Frontiers in Astronomy and Space Sciences最新文献_第2页

Evaluating the impact of commercial radio occultation data using the observation system simulation experiment tool for ionospheric electron density specification 利用观测系统模拟实验工具评估商业无线电掩星数据对电离层电子密度规格的影响

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-06-12 DOI: 10.3389/fspas.2024.1387941

Joseph Hughes, Ian Collett, Geoff Crowley, A. Reynolds, I. Azeem

{"title":"Evaluating the impact of commercial radio occultation data using the observation system simulation experiment tool for ionospheric electron density specification","authors":"Joseph Hughes, Ian Collett, Geoff Crowley, A. Reynolds, I. Azeem","doi":"10.3389/fspas.2024.1387941","DOIUrl":"https://doi.org/10.3389/fspas.2024.1387941","url":null,"abstract":"Decision makers must often choose how many sensors to deploy, of what types, and in what locations to meet a given operational or scientific outcome. An observation system simulation experiment (OSSE) is a numerical experiment that can provide critical decision support to these complex and expensive choices. An OSSE uses a “truth model” or “nature run” to simulate what an observation system would measure and then passes these measurements to an assimilation model. Then, the output of the assimilation model is compared to that of the truth model to assess improvement and the impact of the observation system. Orion Space Solutions has developed the OSSE tool (OSSET) to perform OSSEs for ionospheric electron density specification quickly and accurately. In this study, we use OSSET to predict the impact of adding commercial radio occultation total electron content (TEC) data to an assimilation model. We compare the OSSE’s predictions to the real performance at a group of validation ionosondes and find good agreement. We also demonstrate the global assessments that are possible with the OSSET using the improvement in critical frequency specification as an example. From this, we find that commercial radio occultation data can improve the critical frequency specification by nearly 20% at high latitudes, which are not covered by COSMIC-2. The commercial satellites are in sun-synchronous orbits with constant local times, and this improvement is concentrated at these local times.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141351932","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}

引用次数: 0

Response of the low latitude mesosphere and lower thermosphere to the recent sudden stratospheric warming events of 2017–18 and 2019 低纬度中间层和低热层对最近 2017-18 年和 2019 年平流层突然变暖事件的响应

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-06-10 DOI: 10.3389/fspas.2024.1308198

S. Sathishkumar, S. Sridharan, K. Krishnapriya, P. T. Patil

{"title":"Response of the low latitude mesosphere and lower thermosphere to the recent sudden stratospheric warming events of 2017–18 and 2019","authors":"S. Sathishkumar, S. Sridharan, K. Krishnapriya, P. T. Patil","doi":"10.3389/fspas.2024.1308198","DOIUrl":"https://doi.org/10.3389/fspas.2024.1308198","url":null,"abstract":"Upper mesospheric wind data acquired by the medium frequency radar at Kolhapur (16.7oN, 74.2oE) and Modern–Era Retrospective analysis for Research and Application version 2 (MERRA-2) temperature and wind reanalysis datasets are used to investigate the dynamical response of the low-latitude middle atmosphere to the sudden stratospheric warming (SSW) events that occurred during the 2017–18 and 2018–19 winters. When the amplitude of the high-latitude stratospheric planetary wave (PW) of zonal wavenumber one reduces considerably with the onset of the SSW event, the low-latitude mesospheric PW over Kolhapur also shows a considerable reduction in the PW activity. It is noteworthy that the upper mesospheric winds are eastward for approximately 3 weeks after the onset of SSW. The reduced PW activity is associated with the enhanced gravity wave activity in the meridional wind during the SSW 2018–19 event. The plane of propagation of gravity waves obtained from the perturbation ellipse method suggests that their predominant plane of propagation is in the north–south direction. The persistence of the eastward winds is suggested to be due to the interaction of the northward propagating gravity waves with the mean flow, leading to the eastward acceleration due to the Coriolis force.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141361772","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}

引用次数: 0

Rapid multi-band space-based optical timing: revolutionizing accretion physics 快速多波段天基光学计时：吸积物理学的革命性变革

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-06-06 DOI: 10.3389/fspas.2024.1401787

Krista Lynne Smith

引用次数: 0

Hetero-bonding strength investigation into opto-mechanical interface 光机电界面异键强度研究

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-05-23 DOI: 10.3389/fspas.2024.1406090

Haifei Hu, Di Zhou, Chenchen Zhao, E. Qi, Xiao Luo

引用次数: 0

The 2023 GEM climate survey: results and recommendations 2023 年 GEM 气候调查：结果与建议

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-05-22 DOI: 10.3389/fspas.2024.1395896

Connor O’Brien, Brian M. Walsh, Sarah K. Vines, Deborah Carr, Megan Segoshi

{"title":"The 2023 GEM climate survey: results and recommendations","authors":"Connor O’Brien, Brian M. Walsh, Sarah K. Vines, Deborah Carr, Megan Segoshi","doi":"10.3389/fspas.2024.1395896","DOIUrl":"https://doi.org/10.3389/fspas.2024.1395896","url":null,"abstract":"In order to help inform efforts to fulfill the National Science Foundation (NSF) Geospace Environment Modeling (GEM) community’s ethical goal toward pursuing diversity, equity, inclusion, and justice (DEIJ) the authors administered the 2023 GEM Climate Survey to attendees of the 2023 GEM Workshop. Its main goals were to 1) obtain organized demographic information about the GEM community, and 2) to provide a quantitative assessment of the GEM community’s perceptions of its own culture primarily with respect to inclusion and belonging. Responses indicate the GEM community is comparable or slightly more diverse than heliophysics as a whole and the American Geophysical Union (AGU) general membership, but still not close to reflecting the population of the United States or the world. The average responses to survey items about feelings of belonging in the GEM community indicate that members feel they belong in the GEM community, that the GEM community climate is broadly inclusive, and that efforts to support that cultural climate are improving over time. This is true across the entire population regardless of career stage, as well as for female respondents; Lesbian, Gay, Bisexual, Transgender, Queer/Questioning, Pansexual, Asexual (LGBTQPA+) respondents; Asian/Asian Subcontinent respondents; and non-Asian respondents of color. Division of the dataset into subgroups also indicates work to build a fully inclusive community is not complete, particularly with respect to workplace hostility these groups witness. This report recommends continuing work to capture the time history of demographics and trends in the community culture in response to inclusion efforts and initiatives.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141112473","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}

引用次数: 0

Electron cyclotron maser instability by evolving fast electron beams in the flare loops 耀斑环路中演化的快速电子束导致的电子回旋 maser 不稳定性

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-05-21 DOI: 10.3389/fspas.2024.1404145

J. Tang, D. J. Wu, L. Chen, C. Tan, J. B. Wang

{"title":"Electron cyclotron maser instability by evolving fast electron beams in the flare loops","authors":"J. Tang, D. J. Wu, L. Chen, C. Tan, J. B. Wang","doi":"10.3389/fspas.2024.1404145","DOIUrl":"https://doi.org/10.3389/fspas.2024.1404145","url":null,"abstract":"The electron cyclotron maser instability (ECMI) stands as a pivotal coherent radio emission mechanism widely implicated in various astrophysical phenomena. In the context of solar activity, ECMI is primarily instigated by energetic electrons generated during solar eruptions, notably flares. These electrons, upon leaving the acceleration region, traverse the solar atmosphere, forming fast electron beams (FEBs) along magnetic field lines. It is widely accepted that as these FEBs interact with the ambient plasma and magnetic fields, they give rise to radio and hard X-ray emission. Throughout their journey in the plasma, FEBs undergo modifications in their energy spectrum and velocity spatial distribution due to diverse energy loss mechanisms and changes in ambient plasma parameters. In this study, we delve into the impact of the evolving energy spectrum and velocity anisotropic distribution of FEBs on ECMI during their propagation in flare loops. Our findings indicate that if we solely consider the progressively flattened lower energy cutoff behavior as FEBs descend along flare loops, the growth rates of ECMI decrease accordingly. However, when accounting for the evolution of ambient magnetic plasma parameters, the growth rates of ECMI increase as FEBs delve into denser atmosphere. This underscores the significant influence of the energy spectrum and velocity anisotropy distribution evolution of FEBs on ECMI. Our study sheds light on a more comprehensive understanding of the dynamic spectra of solar radio emissions.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141116720","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}

引用次数: 0

Taphonomy of biosignatures in carbonate nodules from the Mars-analog Qaidam Basin: constraints from microscopic, spectroscopic, and geochemical analyses 与火星类似的盖达姆盆地碳酸盐结核中的生物特征：显微镜、光谱和地球化学分析的制约因素

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-05-21 DOI: 10.3389/fspas.2024.1291847

Yan Chen, Zongjun Yin, Wei Lin

{"title":"Taphonomy of biosignatures in carbonate nodules from the Mars-analog Qaidam Basin: constraints from microscopic, spectroscopic, and geochemical analyses","authors":"Yan Chen, Zongjun Yin, Wei Lin","doi":"10.3389/fspas.2024.1291847","DOIUrl":"https://doi.org/10.3389/fspas.2024.1291847","url":null,"abstract":"Early diagenetic nodules with low permeable and weather-resistant structures are considered to be favorable for biosignature preservation. Numerous nodular structures forming in neutral-to-alkaline and saline diagenetic fluids were previously identified at Gale Crater on Mars, yet their astrobiological significance remains poorly understood. In the Mars-like western Qaidam Basin, China, there are a multitude of carbonate nodules which can be analogous to those found at Gale Crater on Mars in terms of their formation backgrounds and post-depositional processes. In this study, we combine microscopic, spectroscopic, and geochemical methods to characterize the biosignature preservation of the Qaidam nodules. Carbonaceous materials, including an organic annulus inferred to be a fossil spore or algal filament microfossil, are observed in the Qaidam nodules. The total organic carbon contents of the Qaidam nodules are slightly higher than those of the surrounding fluvio-lacustrine deposits, suggesting that early diagenesis of the Qaidam nodules might facilitate the rapid entombment of biomass within magnesium carbonate or aragonite matrixes before complete degradation. The carbonate matrix showing alternating micritic and sparry layers as well as enrichment of 13C could have a physicochemical origin though the possibilities of biomineralization and organomineralization cannot be entirely ruled out. The I-1350/1,600 distribution of carbonaceous materials implies the existence of carbon precursors of various subcellular components or coexisting organisms in pore waters. Organic carbon isotopes indicate the carbon fixation pathways such as the Calvin cycle or the Wood-Ljungdahl pathway utilized by organisms in pore waters. The findings of this study shed light into the taphonomy and detection of biosignatures in terrestrial playa nodules, with potential applications for biosignature exploration on Mars.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141113517","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}

引用次数: 0

The temporal variability of Io’s hotspots 木卫二热点的时变性

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-05-20 DOI: 10.3389/fspas.2024.1369472

A. Mura, F. Zambon, F. Tosi, R. M. C. Lopes, J. Rathbun, M. Pettine, A. Adriani, F. Altieri, M. Ciarniello, A. Cicchetti, G. Filacchione, D. Grassi, R. Noschese, A. Migliorini, G. Piccioni, C. Plainaki, R. Sordini, G. Sindoni, D. Turrini

{"title":"The temporal variability of Io’s hotspots","authors":"A. Mura, F. Zambon, F. Tosi, R. M. C. Lopes, J. Rathbun, M. Pettine, A. Adriani, F. Altieri, M. Ciarniello, A. Cicchetti, G. Filacchione, D. Grassi, R. Noschese, A. Migliorini, G. Piccioni, C. Plainaki, R. Sordini, G. Sindoni, D. Turrini","doi":"10.3389/fspas.2024.1369472","DOIUrl":"https://doi.org/10.3389/fspas.2024.1369472","url":null,"abstract":"We investigate the variability of the power emission of Io’s hotspots by using recent Juno/JIRAM infrared observations. The Jovian Infrared Auroral Mapper (JIRAM) is an imaging spectrometer which began observing Jupiter in August 2016. Although observing Jupiter’s moons is not its primary objective, JIRAM can use the frequent opportunities to observe Io (up to once per orbit) to gather infrared images and spectra of its surface. The present study uses the data acquired by JIRAM during the last 2 years, including the location and morphology of Io’s hotspots, and the temporal variability of the total output. A new photometric model for the hotspots and the dayside surface has been developed, which permits us to disentangle the temporal variability from the changes in the observation geometry. While the latitudinal dependence of the power output is not well constrained, low-latitude hotspots show a significantly more intense temporal variability and greater temperature.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141121256","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}

引用次数: 0

Editorial: The future of space physics 2022 社论：2022 年空间物理学的未来

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-04-24 DOI: 10.3389/fspas.2024.1403148

J. Borovsky, G. Delzanno, Philip J. Erickson, A. J. Halford, Benoit Lavraud, Sabrina Savage

引用次数: 0

Fundamental physics studies in time domain and multi-messenger astronomy 时域和多信使天文学中的基础物理学研究

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-04-16 DOI: 10.3389/fspas.2024.1384587

Chris Fryer

引用次数: 0