Component Of Radiation Research Articles

Multiwavelength Generation of Stokes Radiation Components with a Small Wavelength Spacing under Stimulated Raman Scattering in a SrMoO4 Crystal

Multiwavelength Generation of Stokes Radiation Components with a Small Wavelength Spacing under Stimulated Raman Scattering in a SrMoO4 Crystal

Evaluation of Horizontal Single‐Axis Solar Tracker Algorithms in Terms of Energy Production and Operational Performance

Horizontal single‐axis solar tracking systems with Astronomical tracking algorithm are commonly used in photovoltaic (PV) installations. However, different algorithms can increase the PV installation's performance without implementing new equipment or technologies. In this article, the performance of three tracking algorithms is compared to the Astronomical one. Two algorithms aim at optimizing the received irradiance focusing on the diffuse component. The third one, called Analytical, is presented as a new development in this study, defining the optimal inclination angle depending on all radiation components. The comparison focuses on different parameters like the in‐plane irradiance, DC power output from a monofacial PV system and operational aspects like the performed number of movements. High‐time‐resolution (1 min) simulations are performed with proprietary software taking into account several effects on the effective irradiance and power output estimation, such as shading effects or PV configuration. Eight locations with different climatic conditions are analyzed. All three algorithms derive in higher in‐plane irradiance and power output values than the Astronomical algorithm, although the gain depends on the climatic conditions. At locations with high diffuse fraction, the power output from the Analytical algorithm, which outperforms the others, can be up to 3% higher than the Astronomical one.

Comparative study of energy balance in urban and forest areas in Central Amazonia

Data from two experimental sites in central Amazonia were used, one located in a forested region and the other in an urban region. The values of the radiation and energy balance components were measured at both sites. The observed components of the radiation balance in the forest, and urban areas were quite different. The city, the radiative (albedo and emissivity) and thermal (absorptivity) parameters of the surface produced greater reflection of solar radiation and emission of longwave radiation. Urban pollution reduced the incident solar radiation and increased the longwave radiation emitted by the atmosphere. The energy balance presented marked differences in the partition between sensible and latent heat flux between forest and city. In the forest, much of the available energy is converted into latent heat flux, due to the process of evapotranspiration. Whereas, in the city, energy is equally divided into sensible and latent heat fluxes.

Author Correction: Discovery of a radiation component from the Vela pulsar reaching 20 teraelectronvolts

Author Correction: Discovery of a radiation component from the Vela pulsar reaching 20 teraelectronvolts

On the Pattern and Attribution of Pan Evaporation over China (1951–2021)

Abstract Pan evaporation (Epan) serves as a monitorable method for estimating potential evaporation, evapotranspiration, and reference crop evapotranspiration, providing crucial data and information for fields such as water resource management and agricultural irrigation. Based on the PenPan model, the monthly Epan was calculated over China during 1951–2021, resulting in an average R2 of 0.93 ± 0.045 and an RMSE of 21.48 ± 6.06 mm month−1. The trend of Epan over time was characterized by an initial increase before 1961, followed by a decrease from 1961 to 1993, and a subsequent increase from 1994 to 2021. However, the sustained duration and magnitude of the decreasing trend led to an overall decreasing trend in the long-term dataset. To better understand the drivers of Epan trends, the Epan process was decomposed into radiative and aerodynamic components. While radiation was found to be the dominant component, its trend remained relatively stable over time. In contrast, the aerodynamic component, although smaller in proportion, exhibited larger fluctuations and played a crucial role in the trend of Epan. The primary influencing factors of the aerodynamic component were found to be wind speed and vapor pressure deficit (VPD). Wind speed and VPD jointly promoted Epan before 1961, and the significant decrease in wind speed from 1961 to 1993 led to a decrease in Epan. From 1994 to 2021, the increase in VPD was found to be the main driver of the observed increase in Epan. These results show the complex and dynamic nature of Epan and underscore the need for continued monitoring and in-depth analysis of its drivers. Significance Statement The primary objective of this study is to explore the spatiotemporal patterns and potential driving factors of pan evaporation in China based on constructing a comprehensive dataset of pan evaporation. This is important because pan evaporation is an important indicator of the water cycle, which is currently undergoing modifications and is expected to become more pronounced as the climate continues to warm. Our findings showed that the patterns of pan evaporation were characterized by its drivers. As the drivers are numerous and continuously changing under climate change, it is necessary to pay attention to the pattern and attribution of pan evaporation.

Multiwave Matrix Polarization Lidar

Remote control of the state of the atmosphere is an urgent problem nowadays. The problem of remote monitoring of the optical parameters of the atmosphere is solved using a matrix polarization lidar (MPL). The scattering matrix obtained from polarization measurements contains complete information on the scattering parameters in the atmosphere. The purpose of the present research is the derivation of the theory and description of methods for solving problems of practical implementation of the multiwave MPL (MMPL). The problem is considered within the framework of the concept of the unified methodological approach to polarization studies. The MMPL operation principle is based on simultaneous use for sensing of the first, second, and third harmonics of radiation of a widespread Nd:YAG laser. The basis for achieving this purpose is provided by new methods of optical selection of the polarization components of radiation received in the experiment, methods of conducting polarization studies, and new solutions in experimental data processing methods. It has been shown that this challenge can be solved within the framework of simple solutions. Thus, the proposed MMPL is structurally simple and compact and can be implemented in mobile polarization lidar systems.

Interacting New Tsallis holographic dark energy

We constructed the evolution of a flat FRW universe filled with New Tsallis holographic dark energy (NTHDE) and matter (dust) that interact with each other via a wellknown source term. Assuming the hubble horizon IR cutoff length, extracted the governing equation for the NTHDE density parameter’s evolution and solved it numerically to find the evolution of other relevant cosmological parameters, e.g., equation of state and deceleration parameters. We then repeated same findings when the radiation component was included. According to our findings, the cosmos has a normal thermal history, with radiation, dark matter (DM) and dark energy (DE) eras occurring one after the other until dark energy eventually takes over entirely in the far future. We also found that according to the values of the parameters (δ, b12, b22), the NTHDE equation of state parameter can be either quintessence like or phantom like or very close to cosmological constant during the cosmic evolution. This fascinating feature of the scenario is achieved without the use of an explicit cosmological constant term, and it arises purely from modified cosmology through an interacting NTHDE with varying δ. Finally, the hubble parameter’s evolution is examined and contrasted with the most recent hubble parameter results.

A dense station-based, long-term and high-accuracy dataset of daily surface solar radiation in China

Abstract. The lack of long-term and high-quality solar radiation data has been an obstacle for scientific and industrial fields. In this study, a dense station-based, long-term and high-accuracy dataset of daily surface solar radiation was developed using two surface radiation models. One is the model developed by Yang et al. (2006) for global radiation estimation, and the other is the model developed by Tang et al. (2018) for direct radiation estimation. The main inputs for the development of the dataset are surface pressure, air temperature, relative humidity, horizontal visibility and sunshine duration, which are the routine meteorological variables observed at the 2743 China Meteorological Administration (CMA) weather stations. Validation against in situ observations and comparisons with two satellite-based radiation products shows that our station-based radiation dataset clearly outperforms the satellite-based radiation products at both daily and monthly scales. In addition, our dataset is available for more than 60 years and includes three radiation components of global, direct and diffuse radiation, which is not possible with satellite products. This station-based radiation dataset will contribute to the climate change research and solar energy engineering applications in the future. The station-based dataset is now available at https://doi.org/10.11888/Atmos.tpdc.300461 (Tang, 2023).

Validation and Spatiotemporal Analysis of Surface Net Radiation from CRA/Land and ERA5-Land over the Tibetan Plateau

High spatial–temporal resolution surface net radiation (RN) data are of great significance to the study of climate, ecology, hydrology and cryosphere changes on the Tibetan Plateau (TP), but the verification of the surface net radiation products on the plateau is not sufficient. In this study, the China Meteorological Administration Global Land Surface Reanalysis Products (CRA/Land) and ECMWF Land Surface Reanalysis version 5 (ERA5-Land) RN data were validated using ground measurements at daily and monthly time scales, and the spatiotemporal patterns were also analyzed. The results indicate the following: (1) CRA/Land overestimated while ERA5-Land underestimated RN, but CRA/Land RN outperformed ERA5-Land in observations at the daily and monthly scale. (2) The CRA/Land RN data had a larger error in the central part and a smaller error in the northeast of the TP, while ERA5-Land showed the opposite. (3) The spatial patterns of RN revealed by CRA/Land and ERA5-Land data showed differences in most regions. The CRA/Land data showed that the RN of the TP had a downward trend during 2000 and 2020 with a slope of −0.112 W·m−2/a, while the ERA5-Land data indicated an upward trend with a change rate of 0.016 W·m−2/a. (4) Downwelling shortwave radiation (DSR), upwelling shortwave radiation (USR), downwelling longwave radiation (DLR) and upwelling longwave radiation (ULR) are the four components of RN, and the evaluation results indicate that the DSR, DLR and ULR recorded via CRA/Land and ERA5-Land are consistent with the observed data, but the consistency between the USR recorded via CRA/Land and ERA5-Land and the observed data is poor. (5) The inconsistency of the USR data is the main reason for the large differences in the spatiotemporal distribution of CRA/Land and ERA5-Land RN data across the TP.

Estimating solar radiation in a clear sky on a horizontal surface from common meteorological a data in Oran, Algeria

This study aimed to calibrate existing model (Platt and Paltridge model) and develop a new models for estimating the different components of the solar radiation on a horizontal surface in a clear sky data using commonly and available measured meteorological records such as water vapor tension and temperature, etc. Four models based on meteorological variables were generated and validated using daily data in 2013-2016 at the Oran Station (Algeria). Validation criteria included coefficient of determination, root mean square error and mean bias error, the results showed that the proposed models can estimate solar radiation values. The model based on the temperature and the water vapor tension gives better results with statistical errors obtained are as follows: NDMBE = 13.36 %, NDRMSE = 47.08 % and the correlation coefficient R = 0.85 for the diffused component, the model based on relative humidity and atmospheric pressure gives better results for the direct component with statistical errors obtained are: NDMBE = -1.54 %, NDRMSE = 22.59 % and the correlation coefficient R = 0.95 and The model based on the relative humidity and the water vapor tension with results: NDMBE = 0.96 %, NDRMSE = 12.08 % and the correlation coefficient R = 0.98 for the global component.

Critical analysis of the existing approach to the calculation of radiation shielding in X-ray rooms

The paper demonstrates the limitations of the existing methodology for calculating the radiation shielding of X-ray rooms presented in SanPin 2.6.1.1192-03. It is shown that the algorithm for calculating the attenuation coefficient by the barrier does not take into account the features of the attenuation of different components of X-ray radiation: direct, scattered, and leakage radiation, which differ in the region of occurrence, intensity, energy spectrum, and other parameters. Instead, a single formula is used for all components, and the differences in their attenuation are taken into account by a parameter the values of which for different radiation components are in no way justified and are questionable. The calculation also does not take into account the distribution of the workload of X-ray machines by the tube voltage, the significant attenuation of direct X-ray radiation by additional structures necessary for image acquisition. The values of the radiation output of X-ray machines recommended for shielding design in SanPiN 2.6.1.1192-03 are 2–3 times overestimated in relation to the measured values. This leads to an unreasonable overestimation of the requirements for the thickness of radiation shielding in X-ray rooms and accordingly to suboptimal spending on healthcare. It is necessary to develop a new document to replace SanPiN 2.6.1.1192-03.

Assessment of the high-resolution estimations of global and diffuse solar radiation using WRF-Solar

Compared with physical models, WRF-Solar, as an excellent numerical forecasting model, includes abundant novel cloud physical and dynamical processes, which enablesenable the high-frequency output of radiation components which are urgently needed by the solar energy industry. However, the popularisation of WRF-Solar in a wide range of applications, such as the estimation of diffuse radiation, suffers from unpredictable influences of cloud and aerosol optical property parameters. This study assessed the accuracy of the improved numerical weather prediction (WRF-Solar) model in simulating global and diffuse radiation. Aerosol optical properties at 550 nm, which were provided by a moderate resolution imaging spectroradiometer, were used as input to analyse the differences in accuracies obtained by the model with/without aerosol input. The sensitivity of WRF-Solar to aerosol and cloud optical properties and solar zenith angle (SZA) was analysed. The results show the superiority of WRF-Solar to WRF-Dudhia in terms of their root mean square error (RMSE) and mean absolute error (MAE). The coefficients of determination between WRF-Solar and WRF-Dudhia revealed no statistically significant difference, with values greater than 0.9 for the parent and nested domains. In addition, the relative RMSE (RRMSE%) reached 46.60%. The experiment on WRF-Solar and WRF-Dudhia revealed a negative bias for global radiation, but WRF-Solar attained a slightly lower RMSE and higher correlation coefficient than WRF-Dudhia. The WRF-Solar-simulated results on diffuse radiation under clear sky conditions were slightly poorer, with RMSE, RRMSE, mean percentage error and MAE of 181.93 W m−2, 170.52%, 93.04% and 138 W m−2, respectively. Based on Himawari-8 cloud data, statistical results on cloud optical thickness (COT) for cloudy days revealed that WRF-Solar overestimated diffuse radiation at COTs greater than 20. Moreover, when the aerosol optical depth was greater than or equal to 0.8, WRF-Solar also overestimated the diffuse radiation, with a mean difference of 58.57 W m−2. The errors of WRF-Solar simulations in global and diffuse radiation exhibited a significant dependence on the SZA. The dispersion degree of deviation increased gradually with the decrease in the SZA. Thus, WRF-Solar serves as an improved numerical tool that can provide high temporal and high-spatial-resolution solar radiation data for the prediction of photovoltaic power. Studies should explore the improvement of cumulus parameterisation schemes to enhance the accuracy of solar radiation component estimation and prediction under cloudy conditions.

Simultaneous 2.25/8.60 GHz Observations of the Magnetar XTE J1810-197

We did 194 epochs of simultaneous 2.25/8.60 GHz observations of XTE J1810−197 in 926 days shortly following its reactivation in 2018 with Shanghai Tian Ma Radio Telescope (TMRT). Although its integrated profiles changed with both time and frequency during this period, they could be classified into 12 types according to phase areas of active radiation components. After MJD 59015, XTE J1810−197 turned from the normal emission state into the spiky emission state that was manifesting as a series of bright narrow sub-pulse bursts at both 2.25 and 8.60 GHz. Due to its variable integrated profiles and unsteady rotations, we got the spin frequency ν and spin-frequency derivatives with the piecewise fitting method. In addition, its long-term declining trend of ν was also obtained as s−2 with the linear fitting method based on our observations spanning a comparatively longer period. We found its flux densities went through three stages: sharp decrease, stabilization, and day-to-day fluctuations in our dual-frequency observations. Although the flux density showed different stages, XTE J1810−197 showed a relatively flat spectrum (α > –1) in most observations. Assuming an ideal dipole magnetic field as some previous research works, we obtained the emission heights of XTE J1810−197 were about 7.5(9) × 104 km and 2.38(7) × 104 km at 2.25 and 8.60 GHz, respectively. We also found that its emission heights would decrease rapidly with the degree of magnetic field twisting.

A dataset of horizontal and slope-parallel installation of radiometer to measure solar radiation components and turbulent energy flux at Maoershan station in 2016

Solar radiation is one of the key parameters driving carbon and water fluxes, as well as other types of terrestrial processes. Radiometers, the most commonly used instruments for measuring local-scale radiation and albedo, are typically installed horizontally according to meteorological observation standards. However, under sloping terrain conditions, their hemispherical view and the surface receiving or reflecting radiation are not vertical. This discrepancy often results in a daily phase shift between net radiation and turbulent energy fluxes. Montane region accounts for one-quarter of the total global land surface area, yet few studies have quantified and corrected the errors resulting from horizontal installation of net radiometers in these areas. The dataset compiled in this paper were solar radiation and turbulent energy flux data measured by horizontal and slope-parallel radiometers in the secondary forest of the Maoershan Forest Ecosystem Research Station in Heilongjiang from March 17, 2016, to April 3, 2017. The data included incident and reflected shortwave radiation, longwave radiation, photosynthetically active radiation, as well as albedo, solar elevation angle, clear sky index, sensible heat flux, latent heat flux, and soil surface heat flux data. These data were stored in half-hour intervals, with radiation and turbulent energy flux data coverage rates during the growing season (May 3, 2016 to October 10, 2016) of 100% and 81.3% respectively. This dataset can provide original data for evaluating the impact of radiometers installation methods on the measurement of radiation components and albedo in montane regions, which not only help to correct historical data or construct more accurate models, but can also provide methodological references for studies related to carbon, water, and energy fluxes.

All-sky surface and top-of-atmosphere shortwave radiation components estimation: Surface shortwave radiation, PAR, UV radiation, and TOA albedo

Surface and top-of-atmosphere (TOA) shortwave radiation components are key parameters in the energy budget of the Earth-atmosphere system, which influence the global climate, ecology, hydrology, etc. However, except for total surface shortwave downward radiation (SWDR), only a few satellite missions consistently release other radiation components such as solar direct/diffuse radiation, photosynthetically active radiation (PAR), ultraviolet radiation-A/B (UVA/UVB), as well as TOA albedo, although they are indispensable for many land and ocean applications. In this study, a unified framework by combining multi-band LUT inversion and classification of the atmospheric condition is proposed, which enables the simultaneous derivation of nine surface and TOA radiation variables and emphasizes the separation of direct and diffuse components. The estimated radiation variables include total and direct components of SWDR, PAR, UVA, UVB, as well as TOA albedo. The proposed method is easy-to-use with only a few inputs and works well with reasonable accuracy. Using Moderate Resolution Imaging Spectroradiometer (MODIS) raw resolution images as test data, the surface radiation variables are validated by 80 global sites from BSRN, SURFRAD, and FLUXNET, and the instantaneous RMSEs (biases) of SWDR, SWDRdir, PAR, PARdiff, and UVB are 103.6 (0.1), 114 (−1.7), 47.8 (6.8), 32.9 (5.7), and 0.14 (0.003) W/m2, respectively, demonstrating comparable or even better accuracy compared with existing products. In particular, the estimated SWDR behaves more accurate than CERES in polar regions. Due to the lack of in-situ measurements, TOA albedo is compared with CERES TOA products and shows good agreement with R2 of 0.9 and RMSE (bias) of 0.055 (−0.003). The unified framework reveals obvious advantages over existing studies in generating almost all physically consistent shortwave components in the same manner with simple inputs, implying the great potentials in globally mapping spatio-temporally continuous multiple components of shortwave radiation with a unified scheme.

The roles of radiative, structural and physiological information of sun-induced chlorophyll fluorescence in predicting gross primary production of a corn crop at various temporal scales

Extensive research suggests that sun-induced chlorophyll fluorescence (SIF) and gross primary productivity (GPP) have a near-linear relationship, providing a promising avenue for estimating the carbon uptake of ecosystems. However, the factors influencing the relationship are not yet clear. This study examines the roles of SIF's radiative, structural, and physiological information in predicting GPP, based on four years of field observations of a corn canopy at various temporal scales. We quantified SIF's radiative component by measuring the intensity of incident photosynthetically active radiation (iPAR), and separated the structural and physiological components from SIF observations using the fluorescence correction vegetation index (FCVI). Our results show that the R2 values between SIF and GPP, as estimated by linear models, increased from 0.66 at a half-hour resolution to 0.86 at a one-month resolution. In comparison, the product of FCVI and iPAR, representing the non-physiological information of SIF, performed consistently well in predicting GPP with R2>0.84 at various temporal scales, suggesting a limited contribution of the physiological information of SIF for GPP estimation.. The results further reveal that SIF's radiative and structural components positively impacted the SIF-GPP linearity, while the physiological component had a negative impact on the linearity for most cases, changing from 0.6 % to -27.5 %. As for the temporal dependency, the controls of the SIF-GPP relationship moved from radiation at diurnal scales to structure at the seasonal scales. The structural contribution changed from 14.8 % at a half-hour resolution to 92.4 % at a one-month resolution, while the radiative contribution decreased from 118.0 % at a half-hour resolution to 11.7 % at a one-month resolution. This study contributes to enhancing our understanding of the physiological information conveyed by SIF and the factors influencing the temporal dependency of the SIF-GPP relationship.

Unimodal distribution of terahertz emission from single-color filament plasma

We study the angular distributions of various spectral components of terahertz radiation generated in an air plasma of a single-color filament with a laser wavelength of 930 nm. It is experimentally shown that at a 20-fold excess over the critical power for self-focusing the distribution of terahertz radiation at all studied frequencies is unimodal. The obtained pattern differs significantly from the angular distribution of terahertz radiation observed in the case of filamentation of pulses with a shorter wavelength.

REDUCED HEAT LOSS THROUGH WINDOW STRUCTURES

The results of theoretical and experimental studies of heat transfer through the window structures of the building are presented, the thermal characteristics of the windows are established and the level of heat loss realized through them is estimated. To determine the heat transfer resistance of two-chamber double-glazed units, numerical modeling of radiative-convective heat transfer is performed, taking into account the thermal conductivity of the gas layer between the glasses. Natural free convection of the gaseous medium in the double-glazed chambers occurs as a result of the temperature difference between the side glass surfaces of the chamber. Modeling is performed by numerically solving the system of fluid dynamics and energy equations for the air layer and glass. On the inner surfaces of the chambers, conditions of the fourth kind are set, which take into account the radiation and conductive components of the total heat flow coming from the glass surface. The results of simulation of heat transfer through double-glazed windows with ordinary glass indicate that about 60 % of heat is transferred by radiation. Therefore, an effective measure to reduce heat loss through windows is to reduce the radiation component of the total heat flow by applying a low-emissivity coating to the inner surfaces of the glass unit. This makes it possible to reduce the total heat flow (and, accordingly, heat loss to the environment) by 20–34 %, depending on the number of glass surfaces with this coating. Conducted independent experimental studies confirm the modeling results. In order to comply with the current requirements of state building regulations and to achieve the energy efficiency class of type C buildings (specific heat consumption for heating 1 sq. m of usable area is less than 75 kWh), for the climatic conditions of Kyiv, it is recommended to use double-chamber windows with two low-emission coatings with the formula of the glass unit: 4M1-10-i4M1-10-i4M1. Bibl. 22, Fig. 8.

Significant discrepancies of land surface daily net radiation among ten remotely sensed and reanalysis products

ABSTRACT Land surface all-wave net radiation (Rn) is crucial in determining Earth's climate by contributing to the surface radiation budget. This study evaluated seven satellite and three reanalysis long-term land surface Rn products under different spatial scales, spatial and temporal variations, and different conditions. The results showed that during 2000-2018, Global Land Surface Satellite Product (GLASS)-Moderate Resolution Imaging Spectroradiometer (MODIS) performed the best (RMSE=25.54 Wm-2, bias=−1.26 Wm-2), followed by ERA5 (the fifth-generation of European Centre for Medium-Range Weather Forecast Reanalysis) (RMSE=32.17 Wm-2, bias=−4.88 Wm-2) and GLASS-AVHRR (Advanced Very-High-Resolution Radiometer) (RMSE=33.10 Wm-2, bias=4.03 Wm-2). During 1983-2018, GLASS-AVHRR and ERA5 ranked top and performed similarly, with RMSE values of 31.70 and 33.08 Wm-2 and biases of −4.56 and 3.48 Wm-2, respectively. The averaged multi-annual mean Rn over the global land surface of satellite products was higher than that of reanalysis products by about 10∼30 Wm-2. These products differed remarkably in long-term trends variations, particularly pre-2000, but no significant trends were observed. Discrepancies were more frequent in satellite data, while reanalysis products showed smoother variations. Large discrepancies were found in regions with high latitudes, reflectance, and elevation which could be attributed to input radiative components, meteorological variables (e.g., cloud properties, aerosol optical thickness), and applicability of the algorithms used. While further research is needed for detailed insights.

Improving the efficiency of solar-driven trigeneration systems using nanofluid coolants

This article provides a technical and economic assessment of the currently available trigeneration and cogeneration plants to produce heat, vapour, electricity, and cold. A thermodynamic analysis of a trigeneration plant that uses a solar collector as a heat source has been carried out. The results of experimental studies have shown the possibility of reducing the cost of the refrigeration cycle to 11.5%. Mathematical models of refrigerating and thermal cycles in trigeneration units are presented. The following optimal parameters of the trigeneration unit are established. The share of the solar radiation component in the process conditions was 50%. The efficiency of the solar collector was 83%, the efficiency of the cold generator was 65%, and the electric generator reached 60%. The pressure in the system ranged from 9 to 11 bar, and the operating temperature of the solar collector was 280 … 380 K. Statistical evaluation of the results showed satisfactory convergence of experimental and theoretical data. The Pearson criterion was χ2 = 0.87, Student's t-test 0.07 … 0.09, the statistical significance of results р ≤ 0.005.