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Showing 1 - 200 of 3030 Journals sorted alphabetically
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 20, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 16, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 79, SJR: 1.109, h-index: 94)
Accounting Forum     Hybrid Journal   (Followers: 22, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 27, SJR: 2.515, h-index: 90)
Achievements in the Life Sciences     Open Access   (Followers: 4)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 5, SJR: 0.338, h-index: 19)
Acta Astronautica     Hybrid Journal   (Followers: 303, SJR: 0.726, h-index: 43)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Biomaterialia     Hybrid Journal   (Followers: 25, SJR: 2.02, h-index: 104)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription  
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.172, h-index: 29)
Acta Haematologica Polonica     Free   (SJR: 0.123, h-index: 8)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.604, h-index: 38)
Acta Materialia     Hybrid Journal   (Followers: 196, SJR: 3.683, h-index: 202)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.615, h-index: 21)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.442, h-index: 21)
Acta Oecologica     Hybrid Journal   (Followers: 9, SJR: 0.915, h-index: 53)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription   (Followers: 1)
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 3, SJR: 0.311, h-index: 16)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2)
Acta Poética     Open Access   (Followers: 4)
Acta Psychologica     Hybrid Journal   (Followers: 21, SJR: 1.365, h-index: 73)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 5, SJR: 1.059, h-index: 77)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 4)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 3)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.383, h-index: 19)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 2)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 5, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 4, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 4)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.967, h-index: 57)
Addictive Behaviors     Hybrid Journal   (Followers: 15, SJR: 1.514, h-index: 92)
Addictive Behaviors Reports     Open Access   (Followers: 5)
Additive Manufacturing     Hybrid Journal   (Followers: 7, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 120, SJR: 5.2, h-index: 222)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.265, h-index: 53)
Advanced Powder Technology     Hybrid Journal   (Followers: 16, SJR: 0.739, h-index: 33)
Advances in Accounting     Hybrid Journal   (Followers: 8, SJR: 0.299, h-index: 15)
Advances in Agronomy     Full-text available via subscription   (Followers: 15, SJR: 2.071, h-index: 82)
Advances in Anesthesia     Full-text available via subscription   (Followers: 24, SJR: 0.169, h-index: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 3)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 6, SJR: 1.054, h-index: 35)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 10, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 21, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 16, SJR: 3.31, h-index: 42)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.277, h-index: 43)
Advances in Botanical Research     Full-text available via subscription   (Followers: 3, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 26, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 24, SJR: 0.183, h-index: 23)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.665, h-index: 29)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 8, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 28, SJR: 0.938, h-index: 33)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18, SJR: 2.314, h-index: 130)
Advances in Computers     Full-text available via subscription   (Followers: 16, SJR: 0.223, h-index: 22)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in Digestive Medicine     Open Access   (Followers: 4)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Ecological Research     Full-text available via subscription   (Followers: 39, SJR: 3.25, h-index: 43)
Advances in Engineering Software     Hybrid Journal   (Followers: 25, SJR: 0.486, h-index: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 38, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 3)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 41, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Genetics     Full-text available via subscription   (Followers: 15, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 18, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.497, h-index: 31)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 33, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 3, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 4)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 4)
Advances in Life Course Research     Hybrid Journal   (Followers: 7, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16, SJR: 1.645, h-index: 45)
Advances in Mathematics     Full-text available via subscription   (Followers: 10, SJR: 3.261, h-index: 65)
Advances in Medical Sciences     Hybrid Journal   (Followers: 5, SJR: 0.489, h-index: 25)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.44, h-index: 51)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 21)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 10)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 6, SJR: 0.324, h-index: 8)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 3)
Advances in Oncobiology     Full-text available via subscription   (Followers: 3)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15, SJR: 2.885, h-index: 45)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 7, SJR: 2.37, h-index: 73)
Advances in Pediatrics     Full-text available via subscription   (Followers: 20, SJR: 0.4, h-index: 28)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 14)
Advances in Pharmacology     Full-text available via subscription   (Followers: 13, SJR: 1.718, h-index: 58)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 7, SJR: 0.384, h-index: 26)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.248, h-index: 11)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 17, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 56)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5, SJR: 0.478, h-index: 32)
Advances in Radiation Oncology     Open Access  
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 1, SJR: 0.1, h-index: 2)
Advances in Space Research     Full-text available via subscription   (Followers: 332, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 7)
Advances in Surgery     Full-text available via subscription   (Followers: 6, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 28, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 14)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 12)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 1.878, h-index: 68)
Advances in Water Resources     Hybrid Journal   (Followers: 42, SJR: 2.408, h-index: 94)
Aeolian Research     Hybrid Journal   (Followers: 5, SJR: 0.973, h-index: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 304, SJR: 0.816, h-index: 49)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.318, h-index: 36)
African J. of Emergency Medicine     Open Access   (Followers: 4, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 7, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 390, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 15, SJR: 2.18, h-index: 116)
Agricultural Systems     Hybrid Journal   (Followers: 29, SJR: 1.275, h-index: 74)
Agricultural Water Management     Hybrid Journal   (Followers: 36, SJR: 1.546, h-index: 79)
Agriculture and Agricultural Science Procedia     Open Access  
Agriculture and Natural Resources     Open Access   (Followers: 1)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 48, SJR: 1.879, h-index: 120)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.434, h-index: 14)
Air Medical J.     Hybrid Journal   (Followers: 3, SJR: 0.234, h-index: 18)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.285, h-index: 3)
Alcohol     Hybrid Journal   (Followers: 9, SJR: 0.922, h-index: 66)
Alcoholism and Drug Addiction     Open Access   (Followers: 5)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.436, h-index: 12)
Alexandria J. of Medicine     Open Access  
Algal Research     Partially Free   (Followers: 7, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 5, SJR: 0.776, h-index: 35)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 6, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 45, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 5)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 3)
American Heart J.     Hybrid Journal   (Followers: 45, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 47, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 34, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 6, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 14, SJR: 1.653, h-index: 93)
American J. of Human Genetics     Hybrid Journal   (Followers: 32, SJR: 8.769, h-index: 256)
American J. of Infection Control     Hybrid Journal   (Followers: 25, SJR: 1.259, h-index: 81)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 31, SJR: 2.313, h-index: 172)
American J. of Medicine     Hybrid Journal   (Followers: 48, SJR: 2.023, h-index: 189)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 174, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 51, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 2)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.249, h-index: 88)
American J. of Otolaryngology     Hybrid Journal   (Followers: 22, SJR: 0.59, h-index: 45)
American J. of Pathology     Hybrid Journal   (Followers: 23, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 21, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 32, SJR: 1.286, h-index: 125)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 13, SJR: 0.653, h-index: 70)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 5)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 52, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 3)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 2, SJR: 0.209, h-index: 27)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription   (SJR: 0.104, h-index: 3)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 2, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 38, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 154, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 7, SJR: 0.18, h-index: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 10)
Anesthésie & Réanimation     Full-text available via subscription  
Anesthesiology Clinics     Full-text available via subscription   (Followers: 21, SJR: 0.421, h-index: 40)
Angiología     Full-text available via subscription   (SJR: 0.124, h-index: 9)
Angiologia e Cirurgia Vascular     Open Access  
Animal Behaviour     Hybrid Journal   (Followers: 143, SJR: 1.907, h-index: 126)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 5, SJR: 1.151, h-index: 83)
Animal Reproduction Science     Hybrid Journal   (Followers: 5, SJR: 0.711, h-index: 78)
Annales d'Endocrinologie     Full-text available via subscription   (SJR: 0.394, h-index: 30)
Annales d'Urologie     Full-text available via subscription  
Annales de Cardiologie et d'Angéiologie     Full-text available via subscription   (SJR: 0.177, h-index: 13)
Annales de Chirurgie de la Main et du Membre Supérieur     Full-text available via subscription  
Annales de Chirurgie Plastique Esthétique     Full-text available via subscription   (Followers: 2, SJR: 0.354, h-index: 22)
Annales de Chirurgie Vasculaire     Full-text available via subscription   (Followers: 1)

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Journal Cover Advances in Space Research
  [SJR: 0.606]   [H-I: 65]   [332 followers]  Follow
   Full-text available via subscription Subscription journal  (Not entitled to full-text)
   ISSN (Print) 0273-1177
   Published by Elsevier Homepage  [3030 journals]
  • EUV data processing methods of the Solar Auto-Calibrating EUV
           Spectrometers (SolACES) aboard the International Space Station
    • Authors: Robert Schäfer; Gerhard Schmidtke; Thomas Strahl; Marcel Pfeifer; Raimund Brunner
      Pages: 2207 - 2228
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Robert Schäfer, Gerhard Schmidtke, Thomas Strahl, Marcel Pfeifer, Raimund Brunner
      Context Since 2008, the Solar Auto-Calibrating EUV Spectrometer (SolACES) experiment monitors the solar EUV radiation. SolACES is part of the SOLAR mission, a device mounted on the COLUMBUS module on the International Space Station (ISS). The SolACES device is capable of measuring the EUV radiation of the full solar disk, with three grazing incidence spectrometers, covering the spectral range from 17 to 135nm. Issue Degradation and ageing effects of hardware components are a major issue in the field of EUV measurements. In addition, propellant pollution from ISS logistic vehicles strongly complicate the instrumental operation as well as the data evaluation. To correct these effects, two double ionization chambers have been mounted onto the device frame. These are considered as a primary radiometric detector standard. By refilling the ionization chambers, the absolute EUV flux can be measured. Efficiency changes, being a severe issue in the field of measurements of EUV radiation, can corrected via an in-situ auto-calibration. The use of this method requires a thorough understanding of electron multiplier degradation and processes inside an ionization chamber. Aims The main focus of this paper lies on the correction of hardware ageing effects in the spectrometer readout, as well as on the usage of ionization chamber measurements for absolute calibration. Additionally, we intend to demonstrate the long term stability of the in-orbit calibration principle of EUV spectrometers with double ionization chambers. Methods In this paper, we first briefly present the instrument and its components. Second, we list, explain, and correct various degradation effects within the spectrometer units. The core part are the adjustments between spectrometer and ionization chamber data, for calibration purposes. Results and perspectives The proof of concept of the in-orbit calibration, via ionization chambers, is given, by intercomparison of EUV data from SolACES with other experiments, over almost one decade. The presented data can be used for further investigations in climate modelling, as well as contribute to a SSI composite.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.036
  • Hemispheric asymmetries in the ionosphere response observed during the
           high-speed solar wind streams of the 24–28 August 2010
    • Authors: N. Zaourar; C. Amory-Mazaudier; R. Fleury
      Pages: 2229 - 2247
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): N. Zaourar, C. Amory-Mazaudier, R. Fleury
      This paper presents the geomagnetic and ionospheric responses to a high speed solar wind stream (HSS) impacting the magnetosphere on 24 August 2010. We focus our study on the interhemispheric conjugated behavior. The solar wind speed remained very high during 5days from 24 to 28 August 2010. By using magnetometer and ground-based GPS data from various approximately conjugated magnetic observatories and GPS stations, we studied the hemispheric asymmetries in the magnetic signature, Vertical Total Electron Content (VTEC) and scintillation activity during this HSS event. Geomagnetic activity reveals larger disturbances in amplitude in the Northern Hemisphere (NH) than in the southern Hemisphere (SH), and stronger asymmetries at higher latitudes, than at lower latitudes, between the conjugate observatories. VTEC variations reveal large increases in amplitude in the NH; while these effects are less pronounced in the SH. We investigate also the GPS scintillation activities occurring in the conjugated polar regions under HSSs conditions. At auroral latitudes, our results show a good correlation between the rate of VTEC index (ROTI) and auroral Al index, with more intense phase fluctuations in the NH.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.01.048
  • Depletion of the outer radiation belt during low activity years
    • Authors: Leonid L. Lazutin
      Pages: 2248 - 2254
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Leonid L. Lazutin
      During the years of high and moderate activity, the energetic flux of electrons at geostationary region increases compensated by the losses and as a result, the overall level of the population persists. The transitions from high to low intensity and back by 3–4 orders of magnitude are fast within hours and caused by the magnetic disturbances, storms and substorms. During the years of the low activity, the balance of increases and losses is violated; the whole flux of electrons is reduced. Particularly noticeable was the devastation of the outer belt during the minimum of 2009–2010years. The slow type of decreases became most active. The transition from the fast type to the slow type of decreases was created by the prolonged periods of the low substorm activity. The slow type of intensity decreases is mostly probable caused by the losses on the magnetopause.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.008
  • Investigation of the radiation properties of magnetospheric ELF waves
           induced by modulated ionospheric heating
    • Authors: Feng Wang; Binbin Ni; Zhengyu Zhao; Shufan Zhao; Guangxin Zhao; Min Wang
      Pages: 2255 - 2264
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Feng Wang, Binbin Ni, Zhengyu Zhao, Shufan Zhao, Guangxin Zhao, Min Wang
      Electromagnetic extremely low frequency (ELF) waves play an important role in modulating the Earth’s radiation belt electron dynamics. High-frequency (HF) modulated heating of the ionosphere acts as a viable means to generate artificial ELF waves. The artificial ELF waves can reside in two different plasma regions in geo-space by propagating in the ionosphere and penetrating into the magnetosphere. As a consequence, the entire trajectory of ELF wave propagation should be considered to carefully analyze the wave radiation properties resulting from modulated ionospheric heating. We adopt a model of full wave solution to evaluate the Poynting vector of the ELF radiation field in the ionosphere, which can reflect the propagation characteristics of the radiated ELF waves along the background magnetic field and provide the initial condition of waves for ray tracing in the magnetosphere. The results indicate that the induced ELF wave energy forms a collimated beam and the center of the ELF radiation shifts obviously with respect to the ambient magnetic field with the radiation power inversely proportional to the wave frequency. The intensity of ELF wave radiation also shows a weak correlation with the size of the radiation source or its geographical location. Furthermore, the combination of ELF propagation in the ionosphere and magnetosphere is proposed on basis of the characteristics of the ELF radiation field from the upper ionospheric boundary and ray tracing simulations are implemented to reasonably calculate magnetospheric ray paths of ELF waves induced by modulated ionospheric heating.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.009
  • Multifractal characteristics of magnetospheric dynamics and their
           relationship with sunspot cycle
    • Authors: Sumesh Gopinath; P.R. Prince
      Pages: 2265 - 2278
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Sumesh Gopinath, P.R. Prince
      Multifractal analysis deals with a process whose power-law scaling behavior is a nonlinear function of statistical moments having a spectrum of scaling exponents. In contrast, monofractal process has a scaling behavior which is a linear function of moments with a single scaling exponent. In this study, multifractal analysis of complex magnetosphere using box-counting approach has been considered for a better understanding of intermittent and persistent features, focusing on the auroral electrojet index (AE), SYM-H and Dst indices. For the analysis, 1-min AE, SYM-H and Dst indices are taken during the interval 1985–2007. We compare the sunspot cycle dependence of self-similarity and multifractality of magnetospheric proxies such as AE, SYM-H and Dst indices, using both monofractal and multifractal paradigms. The results indicate that monofractal features of AE, SYM-H and Dst indices are solar activity dependent. But, while analyzing the multifractal features, multifractal spectrum of AE index is less dependent on solar activity when compared with that of SYM-H and Dst indices. This implies that, other than solar wind forcing, certain complex phenomena of internal origin also modify the dynamics of geomagnetic fluctuations in the high-latitude auroral region.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.011
  • Seasonal characteristics of COSMIC measurements over Indian sub-continent
           during different phases of solar activity
    • Authors: Malini Aggarwal; D.K. Sharma
      Pages: 2279 - 2294
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Malini Aggarwal, D.K. Sharma
      The seasonal characteristics of F2 region is investigated using peak electron density (NmF2) and corresponding altitude (hmF2) measurements obtained by COSMIC observations over Indian sub-continent (Geog. 5–40°N and 60–100°E) for the complete mission during the solar cycle 24 (Apr, 2006–Dec, 2013). A stronger EIA is observed in summer and winter during high solar activity whereas occurs in equinoxes during all levels of solar activity. The noontime winter anomaly in NmF2 is absent/weaker during low (2006–2009)/high (2010–2013) solar activity over equator whereas is stronger in low and moderate solar activity (2006–2007 and 2010–2011) but absent in minimum and maximum (2008–2009 and 2012–2013) solar activity over low-latitude respectively. The higher hmF2 is observed over the equator throughout the day (equator: 230–415km and low-latitude: 220–340km). The observed parameters, NmF2 and hmF2 are compared with the IRI-modeled values using CCIR and URSI options. The comparison exhibits a higher discrepancy in NmF2 in nighttime and morning for equatorial and lower discrepancy for the whole day over the low-latitude whereas smaller (<20%) discrepancy exists in the hmF2 throughout the day using both IRI options. In conclusion, we found CCIR option in more agreement to the observed values for both equatorial and low-latitude regions respectively.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.018
  • Calculation of atmospheric ionization induced by electrons with
           non-vertical precipitation: Updated model CRAC-EPII
    • Authors: Anton Artamonov; Irina Mironova; Gennady Kovaltsov; Alexander Mishev; Evgenii Plotnikov; Natalia Konstantinova
      Pages: 2295 - 2300
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Anton Artamonov, Irina Mironova, Gennady Kovaltsov, Alexander Mishev, Evgenii Plotnikov, Natalia Konstantinova
      In this paper we present a method to compute ionization rates induced by relativistic electron precipitation with arbitrary incidence. Atmospheric ionization for monoenergetic ( > 100keV) relativistic electron precipitation including explicitly ionization by Bremsstrahlung radiation is considered. Two peaks of energy deposition in the atmosphere can be identified. The first ionization peak is related to direct ionization of primary relativistic electrons, while the second corresponds to Bremsstrahlung radiation. The ionization rates are presented us Look-up Tables for vertical, isotropic and angular distributions for 15 ° , 30 ° and 45 ° angles of electron incidence. A computation algorithm is provided to compute ionization for an arbitrary angular distribution of precipitation electrons.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.019
  • A severe negative response of the ionosphere to the intense geomagnetic
           storm on March 17, 2015 observed at mid- and low-latitude stations in the
           China zone
    • Authors: Guoqi Liu; Hua Shen
      Pages: 2301 - 2312
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Guoqi Liu, Hua Shen
      In this paper, the critical frequency of F2 layer of the ionosphere (foF2) and the total electron content (TEC) recorded at mid- and low-latitude observation sites near 120°E in the China zone were used to investigate the response to a severe geomagnetic storm on March 17, 2015 (the minimum Dst −223 nT at 23 UT). The results showed that the strong geomagnetic storm caused a massive effect on the ionosphere. The characteristics of foF2 and TEC did not show obvious perturbation during the main phase. Severe depletion of foF2 and TEC was observed at all stations during the storm recovery period. The maximum absolute discrepancy in TEC compared with the past 27-day average value was 78 TECU, and the minimum percentage deviations reached −71% at Fuzhou (26.1°N,119.3°E). The minimum percentage deviations of decrease in foF2 reached −65% at Sanya (18.1°N,109.3°E) and Mohe (53.5°N,122.3°E). This was an infrequent negative effect that foF2 and TEC sustained throughout the day with extremely low level on March 18. The O/N2 rate showed a distinct reduction on March 18 in the China zone, which may be mainly responsible for the severe depletion of foF2 and TEC. The spread-F seemed to be developed at first but was then suppressed to some extent during the main phase. During the recovery phase, the spread-F was suppressed at Sanya, while it developed at Wuhan and Mohe. The disturbance electric fields and thermospheric circulation may contribute to this phenomenon.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.021
  • Combined electromagnetic geophysical mapping at Arctic perennial saline
           springs: Possible applications for the detection of water in the shallow
           subsurface of Mars
    • Authors: C. Samson; J. Mah; T. Haltigin; S. Holladay; M. Ralchenko; W. Pollard; F.A. Monteiro Santos
      Pages: 2325 - 2334
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): C. Samson, J. Mah, T. Haltigin, S. Holladay, M. Ralchenko, W. Pollard, F.A. Monteiro Santos
      Perennial springs at the Gypsum Hill site on Axel Heiberg Island in the Canadian Arctic (79°24′N, 90°44′W) represent a high-fidelity analogue to hydrothermal systems that might exist on Mars. The springs were surveyed using an electromagnetic induction sounder (EMIS) and ground penetrating radar (GPR). Both instruments probed the subsurface to a depth of approximately 3m. Lateral EMIS soundings were performed every metre along a 400m long reconnaissance line roughly oriented SW-NE and extending through 23 active springs and 1 dry outlet to measure electrical conductivity. Two distinct zones were identified within the survey area on the basis of these data: in the southwest portion, sharp conductivity peaks correspond to isolated springs with well-defined outlets, flowing over dry rocky soil; in the northeast portion, the springs are fed by a pervasive network of saline fluids, resulting in high background readings and muddy surface conditions. These observations are consistent with vertical EMIS sounding data which showed that the brine body feeding the saline springs can be found closer to the ground surface towards the northeast portion of the survey site. In areas of high electrical conductivity, the GPR data exhibits strong scattering. The noisy areas are sharply defined and interpreted to correspond to narrow vertical conduits feeding individual spring outlets. The EMIS is a rugged instrument that could be included as payload in future rover-based Mars exploration missions aiming at probing the shallow subsurface for the presence of brine pockets.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.016
  • Atmospheric correction issues for retrieving total suspended matter
           concentrations in inland waters using OLI/Landsat-8 image
    • Authors: Nariane Bernardo; Fernanda Watanabe; Thanan Rodrigues; Enner Alcântara
      Pages: 2335 - 2348
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Nariane Bernardo, Fernanda Watanabe, Thanan Rodrigues, Enner Alcântara
      The atmospheric effects that influence on the signal registered by remote sensors might be minimized in order to provide reliable spectral information. In aquatic systems, the application of atmospheric correction aims to minimize such effects and avoid the under or overestimation of remote sensing reflectance (Rrs ). Accurately Rrs provides better information about the state of aquatic system, it means, establishing the concentration of aquatic compounds more precisely. The aim of this study is to evaluate the outputs from several atmospheric correction methods (Dark Object Subtraction – DOS; Quick Atmospheric Correction – QUAC; Fast Line-of-sight Atmospheric Analysis of Hypercubes – FLAASH; Atmospheric Correction for OLI ‘lite’ – ACOLITE, and Provisional Landsat-8 Surface Reflectance Algorithm – L8SR) in order to investigate the suitability of Rrs for estimating total suspended matter concentrations (TSM) in the Barra Bonita Hydroelectrical Reservoir. To establish TSM concentrations via atmospherically corrected Operational Land Imager (OLI) scene, the TSM retrieval model was calibrated and validated with in situ data. Thereby, the achieved results from TSM retrieval model application demonstrated that L8SR is able to provide the most suitable Rrs values for green and red spectral bands, and consequently, the lowest TSM retrieval errors (Mean Absolute Percentage Error about 10% and 12%, respectively). Retrieved Rrs from near infrared band is still a challenge for all the tested algorithms.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.017
  • Significance of high resolution GHRSST on prediction of Indian Summer
    • Authors: Buddhi Prakash Jangid; Prashant Kumar; Attada Raju; Raj Kumar
      Pages: 2349 - 2359
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Buddhi Prakash Jangid, Prashant Kumar, Attada Raju, Raj Kumar
      In this study, the Weather Research and Forecasting (WRF) model was used to assess the importance of very high resolution sea surface temperature (SST) on seasonal rainfall prediction. Two different SST datasets available from the National Centers for Environmental Prediction (NCEP) global model analysis and merged satellite product from Group for High Resolution SST (GHRSST) are used as a lower boundary condition in the WRF model for the Indian Summer Monsoon (ISM) 2010. Before using NCEP SST and GHRSST for model simulation, an initial verification of NCEP SST and GHRSST are performed with buoy measurements. It is found that approximately 0.4K root mean square difference (RMSD) in GHRSST and NCEP SST when compared with buoy observations available over the Indian Ocean during 01 May to 30 September 2010. Our analyses suggest that use of GHRSST as lower boundary conditions in the WRF model improve the low level temperature, moisture, wind speed and rainfall prediction over ISM region. Moreover, temporal evolution of surface parameters such as temperature, moisture and wind speed forecasts associated with monsoon is also improved with GHRSST forcing as a lower boundary condition. Interestingly, rainfall prediction is improved with the use of GHRSST over the Western Ghats, which mostly not simulated in the NCEP SST based experiment.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.025
  • Co-state initialization for the minimum-time low-thrust trajectory
    • Authors: Ehsan Taheri; Nan I. Li; Ilya Kolmanovsky
      Pages: 2360 - 2373
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Ehsan Taheri, Nan I. Li, Ilya Kolmanovsky
      This paper presents an approach for co-state initialization which is a critical step in solving minimum-time low-thrust trajectory optimization problems using indirect optimal control numerical methods. Indirect methods used in determining the optimal space trajectories typically result in two-point boundary-value problems and are solved by single- or multiple-shooting numerical methods. Accurate initialization of the co-state variables facilitates the numerical convergence of iterative boundary value problem solvers. In this paper, we propose a method which exploits the trajectory generated by the so-called pseudo-equinoctial and three-dimensional finite Fourier series shape-based methods to estimate the initial values of the co-states. The performance of the approach for two interplanetary rendezvous missions from Earth to Mars and from Earth to asteroid Dionysus is compared against three other approaches which, respectively, exploit random initialization of co-states, adjoint-control transformation and a standard genetic algorithm. The results indicate that by using our proposed approach the percent of the converged cases is higher for trajectories with higher number of revolutions while the computation time is lower. These features are advantageous for broad trajectory search in the preliminary phase of mission designs.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.010
  • Dynamics of motorized momentum exchange tether for payloads capture
    • Authors: Qilong Sun; Yanfang Liu; Naiming Qi; Yong Yang; Zhenpeng Chen
      Pages: 2374 - 2388
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Qilong Sun, Yanfang Liu, Naiming Qi, Yong Yang, Zhenpeng Chen
      The dynamics of motorized momentum exchange tether (MMET) during and after payloads capture is studied. The ideal velocities of payloads with same mass for capture are analyzed, and a mathematical model of capture is proposed. If the MMET captures the payloads at the ideal velocity, the MMET’s orbit and motion state are unchanged. However, considering that capture velocity error exists in practice, and analyzing the velocity error in relation to the payload approaching from the earth as an example, the impact on the MMET’s orbital parameters and state motion are investigated during payload capture for different capture velocity errors, including errors in magnitude and direction. The simulation results show that if the payload velocity has only magnitude error, the perigees remain overlapping and the semi-major axes of the changed orbits also continue to coincide after capture; however, the changes in other orbital parameters are approximately proportional to the error. If the payload velocity has both magnitude and direction errors, then all of the orbital parameters change, including the perigee and the direction of the semi-major axis. However, the normal velocity increment caused by the capture’s normal velocity error changes the orbital parameters far less than the tangential velocity increment.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.013
  • A star-photon sailcraft mission in the Alpha Centauri system
    • Authors: Tommaso Pino; Christian Circi
      Pages: 2389 - 2397
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Tommaso Pino, Christian Circi
      The recent findings of exoplanets have renewed interest in exploration missions of extra-solar star systems. In this context the binary star system of Alpha Centauri A/B plays a scientifically important role. The current paper aims at investigating the capture and the transfer trajectories from A to B performed by a stellar-photon sailcraft, which gives the best performance in long duration missions. The mission has been divided into four phases and minimum transfer time trajectories have been obtained by using a direct optimisation approach. Finally, a preliminary analysis in terms of Zero Velocity Curves has been carried out.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.014
  • A parallel algorithm for the initial screening of space debris collisions
           prediction using the SGP4/SDP4 models and GPU acceleration
    • Authors: Mingpei Lin; Ming Xu; Xiaoyu Fu
      Pages: 2398 - 2406
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Mingpei Lin, Ming Xu, Xiaoyu Fu
      Currently, a tremendous amount of space debris in Earth’s orbit imperils operational spacecraft. It is essential to undertake risk assessments of collisions and predict dangerous encounters in space. However, collision predictions for an enormous amount of space debris give rise to large-scale computations. In this paper, a parallel algorithm is established on the Compute Unified Device Architecture (CUDA) platform of NVIDIA Corporation for collision prediction. According to the parallel structure of NVIDIA graphics processors, a block decomposition strategy is adopted in the algorithm. Space debris is divided into batches, and the computation and data transfer operations of adjacent batches overlap. As a consequence, the latency to access shared memory during the entire computing process is significantly reduced, and a higher computing speed is reached. Theoretically, a simulation of collision prediction for space debris of any amount and for any time span can be executed. To verify this algorithm, a simulation example including 1382 pieces of debris, whose operational time scales vary from 1min to 3days, is conducted on Tesla C2075 of NVIDIA. The simulation results demonstrate that with the same computational accuracy as that of a CPU, the computing speed of the parallel algorithm on a GPU is 30 times that on a CPU. Based on this algorithm, collision prediction of over 150 Chinese spacecraft for a time span of 3days can be completed in less than 3h on a single computer, which meets the timeliness requirement of the initial screening task. Furthermore, the algorithm can be adapted for multiple tasks, including particle filtration, constellation design, and Monte-Carlo simulation of an orbital computation.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.023
  • Oceanus: A multi-spacecraft flagship mission concept to explore Saturn and
    • Authors: J. Mansell; N. Kolencherry; K. Hughes; A. Arora; H.S. Chye; K. Coleman; J. Elliott; S. Fulton; N. Hobar; B. Libben; Y. Lu; J. Millane; A. Mudek; L. Podesta; J. Pouplin; E. Shibata; G. Smith; B. Tackett; T. Ukai; P. Witsberger; S. Saikia
      Pages: 2407 - 2433
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): J. Mansell, N. Kolencherry, K. Hughes, A. Arora, H.S. Chye, K. Coleman, J. Elliott, S. Fulton, N. Hobar, B. Libben, Y. Lu, J. Millane, A. Mudek, L. Podesta, J. Pouplin, E. Shibata, G. Smith, B. Tackett, T. Ukai, P. Witsberger, S. Saikia
      Uranus, together with Neptune in our Solar System, belongs to a class of planets called ice giants, which have never been explored using a dedicated mission. A mission to explore the ice giants is one of the highest priority missions of NASA. In this paper, we present a new and unique multi-probe, multi-planet spacecraft to explore two of the outer planets, Saturn and Uranus. The mission concept addresses the high-priority science goals of Saturn and Uranus as set forth by the National Research Council’s Planetary Sciences Decadal Survey: Visions and Voyages for Planetary Science in the Decade 2013–2022. The growing importance of understanding the evolution and role of ice giants in extra-solar planetary systems makes Uranus a pertinent scientific target. The mission concept employs the Space Launch System to deliver a 1700kg orbiter to Uranus using a ballistic Saturn-Uranus trajectory with a time-of-flight of 11.5years. The baseline mission concept includes two atmospheric entry probes: one deployed at Saturn and another at Uranus prior to an impulsive orbit capture. A payload of nine remote sensing and in situ plasma instruments onboard the orbiter support a broad array of investigations during the nominal 2-year science mission. In addition to the baseline concept, system trade studies were conducted to explore the advantages of aerocapture and use of the Space Launch System. Based on the results of these trade studies, a preferred point design within constraints of NASA’s Flagship program can be launched in the late 2020s. A neural network model using analogy-based data was developed to estimate the mission cost, which was found to be $1.9 billion in FY15$.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.012
  • Study of whistler mode waves for ring distribution function in
           Saturn’s magnetosphere
    • Authors: Rajbir Kaur; R.S. Pandey
      Pages: 2434 - 2441
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): Rajbir Kaur, R.S. Pandey
      In present paper whistler mode waves in magnetosphere of Saturn have been investigated. Linear properties of ring velocity distribution function are used to derive dispersion relation for whistler mode waves in ambient magnetic field of Saturn in extended plasma sheet of planet’s magnetosphere. The derivation for perturbed distribution function, dispersion relation and growth rate have been determined by using the method of characteristic and kinetic approach. Analytical expressions for growth rate and real frequency of whistlers propagating parallel to magnetic field direction are attained. The analysis shows that temperature anisotropy, increases in number density and energy density increases the growth rate of whistler waves along with significant shift in wave number. It has been shown that whistler mode waves have grown due to loss of perpendicular kinetic energy of ring electrons. Calculations have been performed at two radial distances in Saturn’s magnetosphere. The results are of importance in analyzing observed VLF emissions over wide spectrum of frequency range in Saturnian magnetosphere. The analytical model developed can also be used to study various types of instabilities in planetary magnetospheres.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.015
  • Data imputation analysis for Cosmic Rays time series
    • Authors: R.C. Fernandes; P.S. Lucio; J.H. Fernandez
      Pages: 2442 - 2457
      Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): R.C. Fernandes, P.S. Lucio, J.H. Fernandez
      The occurrence of missing data concerning Galactic Cosmic Rays time series (GCR) is inevitable since loss of data is due to mechanical and human failure or technical problems and different periods of operation of GCR stations. The aim of this study was to perform multiple dataset imputation in order to depict the observational dataset. The study has used the monthly time series of GCR Climax (CLMX) and Roma (ROME) from 1960 to 2004 to simulate scenarios of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 90% of missing data compared to observed ROME series, with 50 replicates. Then, the CLMX station as a proxy for allocation of these scenarios was used. Three different methods for monthly dataset imputation were selected: AMÉLIA II – runs the bootstrap Expectation Maximization algorithm, MICE – runs an algorithm via Multivariate Imputation by Chained Equations and MTSDI – an Expectation Maximization algorithm-based method for imputation of missing values in multivariate normal time series. The synthetic time series compared with the observed ROME series has also been evaluated using several skill measures as such as RMSE, NRMSE, Agreement Index, R, R2, F-test and t-test. The results showed that for CLMX and ROME, the R2 and R statistics were equal to 0.98 and 0.96, respectively. It was observed that increases in the number of gaps generate loss of quality of the time series. Data imputation was more efficient with MTSDI method, with negligible errors and best skill coefficients. The results suggest a limit of about 60% of missing data for imputation, for monthly averages, no more than this. It is noteworthy that CLMX, ROME and KIEL stations present no missing data in the target period. This methodology allowed reconstructing 43 time series.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.02.022
  • Suomi NPP VIIRS/DNB imagery of nightglow gravity waves from various
           sources over China
    • Authors: Chang Lai; Jia Yue; Jiyao Xu; William C. Straka; Steven D. Miller; Xiao Liu
      Pages: 1951 - 1961
      Abstract: Publication date: 15 April 2017
      Source:Advances in Space Research, Volume 59, Issue 8
      Author(s): Chang Lai, Jia Yue, Jiyao Xu, William C. Straka, Steven D. Miller, Xiao Liu
      Observation of atmospheric gravity waves provides critical insight to weather and climate researches. Some gravity waves survive middle-atmospheric filtering as they propagate upward to the mesopause region and disturb the nightglow emission layer near 90km AMSL, making the waves visible to both ground and space sensors. Based on the high-resolution images obtained by Day/Night Band on NOAA/NASA Suomi National Polar-orbiting Partnership environmental satellite, four representative gravity wave events over China are analyzed. With the help of VIIRS thermal infrared brightness temperature and MERRA wind data, we surmise that these waves originated from orography, thunderstorm, typhoon and baroclinic, respectively. Nadir viewing satellite observations cover a wide area and unlike the surface-based perspective, do not suffer from cloud obscuration. These new observations over remote areas provide important guidance for future deployment of ground based camera systems in China.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.01.041
  • Wave propagation in strongly dispersive superthermal dusty plasma
    • Authors: S.K. El-Labany; E.K. El-Shewy; H.N. Abd El-Razek; A.A. El-Rahman
      Pages: 1962 - 1968
      Abstract: Publication date: 15 April 2017
      Source:Advances in Space Research, Volume 59, Issue 8
      Author(s): S.K. El-Labany, E.K. El-Shewy, H.N. Abd El-Razek, A.A. El-Rahman
      The attributes of acoustic envelope waves in a collisionless dust ion unmagnetized plasmas model composed of cold ions, superthermal electrons and positive-negative dust grains have been studied. Using the derivative expansion technique in a strong dispersive medium, the system model is reduced to a nonlinearly form of Schrodinger equation (NLSE). Rational solution of NLSE in unstable region is responsible for the creation of large shape waves; namely rogue waves. The subjection of instability regions upon electron superthermality (via κ ), carrier wave number and dusty grains charge is discussed.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.01.042
  • Characterization of GNSS amplitude scintillations over Addis Ababa during
    • Authors: A.O. Akala; A.H. Ejalonibu; P.H. Doherty; S.M. Radicella; K.M. Groves; C.S. Carrano; C.T. Bridgwood; R.A. Stoneback
      Pages: 1969 - 1983
      Abstract: Publication date: 15 April 2017
      Source:Advances in Space Research, Volume 59, Issue 8
      Author(s): A.O. Akala, A.H. Ejalonibu, P.H. Doherty, S.M. Radicella, K.M. Groves, C.S. Carrano, C.T. Bridgwood, R.A. Stoneback
      This study characterizes GNSS amplitude scintillations over an African equatorial station: Addis Ababa (Lat 9.03°N, Lon 38.77°E, Mag. lat 0.18°N), Ethiopia during a five-year period (2009–2013). Scintillations were majorly localized within the hours of 2200–2400 LT. On a monthly basis, the highest occurrences of scintillation at Addis Ababa were recorded in April, and the lowest in June. Seasonally, the highest occurrences were recorded in equinoxes, and the lowest in June solstices. On a yearly scale, scintillations recorded the highest occurrences in 2012 and the lowest in 2009. Large proportions of the scintillations were localized within the northern sky of Addis Ababa. Supporting the characterization of the GNSS data with C/NOFS data, we noted that small-spatial scale density depletions are more detrimental to GNSS signals than their large-scale counterparts. Finally, EGNOS geostationary satellites’ signals also scintillated steadily at Addis Ababa, with noticeable occurrences on the low elevation EGNOS satellite’s (PRN 120) data. These events commenced around local sunset terminator, forming plateaus that vanished around local midnight.

      PubDate: 2017-04-09T02:43:26Z
      DOI: 10.1016/j.asr.2017.01.044
  • On the Lagrange stability of motion in the planar restricted three-body
    • Authors: S.P. Sosnitskii
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): S.P. Sosnitskii
      We study the Lagrange stability in the planar restricted three-body problem. In particular, in the case of the circular restricted three-body problem, we prove a theorem on the Lagrange stability of the infinitesimal particle. A weaker version of this theorem can be obtained in the case of the elliptic restricted three-body problem.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.026
  • Identification and calibration of one-way delays in satellite laser
           ranging systems
    • Authors: Ivan Prochazka; Jan Kodet; Josef Blazej; Georg Kirchner; Franz Koidl; Peiyuan Wang
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Ivan Prochazka, Jan Kodet, Josef Blazej, Georg Kirchner, Franz Koidl, Peiyuan Wang
      We are reporting on identification and calibration of one-way delays in satellite laser ranging systems. Satellite Laser Ranging (SLR) is a standard technique to measure the distance of satellites as a function of time with millimeter precision and a few millimeters accuracy. For one-way laser ranging, laser time transfer ground to space and for bi- and multi-static laser ranging to space objects identification and measurement of system delays related separately to transmitting and receiving parts of the system are needed. The epochs of transmission and reception of optical signals have to be referred to the coordinated time scale with the accuracy reaching one nanosecond level or better for one-way ranging and space debris multi-static ranging. For transponder ranging and laser time transfer an even higher accuracy of 50ps or better is needed. These accuracy requirements are by several orders of magnitude higher in comparison to standard SLR applications. A new procedure of calibration of one-way delays related to the SLR systems has been developed and tested. The necessary hardware components needed for calibration measurements were designed and developed in a form of a Calibration Device. It consists of a photon counting detector, an epoch timing device and a dedicated signal cable. The signal propagation delays of these components were determined with an accuracy of better than 20ps. The signal propagation delay stability of the Calibration Device is on a level of units of picoseconds over days of operation. The Calibration Device and calibration procedure were tested in real measurements at the SLR site in Graz, Austria. The time needed to complete a calibration of one-way delays of the SLR system is less than two days. The one-way system delays were determined with the accuracy better than 50ps. The measurement principle, Calibration Device and the first results are presented.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.027
  • Adaptive variable-structure finite-time mode control for spacecraft
           proximity operations with actuator saturation
    • Authors: Daero Lee; George Vukovich; Haichao Gui
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Daero Lee, George Vukovich, Haichao Gui
      This paper presents an adaptive variable-structure finite-time control for spacecraft proximity maneuvers under parameter uncertainties, external disturbances and actuator saturation. The coupled six degrees-of-freedom dynamics are modeled for spacecraft relative motion, where the exponential coordinates on the Lie group SE(3) are employed to describe relative configuration. No prior knowledge of inertia matrix and mass of the spacecraft is required for the proposed control law, which implies that the proposed control scheme can be applied in spacecraft systems with large parametric uncertainties in inertia matrix and mass. Finite-time convergence of the feedback system with the proposed control law is established. Numerical simulation results are presented to illustrate the effectiveness of the proposed control law for spacecraft proximity operations with actuator saturation.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.029
  • Reflectance spectroscopy characterization of space debris
    • Authors: A. Vananti; T. Schildknecht; H. Krag
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): A. Vananti, T. Schildknecht, H. Krag
      When characterizing the space debris environment one important point is the identification of the physical properties of the space debris objects. Reflectance spectroscopy is a possible technique to study the surface material of these objects with observations from the ground. In this work the results collected from spectroscopy observations of space debris in orbit are presented. The observations were performed at the 1-m ESA Space Debris Telescope (ESASDT) in Tenerife equipped with a spectrograph in the 450–960nm wavelength range. A preliminary classification using three different categories purely based on the shape and appearance of the spectra was proposed. Two debris objects with high AMR could be successfully associated with materials analyzed in the laboratory. The results show that the two debris objects are probably pieces of Kapton MLI with ‘gold’ and ‘silver’ coating, respectively. Color indices were extracted from the spectroscopic measurements. For high AMR objects the colors seem to be consistent with the proposed classification in three categories. The B-R and R-I laboratory measurements of ‘gold’ and ‘silver’ MLI taken from the literature are comparable with the obtained results.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.033
  • Investigations of associated multi-band observations for GEO space debris
    • Authors: Yao Lu; Chen Zhang; Rong-yu Sun; Chang-yin Zhao; Jian-ning Xiong
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Yao Lu, Chen Zhang, Rong-yu Sun, Chang-yin Zhao, Jian-ning Xiong
      According to the proposal of active space debris removal, the knowledge of the shape, rotational state and surface characteristics of space debris is demanding. An associated multi-band observation of the Geosynchronous Earth Orbit space debris is performed to investigate the improvement and promotion while infrared and g ′ Vr ′ i ′ information are provided. The Quad-Channel Telescope and the famous United Kingdom Infrared Telescope are adopted in our observation, along with other two dedicated space debris telescopes. Due to the limitation of geometry, the infrared data of 13 objects are acquired, and the photometry results are obtained. The tumbling motion is analyzed with the brightness variations, and the color indices are investigated according to the bus type of objects. At last the frequency analysis of the multi-band light curves is performed, the consistency and non-consistency of the results under different circumstances are presented. It is demonstrated that the adoption of multi-band observations is useful for increasing the knowledge of space debris, and the applications are deserved to be further promoted.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.035
  • Validation of Swarm accelerometer data by modelled nongravitational forces
    • Authors: Aleš Bezděk; Josef Sebera; Jaroslav Klokočník
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Aleš Bezděk, Josef Sebera, Jaroslav Klokočník
      Swarm is a three-satellite mission of the European Space Agency, in orbit since November 2013, whose main objective is the study of the Earth’s magnetic field from space. As part of other scientific payload, each Swarm satellite is equipped with an accelerometer that measures the nongravitational forces (e.g. atmospheric drag and radiation pressure). Since the mission beginning, the Swarm onboard accelerometer observations have been facing a problem of much higher temperature influence than it had been anticipated in the pre-launch tests. In our paper, we use the a posteriori computed models of physical nongravitational forces acting on each satellite for external validation of the accelerometer measurements. To reduce the high temperature dependence, we apply a simple and straightforward method of linear temperature correction. The most successful application of this approach is for the along-track component of the accelerometer data, where the signal magnitude is strongest. The best performing accelerometer is that of the Swarm C satellite, the accelerometer of Swarm A displays more temperature dependence and noise, the noisiest accelerometer data set is provided by Swarm B. We analyzed the occurrence of anomalous periods in the along-track accelerometer component of Swarm A and Swarm C, when the number of accelerometer hardware anomalies is peaking. Over the time interval from June 2014 to December 2015, we found a correlation between these anomalous periods and the minima in the time-varying part of the modelled nongravitational signal.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.037
  • TLE uncertainty estimation using robust weighted differencing
    • Authors: Jacco Geul; Erwin Mooij; Ron Noomen
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Jacco Geul, Erwin Mooij, Ron Noomen
      Accurate knowledge of satellite orbit errors is essential for many types of analyses. Unfortunately, for two-line elements (TLEs) this is not available. This paper presents a weighted differencing method using robust least-squares regression for estimating many important error characteristics. The method is applied to both classic and enhanced TLEs, compared to previous implementations, and validated using Global Positioning System (GPS) solutions for the GOCE satellite in Low-Earth Orbit (LEO), prior to its re-entry. The method is found to be more accurate than previous TLE differencing efforts in estimating initial uncertainty, as well as error growth. The method also proves more reliable and requires no data filtering (such as outlier removal). Sensitivity analysis shows a strong relationship between argument of latitude and covariance (standard deviations and correlations), which the method is able to approximate. Overall, the method proves accurate, computationally fast, and robust, and is applicable to any object in the satellite catalogue (SATCAT).

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.038
  • First prospects in a new approach for structure monitoring from GPS
           multipath effect and wavelet spectrum
    • Authors: Eniuce Menezes Souza; Tamiris Trevisan Negri
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Eniuce Menezes Souza, Tamiris Trevisan Negri
      Continuous monitoring of large structures is essential to ensure their integrity. Many instruments and methods have been developed to support structure monitoring. Global Positioning System (GPS) plays an important role in such task thanks to the precision and millimeter level accuracy of the provided position information in near real-time. However, installing a GPS receiver can be a really difficult task depending on the structure, mainly when it is under collapse danger. To address this issue, this paper presents a new methodology for structure monitoring, without installing a receiver directly on the structure. Instead, a time-frequency analysis of the multipath effect, caused by GPS signal reflections, is performed. As this effect repeats in consecutive days, a change on its pattern indicates structure movement. This work investigates the feasibility of using wavelet spectra analysis of the multipath signal to monitor structure movement. An experiment simulating a structure movement was carried out and real GPS data were collected. Pseudorange and carrier phase data were evaluated using different wavelet bases. The experimental results have shown that the proposed methodology has great potential for detection of structure movements, especially using the pseudorange signals combined to Symmlets wavelet basis with 10 vanishing moments. From Receiver Operating Characteristic (ROC) analysis, accuracy measure, Spearman and Matthews correlation coefficients, the simulated movement was correctly detected for all signals at a 5% significance level.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.043
  • Global tracking of space debris via CPHD and consensus
    • Authors: Baishen Wei; Brett Nener; Weifeng Liu; Liang Ma
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Baishen Wei, Brett Nener, Weifeng Liu, Liang Ma
      Space debris tracking is of great importance for safe operation of spacecraft. This paper presents an algorithm that achieves global tracking of space debris with a multi-sensor network. The sensor network has unknown and possibly time-varying topology. A consensus algorithm is used to effectively counteract the effects of data incest. Gaussian Mixture-Cardinalized Probability Hypothesis Density (GM-CPHD) filtering is used to estimate the state of the space debris. As an example of the method, 45 clusters of sensors are used to achieve global tracking. The performance of the proposed approach is demonstrated by simulation experiments.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.03.002
  • Possible Fengyun-1C debris fall
    • Authors: J. Golebiewska; M. Nowak; A. Muszyński; E. Wnuk
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): J. Golebiewska, M. Nowak, A. Muszyński, E. Wnuk
      A fall of small objects took place on 27th April 2012 in Wargowo village near Oborniki, about 25km NW from Poznań (Poland). There was only one eye-witness of the fall, who found two separate pieces (ca. 2.7cm and ca. 2cm), with several small additional fragments. After microscopic observations and chemical analysis a meteoritic origin of these objects was excluded. They are identified as space debris, therefore man-made. The most probable source of the observed fall was space debris 35127 Fengyun 1C DEB, created during destruction of the Chinese weather satellite Fengyun-1C (FY-1C).

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.03.005
  • On-ground testing of the role of adhesion in the LISA-Pathfinder test mass
           injection phase
    • Authors: D. Bortoluzzi; C. Zanoni; J.W. Conklin
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): D. Bortoluzzi, C. Zanoni, J.W. Conklin
      Many space missions share the need to fly a free-falling body inside the spacecraft, as a reference for navigation and/or as a probe for the local gravitational field. When a mechanism is required to cage such an object during the launch phase, the need arises to release it to free-fall once the operational phase must be initiated in orbit. The criticality of this phase increases when the mechanical interfaces between the body and the mechanism are affected by adhesion and the actuation authority of the control system on the free-falling body is limited. Both conditions are realized in the LISA Pathfinder mission, which aims at injecting a gold-coated 2kg cubic test mass into a nearly perfect geodesic trajectory to demonstrate the readiness of the developed technology for in-space gravity wave detection. The criticality of adhesion is widely recognized in space technology, because it can affect and jeopardize the functionality of mechanisms, when arising between moving parts. In the LISA Pathfinder case, metallic adhesion potentially plays a relevant role, mainly for two reasons. First, thanks to its properties (ductility, high surface energy) the gold coating on the proof mass easily produces cold weldings, especially in vacuum conditions. Second, the detachment of the proof mass from the releasing device occurs abruptly and a relevant influence of the separation velocity is expected on the strength of the welding. This can produce an excessive velocity of the proof mass at the retraction of the releasing device for the following capture and centring phase on behalf of the control system. A testing activity is performed to characterize the dynamic behaviour of the adhesive bonds between the proof mass and the releasing device, which can be used to predict their contribution on the residual velocity of the proof mass after in-flight release. The study of such a dynamic phenomenon sets some challenging requirements on the measurement technique, both on the instrumental and on the signal analysis sides. However, the recent improvements on the testing activities make it possible to refine the contribution of adhesion on the proof mass velocity budget at the release. In this paper we describe the recent experimental results, the developments in the measurement technique, the improvements in the repeatability of the results and the related projection to in-flight release dynamics, in comparison with the previous results.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.030
  • A PFC3D-based numerical simulation of cutting load for lunar rock simulant
           and experimental validation
    • Authors: Peng Li; Shengyuan Jiang; Dewei Tang; Bo Xu
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Peng Li, Shengyuan Jiang, Dewei Tang, Bo Xu
      For sake of striking a balance between the need of drilling efficiency and the constrains of power budget on the moon, the penetrations per revolution of drill bit are generally limited in the range around 0.1mm, and besides the geometric angle of the cutting blade need to be well designed. This paper introduces a simulation approach based on PFC3D (particle flow code 3 dimensions) for analyzing the cutting load feature on lunar rock simulant, which is derived from different geometric-angle blades with a small cutting depth. The mean values of the cutting force of five blades in the survey region (four on the boundary points and one on the center point) are selected as the macroscopic responses of model. The method of experimental design which includes Plackett-Burman (PB) design and central composite design (CCD) method is adopted in the matching procedure of microparameters in PFC model. Using the optimization method of enumeration, the optimum set of microparameters is acquired. Then, the experimental validation is implemented by using other twenty-five blades with different geometric angles, and the results from both simulations and laboratory tests give fair agreements. Additionally, the rock breaking process cut by different blades are quantified from simulation analysis. This research provides the theoretical support for the refinement of the rock cutting load prediction and the geometric design of cutting blade on the drill bit.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.032
  • A generalization of the analytical least-squares solution to the 3D
           symmetric Helmert coordinate transformation problem with an approximate
           error analysis
    • Authors: Guobin Chang; Tianhe Xu; Qianxin Wang; Shubi Zhang; Guoliang Chen
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Guobin Chang, Tianhe Xu, Qianxin Wang, Shubi Zhang, Guoliang Chen
      The symmetric Helmert transformation model is widely used in geospatial science and engineering. Using an analytical least-squares solution to the problem, a simple and approximate error analysis is developed. This error analysis follows the Pope procedure solving nonlinear problems, but no iteration is needed here. It is simple because it is not based on the direct and cumbersome error analysis of every single process involved in the analytical solution. It is approximate because it is valid only in the first-order approximation sense, or in other words, the error analysis is performed approximately on the tangent hyperplane at the estimates instead of the original nonlinear manifold of the observables. Though simple and approximate, this error analysis’s consistency is not sacrificed as can be validated by Monte Carlo experiments. So the practically important variance-covariance matrix, as a consistent accuracy measure of the parameter estimate, is provided by the developed error analysis. Further, the developed theory can be easily generalized to other cases with more general assumptions about the measurement errors.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.034
  • Geo-spatial distribution of cloud cover and influence of cloud induced
           attenuation and noise temperature on satellite signal propagation over
    • Authors: Joseph Sunday Ojo
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Joseph Sunday Ojo
      The study of the influence of cloud cover on satellite propagation links is becoming more demanding due to the requirement of larger bandwidth for different satellite applications. Cloud attenuation is one of the major factors to consider for optimum performance of Ka/V and other higher frequency bands. In this paper, the geo-spatial distribution of cloud coverage over some chosen stations in Nigeria has been considered. The substantial scale spatial dispersion of cloud cover based on synoptic meteorological data and the possible impact on satellite communication links at higher frequency bands was also investigated. The investigation was based on 5years (2008–2012) achieved cloud cover data collected by the Nigerian Meteorological Agency (NIMET) Federal Ministry of Aviation, Oshodi Lagos over four synoptic hours of the day covering day and night. The performances of satellite signals as they traverse through the cloud and cloud noise temperature at different seasons and over different hours of days at Ku/W-bands frequency are also examined. The overall result shows that the additional total atmospheric noise temperature due to the clear air effect and the noise temperature from the cloud reduces the signal-to-noise ratio of the satellite receiver systems, leading to more signal loss and if not adequately taken care of may lead to significant outage. The present results will be useful for Earth-space link budgeting, especially for the proposed multi-sensors communication satellite systems in Nigeria.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.03.006
  • Detection of co-seismic earthquake gravity field signals using GRACE-like
           mission simulations
    • Authors: Mohammad Ali Sharifi; Abolfazl Shahamat
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Mohammad Ali Sharifi, Abolfazl Shahamat
      After launching the GRACE satellite mission in 2002, the earth’s gravity field and its temporal variations are measured with a closer inspection. Although these variations are mainly because of the mass transfer of land water storage, they can also happen due to mass movements related to some natural phenomena including earthquakes, volcanic eruptions, melting of polar ice caps and glacial isostatic adjustment. Therefore this paper shows which parameters of an earthquake are more sensitive to GRACE-Like satellite missions. For this purpose, the parameters of the Maule earthquake that occurred in recent years and Alaska earthquake that occurred in 1964 have been chosen. Then we changed their several parameters to serve our purpose. The GRACE-Like sensitivity is observed by using the simulation of the earthquakes along with gravity changes they caused, as well as using dislocation theory under a half space earth. This observation affects the various faulting parameters which include fault length, width, depth and average slip. These changes were therefore evaluated and the result shows that the GRACE satellite missions tend to be more sensitive to Width among the Length and Width, the other parameter is Dip variations than other parameters. This article can be useful to the upcoming scenario designers and seismologists in their quest to study fault parameters.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.031
  • VLF radio wave anomalies associated with the 2010 Ms 7.1 Yushu earthquake
    • Authors: Xuhui Shen; Zeren Zhima; Shufan Zhao; Geng Qian; Qing Ye; Yuri Ruzhin
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Xuhui Shen, Zeren Zhima, Shufan Zhao, Geng Qian, Qing Ye, Yuri Ruzhin
      The VLF radio signals recorded both from the ground based VLF radio wave monitoring network and the DEMETER satellite are investigated during the 2010Ms 7.1 Yushu earthquake. The ground-based observations show that the disturbance intensity of VLF wave’s amplitude relative to the background gets an enhancement over 22% at 11.9kHz, 27% at 12.6kHz and 62% at 14.9kHz VLF radio wave along the path from Novosibirsk - TH one day before the main shock, as compared to the maximum 20% observed during non-earthquake time. The space based observations indicate that there is a decrease of the signal to noise ratio (SNR) for the power spectral density data of 14.9kHz VLF radio signal at electric field four days before the main shock, with disturbance intensity exceeding the background by over 5% as compared to the maximum 3% observed during non-earthquake time. The geoelectric field observations in the epicenter region also show that a sharp enhancement from ∼340 to 430mV/km simultaneously appeared at two monitors 14days before main shock. The comparative analysis from the ground and space based observations during the earthquake and non-earthquake time provides us convincible evidence that there exits seismic anomalies from the VLF radio wave propagation before the 2010 Ms 7.1 Yushu earthquake. The possible mechanism for VLF radio signal propagation anomaly during 2010 Yushu earthquake maybe related to the change of the geoelectric field nearby the earthquake zone.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.040
  • Pre-seismic anomalies in remotely sensed land surface temperature
           measurements: The case study of 2003 Boumerdes earthquake
    • Authors: Mebrouk Bellaoui; Abdelatif Hassini; Kada Bouchouicha
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): Mebrouk Bellaoui, Abdelatif Hassini, Kada Bouchouicha
      Detection of thermal anomaly prior to earthquake events has been widely confirmed by researchers over the past decade. One of the popular approaches for anomaly detection is the Robust Satellite Approach (RST). In this paper, we use this method on a collection of six years of MODIS satellite data, representingland surface temperature (LST) images to predict 21st May 2003 Boumerdes Algeria earthquake. The thermal anomalies results were compared with the ambient temperature variation measured in three meteorological stations of Algerian National Office of Meteorology (ONM) (DELLYS-AFIR, TIZI-OUZOU, and DAR-EL-BEIDA). The results confirm the importance of RST as an approach highly effective for monitoring the earthquakes.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.03.004
  • About a linear polarization of comets: The phase-angle dependences of
           polarization degree
    • Authors: D.I. Shestopalov; L.F. Golubeva
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): D.I. Shestopalov, L.F. Golubeva
      The ground-based astronomic observations of comet cannot provide a proper phase angle coverage that is needed to estimate with a reasonable accuracy all of the attributes of comet polarization phase curve. To find the best approximation to the phase polarization dependences observed for comets, we apply a simple empiric formula that has already shown good results when operating with asteroid and lunar polarimetric curves (Shestopalov, 2004; Shestopalov and Golubeva, 2015). From the set of comets present in DBCP (Kiselev et al., 2006), we selected 20, for which the calculation of regular polarimetric curves (i.e. the phase angle – polarization dependences with a low level of nonsteady activity) was possible. Within the phase angle coverage area for these 20 comets, a potential user can reproduce 82 best-fitting polarimetric phase curves in various spectral domains. Then we analyzed the properties of negative and positive polarization of the comets. The interrelation between the averaged polarimetric slope h at the inversion angle and wavelength was found. In general, the parameters of negative branch vary slightly from one comet to another. We found a close correlation between the maximum polarization degree Pmax and the slope of the segment of polarimetric curve bounded by phase angles of 30° and 50°. This finding allowed to adduce the evidence in support of the idea voiced by Chernova et al. (1993) about two types of comet with high and low Pmax . Moreover, we have found direct correlation between the maximum polarization degree of comets and their dust-to-gas ratio. The latter is actually a visual proof of assumptions voiced many years ago about a mutual effect of gas and dust on observed polarization of comets (see, for instance, a historical review in Kiselev et al., 2015). Thus, the polarimetric effect of resonant fluorescence should be completely eliminated from the phase-dependent polarization curve of comet in order to correctly interpret the physical properties of cometary dust. The simple method that we suggest to deconvolve polarimetric response from comets into “pure dusty” and “gaseous” polarimetric curves meets specific difficulties associated mainly with a shortage of data about the polarized luminescence of molecules and ions commonly present in the gaseous component of cometary atmospheres.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.024
  • Stability of the magnetosonic wave in a cometary multi-ion plasma
    • Authors: G. Sreekala; Anu Varghese; Neethu Jayakumar; Manesh Michael; Sijo Sebastian; Chandu Venugopal
      Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10
      Author(s): G. Sreekala, Anu Varghese, Neethu Jayakumar, Manesh Michael, Sijo Sebastian, Chandu Venugopal
      A generalized dispersion relation of the magnetosonic wave in a four component plasma consisting of electrons and hydrogen ions of solar origin and positively and negatively charged oxygen ions of cometary origin has been derived by using the Vlasov-Maxwell kinetic model. Parallel to the magnetic field, the hydrogen and electron components are modeled by a drifting Maxwellian distribution; perpendicular to the magnetic field, we use a loss cone type distribution obtained by the subtraction of two Maxwellian distributions having different temperatures. The effect of change in the drift velocity of streaming components and number densities and temperatures of each species in driving the instability has been analyzed both analytically and numerically. For typical parameters at comet Halley, we find that both positively and negatively charged oxygen ions can drive the wave unstable.

      PubDate: 2017-04-16T02:52:30Z
      DOI: 10.1016/j.asr.2017.02.039
  • Realization of hydrodynamic experiments on quasi-2D liquid crystal films
           in microgravity
    • Authors: Noel A. Clark; Alexey Eremin; Matthew A. Glaser; Nancy Hall; Kirsten Harth; Christoph Klopp; Joseph E. Maclennan; Cheol S. Park; Ralf Stannarius; Padetha Tin; William N. Thurmes; Torsten Trittel
      Abstract: Publication date: Available online 22 April 2017
      Source:Advances in Space Research
      Author(s): Noel A. Clark, Alexey Eremin, Matthew A. Glaser, Nancy Hall, Kirsten Harth, Christoph Klopp, Joseph E. Maclennan, Cheol S. Park, Ralf Stannarius, Padetha Tin, William N. Thurmes, Torsten Trittel
      Freely suspended films of smectic liquid crystals are unique examples of quasi two-dimensional fluids. Mechanically stable and with quantized thickness of the order of only a few molecular layers, smectic films are ideal systems for studying fundamental fluid physics, such as collective molecular ordering, defect and fluctuation phenomena, hydrodynamics, and nonequilibrium behavior in two dimensions (2D), including serving as models of complex biological membranes. Smectic films can be drawn across openings in planar supports resulting in thin, meniscus-bounded membranes, and can also be prepared as bubbles, either supported on an inflation tube or floating freely. The quantized layering renders smectic films uniquely useful in 2D fluid physics. The OASIS team has pursued a variety of ground-based and microgravity applications of thin liquid crystal films to fluid structure and hydrodynamic problems in 2D and quasi-2D systems. Parabolic flights and sounding rocket experiments were carried out in order to explore the shape evolution of free floating smectic bubbles, and to probe Marangoni effects in flat films. The dynamics of emulsions of smectic islands (thicker regions on thin background films) and of microdroplet inclusions in spherical films, as well as thermocapillary effects, were studied over extended periods within the OASIS (Observation and Analysis of Smectic Islands in Space) project on the International Space Station. We summarize the technical details of the OASIS hardware and give preliminary examples of key observations.

      PubDate: 2017-04-23T10:29:29Z
      DOI: 10.1016/j.asr.2017.04.014
  • A seasonal study on the role of h’F/meridional winds in influencing the
           development of ESF irregularities over Indian sector
    • Authors: Sreeba Sreekumar; S. Sripathi
      Abstract: Publication date: Available online 20 April 2017
      Source:Advances in Space Research
      Author(s): Sreeba Sreekumar, S. Sripathi
      In this paper, we present the seasonal variation of nighttime thermospheric meridional winds over Hyderabad as derived using dual ionosonde observations located at Tirunelveli (8.70N, 77.70E, Dip Lat=0.30N), an equatorial station and Hyderabad (17.380N, 78.450E, Dip Lat=120N), a low latitude station, respectively, over the period of April- December 2013 using h ′ F data as discussed in (Sreekumar and Sripathi, 2016). The calculated winds has been compared with HWM14 wind model. The results show that trends of the derived winds from the ionosonde h’F data matches well with model wind near to midnight hours in all the seasons. However, some dissimilarities were observed during early night hours. Especially, the poleward winds during early night hours for different seasons were not well reproduced by the model. Later, the study is extended to understand the role of meridional winds in causing the variability of ESF occurrence vis a vis h ′ F. The histogram analysis of h ′ F vs wind values just before ESF onset reveals that the most probable combination of wind and h’F on the ESF days are centred around 350 km and 50m/s. Additionally, we also performed Superposed Epoch Analysis (SEA) based on longer and shorter duration ESF events. The analysis reveals the distinct differences in the longer and shorter duration ESF events of Summer and Autumn equinox where the values of h ′ F as well as meridional winds where such that a steep change in reduction of poleward winds prior to ESF onset supported the longer duration ESF events in both seasons. However, this steep reduction is not so significant for the shorter duration ESF events indicating that meridional winds could play a crucial role in extending the spread F durations in longer duration events. The observations clearly demonstrate the reduction of poleward wind velocities during vernal equinox as compared to Autumn equinox, where larger poleward winds were present around ESF onset times. These observations are consistent with the equinoctial asymmetry as seen during year 2013 where more number of ESF occurrences were observed during vernal equinox as compared to Autumn equinox. Additionally on seasonal basis, analysis of the significance of meridional wind magnitudes during scintillation and non scintillation days were performed. The result suggests that non scintillation days were characterized with larger poleward wind magnitudes than scintillation days during vernal equinox and summer season. However, such a trend was not seen in the Autumn equinox season. This might indicate the possible role of poleward meridional wind in reducing the number of scintillation occurences during this season in addition to weakening of PRE height.

      PubDate: 2017-04-23T10:29:29Z
      DOI: 10.1016/j.asr.2017.04.009
  • Scoring Sensor Observations to Facilitate the Exchange of Space
           Surveillance Data
    • Authors: M. Weigel; H. Fiedler; T. Schildknecht
      Abstract: Publication date: Available online 20 April 2017
      Source:Advances in Space Research
      Author(s): M. Weigel, H. Fiedler, T. Schildknecht
      In this paper, a scoring metric for space surveillance sensor observations is introduced. A scoring metric allows for direct comparison of data quantity and data quality, and makes transparent the effort made by different sensor operators. The concept might be applied to various sensor types like tracking and surveillance radar, active optical laser tracking, or passive optical telescopes as well as combinations of different measurement types. For each measurement type, a polynomial least squares fit is performed on the measurement values contained in the track. The track score is the average sum over the polynomial coefficients uncertainties and scaled by reference measurement accuracy. Based on the newly developed scoring metric, an accounting model and a rating model are introduced. Both models facilitate the exchange of observation data within a network of space surveillance sensors operators. In this paper, optical observations are taken as an example for analysis purposes, but both models can also be utilized for any other type of observations. The rating model has the capability to distinguish between network participants with major and minor data contribution to the network. The level of sanction on data reception is defined by the participants themselves enabling a high flexibility. The more elaborated accounting model translates the track score to credit points earned for data provision and spend for data reception. In this model, data reception is automatically limited for participants with low contribution to the network. The introduced method for observation scoring is first applied for transparent data exchange within the Small Aperture Robotic Telescope Network (SMARTnet). Therefore a detailed mathematical description is presented for line of sight measurements from optical telescopes, as well as numerical simulations for different network setups.

      PubDate: 2017-04-23T10:29:29Z
      DOI: 10.1016/j.asr.2017.04.010
  • Shell-type Supernova Remnants as Sources of Cosmic Rays
    • Authors: Vera G. Sinitsyna; Vera Y. Sinitsyna; Sergei S. Borisov; Ivan A. Ivanov; Anatolii I. Klimov; Rim M. Mirzafatikhov; Nikolai I. Moseiko
      Abstract: Publication date: Available online 18 April 2017
      Source:Advances in Space Research
      Author(s): Vera G. Sinitsyna, Vera Y. Sinitsyna, Sergei S. Borisov, Ivan A. Ivanov, Anatolii I. Klimov, Rim M. Mirzafatikhov, Nikolai I. Moseiko
      The investigation of VHE gamma-ray sources by any methods, including mirror Cherenkov telescopes, touches on the problem of the cosmic ray origin and, accordingly, the role of the Galaxy in their generation. The SHALON observations have yielded the results on Galactic supernova remnants (SNR) of different ages. Among them are: the shell-type SNRs Tycho’s SNR (1572y), Cas A (1680y), IC 443 (age ∼(3÷30)×103 y), γCygni SNR (age ∼(5÷7)×103 y), G166.0+4.3 (age ∼24×103 y) and classical nova GK Per (Nova 1901). For each of SNRs the observation results are presented with spectral energy distribution by SHALON in comparison with other experiment data and images by SHALON in together with data from X-ray by Chandra and radio-data by CGPS. The collected experimental data have confirmed the prediction of the theory about the hadronic generation mechanism of very high energy 800 GeV - 100 TeV gamma-rays in Tycho’s SNR, Cas A and IC443. For the first time, unique data on GK Per (Nova1901) TeV gamma-ray emission were obtained with SHALON experiment. The X-ray data shows that, the nova remnant of GK Per could be a younger remnant that will resemble older SNRs like IC 443 which interact with molecular clouds. GK Per is supposed to be a candidate for TeV gamma-ray emission due to the accelerated particles in the reverse shock region.

      PubDate: 2017-04-23T10:29:29Z
      DOI: 10.1016/j.asr.2017.04.007
  • Analytic forms of the cosmic ray perpendicular diffusion coefficient with
           implicit contribution of slab modes
    • Authors: Shalchi
      Abstract: Publication date: Available online 18 April 2017
      Source:Advances in Space Research
      Author(s): A. Shalchi
      The analytical description of the diffusion of cosmic rays is an important topic in space and astrophysics. Recently an extension of non-linear diffusion theory for the perpendicular transport of energetic particles interacting with magnetic turbulence was developed. This theory can be used to compute the perpendicular diffusion coefficient for two-component turbulence in which the turbulent magnetic field is a superposition of slab and two-dimensional modes. It was demonstrated earlier that there is no explicit contribution from the slab modes but the new extended theory takes into account their implicit contribution leading to a reduction of the perpendicular diffusion coefficient. The latter effect is in particular important for high energy cosmic rays. In the current paper we derive simple analytical forms for this case to understand for which parameter regime the new effect is important. The new formulas will be important for different astrophysical applications such as diffusive shock acceleration at perpendicular interstellar shock waves.

      PubDate: 2017-04-23T10:29:29Z
  • List of Referees
    • Abstract: Publication date: 15 May 2017
      Source:Advances in Space Research, Volume 59, Issue 10

      PubDate: 2017-04-16T02:52:30Z
  • List of Referees
    • Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9

      PubDate: 2017-04-09T02:43:26Z
  • Poleward currents from coastal altimetry: The west coast of Southern Baja
           California, Mexico
    • Abstract: Publication date: 1 May 2017
      Source:Advances in Space Research, Volume 59, Issue 9
      Author(s): J. Valle-Rodríguez, A. Trasviña-Castro
      The west coast of Southern Baja California is subject to intense seasonal variability, presenting lowest temperatures from February to April partly due to the upwelling season but also to cold water advection associated to the California Current. The summer advance of a poleward current is responsible for the coastal temperature maxima. In this work we use a time series of currents from a moored Acoustic Doppler Profiler (ADP) to validate coastal altimetry data, in order to study seasonal and interannual coastal current variability. Almost eleven years of coastal altimetry data (2002–2012) from X-TRACK, 20–40km from the coast, reveal a persistent seasonal poleward flow from July to October and equatorward flow, modulated by mesoscale processes the rest of the year. Near the coast of the peninsula sea level raises towards the coast while the poleward current carries a warm water mass against the climatological wind. It is present from July to October in a coastal band 100km wide from the surface to 80m depth with speeds 0.2–0.3ms−1. The interannual variability observed in this period is unusually weak, compared to the previous decade.

      PubDate: 2017-04-09T02:43:26Z
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