Pub Date : 2025-01-30DOI: 10.1016/j.jqsrt.2025.109378
Salvador Bará , José J. Castro-Torres
The radiance of nighttime artificial lights measured by the VIIRS-DNB instrument on board the satellite Suomi-NPP increases at an average rate ∼2.2 %/yr worldwide, whereas the artificial radiance of the night sky deduced from the Globe at Night (GAN) unaided-eye observations of the number of visible stars is reported to increase at an average rate ∼9.6 %/yr. The difference between these two estimates is remarkable. This raises the question of whether the diverging temporal evolution of these indicators could be due to changes in the spectral composition of outdoor artificial light, consequence of the current process of replacement of lighting technologies. This paper presents a model for evaluating the temporal rate of change of different light pollution indicators and applies it to the VIIRS-DNB vs GAN issue, based on available data. The results show that the reported difference could be explained by spectral changes alone, if the visual GAN observations are made with scotopic or mesopic adaptation at definite times under some particular transition conditions. In case of photopic adapted observers, however, reconciling these two measurement sets requires the existence of GAN-specific light sources that affect the Globe at Night observations but do not show up in the VIIRS-DNB data. The lumen emissions of these GAN-specific sources for photopic observers should increase at a rate larger than 9 %/yr worldwide.
{"title":"Diverging evolution of light pollution indicators: Can the globe at night and VIIRS-DNB measurements be reconciled?","authors":"Salvador Bará , José J. Castro-Torres","doi":"10.1016/j.jqsrt.2025.109378","DOIUrl":"10.1016/j.jqsrt.2025.109378","url":null,"abstract":"<div><div>The radiance of nighttime artificial lights measured by the VIIRS-DNB instrument on board the satellite Suomi-NPP increases at an average rate ∼2.2 %/yr worldwide, whereas the artificial radiance of the night sky deduced from the Globe at Night (GAN) unaided-eye observations of the number of visible stars is reported to increase at an average rate ∼9.6 %/yr. The difference between these two estimates is remarkable. This raises the question of whether the diverging temporal evolution of these indicators could be due to changes in the spectral composition of outdoor artificial light, consequence of the current process of replacement of lighting technologies. This paper presents a model for evaluating the temporal rate of change of different light pollution indicators and applies it to the VIIRS-DNB vs GAN issue, based on available data. The results show that the reported difference could be explained by spectral changes alone, if the visual GAN observations are made with scotopic or mesopic adaptation at definite times under some particular transition conditions. In case of photopic adapted observers, however, reconciling these two measurement sets requires the existence of GAN-specific light sources that affect the Globe at Night observations but do not show up in the VIIRS-DNB data. The lumen emissions of these GAN-specific sources for photopic observers should increase at a rate larger than 9 %/yr worldwide.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"335 ","pages":"Article 109378"},"PeriodicalIF":2.3,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1016/j.jqsrt.2025.109376
Xin Liu , Fanhu Qu , Jiguang Li , Xianwen Zhang , Yiming Xie , Baoren Wei , Yaming Zou , Jun Xiao
The hyperfine structure constants of the 1s22s22p2P1/2 and 2P3/2 states in the boron-like isoelectronic sequence with nuclear charges Z = 6 to 36 were calculated using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. In these calculations, we included electron correlation, Breit interaction, and one-electron quantum electrodynamics (QED) corrections. It was found that taking into account the 1s core electron correlation and higher-order electron correlation (i.e., triple and quadrupole excitations) effects improves the accuracy of the hyperfine structure constants to the order of 10–5 ∼ 10–6. Additionally, we obtained fitting formulas for the hyperfine structure constants as a function of Z, useful to predict hyperfine structure constants for any isotopes of boron-like ions in the region of 6 ≤ Z ≤ 36.
{"title":"Theoretical study on ground-state hyperfine structure for boron-like ions with 6 ≤ Z ≤ 36","authors":"Xin Liu , Fanhu Qu , Jiguang Li , Xianwen Zhang , Yiming Xie , Baoren Wei , Yaming Zou , Jun Xiao","doi":"10.1016/j.jqsrt.2025.109376","DOIUrl":"10.1016/j.jqsrt.2025.109376","url":null,"abstract":"<div><div>The hyperfine structure constants of the 1<em>s</em><sup>2</sup>2<em>s</em><sup>2</sup>2<em>p</em> <sup>2</sup><em>P</em><sub>1/2</sub> and <sup>2</sup><em>P</em><sub>3/2</sub> states in the boron-like isoelectronic sequence with nuclear charges <em>Z</em> = 6 to 36 were calculated using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. In these calculations, we included electron correlation, Breit interaction, and one-electron quantum electrodynamics (QED) corrections. It was found that taking into account the 1<em>s</em> core electron correlation and higher-order electron correlation (i.e., triple and quadrupole excitations) effects improves the accuracy of the hyperfine structure constants to the order of 10<sup>–5</sup> ∼ 10<sup>–6</sup>. Additionally, we obtained fitting formulas for the hyperfine structure constants as a function of <em>Z</em>, useful to predict hyperfine structure constants for any isotopes of boron-like ions in the region of 6 ≤ <em>Z</em> ≤ 36.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"335 ","pages":"Article 109376"},"PeriodicalIF":2.3,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143077783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.jqsrt.2025.109365
Soumyajyoti Jana , Mukunda M. Gogoi , T. C. Ajith , Prashant Hegde , Sobhan Kumar Kompalli , S. Suresh Babu
Estimating Top-of-Atmosphere (TOA) flux and radiance is essential for understanding Earth's radiation budget and climate dynamics. This study utilized polar nephelometer measurements of aerosol scattering coefficients at 17 angles (9–170°), enabling the experimental determination of aerosol phase functions and the calculation of Legendre moments. These moments were then used to estimate TOA flux and radiance. Conducted at a tropical coastal site in India, the study observed significant seasonal and diurnal variations in angular scattering patterns, with the highest scattering during winter and the lowest during the monsoon. Notably, a prominent secondary scattering mode, with varying magnitude across different seasons, was observed in the 20–30° angular range, highlighting the influence of different air masses and aerosol sources. Chemical analysis of size-segregated aerosols revealed that fine-mode aerosols were dominated by anthropogenic species, such as sulfate, nitrate, and ammonium, throughout all seasons. In contrast, coarse-mode aerosols showed a clear presence of sea-salt aerosols during the monsoon and mineral dust during the pre-monsoon periods. The presence of very large coarse-mode non-spherical aerosols caused increased oscillations in the phase function beyond 60° during the pre-monsoon and monsoon seasons. This also led to a weak association between the phase function derived from angular scattering measurements and those predicted by the Henyey-Greenstein approximation. As a result, TOA fluxes and radiances derived using the Henyey-Greenstein approximation (with the asymmetry parameter as input in the radiative transfer model) showed a significant difference - up to 24% in seasons with substantial coarse-mode aerosol presence - compared to those derived using the Legendre moments of the phase function. Therefore, TOA flux and radiance estimates using Legendre moments are generally more accurate in the presence of complex aerosol scattering characteristics, particularly for non-spherical or coarse-mode aerosols, while the Henyey-Greenstein phase function may yield less accurate results due to its simplified representation of scattering behavior.
{"title":"Estimation of TOA flux and radiance based on the angular distribution of aerosol light scattering measurements","authors":"Soumyajyoti Jana , Mukunda M. Gogoi , T. C. Ajith , Prashant Hegde , Sobhan Kumar Kompalli , S. Suresh Babu","doi":"10.1016/j.jqsrt.2025.109365","DOIUrl":"10.1016/j.jqsrt.2025.109365","url":null,"abstract":"<div><div>Estimating Top-of-Atmosphere (TOA) flux and radiance is essential for understanding Earth's radiation budget and climate dynamics. This study utilized polar nephelometer measurements of aerosol scattering coefficients at 17 angles (9–170°), enabling the experimental determination of aerosol phase functions and the calculation of Legendre moments. These moments were then used to estimate TOA flux and radiance. Conducted at a tropical coastal site in India, the study observed significant seasonal and diurnal variations in angular scattering patterns, with the highest scattering during winter and the lowest during the monsoon. Notably, a prominent secondary scattering mode, with varying magnitude across different seasons, was observed in the 20–30° angular range, highlighting the influence of different air masses and aerosol sources. Chemical analysis of size-segregated aerosols revealed that fine-mode aerosols were dominated by anthropogenic species, such as sulfate, nitrate, and ammonium, throughout all seasons. In contrast, coarse-mode aerosols showed a clear presence of sea-salt aerosols during the monsoon and mineral dust during the pre-monsoon periods. The presence of very large coarse-mode non-spherical aerosols caused increased oscillations in the phase function beyond 60° during the pre-monsoon and monsoon seasons. This also led to a weak association between the phase function derived from angular scattering measurements and those predicted by the Henyey-Greenstein approximation. As a result, TOA fluxes and radiances derived using the Henyey-Greenstein approximation (with the asymmetry parameter as input in the radiative transfer model) showed a significant difference - up to 24% in seasons with substantial coarse-mode aerosol presence - compared to those derived using the Legendre moments of the phase function. Therefore, TOA flux and radiance estimates using Legendre moments are generally more accurate in the presence of complex aerosol scattering characteristics, particularly for non-spherical or coarse-mode aerosols, while the Henyey-Greenstein phase function may yield less accurate results due to its simplified representation of scattering behavior.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"335 ","pages":"Article 109365"},"PeriodicalIF":2.3,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.jqsrt.2025.109362
O. Ben Fathallah , S. Béguier , M. Rey , J. Vander Auwera , A. Campargue
The congested absorption spectrum of ethylene (C2H4) is analyzed in the 2912-3270 cm-1 region dominated by the strong ν9 and ν11 CH stretching bands. A list of about 6870 lines has been retrieved from a room temperature Fourier transform spectrum (P = 2.568 hPa, L = 19.7 cm). Relying on the position and intensity agreements with a line list of 12C2H4 transitions calculated by the variational method, a total of 4287 lines are assigned to 5797 transitions of eight cold bands, four of them being newly reported. In addition, about 200 transitions are assigned to four hot bands. Most of the reported assignments are confirmed by Lower State Combination Difference (LSCD) relations i.e. that 1824 of the 1897 determined upper states energies have coinciding determinations through several transitions (up to 8). Compared to their variational counterpart, the obtained empirical energy values show a good agreement with a small overestimation with an amplitude increasing with the rotational energy but limited to 0.6 cm-1 at most.
Overall, the assigned lines represent 94.0 % of the total experimental intensity in the region. The band-by-band intensity comparison with variational calculations shows an excellent agreement, mostly within the experimental uncertainties of about 3 %.
Systematic line-by-line comparisons with previous literature studies are discussed in detail. In the current HITRAN line list, rovibrational assignments are limited to the four strongest cold bands and one hot band. Excellent agreement is observed for line positions and line intensities. Suggestions for improvements are provided. Comparisons with the recent ECaSDa line list (Ben Fathallah et al., J Quant Spectrosc Radiat Transf 2024;323:108995 https://doi.org/10.1016/j.jqsrt.2024.108995), calculated using an effective operator approach developed within the tensorial formalism and limited to the four strongest cold bands, show a number of significant disagreements.
{"title":"Rovibrational assignments of the ethylene absorption spectrum near 3.3 µm based on variational calculations","authors":"O. Ben Fathallah , S. Béguier , M. Rey , J. Vander Auwera , A. Campargue","doi":"10.1016/j.jqsrt.2025.109362","DOIUrl":"10.1016/j.jqsrt.2025.109362","url":null,"abstract":"<div><div>The congested absorption spectrum of ethylene (C<sub>2</sub>H<sub>4</sub>) is analyzed in the 2912-3270 cm<sup>-1</sup> region dominated by the strong ν<sub>9</sub> and ν<sub>11</sub> CH stretching bands. A list of about 6870 lines has been retrieved from a room temperature Fourier transform spectrum (<em>P</em> = 2.568 hPa, <em>L</em> = 19.7 cm). Relying on the position and intensity agreements with a line list of <sup>12</sup>C<sub>2</sub>H<sub>4</sub> transitions calculated by the variational method, a total of 4287 lines are assigned to 5797 transitions of eight cold bands, four of them being newly reported. In addition, about 200 transitions are assigned to four hot bands. Most of the reported assignments are confirmed by Lower State Combination Difference (LSCD) relations <em>i.e.</em> that 1824 of the 1897 determined upper states energies have coinciding determinations through several transitions (up to 8). Compared to their variational counterpart, the obtained empirical energy values show a good agreement with a small overestimation with an amplitude increasing with the rotational energy but limited to 0.6 cm<sup>-1</sup> at most.</div><div>Overall, the assigned lines represent 94.0 % of the total experimental intensity in the region. The band-by-band intensity comparison with variational calculations shows an excellent agreement, mostly within the experimental uncertainties of about 3 %.</div><div>Systematic line-by-line comparisons with previous literature studies are discussed in detail. In the current HITRAN line list, rovibrational assignments are limited to the four strongest cold bands and one hot band. Excellent agreement is observed for line positions and line intensities. Suggestions for improvements are provided. Comparisons with the recent ECaSDa line list (Ben Fathallah et al., J Quant Spectrosc Radiat Transf 2024;323:108995 <span><span>https://doi.org/10.1016/j.jqsrt.2024.108995</span><svg><path></path></svg></span>), calculated using an effective operator approach developed within the tensorial formalism and limited to the four strongest cold bands, show a number of significant disagreements.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"336 ","pages":"Article 109362"},"PeriodicalIF":2.3,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.jqsrt.2025.109363
Qianjun Mao , Xiaoyan Zhang , Piaopiao Chen , Yunlu Tan , Xiaohu Wu
Aerosols are an important factor leading to reduced visibility. In order to better comprehend the connection between visibility and aerosols, aerosol optical depth (AOD) and Angström exponent (AE) data from the Himawari-8 Advanced Himawari Imager (AHI) are used for validation in comparison with the data from the Aerosol Robotic Network (AERONET) observations in this paper, which amounted to 69,026 sets of data. The results indicate that the AOD of AHI is in good agreement with AERONET observations, but AE performs poorly. The correlation coefficients between the AOD of AHI and AERONET data increase with decreasing visibility and the root mean square error increase. The AE of AHI performs poorly in different visibility conditions. The conclusion drawn from further analysis of the correlation between aerosol products and meteorological factors is that the factor with the highest correlation with visibility. Mixed aerosols dominate at higher visibility and biomass burning/urban-industrial aerosols dominate at lower visibility. The visibility in a typical city (Beijing) has a strong negative correlation with AOD, a weak negative correlation with AE, and a strong correlation with aerosol radiative forcing. The reduction in visibility may be caused by the scattering and adsorption effects of aerosols. The results are important for the improvement and application of AHI aerosol products in regional pollution studies.
{"title":"Study on the Himawari-8 aerosol products and aerosol types under the environmental pollution in selected regions of Asia","authors":"Qianjun Mao , Xiaoyan Zhang , Piaopiao Chen , Yunlu Tan , Xiaohu Wu","doi":"10.1016/j.jqsrt.2025.109363","DOIUrl":"10.1016/j.jqsrt.2025.109363","url":null,"abstract":"<div><div>Aerosols are an important factor leading to reduced visibility. In order to better comprehend the connection between visibility and aerosols, aerosol optical depth (AOD) and Angström exponent (AE) data from the Himawari-8 Advanced Himawari Imager (AHI) are used for validation in comparison with the data from the Aerosol Robotic Network (AERONET) observations in this paper, which amounted to 69,026 sets of data. The results indicate that the AOD of AHI is in good agreement with AERONET observations, but AE performs poorly. The correlation coefficients between the AOD of AHI and AERONET data increase with decreasing visibility and the root mean square error increase. The AE of AHI performs poorly in different visibility conditions. The conclusion drawn from further analysis of the correlation between aerosol products and meteorological factors is that the factor with the highest correlation with visibility. Mixed aerosols dominate at higher visibility and biomass burning/urban-industrial aerosols dominate at lower visibility. The visibility in a typical city (Beijing) has a strong negative correlation with AOD, a weak negative correlation with AE, and a strong correlation with aerosol radiative forcing. The reduction in visibility may be caused by the scattering and adsorption effects of aerosols. The results are important for the improvement and application of AHI aerosol products in regional pollution studies.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"334 ","pages":"Article 109363"},"PeriodicalIF":2.3,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.jqsrt.2025.109344
Bingqiang Sun , Chenxu Gao
The scattering phase function of atmospheric particle usually has a strong forward peak due to the diffraction effect so that the scattering energy spans large order differences of magnitude in all scattering directions. Correspondingly, the accurate computation of multiple scattering processes in the radiative transfer is high resolution required and time-consuming. A decomposition method is described in this study for the separation of radiative transfer into a rapidly-varying process (RVP) and a slowly-varying process (SVP). The proposed diffraction decomposition order (DDO) method is developed by considering the difference between a delta function and the RVP in a series order of radiative transfer equations, and is generalized to solve the radiative transfer equation in a multi-layer atmosphere. The zeroth-order equation has the forward phase function reduced to the delta function, and the high-order equations successively consider the contribution of the RVP. In this study, the DDO radiative transfer calculation is realized by successive order of scattering approximation and is derived for the multi-layer polarized scenario. By considering the convergences in the orders of both scattering and decomposition, the radiative results are obtained efficiently and accurately as the sum over all order. Finally, numerical simulations are verified using the successive order of scattering method and their accuracy variation associated with orders is discussed.
{"title":"Diffraction Decomposition Order Method for Solving the Vector Radiative Transfer Equation in the Multi-Layer Atmosphere","authors":"Bingqiang Sun , Chenxu Gao","doi":"10.1016/j.jqsrt.2025.109344","DOIUrl":"10.1016/j.jqsrt.2025.109344","url":null,"abstract":"<div><div>The scattering phase function of atmospheric particle usually has a strong forward peak due to the diffraction effect so that the scattering energy spans large order differences of magnitude in all scattering directions. Correspondingly, the accurate computation of multiple scattering processes in the radiative transfer is high resolution required and time-consuming. A decomposition method is described in this study for the separation of radiative transfer into a rapidly-varying process (RVP) and a slowly-varying process (SVP). The proposed diffraction decomposition order (DDO) method is developed by considering the difference between a delta function and the RVP in a series order of radiative transfer equations, and is generalized to solve the radiative transfer equation in a multi-layer atmosphere. The zeroth-order equation has the forward phase function reduced to the delta function, and the high-order equations successively consider the contribution of the RVP. In this study, the DDO radiative transfer calculation is realized by successive order of scattering approximation and is derived for the multi-layer polarized scenario. By considering the convergences in the orders of both scattering and decomposition, the radiative results are obtained efficiently and accurately as the sum over all order. Finally, numerical simulations are verified using the successive order of scattering method and their accuracy variation associated with orders is discussed.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"334 ","pages":"Article 109344"},"PeriodicalIF":2.3,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.1016/j.jqsrt.2025.109364
Saeid Esmaeil Nia , Ali Shokri
The attenuation of electromagnetic waves due to rainfall is a critical factor in radar and telecommunication systems, particularly in frequency bands above 10 GHz, which is increasingly utilised for data transfer. This study addresses the gaps in understanding how these attenuation effects vary across different rainfall intensities and Drop Size Distributions (DSD). By analytically investigating the irregularities in the cross-sections of raindrops within the 1 to 30 GHz frequency range, the study mentions significant peaks in attenuation at frequencies below 10 GHz, which are more pronounced as DSD changes with rainfall intensity. Using the extinction and efficiency cross-sections of raindrops in 1–30 GHz microwave transmission, the coefficients of rainfall-attenuation correlation were derived for each sector of rainfall intensity of 1–300 mm/hr. Building on these findings, we propose an enhanced rainfall-attenuation relationship, incorporating dynamic coefficients, varying with both factors, DSD and rainfall intensity. Unlike previous models that only suggest calibration of the attenuation-rainfall relationship with DSD, our results indicate that the coefficients should also dynamically adjust based on rainfall intensity. We further demonstrate how these varying coefficients differ from the ITU's recommendations, providing detailed graphical comparisons. This advancement allows for more accurate calculations of rainfall intensity, improving the precision of telecommunication and radar systems in diverse weather conditions.
{"title":"Exploring the impact of rainfall intensity on the attenuation-rainfall relationship","authors":"Saeid Esmaeil Nia , Ali Shokri","doi":"10.1016/j.jqsrt.2025.109364","DOIUrl":"10.1016/j.jqsrt.2025.109364","url":null,"abstract":"<div><div>The attenuation of electromagnetic waves due to rainfall is a critical factor in radar and telecommunication systems, particularly in frequency bands above 10 GHz, which is increasingly utilised for data transfer. This study addresses the gaps in understanding how these attenuation effects vary across different rainfall intensities and Drop Size Distributions (DSD). By analytically investigating the irregularities in the cross-sections of raindrops within the 1 to 30 GHz frequency range, the study mentions significant peaks in attenuation at frequencies below 10 GHz, which are more pronounced as DSD changes with rainfall intensity. Using the extinction and efficiency cross-sections of raindrops in 1–30 GHz microwave transmission, the coefficients of rainfall-attenuation correlation were derived for each sector of rainfall intensity of 1–300 mm/hr. Building on these findings, we propose an enhanced rainfall-attenuation relationship, incorporating dynamic coefficients, varying with both factors, DSD and rainfall intensity. Unlike previous models that only suggest calibration of the attenuation-rainfall relationship with DSD, our results indicate that the coefficients should also dynamically adjust based on rainfall intensity. We further demonstrate how these varying coefficients differ from the ITU's recommendations, providing detailed graphical comparisons. This advancement allows for more accurate calculations of rainfall intensity, improving the precision of telecommunication and radar systems in diverse weather conditions.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"334 ","pages":"Article 109364"},"PeriodicalIF":2.3,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-14DOI: 10.1016/j.jqsrt.2025.109361
F. Hendaoui , D. Jacquemart , A. Hessani , B. Tremblay , H. Aroui , H. Tran
He-collision-induced line-shape parameters of CO2 lines were measured in the ν3 band using Fourier transform spectra recorded at room temperature and with pressures ranging from 263 mbar to 1106 mbar. The measured transmission spectra were analyzed with the Voigt profile combined with the first-order line-mixing approximation, accounting for the instrument line-shape function. The He-broadening coefficients, pressure shifts, and first-order line-mixing parameters were determined for 51 lines, from the P(50) to the R(51). The obtained He-broadening coefficients are in excellent agreement with various literature values. These broadening coefficients, together with data for higher J lines, extrapolated from available high-temperature measurements, allowed us to propose an improved dataset for He-broadening coefficients of CO2 lines. We demonstrated that accounting for line-mixing effects is essential to accurately determine the pressure shifts. The latter, measured for the first time for the ν3 band, exhibited a weak rotational dependence, in contrast to the strong dependence observed for air- and self-pressure shifts for CO2. The obtained line-mixing coefficients agree well with those calculated using the Energy Corrected Sudden model. The results of this study significantly enhance the line-shape parameters dataset for CO2 perturbed by He, providing improved data for spectroscopic databases and for studies of planetary and exoplanetary atmospheres.
{"title":"Measurements of He-collision-induced line-shape parameters of CO2 lines in the ν3 band","authors":"F. Hendaoui , D. Jacquemart , A. Hessani , B. Tremblay , H. Aroui , H. Tran","doi":"10.1016/j.jqsrt.2025.109361","DOIUrl":"10.1016/j.jqsrt.2025.109361","url":null,"abstract":"<div><div>He-collision-induced line-shape parameters of CO<sub>2</sub> lines were measured in the ν<sub>3</sub> band using Fourier transform spectra recorded at room temperature and with pressures ranging from 263 mbar to 1106 mbar. The measured transmission spectra were analyzed with the Voigt profile combined with the first-order line-mixing approximation, accounting for the instrument line-shape function. The He-broadening coefficients, pressure shifts, and first-order line-mixing parameters were determined for 51 lines, from the <em>P</em>(50) to the <em>R</em>(51). The obtained He-broadening coefficients are in excellent agreement with various literature values. These broadening coefficients, together with data for higher <em>J</em> lines, extrapolated from available high-temperature measurements, allowed us to propose an improved dataset for He-broadening coefficients of CO<sub>2</sub> lines. We demonstrated that accounting for line-mixing effects is essential to accurately determine the pressure shifts. The latter, measured for the first time for the <em>ν</em><sub>3</sub> band, exhibited a weak rotational dependence, in contrast to the strong dependence observed for air- and self-pressure shifts for CO<sub>2</sub>. The obtained line-mixing coefficients agree well with those calculated using the Energy Corrected Sudden model. The results of this study significantly enhance the line-shape parameters dataset for CO<sub>2</sub> perturbed by He, providing improved data for spectroscopic databases and for studies of planetary and exoplanetary atmospheres.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"334 ","pages":"Article 109361"},"PeriodicalIF":2.3,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-13DOI: 10.1016/j.jqsrt.2025.109347
Fangshi Jia , Zhaoying Chen , Jialin Liu , Jihui Chen , Liangyu Huang , Zhencen He , Yaming Zou , Yunqing Fu , Baoren Wei , Ke Yao
The spectroscopic investigations on transitions of phosphorus-like Ge, As, Se, Br, and Kr ions at an electron beam ion trap were presented. The direct wavelength measurements were reported for the first time for Ge Br ions. All the measurements reached precision levels of a few ppm. The theoretical calculations were carried out using multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction methods including a large set of configuration state functions, in which the Breit interaction and QED effects were taken into account. The present results showed a good agreement between the theory and the experiment, and the divisions were less than 0.6%. Especially for the Kr ions, meticulous scrutiny of line strengths with charge state distributions and continuity of results with isoelectronic sequence were performed to identify the measured spectral line as transition. The present work resolved the long-standing confusion of the Kr spectral line. Our accurate experimental results could be reference data for further calculations.
{"title":"Determination of the energy splitting between 3p3 2D5/2 and 2D3/2 states in phosphorus-like ions","authors":"Fangshi Jia , Zhaoying Chen , Jialin Liu , Jihui Chen , Liangyu Huang , Zhencen He , Yaming Zou , Yunqing Fu , Baoren Wei , Ke Yao","doi":"10.1016/j.jqsrt.2025.109347","DOIUrl":"10.1016/j.jqsrt.2025.109347","url":null,"abstract":"<div><div>The spectroscopic investigations on <span><math><mrow><mn>3</mn><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span> <span><math><mrow><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup><msub><mrow><mi>D</mi></mrow><mrow><mn>5</mn><mo>/</mo><mn>2</mn></mrow></msub></mrow></math></span> <span><math><mo>−</mo></math></span> <span><math><mrow><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup><msub><mrow><mi>D</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msub></mrow></math></span> transitions of phosphorus-like Ge<span><math><msup><mrow></mrow><mrow><mn>17</mn><mo>+</mo></mrow></msup></math></span>, As<span><math><msup><mrow></mrow><mrow><mn>18</mn><mo>+</mo></mrow></msup></math></span>, Se<span><math><msup><mrow></mrow><mrow><mn>19</mn><mo>+</mo></mrow></msup></math></span>, Br<span><math><msup><mrow></mrow><mrow><mn>20</mn><mo>+</mo></mrow></msup></math></span>, and Kr<span><math><msup><mrow></mrow><mrow><mn>21</mn><mo>+</mo></mrow></msup></math></span> ions at an electron beam ion trap were presented. The direct wavelength measurements were reported for the first time for Ge<span><math><msup><mrow></mrow><mrow><mn>17</mn><mo>+</mo></mrow></msup></math></span> <span><math><mo>−</mo></math></span>Br<span><math><msup><mrow></mrow><mrow><mn>20</mn><mo>+</mo></mrow></msup></math></span> ions. All the measurements reached precision levels of a few ppm. The theoretical calculations were carried out using multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction methods including a large set of configuration state functions, in which the Breit interaction and QED effects were taken into account. The present results showed a good agreement between the theory and the experiment, and the divisions were less than 0.6%. Especially for the Kr<span><math><msup><mrow></mrow><mrow><mn>21</mn><mo>+</mo></mrow></msup></math></span> ions, meticulous scrutiny of line strengths with charge state distributions and continuity of results with isoelectronic sequence were performed to identify the measured spectral line as <span><math><mrow><mn>3</mn><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span> <span><math><mrow><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup><msub><mrow><mi>D</mi></mrow><mrow><mn>5</mn><mo>/</mo><mn>2</mn></mrow></msub></mrow></math></span> <span><math><mo>−</mo></math></span> <span><math><mrow><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup><msub><mrow><mi>D</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msub></mrow></math></span> transition. The present work resolved the long-standing confusion of the Kr<span><math><msup><mrow></mrow><mrow><mn>21</mn><mo>+</mo></mrow></msup></math></span> spectral line. Our accurate experimental results could be reference data for further calculations.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"334 ","pages":"Article 109347"},"PeriodicalIF":2.3,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-10DOI: 10.1016/j.jqsrt.2025.109345
Sergey Korkin , Andrew M. Sayer , Amir Ibrahim , Alexei Lyapustin
We present two new open-source codes, in the C language, for simulation of the line-by-line molecular (gas) absorption in the solar spectral region with wavelengths up to ∼2500 (nm). The first one, gcell, simulates absorption spectroscopy in a gas cell for a given length of the cell, temperature, and pressure. The second one, aspect, is for spectroscopy in Earth's atmosphere - a common need for remote sensing applications. Both use the HITRAN database for line shape (Voigt) modeling. Aspect adapts height variations of the thermodynamic parameters (profiles) from MODTRAN. Separate discussion of the gas cell and the atmospheric modes simplifies software development, documentation, and support, and ultimately the transfer of knowledge between generations of scientists. These are the main goals of the current paper. Despite the existence of numerous computer programs for absorption spectroscopy, the code development process is poorly covered in literature. As a result, it is difficult for a non-developer to confidently modify an existing code or create a new tool within a reasonable amount of time.
{"title":"A practical guide to coding line-by-line trace gas absorption in Earth's atmosphere","authors":"Sergey Korkin , Andrew M. Sayer , Amir Ibrahim , Alexei Lyapustin","doi":"10.1016/j.jqsrt.2025.109345","DOIUrl":"10.1016/j.jqsrt.2025.109345","url":null,"abstract":"<div><div>We present two new open-source codes, in the C language, for simulation of the line-by-line molecular (gas) absorption in the solar spectral region with wavelengths up to ∼2500 (<em>nm</em>). The first one, <span>gcell</span>, simulates absorption spectroscopy in a gas cell for a given length of the cell, temperature, and pressure. The second one, <span>aspect</span>, is for spectroscopy in Earth's atmosphere - a common need for remote sensing applications. Both use the HITRAN database for line shape (Voigt) modeling. <span>Aspect</span> adapts height variations of the thermodynamic parameters (profiles) from MODTRAN. Separate discussion of the gas cell and the atmospheric modes simplifies software development, documentation, and support, and ultimately the transfer of knowledge between generations of scientists. These are the main goals of the current paper. Despite the existence of numerous computer programs for absorption spectroscopy, the code development process is poorly covered in literature. As a result, it is difficult for a non-developer to confidently modify an existing code or create a new tool within a reasonable amount of time.</div></div>","PeriodicalId":16935,"journal":{"name":"Journal of Quantitative Spectroscopy & Radiative Transfer","volume":"337 ","pages":"Article 109345"},"PeriodicalIF":2.3,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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