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Zhang H, Tang H, Zhang W. Aurora retrieval in all-sky images based on hash vision transformer. Heliyon 2023; 9:e20609. [PMID: 37916095 PMCID: PMC10616155 DOI: 10.1016/j.heliyon.2023.e20609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023] Open
Abstract
Auroras are bright occurrences when high-energy particles from the magnetosphere and solar wind enter Earth's atmosphere through the magnetic field and collide with atoms in the upper atmosphere. The morphological and temporal characteristics of auroras are essential for studying large-scale magnetospheric processes. While auroras are visible to the naked eye from the ground, scientists use deep learning algorithms to analyze all-sky images to understand this phenomenon better. However, the current algorithms face challenges due to inefficient utilization of global features and neglect the excellent fusion of local and global feature representations extracted from aurora images. Hence, this paper introduces a Hash-Transformer model based on Vision Transformer for aurora retrieval from all-sky images. Experimental results based on real-world data demonstrate that the proposed method effectively improves aurora image retrieval performance. It provides a new avenue to study aurora phenomena and facilitates the development of related fields.
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Affiliation(s)
- Hengyue Zhang
- School of Information Science and Engineering, Qilu Normal University, Jinan, 250200, China
| | - Hailiang Tang
- School of Information Science and Engineering, Qilu Normal University, Jinan, 250200, China
| | - Wenxiao Zhang
- School of Finance and Economics, Shandong University of Engineering and Vocational Technology, Jinan, China
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Montesinos CA, Khalid R, Cristea O, Greenberger JS, Epperly MW, Lemon JA, Boreham DR, Popov D, Gorthi G, Ramkumar N, Jones JA. Space Radiation Protection Countermeasures in Microgravity and Planetary Exploration. Life (Basel) 2021; 11:life11080829. [PMID: 34440577 PMCID: PMC8398261 DOI: 10.3390/life11080829] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Space radiation is one of the principal environmental factors limiting the human tolerance for space travel, and therefore a primary risk in need of mitigation strategies to enable crewed exploration of the solar system. METHODS We summarize the current state of knowledge regarding potential means to reduce the biological effects of space radiation. New countermeasure strategies for exploration-class missions are proposed, based on recent advances in nutrition, pharmacologic, and immune science. RESULTS Radiation protection can be categorized into (1) exposure-limiting: shielding and mission duration; (2) countermeasures: radioprotectors, radiomodulators, radiomitigators, and immune-modulation, and; (3) treatment and supportive care for the effects of radiation. Vehicle and mission design can augment the overall exposure. Testing in terrestrial laboratories and earth-based exposure facilities, as well as on the International Space Station (ISS), has demonstrated that dietary and pharmacologic countermeasures can be safe and effective. Immune system modulators are less robustly tested but show promise. Therapies for radiation prodromal syndrome may include pharmacologic agents; and autologous marrow for acute radiation syndrome (ARS). CONCLUSIONS Current radiation protection technology is not yet optimized, but nevertheless offers substantial protection to crews based on Lunar or Mars design reference missions. With additional research and human testing, the space radiation risk can be further mitigated to allow for long-duration exploration of the solar system.
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Affiliation(s)
| | - Radina Khalid
- School of Engineering, Rice University, Houston, TX 77005, USA;
| | - Octav Cristea
- Department of Surgery, Emory University School of Medicine, Atlanta, GA 30322, USA;
| | - Joel S. Greenberger
- Department of Radiation Oncology, University of Pittsburg Medical Center, Pittsburgh, PA 15213, USA; (J.S.G.); (M.W.E.)
| | - Michael W. Epperly
- Department of Radiation Oncology, University of Pittsburg Medical Center, Pittsburgh, PA 15213, USA; (J.S.G.); (M.W.E.)
| | - Jennifer A. Lemon
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, ON P3E 2C6, Canada; (J.A.L.); (D.R.B.)
| | - Douglas R. Boreham
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, ON P3E 2C6, Canada; (J.A.L.); (D.R.B.)
| | - Dmitri Popov
- Advanced Medical Technologies and Systems Inc., Richmond Hill, ON L4B 1N1, Canada;
| | | | - Nandita Ramkumar
- Center for Space Medicine, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Jeffrey A. Jones
- Center for Space Medicine, Department of Urology, Baylor College of Medicine, Houston, TX 77030, USA
- Correspondence:
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Multifractal Characteristics of Geomagnetic Field Fluctuations for the Northern and Southern Hemispheres at Swarm Altitude. ENTROPY 2021; 23:e23050558. [PMID: 33946286 PMCID: PMC8146999 DOI: 10.3390/e23050558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 11/17/2022]
Abstract
This paper explores the spatial variations of the statistical scaling features of low to high latitude geomagnetic field fluctuations at Swarm altitude. The data for this study comes from the vector field magnetometer onboard Swarm A satellite, measured at low resolution (1 Hz) for one year (from 9 March 2016, to 9 March 2017). We estimated the structure-function scaling exponents using the p-leaders discrete wavelet multifractal technique, from which we obtained the singularity spectrum related to the magnetic fluctuations in the North-East-Center (NEC) coordinate system. From this estimation, we retain just the maximal fractal subset, associated with the Hurst exponent H. Here we present thresholding for two levels of the Auroral Electrojet index and almost the whole northern and southern hemispheres, the Hurst exponent, the structure-function scaling exponent of order 2, and the multifractal p-exponent width for the geomagnetic fluctuations. The latter quantifies the relevance of the multifractal property. Sometimes, we found negative values of H, suggesting a behavior similar to wave breaking or shocklet-like propagating front. Furthermore, we found some asymmetries in the magnetic field turbulence between the northern and southern hemispheres. These estimations suggest that different turbulent regimes of the geomagnetic field fluctuations exist along the Swarm path.
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Paty C, Arridge CS, Cohen IJ, DiBraccio GA, Ebert RW, Rymer AM. Ice giant magnetospheres. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190480. [PMID: 33161869 DOI: 10.1098/rsta.2019.0480] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/16/2020] [Indexed: 05/20/2023]
Abstract
The ice giant planets provide some of the most interesting natural laboratories for studying the influence of large obliquities, rapid rotation, highly asymmetric magnetic fields and wide-ranging Alfvénic and sonic Mach numbers on magnetospheric processes. The geometries of the solar wind-magnetosphere interaction at the ice giants vary dramatically on diurnal timescales due to the large tilt of the magnetic axis relative to each planet's rotational axis and the apparent off-centred nature of the magnetic field. There is also a seasonal effect on this interaction geometry due to the large obliquity of each planet (especially Uranus). With in situ observations at Uranus and Neptune limited to a single encounter by the Voyager 2 spacecraft, a growing number of analytical and numerical models have been put forward to characterize these unique magnetospheres and test hypotheses related to the magnetic structures and the distribution of plasma observed. Yet many questions regarding magnetospheric structure and dynamics, magnetospheric coupling to the ionosphere and atmosphere, and potential interactions with orbiting satellites remain unanswered. Continuing to study and explore ice giant magnetospheres is important for comparative planetology as they represent critical benchmarks on a broad spectrum of planetary magnetospheric interactions, and provide insight beyond the scope of our own Solar System with implications for exoplanet magnetospheres and magnetic reversals. This article is part of a discussion meeting issue 'Future exploration of ice giant systems'.
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Affiliation(s)
- Carol Paty
- Department of Earth Sciences, University of Oregon, 100 Cascade Hall, Eugene, OR 97403-1272, USA
| | - Chris S Arridge
- Department of Physics, Lancaster University, Bailrigg, Lancaster LA1 4YW, UK
| | - Ian J Cohen
- The Johns Hopkins University Applied Physics Laboratory, 11000 Johns Hopkins Road, Laurel, MD 20723, USA
| | - Gina A DiBraccio
- Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - Robert W Ebert
- Department of Space Research, Southwest Research Institute, San Antonio, TX 78228-0510, USA
- Department of Physics and Astronomy, University of Texas, San Antonio, TX 78249-0600, USA
| | - Abigail M Rymer
- The Johns Hopkins University Applied Physics Laboratory, 11000 Johns Hopkins Road, Laurel, MD 20723, USA
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Fletcher LN, de Pater I, Orton GS, Hofstadter MD, Irwin PGJ, Roman MT, Toledo D. Ice Giant Circulation Patterns: Implications for Atmospheric Probes. SPACE SCIENCE REVIEWS 2020. [PMID: 32165773 DOI: 10.1007/s11214-019-0619-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Atmospheric circulation patterns derived from multi-spectral remote sensing can serve as a guide for choosing a suitable entry location for a future in situ probe mission to the Ice Giants. Since the Voyager-2 flybys in the 1980s, three decades of observations from ground- and space-based observatories have generated a picture of Ice Giant circulation that is complex, perplexing, and altogether unlike that seen on the Gas Giants. This review seeks to reconcile the various competing circulation patterns from an observational perspective, accounting for spatially-resolved measurements of: zonal albedo contrasts and banded appearances; cloud-tracked zonal winds; temperature and para-H2 measurements above the condensate clouds; and equator-to-pole contrasts in condensable volatiles (methane, ammonia, and hydrogen sulphide) in the deeper troposphere. These observations identify three distinct latitude domains: an equatorial domain of deep upwelling and upper-tropospheric subsidence, potentially bounded by peaks in the retrograde zonal jet and analogous to Jovian cyclonic belts; a mid-latitude transitional domain of upper-tropospheric upwelling, vigorous cloud activity, analogous to Jovian anticyclonic zones; and a polar domain of strong subsidence, volatile depletion, and small-scale (and potentially seasonally-variable) convective activity. Taken together, the multi-wavelength observations suggest a tiered structure of stacked circulation cells (at least two in the troposphere and one in the stratosphere), potentially separated in the vertical by (i) strong molecular weight gradients associated with cloud condensation, and by (ii) transitions from a thermally-direct circulation regime at depth to a wave- and radiative-driven circulation regime at high altitude. The inferred circulation can be tested in the coming decade by 3D numerical simulations of the atmosphere, and by observations from future world-class facilities. The carrier spacecraft for any probe entry mission must ultimately carry a suite of remote-sensing instruments capable of fully constraining the atmospheric motions at the probe descent location.
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Affiliation(s)
- Leigh N Fletcher
- 1School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Imke de Pater
- 3Department of Astronomy, University of California, 501 Campbell Hall, Berkeley, CA 94720 USA
| | - Glenn S Orton
- 2Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 USA
| | - Mark D Hofstadter
- 2Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 USA
| | - Patrick G J Irwin
- 4Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, OX1 3PU UK
| | - Michael T Roman
- 1School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Daniel Toledo
- 4Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, OX1 3PU UK
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