World Library  


 
  • Cover Image

Read More
  • Cover Image

Significance Tests for the Wavelet Cross Spectrum and Wavelet Line...

By: Z. Ge

Description: Ecosystems Research Division, NERL, USEPA, 960 College Station Road, Athens, GA 30605, USA. This work attempts to develop significance tests for the wavelet cross spectrum and the wavelet linear coherence as a follow-up study on Ge (2007). Conventional approaches that are used by Torrence and Compo (1998) based on stationary background noise time series were used here in estimating the sampling distributions of the wavelet cross spectrum and the wavelet l...

Elsayed, M. A. K.: Nonlinear wave-wave interactions, J. Coastal Res., 24, 798–803, 2008.; Foufoula-Georgiou, E. and Kumar, P. (Eds.): Wavelets in Geophysics, Academic, San Diego, 1994.; Ge, Z.: Significance tests for the wavelet power and the wavelet power spectrum, Ann. Geophys., 25, 2259–2269, 2007.; Ge, Z. and Liu, P. C.: A time-localized response of wave growth process under turbulent winds, Ann. Geophys., 25, 1253–1262, 2007.; Ge, Z. and Liu, P. C.: Long-term wave g...

Read More
  • Cover Image

Diffusion at the Earth Magnetopause: Enhancement by Kelvin-helmhol...

By: L. Rezeau; D. Delcourt; R. Smets; G. Belmont

Description: CETP/CNRS/UVSQ/UPMC/IPSL, 10–12 Avenue de l'Europe, 78140 Vélizy, France. Using hybrid simulations, we examine how particles can diffuse across the Earth's magnetopause because of finite Larmor radius effects. We focus on tangential discontinuities and consider a reversal of the magnetic field that closely models the magnetopause under southward interplanetary magnetic field. When the Larmor radius is on the order of the field reversal thickness, we sho...

Belmont, G. and Chanteur, G.: Advances in magnetopause Kelvin-Helmholtz instability studies, Phys. Scripta, 40, 124–128, 1989.; Büchner, J. and Zelenyi, L. M.: Regular and chaotic charged particle motion in magnetotaillike field reversal 1. Basic theory of trapped motion, J. Geophys. Res., 94, 11 821–11 842, 1989.; Chandrasekhar, S.: Hydrodynamic and hydromagnetic stability, Dover Publication, New York, 1961.; Channell, P. J.: Exact Vlasov-Maxwell equilibria with sheared...

Read More
  • Cover Image

Planar Charged-particle Trajectories in Multipole Magnetic Fields ...

By: A. R. Gardiner; V. N. Davda; V. J. Bone; D. M. Willis

Description: Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, UK. This paper provides a complete generalization of the classic result that the radius of curvature (ρ) of a charged-particle trajectory confined to the equatorial plane of a magnetic dipole is directly proportional to the cube of the particle's equatorial distance (ϖ) from the dipole (i.e. ρ ∝ ϖ3). Comparable results are derived for the radii of curvature of all ...

Read More
  • Cover Image

Quiet-condition Variations in the Scale Height at F2-layer Peak at...

By: B. W. Reinisch; C.-c. Lee

Description: General Education Center, Ching-Yun University, Jhongli City, Taoyuan County, Taiwan. This study is the first attempt to examine the quiet-condition variations in scale height (Hm) near the F2-layer peak in the equatorial ionosphere. The data periods of Hm derived from the Jicamarca ionograms are January-December 1996 and April 1999–March 2000. The results show that the greatest and smallest Hm values are generally at 11:00–12:00 LT and 04:00–05:00 LT, ...

Stankov, S. M. and Jakowski, N.: Topside plasma scale height retrieved from radio occultation measurements, Adv. Space Res., 37, 958–962, 2006.; Belehaki, A., Marinov, P., Kutiev, I., Jakowski, N., and Stankov, S.: Comparison of the topside ionosphere scale height determined by topside sounders model and bottomside digisonde profile, Adv. Space Res., 37, 963–966, 2006.; Bilitza, D.: International Reference ionosphere 2000, Radio Sci., 36, 261–275, 2001.; Booker, H. G.: F...

Read More
  • Cover Image

Spectrum Analysis of Short-period K Index Behaviour at High and Mi...

By: P. B. Kotzé

Description: South African National Space Agency (SANSA), Space Science, P.O. Box 32, Hermanus 7200, South Africa. Geomagnetic activity levels during the declining phase and solar minimum period of the solar cycle are considerably different from those during the solar maximum phase. Previous studies revealed variations in the pattern of recurrent activity from cycle to cycle as well as variations in the average geomagnetic activity levels during a solar cycle. During...

Gosling, J. T., McComas, D. J., Phillips, J. L., and Bame, S. J.: Geomagnetic activity associated with Earth passage of interplanetary shock disturbances and coronal mass ejections, J. Geophys. Res., 96, 7831–7839, 1991.; Katsavrias, C., Preka-Papadema, P., and Moussas, X.: Wavelet analysis on solar wind parameters and geomagnetic indices, Sol. Phys., 280, 623–640, doi:10.1007/s11207-012-0078-6, 2012.; Kojima, M. an...

Read More
  • Cover Image

Polarisation and Propagation of Lion Roars in the Dusk Side Magnet...

By: O. Santolík; C. Lacombe; D. Hubert; I. Dandouras; E. A. Lucek; M. Maksimovic; Y. De Conchy; A. Balogh; F. Pantellini; N. Cornilleau-werhlin; C. C. Harvey

Description: DESPA, Observatoire de Paris, France. We present observations of "lion roars" obtained in the magnetosheath by the Spectrum Analyser (SA) of the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment aboard Cluster. STAFF-SA calculates, in near real time, the complete auto- and cross-spectral matrix derived from three magnetic and two electric components of the electromagnetic field at 27 frequencies in the range of 8 Hz to 4 kHz. This...

Read More
  • Cover Image

Imaging and Eiscat Radar Measurements of an Auroral Prebreakup Eve...

By: T. Turunen; W. Lyatsky; J. Manninen; V. Safargaleev; A. Kozlovsky

Description: Polar Geophysical Institute, Fersman St. 14, 184200 Apatity, Russia. The results of coordinated EISCAT and TV-camera observations of a prebreakup event on 15 November 1993 have been considered. The variations of the luminosity of two parallel auroral arcs, plasma depletion on the poleward edge of one of these arcs as well as electron and ion temperatures in front of a westward travelling surge were studied. It was found that a short-lived brightening of...

Read More
  • Cover Image

Upper-mesospheric Temperatures Measured During Intense Substorms i...

By: U.-p. Hoppe; B. P. Williams; F. Honary; D. Heinrich; J. Stadsnes; H. Nesse Tyssøy; M. Sørbø; D. S. Evans

Description: Norwegian Defence Research Establishment, Kjeller, Norway. Temperature measurements from the ALOMAR Weber Na lidar together with cosmic radio noise absorption measurements from IRIS and particle measurements from NOAA 15, 16 and 17 are used to study effects of geomagnetic activity on the polar winter upper-mesospheric temperature. On 21–22 January 2005 we have 14 h of continuous temperature measurement with the Na lidar coinciding with strong geomagneti...

Arnold, K. S. and She, C.-Y.: Metal fluorescence lidar (light detection and ranging) and the middle atmosphere, Contemp. Phys., 44, 35–49, 2003.; Banks, P. M.: Observation of Joule and particle heating in the auroral zone, J. Atmos. Terr. Phys., 39, 179–193, 1977.; Banks, P. M.: Joule heating in the high-latitude mesosphere, J. Geophys. Res., 84, 6709–6712, 1979.; Barabash, V., Kirkwood, S., Feofilov, A., and Kutepov, A.: Polar mesosphere summer echoes during the July 20...

Read More
  • Cover Image

Cluster Observations of the Substructure of a Flux Transfer Event:...

By: M. André; A. N. Fazakerley; A. P. Walsh; I. Dandouras; A. Varsani; C. Forsyth; C. J. Owen; C. M. Carr

Description: UCL Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, RH5 6NT, UK. Flux transfer events (FTEs) are signatures of transient reconnection at the dayside magnetopause, transporting flux from the dayside of the magnetosphere into the magnetotail lobes. They have previously been observed to contain a combination of magnetosheath and magnetospheric plasma. On 12 February 2007, the four Cluster spacecraft were widely separated across the magnetopaus...

André, M., Vaivads, A., Buchert, S. C., Fazakerley, A. N., and Lahiff, A.: Thin electron-scale layers at the magnetopause, Geophys. Res. Lett., 31, L03803, doi:10.1029/2003gl018137, 2004.; André, M., Vaivads, A., Khotyaintsev, Y. V., Laitinen, T., Nilsson, H., Stenberg, G., Fazakerley, A., and Trotignon, J. G.: Magnetic reconnection and cold plasma at the magnetopause, Geophys. Res. Lett., 37, L22108,

Read More
  • Cover Image

Read More
  • Cover Image

Terrestrial Exospheric Hydrogen Density Distributions Under Solar ...

By: U. Nass; H. J. Fahr; J. H. Zoennchen

Description: Argelander Institut für Astronomie, Astrophysics Department, University of Bonn, Auf dem Huegel 71, 53121 Bonn, Germany. Circumterrestrial Lyman-α column brightness observations above 3 Earth radii (Re) have been used to derive separate 3-D neutral hydrogen density models of the Earth's exosphere for solar minimum (2008, 2010) and near-solar-maximum (2012) conditions. The data used were measured by Lyman-α detectors (LAD1/2) onboard eac...

Anderson, D. E. and Hord Jr., C. W.: Multidimensional radiative transfer – Applications to planetary coronae, Planet. Space Sci., 25, 563–571, doi:10.1016/0032-0633(77)90063-0, 1977.; Bailey, J. and Gruntman, M.: Experimental study of exospheric hydrogen atom distributions by Lyman-α detectors on the TWINS mission, J. Geophys. Res., 116, A09302, doi:10.1029/2011JA016...

Read More
  • Cover Image

A New Southern High-latitude Index : Volume 16, Issue 12 (30/11/-0001)

By: M. J. Engebretson; C. G. MacLennan; M. Candidi; G. Burns; J. Bitterly; C.-i. Meng; P. Ballatore

Description: IFSI/CNR, c.p.27, 00044 Frascati, Rome, Italy. We have developed and examined a new regional geomagnetic index AES-80, defined similarly to the classical auroral electrojet AE index, using data from five Antarctic stations located at corrected geomagnetic latitudes about 80 °S. Because only sparse ground-based information can be derived from auroral latitudes in the Southern Hemisphere, and because no index comparable to AE can be constructed from locat...

Read More
  • Cover Image

Modeling Solar Flare Induced Lower Ionosphere Changes Using Vlf/Lf...

By: E. D. Schmitter

Description: University of Applied Sciences Osnabrück, 49076 Osnabrück, Germany. Remote sensing of the ionosphere bottom using long wave radio signal propagation is a still going strong and inexpensive method for continuous monitoring purposes. We present a propagation model describing the time development of solar flare effects. Based on monitored amplitude and phase data from VLF/LF transmitters gained at a mid-latitude site during the currently increasing solar c...

Aiken, A. C.: The Ion Pair Production Function of the Lower Ionosphere, National Aeronautics and Space Administration. Goddard Space Flight Center, Technical report N70-18945, 1969.; Aschwanden, M. J.: Solar Flare Physics Enlivened by TRACE and RHESSI, J. Astrophys. Astr., 29, 115–124, 2008.; Belenkiy, M. I., Orlov, A. B., Petrova, G. A., and Uvarov, A. N.: Modeling of the electron density profile of the lower ionosphere (45–75 km) for sudden ionospheric disturbance cond...

Read More
  • Cover Image

Properties and Origin of Energetic Particles at the Duskside of th...

By: M. A. Athanasiu; E. T. Sarris; T. Yamamoto; S. Kokubun; D. V. Sarafopoulos

Description: Demokritos University of Thrace, Department of Electrical and Computer Engineering, Xanthi, GR-67100, Greece. We study an interval of 56 h on January 16 to 18, 1995, during which the GEOTAIL spacecraft traversed the duskside magnetosheath from 
X @ -15 to -40 RE and the EPIC/ICS and EPIC/STICS sensors sporadically detected tens of energetic particle bursts. This interval coincides with the expansion and gro...

Read More
  • Cover Image

On the Observed Changes in Upper Stratospheric and Mesospheric Tem...

By: E. Remsberg

Description: Science Directorate, NASA Langley Research Ctr., Hampton, VA, USA. Temperature versus pressure or T(p) time series from the Halogen Occultation Experiment (HALOE) of the Upper Atmosphere Research Satellite (UARS) have been extended and re-analyzed for the period of 1991–2005 and for the upper stratosphere and mesosphere in 10-degree wide latitude zones from 60 S to 60 N. Even though sampling from a solar occultation experiment is somewhat limited...

Akmaev, R. A., Fomichev, V. I., and Zhu, X.: Impact of middle-atmospheric composition changes on greenhouse cooling in the upper atmosphere, J. Atmos. Solar Terr. Phys., 68, 1879–1889, doi:10.1016/j.jastp.2006.03.008, 2006.; Baldwin, M. P., Gray, L. L., Dunkerton, T. J., et al.: The quasi-biennial oscillation, Rev. Geophys., 39, 179–229, 2001.; Barnett, J. J., Corney, M., and Labitzke, K.: Annual and semiannual cycles based on the middle atmosphere reference model in Sec...

Read More
  • Cover Image

Time Derivative of the Horizontal Geomagnetic Field as an Activity...

By: A. Pulkkinen; H. Nevanlinna; K. Pajunpää; A. Viljanen

Description: Finnish Meteorological Institute, Geophysical Research Division, P.O. Box 503, FIN-00101 Helsinki, Finland. Geomagnetically induced currents (GICs) in technological conductor systems are a manifestation of the ground effects of space weather. Large GICs are always associated with large values of the time derivative of the geomagnetic field, and especially with its horizontal component (dH/dt). By using the IMAGE magnetometer data from...

Read More
  • Cover Image

Survey of Cold Ionospheric Outflows in the Magnetotail : Volume 27...

By: M. André; C. M. Cully; A. I. Eriksson; H. Vaith; P. A. Puhl-quinn; R. Torbert; E. Engwall

Description: Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden. Low-energy ions escape from the ionosphere and constitute a large part of the magnetospheric content, especially in the geomagnetic tail lobes. However, they are normally invisible to spacecraft measurements, since the potential of a sunlit spacecraft in a tenuous plasma in many cases exceeds the energy-per-charge of the ions, and little is therefore known about their outflow prop...

Abe, T., Whalen, B A., Yau, A W., Horita, R E., Watanabe, S., and Sagawa, E.: EXOS-D (Akebono) SMS Observations of the Polar Wind, J. Geophys. Res., 98, 11191–11203, 1993.; Axford, W I.: The polar wind and the terrestrial helium budget, J. Geophys. Res., 73, 6855–6859, 1968.; Abe, T., Watanabe, S., Whalen, B A., Yau, A W., and Sagawa, E.: Observations of Polar Wind and Thermal Ion Outflow by Akebono/SMS, J. Geomag. Geoel., 48, 319–325, 1996.; Abe, T., Yau, A W., Watanabe...

Read More
  • Cover Image

Geomagnetic and Ionospheric Data Analysis Over Antarctica: a Contr...

By: G. De Franceschi; A. De Santis; L. Alfonsi

Description: Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143 Rome, Italy. The analysis of the foF2 ionosonde data acquired at mid and high latitudes reveals a general decreasing of the F2 plasma frequency over more than two solar cycles, showing steeper trends over the high latitude stations and, in particular, over Antarctica. A careful analysis of the foF2 hourly data, opportunely catalogued in different levels of magne...

Alfonsi, L., De Franceschi, G., and Perrone, L.: Long-term trend in the high latitude ionosphere, Physics and Chemistry of the Earth 26/5, 303-307, 2001.; Alfonsi, L., De Franceschi, G., Perrone, L., Materassi, M.: Long term trends of the critical frequency of the f2 layer at northern and southern high latitude regions, Phys. Chem. Earth, 27/6-8, 595–600, 2002.; Bremer, J.: Ionospheric trends in mid-latitudes as a possible indicator of the atmospheric greenhouse effect, ...

Read More
  • Cover Image

Gnevyshev Peaks in Solar Radio Emissions at Different Frequencies ...

By: R. P. Kane

Description: Instituto Nacional de Pesquisas Espacias, C.P. 515 São Jose dos Campos, 12201-970, SP, Brazil. Sunspots have a major 11-year cycle, but the years near the sunspot maximum show two or more peaks called GP (Gnevyshev Peaks). In this communication, it was examined whether these peaks in sunspots are reflected in other parameters such as Lyman-α (the chromospheric emission 121.6 nm), radio emissions 242–15 400 MHz emanating from altitude levels 2000–12 000 ...

Aschwanden, M. J. and Benz, A. O.: Chromospheric Evaporation and Decimetric Radio Emission in Solar Flares, Astrophys. J., 438, 997–1012, 1995.; Fontenla, J., White, O. R., Fox, P. A., Avrett, E. H., and Kurucz, R. L.: Calculation of Solar irradiances. I. Synthesis of the Solar spectrum, Astrophys. J., 518, 480–499, 1999.; Gnevyshev, M. N.: On the 11-Years Cycle of Solar Activity, Solar Phys., 1, 107–120, 1967.; Gnevyshev, M. N.: Essential features of the 11-year solar c...

Read More
 
1
|
2
|
3
Records: 1 - 20 of 45 - Pages: 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.