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Different microphysics parameterizations of hydrometeor pathways in WRF simulation: A case of two high rainfall events in Nigeria
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-06 DOI: 10.1016/j.jastp.2025.106455
Anselem Onyejuruwa , Zhenghua Hu , Abu Reza Md Towfiqul Islam , Eniola Olaniyan , Kyaw Than Oo
This study evaluates the role and performance of microphysical processes and parameterizations in simulating two distinct rainfall events over Nigeria. Four microphysics (MP) schemes in the Weather Research and Forecasting (WRF) model—Goddard, Morrison, Thompson, and WDM6—were utilized. The analysis focused on mean rainfall rates, hydrometeor pathways, and spatial rainfall accumulation amounts and patterns.
Results indicate that while most MP schemes underestimated the mean rainfall rate, they reasonably captured the spatial distributions in both events. Based on statistical metrics of 24-h accumulated rainfall, the Goddard scheme produced the lowest mean absolute bias (MAB) and the highest rainfall detection ability (POD and TS) for the June rainfall event. For the February event, the Morrison scheme exhibited the least absolute bias and achieved high POD and TS values. The differences in rainfall production among the MP schemes were primarily attributed to variations in the growth rates of rainwater hydrometeors within the hydrometeor pathways (HPs), while rainfall duration was influenced by consistent collision and coalescence of cloud droplets. Excessive cloud water production also contributed to delays in rainwater formation, leading to reduced simulated rainfall. Additionally, the rapid melting of large graupel mass significantly affected the performance of different schemes in simulating rainfall. Furthermore, variations in low to mid-tropospheric vertical velocity and surface parameters (such as temperature and specific humidity) were shown to significantly control microphysical processes and, consequently, impact rainfall production.
Overall, the analysis suggests that more sophisticated MP schemes do not necessarily provide better simulations of precipitable hydrometeor pathways.
{"title":"Different microphysics parameterizations of hydrometeor pathways in WRF simulation: A case of two high rainfall events in Nigeria","authors":"Anselem Onyejuruwa ,&nbsp;Zhenghua Hu ,&nbsp;Abu Reza Md Towfiqul Islam ,&nbsp;Eniola Olaniyan ,&nbsp;Kyaw Than Oo","doi":"10.1016/j.jastp.2025.106455","DOIUrl":"10.1016/j.jastp.2025.106455","url":null,"abstract":"<div><div>This study evaluates the role and performance of microphysical processes and parameterizations in simulating two distinct rainfall events over Nigeria. Four microphysics (MP) schemes in the Weather Research and Forecasting (WRF) model—Goddard, Morrison, Thompson, and WDM6—were utilized. The analysis focused on mean rainfall rates, hydrometeor pathways, and spatial rainfall accumulation amounts and patterns.</div><div>Results indicate that while most MP schemes underestimated the mean rainfall rate, they reasonably captured the spatial distributions in both events. Based on statistical metrics of 24-h accumulated rainfall, the Goddard scheme produced the lowest mean absolute bias (MAB) and the highest rainfall detection ability (POD and TS) for the June rainfall event. For the February event, the Morrison scheme exhibited the least absolute bias and achieved high POD and TS values. The differences in rainfall production among the MP schemes were primarily attributed to variations in the growth rates of rainwater hydrometeors within the hydrometeor pathways (HPs), while rainfall duration was influenced by consistent collision and coalescence of cloud droplets. Excessive cloud water production also contributed to delays in rainwater formation, leading to reduced simulated rainfall. Additionally, the rapid melting of large graupel mass significantly affected the performance of different schemes in simulating rainfall. Furthermore, variations in low to mid-tropospheric vertical velocity and surface parameters (such as temperature and specific humidity) were shown to significantly control microphysical processes and, consequently, impact rainfall production.</div><div>Overall, the analysis suggests that more sophisticated MP schemes do not necessarily provide better simulations of precipitable hydrometeor pathways.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"268 ","pages":"Article 106455"},"PeriodicalIF":1.8,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Possible ionospheric effects of two major earth quakes in Papua New Guinea
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-05 DOI: 10.1016/j.jastp.2025.106457
B. Felix Pereira, Jessy Sekere
Pre-seismic ionospheric F2 layer instabilities have been studied which could help in predicting earthquakes. Two major earthquakes in the western province of Papua New Guinea, one in Sissano in 1998 of magnitude 7.1 and the other in Aitape in 2002 of magnitude 6.7 were analyzed. An analysis of the perturbations in the electron content up to the ionospheric F2 layer peak and F2 layer peak height (hmF2) variations during earthquake time has been done using published ionosonde data. A decrease in peak electron density ranging from 20 to 30% was observed within 10 days during pre-seismic as well as post-seismic periods during both earthquakes. On these days, an increase in the height of the peak electron density was also observed. This could be because during seismic periods, a large amount of radon gas is emitted during earthquake preparation time, which ionize neutral atoms and molecules and the ions raise to ionospheric heights by electric fields created and produce ionospheric fluctuations. This helps in predicting the earthquake in advance.
{"title":"Possible ionospheric effects of two major earth quakes in Papua New Guinea","authors":"B. Felix Pereira,&nbsp;Jessy Sekere","doi":"10.1016/j.jastp.2025.106457","DOIUrl":"10.1016/j.jastp.2025.106457","url":null,"abstract":"<div><div>Pre-seismic ionospheric F2 layer instabilities have been studied which could help in predicting earthquakes. Two major earthquakes in the western province of Papua New Guinea, one in Sissano in 1998 of magnitude 7.1 and the other in Aitape in 2002 of magnitude 6.7 were analyzed. An analysis of the perturbations in the electron content up to the ionospheric F<sub>2</sub> layer peak and F2 layer peak height (h<sub>m</sub>F2) variations during earthquake time has been done using published ionosonde data. A decrease in peak electron density ranging from 20 to 30% was observed within 10 days during pre-seismic as well as post-seismic periods during both earthquakes. On these days, an increase in the height of the peak electron density was also observed. This could be because during seismic periods, a large amount of radon gas is emitted during earthquake preparation time, which ionize neutral atoms and molecules and the ions raise to ionospheric heights by electric fields created and produce ionospheric fluctuations. This helps in predicting the earthquake in advance.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106457"},"PeriodicalIF":1.8,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Assessment of variability in chlorophyll-a and covariates in East/Japan sea: New insights from the ARIMAX model and wavelet coherence
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-05 DOI: 10.1016/j.jastp.2025.106450
Salman Tariq , Ayesha Mariam , Muhammad Khan
The atmospheric aerosols and the concentration of Chlorophyll-a (Chl-a) in coastal and clear water is an important research field that involves the multiple aspects of environmental degradation and analyzing the health of the marine environment. Therefore, ocean color satellite remote sensing is an efficient way to observe and monitor the aquatic system and the ocean at various spatial, temporal, and spectral scales. Therefore, this study analyzes the spatiotemporal dynamic variability in various ocean color variables, i.e., Sea surface temperature (SST), Aerosol optical depth (AOD), Black carbon dry deposition (BCD), Calcite concentration (CC), Ocean Rain (O-Rain), and Sensible heat flux (SHF) over the East/Japan Sea (EJS) from 2002 to 2023. Furthermore, we used the ARIMAX model and Wavelet coherence (WTC) analysis for analyzing the variability of these oceanic parameters with Chl-a. The spatial concentration of Chl-a is observed high over the northern EJS, particularly around 141ᵒ E, 50ᵒ N, southwestern EJS, and around 141ᵒ E, 43ᵒ N (along the Japanese coast). Furthermore, the western EJS also showed the highest concentration of Chl-a than the eastern EJS. Generally, the mean concentration of Chl-a in EJS increasing at the rate of 0.4 mg m−3/yr showed the maximum value of 0.8 mg m−3 during the study period. Moreover, the ARIMAX models elucidated a direct coupling of the Chl-a with O-Rain and BCD while it showed an inverse and statistically significant association with AOD, SST, CC, and SHF. The WTC analysis indicated a strong association of above 0.8 of Chl-a with all selected variables between a scale period of 8–16. Among all selected variables, CC, SHF, and BCD show a stronger association with Chl-a over the EJS. Therefore, this study will help the policymakers in identifying the major hotspots of Chl-a in EJS to analyze the water quality and health of the marine environment.
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引用次数: 0
Study of VLF signal during partial solar eclipse of 25 October 2022
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-05 DOI: 10.1016/j.jastp.2025.106458
Ramesh Krishna B, P. Chaithra, Kamsali Nagaraja
The partial solar eclipse on October 25, 2022, had an observable effect on very low frequency (VLF) signals along the transmission paths of GQD (22.10 kHz) and DHO (23.40 kHz). Signal variations were analyzed for October 22–28, 2022, with a focus on amplitude changes during the greatest eclipse (GE) phase. During the partial solar eclipse, the GQD and DHO signal paths experienced 11% and 14% obstructions, respectively. On the day of the eclipse, the amplitude of the GQD is 0.83 dB lower compared to pre-days and 0.11 dB greater than post-days, and for DHO it is increased by 0.26 dB and 0.57 dB for pre- and post-eclipse days at the time of GE. Observations revealed stronger solar flare signatures in GQD signal compared to the DHO signal, attributed to differences in ionospheric conditions along the propagation paths. A pronounced rise in amplitude before and after the GE phase was observed in the GQD signal, linked to solar flare activity. Additionally, the analysis confirmed that the PSE was the primary driver of increased VLF signal amplitude during the GE phase along the DHO path. The results emphasize the significant impact of partial solar eclipses on ionospheric dynamics and VLF signal propagation.
2022 年 10 月 25 日的日偏食对 GQD(22.10 kHz)和 DHO(23.40 kHz)传输路径上的甚低频(VLF)信号有明显影响。分析了 2022 年 10 月 22 日至 28 日的信号变化,重点是日偏食(GE)阶段的振幅变化。日偏食期间,GQD 和 DHO 信号路径分别受到 11% 和 14% 的阻挡。日食当天,GQD 的振幅比日食前低 0.83 分贝,比日食后高 0.11 分贝;日食前后,DHO 的振幅比日食前高 0.26 分贝,比日食后高 0.57 分贝。观测结果表明,与 DHO 信号相比,GQD 信号中的太阳耀斑特征更强,这归因于传播路径沿线电离层条件的差异。在 GE 阶段前后,GQD 信号的振幅明显上升,这与太阳耀斑活动有关。此外,分析还证实,在 GE 阶段,PSE 是沿 DHO 路径的甚低频信号振幅增大的主要驱动因素。这些结果强调了日偏食对电离层动态和甚低频信号传播的重大影响。
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引用次数: 0
On the retrieval of particle size information of noctilucent clouds from optical remote sensing measurements
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-04 DOI: 10.1016/j.jastp.2025.106447
Christian von Savigny
Noctilucent clouds (NLCs) are optically thin ice clouds occurring near the polar mesopause in the summer hemisphere. Our understanding of the particle size of NLCs is to a large extent based on optical measurements in different observation geometries and optical NLC particle size retrievals are always based on a priori assumptions on the shape of the particle size distribution. The actual shape of the particle size distribution is generally not well known and can be assumed to be highly variable. In addition, the scattering cross section of NLC particles depends strongly on particle size. This leads to effects that have until now not been considered properly in the literature, i.e. if the assumed shape of the particle size distribution differs from the actual one, NLC size retrievals based on different measurement techniques will be associated with different biases. These differences can be quite substantial, for the retrieved particle number density in particular. In this study we carry out NLC particle size retrievals based on simplified synthetic forward simulations for the following observation techniques: satellite occultation, satellite limb-scatter, ground-based lidar and satellite nadir measurements. For the forward simulations we assume a bi-modal particle size distribution, while for the size retrieval a mono-modal distribution is assumed — which is typically the case in the literature. We assume both normal and log-normal particle size distributions, but the main results of this study are independent of the specific assumption on the shape of particle size distribution. We find that even for small deviations from the assumed shape of the particle size distribution, relatively large differences in retrieved size estimates occur between the different observation geometries considered. The retrieved median radii can differ by up to a factor of 2, while retrieved particle number densities can differ by more than a factor of 10 between the different observation geometries. These results need to be considered when comparing NLC size retrievals from different optical techniques.
{"title":"On the retrieval of particle size information of noctilucent clouds from optical remote sensing measurements","authors":"Christian von Savigny","doi":"10.1016/j.jastp.2025.106447","DOIUrl":"10.1016/j.jastp.2025.106447","url":null,"abstract":"<div><div>Noctilucent clouds (NLCs) are optically thin ice clouds occurring near the polar mesopause in the summer hemisphere. Our understanding of the particle size of NLCs is to a large extent based on optical measurements in different observation geometries and optical NLC particle size retrievals are always based on a priori assumptions on the shape of the particle size distribution. The actual shape of the particle size distribution is generally not well known and can be assumed to be highly variable. In addition, the scattering cross section of NLC particles depends strongly on particle size. This leads to effects that have until now not been considered properly in the literature, i.e. if the assumed shape of the particle size distribution differs from the actual one, NLC size retrievals based on different measurement techniques will be associated with different biases. These differences can be quite substantial, for the retrieved particle number density in particular. In this study we carry out NLC particle size retrievals based on simplified synthetic forward simulations for the following observation techniques: satellite occultation, satellite limb-scatter, ground-based lidar and satellite nadir measurements. For the forward simulations we assume a bi-modal particle size distribution, while for the size retrieval a mono-modal distribution is assumed — which is typically the case in the literature. We assume both normal and log-normal particle size distributions, but the main results of this study are independent of the specific assumption on the shape of particle size distribution. We find that even for small deviations from the assumed shape of the particle size distribution, relatively large differences in retrieved size estimates occur between the different observation geometries considered. The retrieved median radii can differ by up to a factor of 2, while retrieved particle number densities can differ by more than a factor of 10 between the different observation geometries. These results need to be considered when comparing NLC size retrievals from different optical techniques.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106447"},"PeriodicalIF":1.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Ionospheric disturbances over Ukraine through the eyes of standalone GNSS receiver
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-03 DOI: 10.1016/j.jastp.2025.106451
Sayak Ray , Batakrushna Senapati , Bhaskar Kundu , M. Santosh
The atmospheric waves generated from large-scale natural phenomena such as earthquakes, volcanoes, and anthropogenic explosions propagate upward to the upper atmosphere and cause perturbations in the ionosphere. In the present study, we investigate the ionospheric perturbations in terms of total electron content (TEC) signatures induced by the missile/airstrikes over the Ukraine region during the ongoing Russian-Ukrainian conflict, which has been captured through a standalone ground-based Global Navigation Satellite System (GNSS) receiver. We observed an ionospheric electron content change of ∼0.1–0.3 TECU caused by the acoustic wave generated from the missile/air strikes. We also noticed a strong directivity of the ionospheric disturbances over Ukraine, with maximum ionospheric disturbances in the south direction from the epicenter of the events. Further, the ionospheric disturbance's peak-to-peak amplitude was 1.5% of the background electrons, slightly less than the magnitude of volcanic eruptions in the Islands of Japan.
{"title":"Ionospheric disturbances over Ukraine through the eyes of standalone GNSS receiver","authors":"Sayak Ray ,&nbsp;Batakrushna Senapati ,&nbsp;Bhaskar Kundu ,&nbsp;M. Santosh","doi":"10.1016/j.jastp.2025.106451","DOIUrl":"10.1016/j.jastp.2025.106451","url":null,"abstract":"<div><div>The atmospheric waves generated from large-scale natural phenomena such as earthquakes, volcanoes, and anthropogenic explosions propagate upward to the upper atmosphere and cause perturbations in the ionosphere. In the present study, we investigate the ionospheric perturbations in terms of total electron content (TEC) signatures induced by the missile/airstrikes over the Ukraine region during the ongoing Russian-Ukrainian conflict, which has been captured through a standalone ground-based Global Navigation Satellite System (GNSS) receiver. We observed an ionospheric electron content change of ∼0.1–0.3 TECU caused by the acoustic wave generated from the missile/air strikes. We also noticed a strong directivity of the ionospheric disturbances over Ukraine, with maximum ionospheric disturbances in the south direction from the epicenter of the events. Further, the ionospheric disturbance's peak-to-peak amplitude was 1.5% of the background electrons, slightly less than the magnitude of volcanic eruptions in the Islands of Japan.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"268 ","pages":"Article 106451"},"PeriodicalIF":1.8,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143270165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Is heating of ions by Alfvén waves via nonresonant interactions applicable in the Earth’s magnetosphere?
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.jastp.2024.106413
I.A. Barghouthi, W.T. Rabai
Heating of ions in Earth’s magnetosphere by enhanced Alfvén waves below resonance frequency (nonresonant heating) has been presented in many studies, among these is the study of Wang et al. (2006) in which they stated that in any region in space with low beta plasma, this heating process, i.e. nonresonant ion heating is applicable and effective. In this paper we stress on the inapplicability of this type of heating in the Earth’s magnetosphere. We present; (1) a data set that provides a strong proof that the theory presented by Wang et al. (2006) is not applicable in this region of space (i.e. Earth’s magnetosphere), (2) in addition, we plot altitude profiles for parallel, perpendicular, and total temperatures for hydrogen ions in cusp and central polar cap regions by evaluating observed magnetic activity and Alfvén waves into Wang et al. (2006) theory, we find the changes in the altitude behavior in ion temperature profiles are very small, (3) also, we compare between Monte Carlo simulations results of ion temperatures obtained by using Barghouthi model (this model includes the effects of gravity, polarization electric field, divergence geomagnetic field, centrifugal acceleration, resonant ion heating, and with and without nonresonant ion heating effect) in cusp and central polar cap regions with appropriate boundary conditions (Barghouthi et al., 2008), both simulation results of ion temperatures are almost the same. Therefore, we report on the nonresonant ion heating process in central polar cap and cusp regions is not significant.
{"title":"Is heating of ions by Alfvén waves via nonresonant interactions applicable in the Earth’s magnetosphere?","authors":"I.A. Barghouthi,&nbsp;W.T. Rabai","doi":"10.1016/j.jastp.2024.106413","DOIUrl":"10.1016/j.jastp.2024.106413","url":null,"abstract":"<div><div>Heating of ions in Earth’s magnetosphere by enhanced Alfv<span><math><mover><mrow><mi>e</mi></mrow><mrow><mo>́</mo></mrow></mover></math></span>n waves below resonance frequency (nonresonant heating) has been presented in many studies, among these is the study of Wang et al. (2006) in which they stated that in any region in space with low beta plasma, this heating process, i.e. nonresonant ion heating is applicable and effective. In this paper we stress on the inapplicability of this type of heating in the Earth’s magnetosphere. We present; (1) a data set that provides a strong proof that the theory presented by Wang et al. (2006) is not applicable in this region of space (i.e. Earth’s magnetosphere), (2) in addition, we plot altitude profiles for parallel, perpendicular, and total temperatures for hydrogen ions in cusp and central polar cap regions by evaluating observed magnetic activity and Alfv<span><math><mover><mrow><mi>e</mi></mrow><mrow><mo>́</mo></mrow></mover></math></span>n waves into Wang et al. (2006) theory, we find the changes in the altitude behavior in ion temperature profiles are very small, (3) also, we compare between Monte Carlo simulations results of ion temperatures obtained by using Barghouthi model (this model includes the effects of gravity, polarization electric field, divergence geomagnetic field, centrifugal acceleration, resonant ion heating, and with and without nonresonant ion heating effect) in cusp and central polar cap regions with appropriate boundary conditions (Barghouthi et al., 2008), both simulation results of ion temperatures are almost the same. Therefore, we report on the nonresonant ion heating process in central polar cap and cusp regions is not significant.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"267 ","pages":"Article 106413"},"PeriodicalIF":1.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Climate time series variability analysis of Islamabad Capital Territory using fractal dimension and Hurst exponent methods
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.jastp.2024.106406
Ali Khan , Shahid Hussain , Ahmed Bakhet , Afshan Anwer , S.M. Murshid Raza , Sajjad Ali , Mohammed Zakarya
This study is an attempt to examine variability of climatic parameters at local scale, Islamabad Capital Territory (ICT). Climate change can affect temperature trends and precipitation patterns, horticultural activity, agricultural productivity, underground water level, portable water availability, and infrastructure.To assess the impact of climate change of Islamabad Capital Territory, the data of precipitation, minimum and maximum temperatures were obtained for the period from 1983 to 2022 from Pakistan Metrological Department (PMD). Fractal dimension D and Hurt exponent H methods were employed to estimate the monthly maximum and minimum temperatures, and precipitation of the study area. The data was portioned into 4 subsets. Rescaled range analysis method was applied on the datasets to compute values of Hurst exponent and fractal dimension. The results obtained show Brownian random and persistent tendencies, correspondingly. On the other hand, the period from 2013 to 2022 shows anti-persistent trend for H and random trend during (2013–2022) for D, respectively. The time series showing persistent results contain the long-term memory. When a time series shows random Brownian behaviour, thenthere will be no any extended long-term memory. Rescaled range analysis (R/S)method was employed to compute fractal dimensions show consistent outcomes, reveal small fluctuation in the local behaviour of minimum temperatures.Whereas, Hurst exponent values of maximum temperatures show random behavior i.e. there exists no correlation. The Hurst exponents computed confirm persistent results for precipitation pattern. Likewise, the computed values of fractal dimensions also show persistent results. Thus, the precipitation pattern shows cyclic behaviour, i.e. the precipitation time series retain long-run memory. Finally, from the persistent behavior of time series, one would infer that there will bean extended time effect on the local precipitation pattern. Python software was used to perform computations.
{"title":"Climate time series variability analysis of Islamabad Capital Territory using fractal dimension and Hurst exponent methods","authors":"Ali Khan ,&nbsp;Shahid Hussain ,&nbsp;Ahmed Bakhet ,&nbsp;Afshan Anwer ,&nbsp;S.M. Murshid Raza ,&nbsp;Sajjad Ali ,&nbsp;Mohammed Zakarya","doi":"10.1016/j.jastp.2024.106406","DOIUrl":"10.1016/j.jastp.2024.106406","url":null,"abstract":"<div><div>This study is an attempt to examine variability of climatic parameters at local scale, Islamabad Capital Territory (ICT). Climate change can affect temperature trends and precipitation patterns, horticultural activity, agricultural productivity, underground water level, portable water availability, and infrastructure.To assess the impact of climate change of Islamabad Capital Territory, the data of precipitation, minimum and maximum temperatures were obtained for the period from 1983 to 2022 from Pakistan Metrological Department (PMD). Fractal dimension <em>D</em> and Hurt exponent <em>H</em> methods were employed to estimate the monthly maximum and minimum temperatures, and precipitation of the study area. The data was portioned into 4 subsets. Rescaled range analysis method was applied on the datasets to compute values of Hurst exponent and fractal dimension. The results obtained show Brownian random and persistent tendencies, correspondingly. On the other hand, the period from 2013 to 2022 shows anti-persistent trend for H and random trend during (2013–2022) for D, respectively. The time series showing persistent results contain the long-term memory. When a time series shows random Brownian behaviour, thenthere will be no any extended long-term memory. Rescaled range analysis (<em>R/S</em>)method was employed to compute fractal dimensions show consistent outcomes, reveal small fluctuation in the local behaviour of minimum temperatures.Whereas, Hurst exponent values of maximum temperatures show random behavior i.e. there exists no correlation. The Hurst exponents computed confirm persistent results for precipitation pattern. Likewise, the computed values of fractal dimensions also show persistent results. Thus, the precipitation pattern shows cyclic behaviour, i.e. the precipitation time series retain long-run memory. Finally, from the persistent behavior of time series, one would infer that there will bean extended time effect on the local precipitation pattern. Python software was used to perform computations.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"267 ","pages":"Article 106406"},"PeriodicalIF":1.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Theoretical investigations on the reactions of CH3CH2NCH3 radicals in the presence of NO, NO2 and O2
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.jastp.2025.106420
Fei Liu , Chenggang Lu , Yizhen Tang , Yaru Pan
The reactions of CH3CH2NCH3 amino radicals in the presence of NO, NO2 and O2 were investigated by quantum chemistry methods. It was found that CH3CH2N(CH3)NO, CH3CH2N(CH3)NO2 and CH3CH2N(CH3)ONO can be formed dominantly when CH3CH2NCH3 reacts with NO and NO2, while CH3CH=NCH3 and CH3CH2N=CH2 will be feasible when CH3CH2NCH3 is in the presence of oxygen. Time dependent density functional theory (TDDFT) calculation shows that CH3CH2N(CH3)NO and CH3CH2N(CH3)ONO can photolyze under the sunlight, while CH3CH2N(CH3)NO2 cannot undergo photolysis in the daytime. Comparisons among the reactions of (CH3)2N, (CH3CH2)2N and CH3CH2NCH3 with NO, NO2 and O2 indicate that the asymmetric substituted alkyl groups will play a notable role in the formation of stable products.
{"title":"Theoretical investigations on the reactions of CH3CH2NCH3 radicals in the presence of NO, NO2 and O2","authors":"Fei Liu ,&nbsp;Chenggang Lu ,&nbsp;Yizhen Tang ,&nbsp;Yaru Pan","doi":"10.1016/j.jastp.2025.106420","DOIUrl":"10.1016/j.jastp.2025.106420","url":null,"abstract":"<div><div>The reactions of CH<sub>3</sub>CH<sub>2</sub>NCH<sub>3</sub> amino radicals in the presence of NO, NO<sub>2</sub> and O<sub>2</sub> were investigated by quantum chemistry methods. It was found that CH<sub>3</sub>CH<sub>2</sub>N(CH<sub>3</sub>)NO, CH<sub>3</sub>CH<sub>2</sub>N(CH<sub>3</sub>)NO<sub>2</sub> and CH<sub>3</sub>CH<sub>2</sub>N(CH<sub>3</sub>)ONO can be formed dominantly when CH<sub>3</sub>CH<sub>2</sub>NCH<sub>3</sub> reacts with NO and NO<sub>2</sub>, while CH<sub>3</sub>CH=NCH<sub>3</sub> and CH<sub>3</sub>CH<sub>2</sub>N=CH<sub>2</sub> will be feasible when CH<sub>3</sub>CH<sub>2</sub>NCH<sub>3</sub> is in the presence of oxygen. Time dependent density functional theory (TDDFT) calculation shows that CH<sub>3</sub>CH<sub>2</sub>N(CH<sub>3</sub>)NO and CH<sub>3</sub>CH<sub>2</sub>N(CH<sub>3</sub>)ONO can photolyze under the sunlight, while CH<sub>3</sub>CH<sub>2</sub>N(CH<sub>3</sub>)NO<sub>2</sub> cannot undergo photolysis in the daytime. Comparisons among the reactions of (CH<sub>3</sub>)<sub>2</sub>N, (CH<sub>3</sub>CH<sub>2</sub>)<sub>2</sub>N and CH<sub>3</sub>CH<sub>2</sub>NCH<sub>3</sub> with NO, NO<sub>2</sub> and O<sub>2</sub> indicate that the asymmetric substituted alkyl groups will play a notable role in the formation of stable products.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"267 ","pages":"Article 106420"},"PeriodicalIF":1.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The vertically time-dependent aerosol effect on marine water clouds
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-02-01 DOI: 10.1016/j.jastp.2025.106453
Hui Lu , Hui Zhao , Kanike Raghavendra Kumar , Honglin Pan
The aerosol-cloud interactions importantly influence the energy and water cycle of Earth-atmosphere system. The uncertainty of climate models is partly due to the lack of large-scale observational constraints of interaction between aerosol and water cloud. Based on CATS lidar time-resolved observations over the global marine region during 2015–2017, this study investigates the vertical effect of aerosol on marine water clouds, and evaluates the covariate influence of meteorological factors combined with European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis meteorological data. The mutual roles between aerosols as cloud condensation nucleation (CCN) and meteorological variables (temperature and relative humidity) contribute to the non-linear relationship of interactions between aerosol and water clouds. The results provide effective constraints for the parameterizations of aerosol-cloud interactions in current climate models.
{"title":"The vertically time-dependent aerosol effect on marine water clouds","authors":"Hui Lu ,&nbsp;Hui Zhao ,&nbsp;Kanike Raghavendra Kumar ,&nbsp;Honglin Pan","doi":"10.1016/j.jastp.2025.106453","DOIUrl":"10.1016/j.jastp.2025.106453","url":null,"abstract":"<div><div>The aerosol-cloud interactions importantly influence the energy and water cycle of Earth-atmosphere system. The uncertainty of climate models is partly due to the lack of large-scale observational constraints of interaction between aerosol and water cloud. Based on CATS lidar time-resolved observations over the global marine region during 2015–2017, this study investigates the vertical effect of aerosol on marine water clouds, and evaluates the covariate influence of meteorological factors combined with European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis meteorological data. The mutual roles between aerosols as cloud condensation nucleation (CCN) and meteorological variables (temperature and relative humidity) contribute to the non-linear relationship of interactions between aerosol and water clouds. The results provide effective constraints for the parameterizations of aerosol-cloud interactions in current climate models.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106453"},"PeriodicalIF":1.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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Journal of Atmospheric and Solar-Terrestrial Physics
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