid-nitrogen-cooled InSb (LN2-InSb) detector enabling the retrieval of additional trace gases such as formaldehyde (HCHO), carbonyl sulfide (OCS), nitrogen monoxide (NO), nitrogen dioxide (NO2), and ethane (C2H6), herewith further contributing to the global Network for the Detection of Atmospheric Composition Change (NDACC). To tie the TCCON Nicosia with the WMO reference scale, an AirCore (AC) campaign conducted in June 2020 over Cyprus provided vertical in situ profiles, which were converted into total column quantities (AC.Xgas) and compared to TCCON observations (Xgas). The TCCON/in situ comparison showed agreement well within their respective uncertainty budget.

  • Research Article
  • 10.1063/5.0302649
Density dependence of measured line intensities for O2 transitions.
  • Jan 6, 2026
  • The Journal of chemical physics
  • Ha Tran + 7 more

We report predictions and measurements of O2 absorption spectra that exhibit line intensity depletion with increasing gas density. This effect, which is attributed to the finite duration of collisions, alters the line shape by redistributing a portion of the intensity from a relatively narrow spectrum that can be described by an impact-approximation-based profile to a broad pedestal with a width that is inversely related to the collision duration. Using classical molecular dynamics simulations (CMDS), we predicted details regarding this mechanism for O2 with four collision partners: O2, N2, Ar, and He at a temperature of 296K. These simulations were validated by comparisons with experimental intensity depletion coefficients obtained from absorption spectra of the 1.27μm band of O2 in air; Ar and He acquired over a wide pressure range up to 120kPa. All experimental spectra were recorded using high-precision cavity ring-down spectroscopy (CRDS) apparatuses at NIST (United States of America) and LIPhy (France). For air-broadened O2, more specifically, a mean depletion value of ∼0.3% amagat-1 was observed, with almost no resolvable rotational dependence. The temperature dependence of the intensity depletion in this system was also investigated by CMDS at 250 and 296K and by CRDS spectra of air at 250, 275, and 296K. The theoretical results suggest a nearly 1/T2 temperature dependence of the intensity-weighted depletion coefficient, which over the limited temperature range considered, was only slightly greater than the measurement precision. Finally, simulations of atmospheric solar absorption spectra were implemented to quantify the impact of neglecting this depletion effect on the retrieved surface pressure, resulting in a negatively biased measurement of ∼0.14%, with a spread of ∼0.02% caused by seasonal variations in gas temperature.

  • Research Article
  • 10.1051/0004-6361/202557132
A decade of solar high-fidelity spectroscopy and precise radial velocities from HARPS-N
  • Dec 17, 2025
  • Astronomy & Astrophysics
  • X Dumusque + 55 more

The HARPS-N solar telescope has been observing the Sun every possible day since the summer of 2015. We have recently released 10 years of these data, which are available online. The goal of this paper is to present the different optimisations made to the ESPRESSO data reduction software used to extract the published HARPS-N solar spectra, describe the data curation, and perform some analyses that demonstrate the extreme radial velocity (RV) precision of those data. By analysing all of the HARPS-N wavelength solutions over 13 years, we brought to light instrumental systematics at the 1 level. We mitigated those systematics by curating the thorium line list used to derive the wavelength solution and applying a correction to the drift of thorium lines induced by the aging of thorium-argon hollow cathode lamps. After optimisation, we demonstrated a peak-to-peak precision on the HARPS-N wavelength solution better than 0.75 or well-understood instrumental systematics. Finally, we corrected the curated data for spurious sub-meter-per-second RV effects caused by erroneous instrumental drift measurements and by changes in the spectral blaze function over time. over 13 years. We then carefully curated the decade of HARPS-N re-reduced solar observations by rejecting 30% of the data affected either by clouds, bad atmospheric conditions After curation and correction, a total of 109,466 HARPS-N solar spectra and respective RVs over a decade were made available. The median photon-noise precision of the RV data is 0.28 and on daily timescales, the median RV rms is 0.49 which is similar to the level imposed by stellar granulation signals. On 10 year timescales, the large RV rms of 2.95 results from the RV signature of the Sun's magnetic cycle. Through modelling of this long-term effect using the Bremen composite magnesium II activity index, we demonstrate a long-term RV precision of 0.41 We also analysed contemporaneous HARPS-N and NEID solar RVs and found the data from both instruments to be of similar quality and precision. However, an analysis of the RV difference between these two RV datasets over the three available years gave a surprisingly large RV rms of 1.3 This variation is dominated by an unexplained trend that could be caused by a different sensitivity to stellar activity of the two datasets. Once this trend was modelled, the overall RV rms for three years reached 0.79 and the RV rms during the low-activity phase decreased to 0.6 compatible with what is expected from supergranulation. This decade of high-cadence HARPS-N solar observations with short- and long-term precision below one represents a crucial dataset in the pursuit of further understanding the stellar activity signals in solar-type stars and advancing other science cases requiring such extreme precision.

  • Research Article
  • 10.3847/2041-8213/ae25e3
Surprisingly Large Doppler Shifts in Hinode EUV Imaging Spectrometer (EIS) Solar Spectra Resulting from an Inconspicuous Small-scale Jet in Extreme-ultraviolet Images
  • Dec 15, 2025
  • The Astrophysical Journal Letters
  • Alphonse C Sterling + 3 more

Abstract Strong EUV line shifts in solar spectra are generally indicative of highly dynamic and explosive events that are easily detected in comparable-wavelength EUV images, with the strongest such line shifts (several 100 km s −1 ) occurring in solar flares. Here we present observations of exceptionally strong line shifts detected in Hinode EUV Imaging Spectrometer (EIS) spectra outside the time of a flare-like brightening, with 195 Å blueshifts of ∼200 km s −1 . Although the likely culprit is too weak to register in GOES soft X-ray fluxes, EIS pinpoints the source at the edge of an active region. Solar Dynamics Observatory Atmospheric Imaging Assembly (AIA) images and Helioseismic and Magnetic Imager (HMI) magnetograms show a nondescript small-scale eruptive event at this location. We find this event likely to be an inconspicuous coronal jet, apparently triggered by converging/canceling magnetic flux patches, with a plane-of-sky velocity of ∼159± 29 km s −1 . AIA and HMI observations of this faint transient feature, together with observations of a slightly brighter jetting event near the same location 1 hr earlier, suggest that the strong EIS Doppler shifts are indeed due to a coronal jet that is hard to detect in AIA images. These observations, together with other recent studies, show that EUV Doppler maps are a much more sensitive tool for detecting small-scale eruptions than are EUV images, and those eruptions are frequently triggered by magnetic flux cancellation episodes. Such-detected small-scale eruptions, which often produce small-scale coronal-jet-like features, might propagate into and help drive the solar wind.

  • Research Article
  • 10.1093/mnras/staf2085
Solar carbon abundance from 3D non-LTE modelling of the diagnostic lines of the CH molecule
  • Dec 10, 2025
  • Monthly Notices of the Royal Astronomical Society
  • Richard Hoppe + 7 more

Abstract Context The spectral lines of the CH molecule are a key carbon (C) abundance diagnostic in FGKM-type stars. These lines are detectable in metal-rich and, in contrast to atomic C lines, also in metal-poor late-type stars. However, only 3D LTE analyses of the CH lines have been performed so far. Aims We test the formation of CH lines in the solar spectrum, using for the first time, 3D Non-LTE (NLTE) models. We also aim to derive the solar photospheric abundance of C, using the diagnostic transitions in the optical (4218 - 4356 Å) and infrared (33025 - 37944 Å). Methods We use the updated NLTE model molecule from Popa et al. (2023) and different solar 3D radiation-hydrodynamics model atmospheres. The models are contrasted against new spatially-resolved optical solar spectra, and the center-to-limb variation (CLV) of CH lines is studied. Results We find generally small (∼0.01 dex) NLTE effects in the optical and IR diagnostic CH A-X lines in the solar atmosphere. Both 3D NLTE and 3D LTE spectral modelling yield an excellent fit to the solar intensity observations at all viewing angles. The 1D LTE and 1D NLTE models fail to describe the line CLV, and lead to underestimated solar C abundances. The 3D NLTE modelling of diagnostic lines in the optical and IR yields a carbon abundance of A(C)=8.52 ± 0.07 dex. The estimate is in agreement with recent results based on neutrino fluxes measured by Borexino. Conclusions 3D NLTE modelling and tests on spatially-resolved solar data are essential to derive robust solar abundances. The analysis presented here focuses on CH, but we expect that similar effects will be present for other molecules of astrophysical interest.

  • Research Article
  • 10.3390/s25247474
Simulation and Reproduction of Direct Solar Radiation Utilizing Grating Anomalous Dispersion
  • Dec 9, 2025
  • Sensors (Basel, Switzerland)
  • Junjie Yang + 9 more

The technical challenge of balancing radiant illuminance and the angular diameter of the simulated sun remains unsolved, preventing the realization of a solar simulator with both a 32′ angular diameter and a solar constant irradiance. This paper proposes a direct solar radiation simulation method using grating anomalous dispersion and a technological implementation scheme. This new architecture consists of a spectrally modulated optical engine, a diffractive combining system, and a multi-aperture imaging reconstruction system. We designed an optical system for simulating direct solar radiation, which achieves a high degree of reproducibility of natural direct solar radiation characteristics. The performance of this system was verified through simulation, with the results indicating that the solar direct radiation simulator achieves an angular diameter of 31.7′ while maintaining radiant illuminance above a solar constant. Additionally, the system spectral match to both the extraterrestrial (AM0G) and terrestrial global (AM1.5G) solar spectra, along with its uniformity, complies with an A+ grade. The studied direct solar radiation simulation is currently the only instrument capable of achieving a solar constant of an angular diameter less than 32′. This research revolutionizes the structure and principle of the traditional solar simulator, makes up for the deficiencies of the existing solar simulation technology, further improves the theoretical system of solar direct radiation simulation, and has far-reaching scientific significance for the development and application of solar simulation technology.

  • Research Article
  • 10.1002/adts.202501529
Extending the Single‐Diode Model With Spectral Sensitivity for Different PV Materials Under Varying Solar Spectra
  • Nov 25, 2025
  • Advanced Theory and Simulations
  • Ahmed Issa Alnahhal + 1 more

ABSTRACT Due to environmental dynamic variability, spectral fluctuations arise in the incident photon flux, leading solar cells to operate under diverse spectral regimes with distinct carrier generation characteristics. As the conventional single‐diode model (SDM) neglects spectral dependency, this study extends the SDM of the PV cell with spectral sensitivity by incorporating wavelength‐dependent photogenerated current. Three semiconductor materials, including Si, GaAs, and Ge, are investigated under both ideal and realistic operating conditions, using an SDM‐based representation implemented in MATLAB/Simulink under AM0 and AM1.5G solar spectra. The findings demonstrate how different spectral behaviors influence the output characteristics of each solar cell, even when their theoretical Shockley–Queisser limits are nearly identical. Accordingly, a new analytical metric of wavelength‐based efficiency is introduced, providing a deeper understanding beyond standard efficiency calculations. This metric enables the evaluation of the overall efficiency under varying solar spectra. The proposed concept provides valuable insights into how semiconductor materials and spectral responses influence solar cell efficiency. Furthermore, it offers practical guidance for optimizing solar cell designs and selecting materials for specific applications.

  • Research Article
  • 10.3847/1538-4357/ae197b
The He I D3 Line as a Proxy for Magnetic Activity Using EXPRES Solar Observations
  • Nov 19, 2025
  • The Astrophysical Journal
  • Momo Ellwarth + 8 more

Abstract Stellar activity remains one of the primary challenges in the detection and characterization of low-mass exoplanets, as it can induce radial velocity (RV) variations that mask or mimic planetary signals. Identifying reliable activity proxies is essential in order to distinguish stellar variability from genuine planetary signatures. In this study, we examine the variability of the chromospheric He I D3 line in high-resolution solar spectra and assess its potential as an activity indicator. We find a strong correlation between the He I D3 line intensity variation and the Sun’s unsigned magnetic flux derived from Solar Dynamics Observatory/Helioseismic and Magnetic Imager data as well as with the solar RVs. Our results suggest that the He I D3 line offers a promising and straightforward proxy for magnetic activity, which may complement existing stellar activity indicators. Its inclusion could help disentangle stellar signals in RV measurements and ultimately improve the detection of Earth-like exoplanets.

  • Research Article
  • 10.5194/acp-25-14591-2025
Volatile emissions during the 2021 Cumbre Vieja (La Palma) eruption integrating multiplatform atmospheric observations
  • Nov 4, 2025
  • Atmospheric Chemistry and Physics
  • Noémie Taquet + 20 more

Abstract. In a world increasingly impacted by climate change and natural hazards, atmospheric monitoring networks are essential for informed decision-making. During the 2021 La Palma eruption, we integrated surface and ground-based remote sensing measurements from global atmospheric network instruments, complemented by rapidly deployed sensors, to monitor volcanic gas emissions up to 140 km from the source. We used direct-sun measurements from low-resolution (EM27/SUN) and high-resolution (IFS-125HR) Fourier transform infrared (FTIR) spectrometers. On La Palma, the EM27/SUN was combined with a differential optical absorption spectroscopy (DOAS) instrument. We present new FTIR retrieval methods to derive the SO2, CO2, CO, HF, and HCl relative abundance in the plume from both low- and high-resolution solar absorption spectra. Using Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) data, we derived SO2 fluxes and estimated total emissions of 1.8 ± 0.2 Mt SO2, 19.4 ± 1.8 Mt CO2, 0.123 ± 0.005 Mt CO, 0.05 ± 0.01 Mt HCl, and 0.013 ± 0.002 Mt HF over the course of the eruption. These results are consistent with the mass balance derived from petrologic degassing estimates. This study demonstrates that high- and low-resolution FTIR and DOAS spectrometers, integrated within global monitoring networks, can provide quantitative constraints on volcanic gas composition and fluxes over large distances. Such capabilities are directly applicable to volcanic crisis monitoring, complementing dedicated networks, satellite observations and supporting improved assessments of volcanic impacts on the atmospheric composition at regional scales.

  • Research Article
  • 10.5194/gmd-18-7891-2025
Implementation of solar UV and energetic particle precipitation within the LINOZ scheme in ICON-ART
  • Oct 27, 2025
  • Geoscientific Model Development
  • Maryam Ramezani Ziarani + 5 more

Abstract. We extended the Linearized ozone scheme – LINOZ in the ICON (ICOsahedral Nonhydrostatic) – ART (the extension for Aerosols and Reactive Trace gases) model system to include NOy formed by auroral and medium-energy electrons in the upper mesosphere and lower thermosphere, and the corresponding ozone loss, as well as changes in the rate of ozone formation due to the variability of the solar radiation in the ultraviolet wavelength range. This extension allows us to realistically represent variable solar and geomagnetic forcing in the middle atmosphere using a very simple ozone scheme. The LINOZ scheme is computationally very cheap compared to a full middle atmosphere chemistry scheme, yet provides realistic ozone fields consistent with the stratospheric circulation and temperatures, and can thus be used in climate models instead of prescribed ozone climatologies. To include the reactive nitrogen (NOy) produced by auroral and radiation belt electron precipitation in the upper mesosphere and lower thermosphere during polar winter, the so-called energetic particle precipitation indirect effect, an upper boundary condition for NOy has been implemented into the simplified parameterization scheme of the N2O/NOy reactions. This parameterization, which uses the geomagnetic Ap index, is also recommended for chemistry-climate models in the CMIP6 experiments. With this extension, the model simulates realistic “tongues” of NOy propagating downward in polar witner from the model top in the upper mesosphere into the mid-stratosphere with an amplitude that is modulated by geomagnetic activity. We then expanded the simplified ozone description used in the model by applying LINOZ version 3. The additional ozone tendency from NOy is included by applying the corresponding terms of the version 3 of LINOZ. This NOy, coupled as an additional term in the linearized ozone chemistry, led to significant ozone losses in the polar upper stratosphere in both hemispheres which is qualitatively in good agreement with ozone observations and model simulations with EPP-NOy and full stratospheric chemistry. In a subsequent step, the tabulated coefficients forming the basis of the LINOZ scheme were provided separately for solar maximum and solar minimum conditions. These coefficients were then interpolated to ICON-ART using the F10.7 index as a proxy for daily solar spectra (UV) variability to account for solar UV forcing. This solar UV forcing in the model led to changes in ozone in the tropical and mid-latitude stratosphere consistent with observed solar signals in stratospheric ozone.

  • Research Article
  • Cite Count Icon 3
  • 10.31875/2410-2199.2024.11.09
Black Coloured Glazes with Tetragonal CuCr2O4 Ceramic Pigment as Selective Solar Absorbers for Integral Ceramic Solar Collectors
  • Oct 2, 2025
  • Journal of Solar Energy Research Updates
  • G Monrós + 4 more

An efficient and low-cost Selective Solar Absorber for integral ceramic solar collectors, based in glazes pigmented with t-CuCr2O4 and Sb modified t-CuCr2O4 pigments, are characterised and evaluated. The basic kinds of industrial glazes (soda lime glass, double firing glaze 1050 ºC and both single firing glazes of 1080 ºC and porcelain glaze of 1190 ºC) have been checked and characterised by CIEL*a*b* colour, UV-Vis-NIR diffuse reflectance spectra, bandgap measurements, SEM-EDS analysis and solar absorbance spectra. The characteristics of the black powders (L*a*b* and diffuse reflectance spectra with a deviation from the carbon black ΔE*=20.3 and 22.3 respectively) are improved in 0.5 wt% addition of pigments in soda lime glass (ΔE*=6.1 and 9.9 respectively) and in 5 wt% glazed in porcelain glaze 1190 °C (ΔE*=12.0 and 18.4 respectively) which can be considered as low-cost selective solar absorbers (SSA) for integral solar absorber collectors.

  • Research Article
  • Cite Count Icon 1
  • 10.3390/rs17162753
Enhancing Hyperlocal Wavelength-Resolved Solar Irradiance Estimation Using Remote Sensing and Machine Learning
  • Aug 8, 2025
  • Remote Sensing
  • Vinu Sooriyaarachchi + 5 more

Accurate characterization of surface solar irradiance at fine spatial, temporal, and spectral resolution is central to applications such as solar energy and environmental monitoring. On the one hand, modeling radiative transfer to achieve such accuracy requires detailed characterization of a wide range of factors, including the vertical profiles of gaseous and particulate absorbers and scatterers, wavelength-resolved surface reflectivity, and the three-dimensional morphology of clouds. On the other hand, satellite-based remote sensing products typically provide top-of-the-atmosphere irradiance at coarse spatial resolutions, where individual pixels can span several kilometers, failing to capture fine-scale intra-pixel variability. In this study, we introduce a machine learning framework that integrates large-scale remote sensing satellite data with hyperlocal, second-by-second ground-based measurements from an ensemble of low-cost spectral sensors to estimate the wavelength-resolved surface solar irradiance spectra at the hyperlocal level. The satellite data are obtained from the Harmonized Sentinel-2 MSI (MultiSpectral Instrument), Level-2A Surface Reflectance (SR) product, which offers high-resolution surface reflectance data. By leveraging machine learning, we model the relationship between satellite-derived surface reflectance and ground-based spectral measurements to predict high-resolution, wavelength-resolved irradiance, using target data obtained from an NIST-calibrated reference instrument. By utilizing a low-cost sensor ensemble that is easily deployable at scale, combined with downscaled satellite data, this approach enables accurate modeling of intra-pixel variability in surface-level solar irradiance with high temporal resolution. It also enhances the utility of the Harmonized Sentinel-2 MSI data for operational remote sensing. Our results demonstrate that the model is able to estimate surface solar irradiance with an R2 ≈ 0.99 across all 421 spectral bins from 360 nm to 780 nm at 1 nm resolution, offering strong potential for applications in solar energy forecasting, urban climate research, and environmental monitoring.

  • Research Article
  • Cite Count Icon 1
  • 10.1051/0004-6361/202554870
Synthesizing Sun-as-a-star flare spectra from high-resolution solar observations
  • Aug 1, 2025
  • Astronomy & Astrophysics
  • M De Wilde + 24 more

Context. Spatially resolved observations of the Sun and the astronomical sample size of stellar bodies are the respective key strengths of solar and stellar observations. However, the large difference in object brightness between the Sun and other stars has led to distinctly different instrumentation and methodologies between the two fields. Aims. We produced and analyzed synthetic full-disk spectra derived from 19 small area field-of-view optical observations of solar flares acquired by the Swedish 1-m Solar Telescope (SST) between 2011 and 2024. These were used to investigate what can and cannot be inferred about physical processes on the Sun from Sun-as-a-star observations. Methods. The recently released Numerical Empirical Sun-as-a-Star Integrator (NESSI) code provides synthetic full-disk integrated spectral line emission based on smaller field-of-view input while accounting for center-to-limb variations and differential rotation. We used this code to generate pseudo-Sun-as-a-star spectra from the SST observations. Results. We show that limited-area solar observations can be extrapolated to represent the full disk accurately in a manner close to what is achievable with Sun-as-a-star telescopes. Additionally, we identify nine spectral features, four of which are caused by instrumental effects. Most notably, we find a relation between the heliocentric angle of flares and the width of the excess emission left by them as well as a source of false positive coronal mass ejections-like signatures, and we defined an energy scaling law based on chromospheric line intensities that shows that the peak flare contrast roughly scales with the square root of the bolometric energy. Conclusions. The presented method of creating pseudo-Sun-as-a-star observations from limited field-of-view solar observations allows for the accurate comparison of solar flare spectra with their stellar counterparts while allowing for the detection of signals at otherwise unachievable noise levels.

  • Research Article
  • Cite Count Icon 2
  • 10.1080/0972060x.2025.2533310
Modulation of leaf internal volatiles and essential oil contents in patchouli [Pogostemon cablin (Blanco) Benth.] by application of filtered solar spectra
  • Jul 4, 2025
  • Journal of Essential Oil Bearing Plants
  • Lopamudra Ballabh + 2 more

Pogostemon cablin (Blanco) Benth. is a shade-loving aromatic plant popular for its rich aromatic essential oil. Photoselective shade nets allow plants to receive filtered solar spectra which have impact on growth and metabolism; besides, these nets help plants to tolerate biotic or abiotic hazards. Here, we assess the impacts of coloured shade nets on growth and essential oil accumulation in patchouli aiming to introduce this agricultural practice for cultivation of aromatic plants in subtropical climate of eastern India. In this study, the plants were cultivated under four different coloured shade nets, viz. green, blue, brown and black across three seasons (monsoon, winter and summer). Significantly larger and thinner leaves under all the shade nets were observed in every season with enhanced content of photosynthetic pigments. In contrast, small and thick leaves in open field with significantly lower pigment concentration were found when cultivated in open field. A range of variations was observed in concentrations of major sesquiterpenoid, patchouli alcohol along with other terpenoids under different experimental conditions. This suggests alteration in the physiology of patchouli plant under different coloured shade nets in different seasons. Green and brown coloured shade nets in all three seasons recorded higher essential oil content and essential oil yield than the other conditions. The highest concentration of patchouli alcohol was found under blue shade net in winter. Overall, green and brown coloured shade nets were found to be most suitable for patchouli cultivation to harvest high-quality essential oil throughout the year in Indian sub-tropical regions.

  • Research Article
  • 10.1088/1538-3873/adecc3
Conditional Wavelet Diffusion Models for High-resolution Solar Spectra Reconstruction of CHASE Data
  • Jul 1, 2025
  • Publications of the Astronomical Society of the Pacific
  • Cong Xiao + 5 more

Abstract The high-resolution solar spectra are crucial for investigating solar activity, solar periodic variations and the underlying physical mechanisms of solar eruptions. The Chinese Hα Solar Explorer satellite observes the Sun from space, eliminating interference from Earth’s atmosphere and weather conditions to ensure high observational accuracy and stability. However, limitations in observational resolution and technological constraints make the direct acquisition of high-resolution solar spectra a significant challenge. To address this challenge, a conditional wavelet diffusion model for high-resolution solar spectra reconstruction (CWDM-HRSSR) is proposed. Specifically, we apply the reverse Hilbert coding to convert both the residual and low-resolution spectra into two-dimensional spectral images, the residual spectral image serves as the target for the diffusion model, while the low-resolution spectral image acts as the conditional input. We propose dual-core wavelet pooling, which separately processes high-frequency and low-frequency components, and integrates them into the U-Net architecture of the diffusion model. Dual-core wavelet pooling effectively preserves low-frequency information while reducing interference from high-frequency noise. Additionally, by integrating a residual structure, we ensure that low-level features are shared with high-level representations, mitigating the risk of gradient vanishing in deep networks. Experimental results demonstrate that the generated high-resolution solar spectra closely resemble real solar spectra, confirming CWDM-HRSSR’s superiority in detail reconstruction and accuracy.

  • Addendum
  • 10.1016/j.ascom.2025.100952
Corrigendum to “Compression method for solar polarization spectra collected from Hinode SOT/SP observations” [Astronomy and Computing, Vol 51 (2025) 100929
  • Jul 1, 2025
  • Astronomy and Computing
  • Jargalmaa Batmunkh + 3 more

Corrigendum to “Compression method for solar polarization spectra collected from Hinode SOT/SP observations” [Astronomy and Computing, Vol 51 (2025) 100929

  • Research Article
  • 10.1007/s11356-025-36837-y
Critical insights into the dynamics of carbon capture for enhancement of photosynthetic efficiency in microalgae.
  • Jul 1, 2025
  • Environmental science and pollution research international
  • Rashi Vishwakarma + 2 more

The cellular aspects of microbial metabolism can be targeted to alter and redesign the cellular processes for enhanced production of desired compounds. An understanding into the energetics of photosynthesis and its mechanism can be used to considerably enhance photosynthetic productivity together with increased efficiency of utilization of solar energy. Some of the structural aspects include expansion of solar absorption spectra through reduction of light harvesting complex, increase in the flux of electrons transferred through the electron transport chain, increase in the plastoquinone pool size, and increase in levels of Cyt b6f complexes. Herein, we analyze the factors affecting carbon metabolism and its conversion into biomass within the cell. The kinetic and thermodynamic limitations of carbon capture and fixation are explored to favor a photosynthetically efficient system. The study discusses the enhancement of photosynthetic productivity of microalgae through structural modifications of the photosynthetic unit for the efficient utilization of solar energy. A comprehensive understanding of the kinetic and thermodynamic limitations of the cellular processes affecting biomass production in microalgae can be worked out for building an energy-efficient multi-product process system.

  • Research Article
  • 10.1111/tpj.70348
Similar but different: unveiling the roles of atypical E2Fd/DEL2 and E2Ff/DEL3 transcription factors during the DNA damage response after UV-B exposure in Arabidopsis.
  • Jul 1, 2025
  • The Plant journal : for cell and molecular biology
  • Lucio Simonelli + 2 more

Ultraviolet-B (UV-B) radiation is the most energetic part of the solar spectra, and at high intensities inhibits plant growth by repressing cell proliferation. Inhibition of cell division after DNA damage is partly controlled by transcription factors (TFs) from the E2F family. We have previously shown that canonical E2F TFs regulate UV-B responses, and the role of the non-canonical DEL1/E2Fe in these responses was also demonstrated. Nevertheless, the contribution of the atypical DEL2/E2Fd and DEL3/E2Ff in the DNA damage response (DDR) after UV-B exposure in Arabidopsis plants has not been investigated. Therefore, in this work, we show that, despite having high sequence similarities, E2Fd and E2Ff show differences in expression patterns depending on the developmental stage and organ of the plants. Besides, E2Fd, but not E2Ff, controls leaf size under UV-B conditions and regulates DNA damage accumulation in UV-B exposed leaves by controlling the expression of the UVR2 photolyase. However, in UV-B-exposed seedlings, neither E2Fd nor E2Ff regulate primary root elongation or programmed cell death in the meristematic zone. Finally, we here show that E2Fd differentially controls the expression of DDR and cell cycle genes, either or both under conditions without UV-B and after exposure. Together, we provide evidence that E2Fd, but not E2Ff, participates in DDRs in leaves of Arabidopsis plants exposed to UV-B, while neither of them has a role in DDR in the roots.

  • Research Article
  • 10.53625/ijss.v5i1.10789
CROSS-CULTURAL RESONANCE: USING A TRANSDISCIPLINARY FRAMEWORK TO CONNECT INDIGENOUS MUSICAL FREQUENCIES, QUANTUM BIOLOGICAL SYSTEMS, AND COSMIC ENERGY SIGNATURES
  • Jun 30, 2025
  • International Journal of Social Science
  • Ketut Sumerjana

This study brings together indigenous sonic traditions, quantum biological mechanisms, and cosmic energy patterns in a new way to create a new resonance paradigm. We show that sacred musical frequencies (110–132 Hz) improve mitochondrial electron coherence by 37.2% ±5.1 (p<0.001) while also syncing with Schumann resonance harmonics. We did this by combining ethnographic fieldwork in four indigenous communities with advanced quantum biology experiments (2025–2027) and cosmic data triangulation. Our fractal analysis shows that the structures of gamelan overtone patterns (Hausdorff dimension 1.83±0.07) and solar wind turbulence spectra (Parker Solar Probe data 2026) are similar. The Holistic Resonance Index (HRI=0.72±0.08) that was created measures how well therapies work in both biological and ecological systems. These results help bridge the gap between traditional knowledge systems and quantum biophysics. They offer new ways to manage ecosystems in a way that is culturally appropriate through resonance engineering

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