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Sample records for geomagnetic secular variation

  1. Geomagnetic secular variation at the African observatories

    International Nuclear Information System (INIS)

    Haile, T.

    2002-10-01

    Geomagnetic data from ten observatories in the African continent with time series data length of more than three decades have been analysed. All-day annual mean values of the D, H and Z components were used to study secular variations in the African region. The residuals in D, H and Z components obtained after removing polynomial fits have been examined in relation to the sunspot cycle. The occurrence of the 1969-1970 worldwide geomagnetic impulse in each observatory is studied. It is found that the secular variation in the field can be represented for most of the observatories with polynomials of second or third degree. Departures from these trends are observed over the Southern African region where strong local magnetic anomalies have been observed. The residuals in the geomagnetic field components have been shown to exhibit parallelism with the periods corresponding to double solar cycle for some of the stations. A clear latitudinal distribution in the geomagnetic component that exhibits the 1969-70 jerk is shown. The jerk appears in the plots of the first differences in H for the southern most observatories of Hermanus, Hartebeesthoek, and Tsuemb, while the Z plots show the jerk for near equatorial and equatorial stations of Antananarivo, Luanda Belas, Bangui and Addis Ababa. There is some indication for this jerk in the first difference plots of D for the northern stations of M'Bour and Tamanrasset. The plots of D rather strongly suggest the presence of a jerk around 1980 at most of the stations. (author)

  2. Geographical localisation of the geomagnetic secular variation

    DEFF Research Database (Denmark)

    Aubert, Julien; Finlay, Chris; Olsen, Nils

    2013-01-01

    the model and geomagnetic data previously processed in the same way. Our results suggest that conservation of angular momentum and heterogeneous thermochemical boundary control in the coupled inner core / outer core / mantle system are central to understanding how Earth’s magnetic field currently evolves......., westward moving, magnetic flux patches at the core surface. Despite its successes in explaining the main morphological properties of Earth’s magnetic field, self-consistent numerical modelling of the geodynamo has so far failed to reproduce this field variation pattern. Furthermore its magnetohydrodynamic...... control from either, or both, the inner-core boundary and the core-mantle boundary. In addition to presenting an Earth-like magnetic field morphology, these new numerical models also reproduce the morphology and localization of geomagnetic secular variation. In our models, the conservation of the angular...

  3. Geomagnetic Core Field Secular Variation Models

    DEFF Research Database (Denmark)

    Gillet, N.; Lesur, V.; Olsen, Nils

    2010-01-01

    highlight the difficulty of resolving the time variability of the high degree secular variation coefficients (i.e. the secular acceleration), arising for instance from the challenge to properly separate sources of internal and of external origin. In addition, the regularisation process may also result...

  4. geomagnetic secular variation and the 1969–1970 secular jerk

    African Journals Online (AJOL)

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    The plots of D rather strongly suggest the presence of a jerk around 1980 at most of the stations. Key words/phrases: Magnetic observatories, polynomial fitting, residuals, secular variation, secular jerk. INTRODUCTION. The magnetic field of the Earth has been observed to exhibit changes of remarkably wide spectral.

  5. Gravitational dynamos and the low-frequency geomagnetic secular variation.

    Science.gov (United States)

    Olson, P

    2007-12-18

    Self-sustaining numerical dynamos are used to infer the sources of low-frequency secular variation of the geomagnetic field. Gravitational dynamo models powered by compositional convection in an electrically conducting, rotating fluid shell exhibit several regimes of magnetic field behavior with an increasing Rayleigh number of the convection, including nearly steady dipoles, chaotic nonreversing dipoles, and chaotic reversing dipoles. The time average dipole strength and dipolarity of the magnetic field decrease, whereas the dipole variability, average dipole tilt angle, and frequency of polarity reversals increase with Rayleigh number. Chaotic gravitational dynamos have large-amplitude dipole secular variation with maximum power at frequencies corresponding to a few cycles per million years on Earth. Their external magnetic field structure, dipole statistics, low-frequency power spectra, and polarity reversal frequency are comparable to the geomagnetic field. The magnetic variability is driven by the Lorentz force and is characterized by an inverse correlation between dynamo magnetic and kinetic energy fluctuations. A constant energy dissipation theory accounts for this inverse energy correlation, which is shown to produce conditions favorable for dipole drift, polarity reversals, and excursions.

  6. Geomagnetic secular variation in India-regional and local features

    International Nuclear Information System (INIS)

    Srivastava, B.J.; Abbas, H.

    1977-01-01

    A study of the secular variation in the geomagnetic elements H, Z, F and D at Colaba (Bombay)-Alibag for the period 1848-1973, has been made. Fifth degree polynomials are fitted to the data of annual mean values of H, Z and F, and third degree to D, and the residuals discussed. The trends are also examined at the six Indian observatories using the data for 1960-1974. The increasing trend of Z at Alibag is found to decrease from about 1937, while that of H and F from 1965 at 20-30 nT/year, it being of the same order at Sabhawala and Hyderabad but smaller at the equatorial stations, particularly for Z component. The westward annual change in D swings eastward again around 1965 at all the Indian stations. This reversal of the secular variation trend in India after 1965 emerges as an important regional feature connected with a southward migration of the dip equator in India from 1968. The secular change in D at Alibag (+0.4'/year) is somewhat anomalous in the sense that it is reduced as compared to Hyderabad and other stations (+1.6'/year), probably due to the local magnetic anomaly of the Deccan lavas, and calls for detailed investigations. (auth.)

  7. Geomagnetic Secular Variation and Its Applications to the Core

    DEFF Research Database (Denmark)

    Jackson, Andrew; Finlay, Chris

    2015-01-01

    the mathematical models of the field’s evolution that can be derived from them. We discussthe prominent features of the field’s evolution, both at the Earth’s surface and at the surface of theliquid core. The final section concerns itself with a discussion of the interpretation of the field’sevolution, in terms......We review the observational constraints on the morphology and evolution of the magnetic field of the Earth over the last few centuries; these changes are referred to as the secular variation.Starting with a description of the available sources of original observations of the field, we thendiscuss...... of physical core processes. These divide themselves into processes associatedwith movement of core fluid, which is capable of advecting the field, and processes associated withthe finite resistivity of the core, commonly termed diffusive processes. We lay the foundations for some of the more theoretical...

  8. Bottom-up control of geomagnetic secular variation by the Earth's inner core

    DEFF Research Database (Denmark)

    Aubert, Julien; Finlay, Chris; Fournier, Alexandre

    2013-01-01

    of geomagnetic secular variation. Here we show that it can be reproduced provided that two mechanisms relying on the inner core are jointly considered. First, gravitational coupling5 aligns the inner core with the mantle, forcing the flow of liquid metal in the outer core into a giant, westward drifting, sheet...... release in the outer core which in turn distorts the gyre, forcing it to become eccentric, in agreement with recent core flow inversions6, 10, 11. This bottom-up heterogeneous driving of core convection dominates top-down driving from mantle thermal heterogeneities, and localizes magnetic variations......Temporal changes in the Earth’s magnetic field, known as geomagnetic secular variation, occur most prominently at low latitudes in the Atlantic hemisphere1, 2 (that is, from −90 degrees east to 90 degrees east), whereas in the Pacific hemisphere there is comparatively little activity...

  9. Geomagnetic secular variation at Addis Ababa over the last four ...

    African Journals Online (AJOL)

    Addis Ababa Observatory (aae) geomagnetic data analysed over the time-span 1958—1998 show that the annual mean values of the intensity have decreased since 1965 from 36186 nT to 35950 nT at a non-linear regression rate of 8—9 nT per year. Directional changes in the Earth's magnetic field that could be ...

  10. Time-causal decomposition of geomagnetic time series into secular variation, solar quiet, and disturbance signals

    Science.gov (United States)

    Rigler, E. Joshua

    2017-04-26

    A theoretical basis and prototype numerical algorithm are provided that decompose regular time series of geomagnetic observations into three components: secular variation; solar quiet, and disturbance. Respectively, these three components correspond roughly to slow changes in the Earth’s internal magnetic field, periodic daily variations caused by quasi-stationary (with respect to the sun) electrical current systems in the Earth’s magnetosphere, and episodic perturbations to the geomagnetic baseline that are typically driven by fluctuations in a solar wind that interacts electromagnetically with the Earth’s magnetosphere. In contrast to similar algorithms applied to geomagnetic data in the past, this one addresses the issue of real time data acquisition directly by applying a time-causal, exponential smoother with “seasonal corrections” to the data as soon as they become available.

  11. Long-Term Seafloor Electromagnetic Observation in the Northwest Pacific May Detect the Vector Geomagnetic Secular Variation

    Directory of Open Access Journals (Sweden)

    H Toh

    2010-03-01

    Full Text Available Sea Floor ElectroMagnetic Stations (SFEMSs are now operating at two deep seafloor sites called the 'WPB' and the 'NWP' in the West Philippine Basin and the Northwest Pacific Basin, respectively. One of the main objectives of the SFEMSs is to detect the geomagnetic secular variations on the deep seafloor where long-term geomagnetic observations have not so far been achieved. SFEMSs can measure the absolute geomagnetic total force as well as the geomagnetic vector field with precise attitude monitoring systems. The vector geomagnetic time-series that was observed for more than 5 years revealed that the westward drift of the equatorial dipole dominates in the geomagnetic secular variation at the NWP.

  12. The geomagnetic jerk of 2003.5-characterisation with regional observatory secular variation data

    Science.gov (United States)

    Feng, Yan; Holme, Richard; Cox, Grace Alexandra; Jiang, Yi

    2018-05-01

    The 2003.5 geomagnetic jerk was identified in geomagnetic records from satellite data, and a matching feature reported in variations in length-of-day (ΔLOD), but detailed study has been hampered by lack of geomagnetic observatory data where it appears strongest. Here we examine secular variation (annual differences of monthly means) based on a new resource of 43 Chinese observatory records for 1998 until the present, focusing on 10 series of particularly high quality and consistency. To obtain a clean series, we calculate the covariance matrix of residuals between measurements and a state-of-the-art field model, CHAOS-6, and use eigenvalue analysis to remove noisy contributions from the uncorrected data. The magnitude of the most significant eigenvector correlates well with Dcx (corrected, extended Dst), suggesting the noise originates from unmodelled external magnetic field. Removal of this noise eliminates much coherent misfit around 2003-2005; nevertheless, the 2003.5 jerk is seen clearly in the first time derivative of the East component in Chinese data, and is also seen in the first time derivative of the vertical component in European data. Estimates of the jerk time are centred on 2003.5, but with some spatial variation; this variation can be eliminated if we allow a discontinuity in the secular variation as well as its temporal gradient. Both regions also provide evidence for a jerk around 2014, although less clearly than 2003.5. We create a new field model based on new data and CHAOS-6 to further examine the regional signals. The new model is close to CHAOS-6, but better fits Chinese data, although modelling also identifies some data features as unphysical.

  13. Dynamic Responses of the Earth's Outer Core to Assimilation of Observed Geomagnetic Secular Variation

    Science.gov (United States)

    Kuang, Weijia; Tangborn, Andrew

    2014-01-01

    Assimilation of surface geomagnetic observations and geodynamo models has advanced very quickly in recent years. However, compared to advanced data assimilation systems in meteorology, geomagnetic data assimilation (GDAS) is still in an early stage. Among many challenges ranging from data to models is the disparity between the short observation records and the long time scales of the core dynamics. To better utilize available observational information, we have made an effort in this study to directly assimilate the Gauss coefficients of both the core field and its secular variation (SV) obtained via global geomagnetic field modeling, aiming at understanding the dynamical responses of the core fluid to these additional observational constraints. Our studies show that the SV assimilation helps significantly to shorten the dynamo model spin-up process. The flow beneath the core-mantle boundary (CMB) responds significantly to the observed field and its SV. The strongest responses occur in the relatively small scale flow (of the degrees L is approx. 30 in spherical harmonic expansions). This part of the flow includes the axisymmetric toroidal flow (of order m = 0) and non-axisymmetric poloidal flow with m (is) greater than 5. These responses can be used to better understand the core flow and, in particular, to improve accuracies of predicting geomagnetic variability in future.

  14. A model of the geomagnetic field and its secular variation for epoch 2000 estimated from Orsted data

    DEFF Research Database (Denmark)

    Olsen, Nils

    2002-01-01

    as measured simultaneously by globally distributed geomagnetic observatories. In addition, the observatory data are used to constrain secular variation. The model is estimated using an iteratively reweighted least-squares method with Huber weights to account for the non-Gaussian data error distribution...

  15. Constraints on geomagnetic secular variation modeling from electromagnetism and fluid dynamics of the Earth's core

    Science.gov (United States)

    Benton, E. R.

    1986-01-01

    A spherical harmonic representation of the geomagnetic field and its secular variation for epoch 1980, designated GSFC(9/84), is derived and evaluated. At three epochs (1977.5, 1980.0, 1982.5) this model incorporates conservation of magnetic flux through five selected patches of area on the core/mantle boundary bounded by the zero contours of vertical magnetic field. These fifteen nonlinear constraints are included like data in an iterative least squares parameter estimation procedure that starts with the recently derived unconstrained field model GSFC (12/83). Convergence is approached within three iterations. The constrained model is evaluated by comparing its predictive capability outside the time span of its data, in terms of residuals at magnetic observatories, with that for the unconstrained model.

  16. Geomagnetic secular variation from recent lake sediments, ancient fireplaces and historical measurements in southeastern Australia

    Science.gov (United States)

    Barton, C. E.; Barbetti, Mike

    1982-07-01

    Compilations of historical observations, archaeomagnetic data from ancient fireplaces and palaemagetic results from short cores of sediment from lakes in southeastern Australia, particularly Lake Keilambete, provide a detailed record of the geomagnetic secular variation during the last 3000 years. The independent sets of data are in good agreement if the radiocarbon time scale for the lacustrine record is about 450 years too old. The error is attributed to systematic incorporation of ancient carbon into the lake floor sediments, mainly through erosion of sediment on the crater walls at times of low water level. A significant lag between deposition and the acquisition of stable magnetic remanence is ruled out. Inclination has been abnormally steep during the last 500 years but remained fairly close to the axial dipole field value prior to that. During the last 1000 years the predominant sense of looping of the magnetic vector corresponds to westward drift of the nondipole field. Secular variations on a time scale of ˜ 100 years can be resolved by the lacustrine record.

  17. Importance of selecting archaeomagnetic data for geomagnetic modelling: example of the new Western Europe directional and intensity secular variation curves from 1500 BC to 200 AD

    Science.gov (United States)

    Herve, Gwenael; Chauvin, Annick; Lanos, Philippe

    2014-05-01

    At the regional scale, the dispersion between archaeomagnetic data and especially archaeointensities suggests that some of them may be biased. As a consequence, it appears necessary to perform a selection of available data before to compute mean regional secular variation curves or geomagnetic models. However the definition of suitable selection criteria is not obvious and we need to know how to manage "old" data acquired during the 60-70s. The Western Europe directional and intensity data set from 1500 BC to 200 AD allows to discuss these issues. It has recently been enhanced by 39 new archaeodirections and 23 new archaeointensities (Hervé et al., 2013a and 2013b data sets and 5 unpublished data). First, the whole Western Europe data set was selected but the strong dispersion restricted the accuracy and the reliability of the new Western Europe secular variation curves at Paris. The causes of the dispersion appear different between archaeodirections and archaeointensities. In the directional data set, the main problem comes from some age errors in the oldest published data. Since their publication their archaeological dating may have changed of 50 years or more. For intensity data that were acquired much more recently, the dispersion mainly results from the use of unreliable archaeointensity protocols. We propose a weighting approach based on the number of specimens and the use of pTRM-checks, anisotropy and cooling rate corrections. Only 63% of available archaeodirections and 32% of archaeointensities were used to build the new Western Europe secular variation curves from 1500 BC to 200 AD. These curves reveal that selecting the reference data avoids wrong estimations of the shape of the secular variation curves, the secular variation rate, the dating of archaeomagnetic jerks... Finally, it is worth pointing out that current geomagnetic global models take into account almost all the data that we decided to reject. It could partly explain why their predictions at

  18. Prospect of Using Numerical Dynamo Model for Prediction of Geomagnetic Secular Variation

    Science.gov (United States)

    Kuang, Weijia; Tangborn, Andrew

    2003-01-01

    Modeling of the Earth's core has reached a level of maturity to where the incorporation of observations into the simulations through data assimilation has become feasible. Data assimilation is a method by which observations of a system are combined with a model output (or forecast) to obtain a best guess of the state of the system, called the analysis. The analysis is then used as an initial condition for the next forecast. By doing assimilation, not only we shall be able to predict partially secular variation of the core field, we could also use observations to further our understanding of dynamical states in the Earth's core. One of the first steps in the development of an assimilation system is a comparison between the observations and the model solution. The highly turbulent nature of core dynamics, along with the absence of any regular external forcing and constraint (which occurs in atmospheric dynamics, for example) means that short time comparisons (approx. 1000 years) cannot be made between model and observations. In order to make sensible comparisons, a direct insertion assimilation method has been implemented. In this approach, magnetic field observations at the Earth's surface have been substituted into the numerical model, such that the ratio of the multiple components and the dipole component from observation is adjusted at the core-mantle boundary and extended to the interior of the core, while the total magnetic energy remains unchanged. This adjusted magnetic field is then used as the initial field for a new simulation. In this way, a time tugged simulation is created which can then be compared directly with observations. We present numerical solutions with and without data insertion and discuss their implications for the development of a more rigorous assimilation system.

  19. Low Amplitude of Geomagnetic Secular Variations Recorded in Traps of the Southern Siberian Platform: Very Fast Emplacement or Regional Remagnetization?

    Science.gov (United States)

    Veselovskiy, R. V.; Latyshev, A. V.; Pavlov, V. E.

    2011-12-01

    We have studied the lowest part of the Permo-Triassic Siberian trap sequence which is located in the middle course of the Angara river (Southern Siberia). This sequenced is composed by 200m thick volcanoclastic rocks (tuffs with bombs of different composition) and includes numerous mafic subvolcanic bodies (dykes and sills). Altogether more than 20 sites representing tuffs, bombs, dykes and sills stretched along the valley of the Angara river over the distance more than 30 km have been sampled and studied. Obtained site mean paleomagnetic directions are tightly grouped, showing very lower scatter. Taking into account that amplitude of geomagnetic secular variation at the P-T boundary was about of same order as in Late Cenozoic (Pavlov et al., 2011) this lower scatter can be either a sequence of very fast traps emplacement which could have disastrous environmental impact or a result of subsequent regional remagnetization. The only geological event in the region which seems to be capable to cause this remagnetization is emplacement of Early Triassic sills in nearby areas. In such the case we should expect that mean paleomagnetic directions from these sills will be very close to these ones obtained from site presented in this report. We present results of paleomagnetic studies of these sills and make a choice in favor of one of discussed options. This work was supported by grants NSF EAR 0807585 ("The Siberian Traps and end-Permian extinction") and RFBR 09-05-01180, 10-05-00557.

  20. Recent geomagnetic secular variation from Swarm and ground observatories as estimated in the CHAOS-6 geomagnetic field model

    DEFF Research Database (Denmark)

    Finlay, Chris; Olsen, Nils; Kotsiaros, Stavros

    2016-01-01

    We use more than 2 years of magnetic data from the Swarm mission, and monthly means from 160 ground observatories as available in March 2016, to update the CHAOS time-dependent geomagnetic field model. The new model, CHAOS-6, provides information on time variations of the core-generated part......, jets at low latitudes, for example close to 40 degrees W, that may be responsible for localized SA oscillations. In addition to scalar data from Orsted, CHAMP, SAC-C and Swarm, and vector data from Orsted, CHAMP and Swarm, CHAOS-6 benefits from the inclusion of along-track differences of scalar...... and vector field data from both CHAMP and the three Swarm satellites, as well as east-west differences between the lower pair of Swarm satellites, Alpha and Charlie. Moreover, ground observatory SV estimates are fit to a Huber-weighted rms level of 3.1 nT/year for the eastward components and 3.8 and 3.7 n...

  1. Evaluating secular acceleration in geomagnetic field model GRIMM-3

    Science.gov (United States)

    Lesur, V.; Wardinski, I.

    2012-12-01

    Secular acceleration of the magnetic field is the rate of change of its secular variation. One of the main results of studying magnetic data collected by the German survey satellite CHAMP was the mapping of field acceleration and its evolution in time. Questions remain about the accuracy of the modeled acceleration and the effect of the applied regularization processes. We have evaluated to what extent the regularization affects the temporal variability of the Gauss coefficients. We also obtained results of temporal variability of the Gauss coefficients where alternative approaches to the usual smoothing norms have been applied for regularization. Except for the dipole term, the secular acceleration of the Gauss coefficients is fairly well described up to spherical harmonic degree 5 or 6. There is no clear evidence from observatory data that the spectrum of this acceleration is underestimated at the Earth surface. Assuming a resistive mantle, the observed acceleration supports a characteristic time scale for the secular variation of the order of 11 years.

  2. On polar daily geomagnetic variation

    Directory of Open Access Journals (Sweden)

    Paola De Michelis

    2015-11-01

    Full Text Available The aim of this work is to investigate the nature of the daily magnetic field perturbations produced by ionospheric and magnetospheric currents at high latitudes. We analyse the hourly means of the X and Y geomagnetic field components recorded by a meridian chain of permanent geomagnetic observatories in the polar region of the Northern Hemisphere during a period of four years (1995-1998 around the solar minimum. We apply a mathematical method, known as natural orthogonal component (NOC, which is capable of characterizing the dominant modes of the geomagnetic field daily variability through a set of empirical orthogonal functions (EOFs. Using the first two modes we reconstruct a two-dimensional equivalent current representation of the ionospheric electric currents, which contribute substantially to the geomagnetic daily variations. The obtained current structures resemble the equivalent current patterns of DP2 and DP1. We characterize these currents by studying their evolution with the geomagnetic activity level and by analysing their dependence on the interplanetary magnetic field. The obtained results support the idea of a coexistence of two main processes during all analysed period although one of them, the directly driven process, represents the dominant component of the geomagnetic daily variation.

  3. Refined permo-triassic paleomagnetic pole for the Siberian platform and geomagnetic secular variations at the Paleozoic-Mesozoic boundary as recorded in volcanic traps key sections of northern Siberia

    Science.gov (United States)

    Pavlov, V. E.; Veselovskiy, R. V.; Khokhlov, A.; Latyshev, A. V.; fluteau, F.

    2011-12-01

    Two new volcanic key sections of the Siberian traps erupted ~ 250 million years ago have been studied in the Norilsk region (NW of the Siberian platform). Along with results obtained earlier from both this area (Heunemann et al., 2004) and Maymecha-Kotuy region (northern Siberian platform, Pavlov et al., 2011) these data constitute rather extensive database, including paleomagnetic information on about 200 volcanic flows. Using this information we can not only get refined permo-triassic paleomagnetic pole for the Siberian platform, based exceptionally on lava flows data, but also estimate amplitude of geomagnetic secular variation at the Paleozoic-Mesozoic boundary and check their compatibility with statistic models, suggested for description of recent (Late Cenozoic) Earth's magnetic field. Moreover, our results can be also used to obtain additional time constraints on duration of the trap emplacement and to isolate volcanic pulses within the traps sections. We present a report where we discuss all these topics. This work was supported by grants NSF # EAR 0807585 and RBRF #09-05-01180, 11-05-00601,10-05- 00557.

  4. Time variations in geomagnetic intensity

    Science.gov (United States)

    Valet, Jean-Pierre

    2003-03-01

    After many years spent by paleomagnetists studying the directional behavior of the Earth's magnetic field at all possible timescales, detailed measurements of field intensity are now needed to document the variations of the entire vector and to analyze the time evolution of the field components. A significant step has been achieved by combining intensity records derived from archeological materials and from lava flows in order to extract the global field changes over the past 12 kyr. A second significant step was due to the emergence of coherent records of relative paleointensity using the remanent magnetization of sediments to retrace the evolution of the dipole field. A third step was the juxtaposition of these signals with those derived from cosmogenic isotopes. Contemporaneous with the acquisition of records, new techniques have been developed to constrain the geomagnetic origin of the signals. Much activity has also been devoted to improving the quality of determinations of absolute paleointensity from volcanic rocks with new materials, proper selection of samples, and investigations of complex changes in magnetization during laboratory experiments. Altogether these developments brought us from a situation where the field changes were restricted to the past 40 kyr to the emergence of a coherent picture of the changes in the geomagnetic dipole moment for at least the past 1 Myr. On longer timescales the field variability and its average behavior is relatively well documented for the past 400 Myr. Section 3 gives a summary of most methods and techniques that are presently used to track the field intensity changes in the past. In each case, current limits and potential promises are discussed. The section 4 describes the field variations measured so far over various timescales covered by the archeomagnetic and the paleomagnetic records. Preference has always been given to composite records and databases in order to extract and discuss major and global geomagnetic

  5. Lunar nitrogen: Secular variation or mixing?

    International Nuclear Information System (INIS)

    Norris, S.J.; Wright, I.P.; Pillinger, C.T.

    1986-01-01

    The two current models to explain the nearly 40% variation of the lunar nitrogen isotopic composition are: (1) secular variation of solar wind nitrogen; and (2) a two component mixing model having a constant, heavy solar wind admixed with varying amounts of indigenous light lunar N (LLN). Both models are needed to explain the step pyrolysis extraction profile. The secular variation model proposes that the low temperature release is modern day solar wind implanted into grain surfaces, the 900 C to 1100 C release is from grain surfaces which were once exposed to the ancient solar wind but which are now trapped inside agglutinates, and the >1100 C release as spallogenic N produced by cosmic rays. The mixing model ascribes the components to solar wind, indigenous lunar N and spallogenic N respectively. An extension of either interpretation is that the light N seen in lunar breccias or deep drill cores represent conditions when more N-14 was available to the lunar surface

  6. Daily variation characteristics at polar geomagnetic observatories

    Science.gov (United States)

    Lepidi, S.; Cafarella, L.; Pietrolungo, M.; Di Mauro, D.

    2011-08-01

    This paper is based on the statistical analysis of the diurnal variation as observed at six polar geomagnetic observatories, three in the Northern and three in the Southern hemisphere. Data are for 2006, a year of low geomagnetic activity. We compared the Italian observatory Mario Zucchelli Station (TNB; corrected geomagnetic latitude: 80.0°S), the French-Italian observatory Dome C (DMC; 88.9°S), the French observatory Dumont D'Urville (DRV; 80.4°S) and the three Canadian observatories, Resolute Bay (RES; 83.0°N), Cambridge Bay (CBB; 77.0°N) and Alert (ALE, 87.2°N). The aim of this work was to highlight analogies and differences in daily variation as observed at the different observatories during low geomagnetic activity year, also considering Interplanetary Magnetic Field conditions and geomagnetic indices.

  7. The use of MAGSAT data to determine secular variation.

    Science.gov (United States)

    Cain, J.C.; Frayser, J.; Muth, L.; Schmitz, D.

    1983-01-01

    A combined spatial and secular variation model of the geomagnetic field, labeled M061581, is derived from a selection of MAGSAT data. Secular variation (SV) data computed from linear fits to midnight hourly values from 19 magnetic observatories were also included in the analysis but were seen to have little effect on the model. The SV patterns from this new model are compared with those from the 1980 IGRF and with those for 1970 computed by the DGRF and with the 1960 patterns computed using the GSFC(12/66) model. Most of the features of the M061581 are identical in location and level with those of the 1980 IGRF. Together they confirm that the reversals in sign of field change seen over Asia and North America between 1965 and 1975 are reverting to the pre-1965 states. The M061581 model gives -32 nT/yr for the dipole decay rate, larger than the 70% increase already reported since 1965. -Authors

  8. Evaluation of a new paleosecular variation activity index as a diagnostic tool for geomagnetic field variations

    Science.gov (United States)

    Panovska, Sanja; Constable, Catherine

    2015-04-01

    Geomagnetic indices like Dst, K and A, have been used since the early twentieth century to characterize activity in the external part of the modern geomagnetic field and as a diagnostic for space weather. These indices reflect regional and global activity and serve as a proxy for associated physical processes. However, no such tools are yet available for the internal geomagnetic field driven by the geodynamo in Earth's liquid outer core. To some extent this reflects limited spatial and temporal sampling for longer timescales associated with paleomagnetic secular variation, but recent efforts in both paleomagnetic data gathering and modeling activity suggest that longer term characterization of the internal geomagnetic weather/climate and its variability would be useful. Specifically, we propose an index for activity in paleosecular variation, useful as both a local and global measure of field stability during so-called normal secular variation and as a means of identifying more extreme behavior associated with geomagnetic excursions and reversals. To date, geomagnetic excursions have been identified by virtual geomagnetic poles (VGPs) deviating more than some conventional limit from the geographic pole (often 45 degrees), and/or by periods of significant intensity drops below some critical value, for example 50% of the present-day field. We seek to establish a quantitative definition of excursions in paleomagnetic records by searching for synchronous directional deviations and lows in relative paleointensity. We combine paleointensity variations with deviations from the expected geocentric axial dipole (GAD) inclination in a single parameter, which we call the paleosecular variation (PSV) activity index. This new diagnostic can be used on any geomagnetic time series (individual data records, model predictions, spherical harmonic coefficients, etc.) to characterize the level of paleosecular variation activity, find excursions, or even study incipient reversals

  9. Study about geomagnetic variations from data recorded at Surlari Geomagnetic Observatory

    Science.gov (United States)

    Asimopolos, Laurentiu; Asimopolos, Natalia-Silvia; Sandulescu, Agata Monica; Niculici, Eugen

    2013-04-01

    This paper presents statistical and spectral analysis of data from Surlari Geomagnetic Observatory that contributing to study of geomagnetic variations. Thus were highlighted, for long series of records over several solar cycles, periodicities of 22 years and 11 years. Following the same procedures for medium recording series (multi-annual) have highlighted annual, seasonal and monthly periodicities. For shorter data series, we highlighted diurnal, semidiurnal, 8 hours and even lower periodicities. For very short series with a high sample rate and for few magnetotellurics records, we highlight different types of pulsations (Pc2 - Pc5 and Pi 2). Geomagnetic signals are the convolution product of the atomic stationary signals mono-frequential of different amplitudes associated to phenomena with a very broad band of periodicities and nondeterministic signals associated with geomagnetic disturbances and non-periodic phenomena. Among analysis processes used for discrete series of geomagnetic data with different lengths and sampling rates, can conclude the following: Moving average works as a low pass filter in frequency or high pass in time. By eliminating high frequency components (depending on mobile window size used) can be studied preferential periodicities greater than a given value. Signal linearization (using least squares) provides information on linear trend of the entire series analyzed. Thus, for the very long data series (several decades) we extracted the secular variation slope for each geomagnetic component, separately. The numeric derivative of signal versus time proved to be a very reliable indicator for geomagnetic disturbed periods. Thus, the derivative value may be increased by several orders of magnitude during periods of agitation in comparisons to calm periods. The correlation factor shows significant increases when between two time series a causal relationship exists. Variation of the correlation factor, calculated for a mobile window containing k

  10. Secular variation of cosmic ray intensity recorded in the radiocarbon concentration of tree rings

    International Nuclear Information System (INIS)

    Kigoshi, K.

    1978-01-01

    Study of the secular variations of cosmic ray intensity on the basis of the secular variations of atmospheric radiocarbon concentration in 8000 years is considered. The data on the radiocarbon concentration is received by three laboratories using the dendrochronologically dated tree ring samples. In order to use the data the variations due to geochemical process must be eliminated. From this point of view the climatic effect on the atmospheric radiocarbon concenttration is estimated using the data on sunspot number and global surface temperature during 1650-1800 y. The barge influence of climate on the atmospheric radiocarbon concentration syggests the small contribution of change of radiocarbon production rate to the short-period fluctuations in the atmospheric radiocarbon concentration. Elimination of variations caused by climate and sunspot activities from the variations in atmospheric radiocarbon concentration gives a long-term scale of its concentration which agrees well to the observed paleo-geomagnetic data

  11. Solar wind velocity and geomagnetic moment variations

    International Nuclear Information System (INIS)

    Kalinin, Yu.D.; Rozanova, T.S.

    1982-01-01

    The mean year values of the solar wind velocity have been calculated from the mean-year values of a geomagnetic activity index am according to the Svalgard equation of regression for the pe-- riod from 1930 to 1960. For the same years the values of the geomagnetic moment M and separately of its ''inner'' (causes of which'' are inside the Earth) and ''external'' (causes of which are outside the Earth) parts have been calculated from the mean year data of 12 magnetic observatories. The proof of the presence of the 11-year variation in the moment M has been obtained. It is concluded that the 11-year variations in M result from the variations of the solar wind velocity

  12. A Statistical Model of the Fluctuations in the Geomagnetic Field from Paleosecular Variation to Reversal

    Science.gov (United States)

    Camps; Prevot

    1996-08-09

    The statistical characteristics of the local magnetic field of Earth during paleosecular variation, excursions, and reversals are described on the basis of a database that gathers the cleaned mean direction and average remanent intensity of 2741 lava flows that have erupted over the last 20 million years. A model consisting of a normally distributed axial dipole component plus an independent isotropic set of vectors with a Maxwellian distribution that simulates secular variation fits the range of geomagnetic fluctuations, in terms of both direction and intensity. This result suggests that the magnitude of secular variation vectors is independent of the magnitude of Earth's axial dipole moment and that the amplitude of secular variation is unchanged during reversals.

  13. The Egyptian geomagnetic reference field to the Epoch, 2010.0

    Directory of Open Access Journals (Sweden)

    H.A. Deebes

    2017-06-01

    The geomagnetic anomaly maps, the normal geomagnetic field maps with their corresponding secular variation maps, the normal geomagnetic field equations of the geomagnetic elements (EGRF and their corresponding secular variations equations, are outlined. The anomalous sites, as discovered from the anomaly maps are, only, mentioned. In addition, a correlation between the International Geomagnetic Reference Field (IGRF 2010.0 and the Egyptian Geomagnetic Reference Field (EGRF 2010 is indicated.

  14. Statistical analysis of geomagnetic field variations during solar eclipses

    Science.gov (United States)

    Kim, Jung-Hee; Chang, Heon-Young

    2018-04-01

    We investigate the geomagnetic field variations recorded by INTERMAGNET geomagnetic observatories, which are observed while the Moon's umbra or penumbra passed over them during a solar eclipse event. Though it is generally considered that the geomagnetic field can be modulated during solar eclipses, the effect of the solar eclipse on the observed geomagnetic field has proved subtle to be detected. Instead of exploring the geomagnetic field as a case study, we analyze 207 geomagnetic manifestations acquired by 100 geomagnetic observatories during 39 solar eclipses occurring from 1991 to 2016. As a result of examining a pattern of the geomagnetic field variation on average, we confirm that the effect can be seen over an interval of 180 min centered at the time of maximum eclipse on a site of a geomagnetic observatory. That is, demonstrate an increase in the Y component of the geomagnetic field and decreases in the X component and the total strength of the geomagnetic field. We also find that the effect can be overwhelmed, depending more sensitively on the level of daily geomagnetic events than on the level of solar activity and/or the phase of solar cycle. We have demonstrated it by dividing the whole data set into subsets based on parameters of the geomagnetic field, solar activity, and solar eclipses. It is suggested, therefore, that an evidence of the solar eclipse effect can be revealed even at the solar maximum, as long as the day of the solar eclipse is magnetically quiet.

  15. Variations in the geomagnetic dipole moment during the Holocene and the past 50 kyr

    Science.gov (United States)

    Knudsen, Mads Faurschou; Riisager, Peter; Donadini, Fabio; Snowball, Ian; Muscheler, Raimund; Korhonen, Kimmo; Pesonen, Lauri J.

    2008-07-01

    All absolute paleointensity data published in peer-reviewed journals were recently compiled in the GEOMAGIA50 database. Based on the information in GEOMAGIA50, we reconstruct variations in the geomagnetic dipole moment over the past 50 kyr, with a focus on the Holocene period. A running-window approach is used to determine the axial dipole moment that provides the optimal least-squares fit to the paleointensity data, whereas associated error estimates are constrained using a bootstrap procedure. We subsequently compare the reconstruction from this study with previous reconstructions of the geomagnetic dipole moment, including those based on cosmogenic radionuclides ( 10Be and 14C). This comparison generally lends support to the axial dipole moments obtained in this study. Our reconstruction shows that the evolution of the dipole moment was highly dynamic, and the recently observed rates of change (5% per century) do not appear unique. We observe no apparent link between the occurrence of archeomagnetic jerks and changes in the geomagnetic dipole moment, suggesting that archeomagnetic jerks most likely represent drastic changes in the orientation of the geomagnetic dipole axis or periods characterized by large secular variation of the non-dipole field. This study also shows that the Holocene geomagnetic dipole moment was high compared to that of the preceding ˜ 40 kyr, and that ˜ 4 · 10 22 Am 2 appears to represent a critical threshold below which geomagnetic excursions and reversals occur.

  16. Geomagnetic Field Variation during Winter Storm at Localized ...

    Indian Academy of Sciences (India)

    that transports plasma and magnetic flux which create the geomagnetic field variation. Key words. Dst—vertical component of interplanetary magnetic field and geomagnetic field components. 1. Introduction. The magnetic field is one of the important properties of the earth. The main magnetic field originates from ...

  17. Secular variations of radon in metropolitan Vancouver, British Columbia, Canada

    International Nuclear Information System (INIS)

    Ghomshei, M.M.; Slawson, W.F.

    1990-01-01

    In this paper sampling of radon within the soil from three sites in metropolitan Vancouver is reported. Alpha trace bi-weekly measurements during a period of 4 years show secular variations with a period of 8-15 months. There are low-radon and high-radon episodes enduring several months to a year. Average radon level during the high-radon episodes reaches 5-10 times that of the low-radon periods. During high-radon episodes the high-frequency variations show very high amplitudes. After filtering of the high-frequency fluctuations, the data from different sites demonstrate remarkably similar trends. It is suggested that along with hydrogeological events, stress relaxation in rocks, earthquake, and magma emplacement may contribute to the sources of secular variations of radon. Because of long-term variations, radon level in urban areas should be monitored on a continuous basis. Single measurements, even those integrating radiation over a period of few months, may sample a low-radon episode, and provide a false assurance, or occur during a high-radon episode and give a false alarm

  18. A case for variational geomagnetic data assimilation: insights from a one-dimensional, nonlinear, and sparsely observed MHD system

    Directory of Open Access Journals (Sweden)

    A. Fournier

    2007-01-01

    Full Text Available Secular variations of the geomagnetic field have been measured with a continuously improving accuracy during the last few hundred years, culminating nowadays with satellite data. It is however well known that the dynamics of the magnetic field is linked to that of the velocity field in the core and any attempt to model secular variations will involve a coupled dynamical system for magnetic field and core velocity. Unfortunately, there is no direct observation of the velocity. Independently of the exact nature of the above-mentioned coupled system – some version being currently under construction – the question is debated in this paper whether good knowledge of the magnetic field can be translated into good knowledge of core dynamics. Furthermore, what will be the impact of the most recent and precise geomagnetic data on our knowledge of the geomagnetic field of the past and future? These questions are cast into the language of variational data assimilation, while the dynamical system considered in this paper consists in a set of two oversimplified one-dimensional equations for magnetic and velocity fields. This toy model retains important features inherited from the induction and Navier-Stokes equations: non-linear magnetic and momentum terms are present and its linear response to small disturbances contains Alfvén waves. It is concluded that variational data assimilation is indeed appropriate in principle, even though the velocity field remains hidden at all times; it allows us to recover the entire evolution of both fields from partial and irregularly distributed information on the magnetic field. This work constitutes a first step on the way toward the reassimilation of historical geomagnetic data and geomagnetic forecast.

  19. Fast geomagnetic Field Intensity Variations between 1400 and 400 BCE: New Archaeointensity Data from Germany

    Science.gov (United States)

    Hervé, G.; Schnepp, E.; Metzler-Nebelsick, C.; Lhuillier, F.; Gilder, S.; Genevey, A.; Fassbinder, J.; Gallet, Y.

    2017-12-01

    Thirty-five mean archaeointensity data were obtained on ceramic sherds dated between 1400 and 400 BCE from sites located near Munich, Germany. The 453 sherds were collected from 52 graves, pits and wells dated by archaeological correlation, radiocarbon and/or dendrochronology. Rock magnetic analyses indicate that the remanent magnetization was mainly carried by magnetite. Data from Thellier-Thellier experiments were corrected for anisotropy and cooling rate effects. Triaxe and multispecimen (MSP-DSC) protocols were also measured on a subset of specimens. Around 60% of the samples provide reliable results when using stringent criteria selection. The 35 average archaeointensity values based on 154 pots are consistent with previous data and triple the Western Europe database between 1400 and 400 BCE. A secular variation curve for central-western Europe, built using a Bayesian approach, shows a double oscillation in geomagnetic field strength with intensity maxima of 70 μT around 1000-900 BCE and another up to 90 μT around 600-500 BCE. The maximum rate of variation was 0.25 μT/yr circa 700 BCE. The secular variation trend in Western Europe is similar to that observed in the Middle East and the Caucasus except that we find no evidence for hyper-rapid field variations (i.e. geomagnetic spikes). Virtual Axial Dipole Moments from Western Europe, the Middle East and central Asia differ by more than 20 ZA·m2 prior to 600 BCE, which signifies a departure from an axial dipole field especially between 1000 and 600 BCE. Our observations suggest that the regional Levantine Iron Age anomaly has been accompanied by an increase of the axial dipole moment together with a tilt of the dipole.

  20. Archeointensities in Greece during the Neolithic period: New insights into material selection and secular variation curve

    Science.gov (United States)

    Fanjat, G.; Aidona, E.; Kondopoulou, D.; Camps, P.; Rathossi, C.; Poidras, T.

    2013-02-01

    Numerous archeomagnetic studies have provided high quality data for both the direction and the intensity of the geomagnetic field, essentially in Europe for the last 10 millennia. In particular, Greece supplies a lot of archeological materials due to its impressive cultural heritage and volcanic activity, so that numerous data have been obtained from burnt clays or historical lava flows. The most recent Greek secular variation curves are available for the last 8 millennia for the intensity and the last 6 millennia for the direction. Nevertheless, the coverage still presents several gaps for periods older than 2500 BC. In an effort to complete the Greek curve and extend it to older times, we present the archeointensity results from three Neolithic settlements in Northern Greece. The samples are of two different natures: burnt structures from Avgi (5250 ± 150 BC) and Vasili (4800 ± 200 BC), as well as ceramics from Dikili Tash (4830 ± 80 BC) and Vasili (4750 ± 250 BC). The samples have been subjected to standard rock magnetic analyses in order to estimate the thermal stability and the domain state of the magnetic carriers before archeointensity measurements. Surprisingly, very few ceramic samples provided reliable archeointensities whereas samples from burnt structures presented a very good success rate. Complementary studies showed that a detailed examination of the matrix color, following archeological information and classification standards can be a decisive test for pre-selection of sherds. In spite of these unsuccessful measurements from ceramics, we obtained an intensity value of 73.5 ± 1.1 μT for Dikili Tash, a higher value than the other data obtained in the same area, during the same period. However we do not have evidences for a technical artefact during the experiment. The burnt structures yielded two reliable archeointensities of 36.1 ± 1.8 μT and 46.6 ± 3.4 μT for Avgi and Vasili, respectively. Finally, we achieved a new archeomagnetic dating

  1. Secular Orbit and Spin Variations of Asteroid (16) Psyche

    Science.gov (United States)

    Bills, B. G.; Park, R. S.; Scott, B.

    2016-12-01

    The obliquity, or angular separation between spin and orbit poles, of asteroid (16) Psyche is currently 95 degrees. We are interested in knowing how much that angular separation varies, on time scales of 104 to 106 years. To answer that question, we have done several related analyses. On short time scales, the orbital element variations of Psyche are dominated by perturbations from Jupiter. Jupiter's dominance has two basic causes: first is the large mass and relatively close position of Jupiter, and second is a 19:8 mean motion resonance. Jupiter completes 8 orbits in 94.9009 years, while Psyche takes 94.9107 years to complete 19 orbits. As a result of this, all of the orbital elements of Psyche exhibit significant periodic variations, with a 94.9 year period dominating. There are also significant variations at the synodic period, which is 8.628 years, or 1/11 of the resonant period. Over a 1000 year time span, centered on the present, the eccentricity varies from 0.133 to 0.140, and the inclination varies from 2.961 to 3.229 degrees. On longer time scales, the orbital elements of Psyche vary considerably more than that, due to secular perturbations from the planets. The secular variations are modeled as the response of interacting mass rings, rather than point masses. Again, Jupiter is the main perturbing influence on Psyche. The eccentricity and inclination both oscillate, with dominant periods of 18.667 kyr. The range of values seen over a million year time span, is 0.057 to 0.147 for eccentricity, and 0.384 to 4.777 degrees for inclination. Using a recent shape model, and assumption of uniform density, to constrain relevant moments of inertia, we estimate the spin pole precession rate parameter to be 8.53 arcsec/year. The current spin pole is at ecliptic {lon, lat} = { 32, -7} deg, whereas the orbit pole is at {lon, lat} = {60.47, 86.91} deg. The current obliquity is thus 94.3 degree. Using nominal values of the input parameters, the recovered spin pole

  2. The visible spectrum of Pluto: secular and longitudinal variation

    Science.gov (United States)

    Lorenzi, Vania; Pinilla-Alonso, Noemí; Emery, Joshua P.; Licandro, Javier; Cruikshank, Dale P.; Grundy, Will; Binzel, Richard P.

    2015-11-01

    Continuous near-infrared spectroscopic observations during the last 30 years enabled the characterization of the Pluto's surface and the study of its variability. Nevertheless, only few data are available in the visible range, where the nature of the complex-organics can be studied.For this reason, we started an observational campaign to obtain the Pluto's relative reflectance in the visible range, with the aim of characterizing the different components of its surface, and providing ground based observations in support of the New Horizons mission. We observed Pluto on six nights in 2014, with the imager/spectrograph ACAM@WHT (La Palma, Spain). We obtained six spectra in the 0.40 - 0.93 µm range, that covered a whole Pluto's rotational period (6.4 days).To study longitudinal variations, we computed for all the spectra the spectral slope, and the position and the depth of the methane ice absorption bands. Also, to search for secular or seasonal variations we compared our data with previously published results.All the spectra present a red slope, indicating the presence of complex organics on Pluto's surface, and show the methane ice absorption bands between 0.73 and 0.90 μm. We also report the detection of the CH4 absorption band at 0.62 μm, already detected in the spectra of Makemake and Eris. The measurement of the band depth at 0.62 μm in the new spectra of Pluto, and in the spectra of Makemake and Eris, permits us to estimate the Lambert coefficient, not measured yet at this wavelength, at a temperature of 30 K and 40 K.We find that all the CH4 bands present a blue shift. This shift is minimum at the Charon-facing hemisphere, where the CH4 is also more abundant, indicating a higher degree of saturation of CH4 in the CH4:N2 dilution at this hemisphere.Comparing with data in the literature, we found that the longitudinal and secular variations of the parameters measured in our spectra are in accordance with previous results and with the distribution of the dark

  3. A study of geomagnetic field variations along the 80° S geomagnetic parallel

    Directory of Open Access Journals (Sweden)

    S. Lepidi

    2017-01-01

    Full Text Available The availability of measurements of the geomagnetic field variations in Antarctica at three sites along the 80° S geomagnetic parallel, separated by approximately 1 h in magnetic local time, allows us to study the longitudinal dependence of the observed variations. In particular, using 1 min data from Mario Zucchelli Station, Scott Base and Talos Dome, a temporary installation during 2007–2008 Antarctic campaign, we investigated the diurnal variation and the low-frequency fluctuations (approximately in the Pc5 range, ∼ 1–7 mHz. We found that the daily variation is clearly ordered by local time, suggesting a predominant effect of the polar extension of midlatitude ionospheric currents. On the other hand, the pulsation power is dependent on magnetic local time maximizing around magnetic local noon, when the stations are closer to the polar cusp, while the highest coherence between pairs of stations is observed in the magnetic local nighttime sector. The wave propagation direction observed during selected events, one around local magnetic noon and the other around local magnetic midnight, is consistent with a solar-wind-driven source in the daytime and with substorm-associated processes in the nighttime.

  4. Modeling Geomagnetic Variations using a Machine Learning Framework

    Science.gov (United States)

    Cheung, C. M. M.; Handmer, C.; Kosar, B.; Gerules, G.; Poduval, B.; Mackintosh, G.; Munoz-Jaramillo, A.; Bobra, M.; Hernandez, T.; McGranaghan, R. M.

    2017-12-01

    We present a framework for data-driven modeling of Heliophysics time series data. The Solar Terrestrial Interaction Neural net Generator (STING) is an open source python module built on top of state-of-the-art statistical learning frameworks (traditional machine learning methods as well as deep learning). To showcase the capability of STING, we deploy it for the problem of predicting the temporal variation of geomagnetic fields. The data used includes solar wind measurements from the OMNI database and geomagnetic field data taken by magnetometers at US Geological Survey observatories. We examine the predictive capability of different machine learning techniques (recurrent neural networks, support vector machines) for a range of forecasting times (minutes to 12 hours). STING is designed to be extensible to other types of data. We show how STING can be used on large sets of data from different sensors/observatories and adapted to tackle other problems in Heliophysics.

  5. Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin

    Science.gov (United States)

    Cordaro, Enrique G.; Venegas, Patricio; Laroze, David

    2018-03-01

    We present a different view of secular variation of the Earth's magnetic field, through the variations in the threshold rigidity known as the variation rate of geomagnetic cutoff rigidity (VRc). As the geomagnetic cutoff rigidity (Rc) lets us differentiate between charged particle trajectories arriving at the Earth and the Earth's magnetic field, we used the VRc to look for internal variations in the latter, close to the 70° south meridian. Due to the fact that the empirical data of total magnetic field BF and vertical magnetic field Bz obtained at Putre (OP) and Los Cerrillos (OLC) stations are consistent with the displacement of the South Atlantic magnetic anomaly (SAMA), we detected that the VRc does not fully correlate to SAMA in central Chile. Besides, the lower section of VRc seems to correlate perfectly with important geological features, like the flat slab in the active Chilean convergent margin. Based on this, we next focused our attention on the empirical variations of the vertical component of the magnetic field Bz, recorded in OP prior to the Maule earthquake in 2010, which occurred in the middle of the Chilean flat slab. We found a jump in Bz values and main frequencies from 3.510 to 5.860 µHz, in the second derivative of Bz, which corresponds to similar magnetic behavior found by other research groups, but at lower frequency ranges. Then, we extended this analysis to other relevant subduction seismic events, like Sumatra in 2004 and Tohoku in 2011, using data from the Guam station. Similar records and the main frequencies before each event were found. Thus, these results seem to show that magnetic anomalies recorded on different timescales, as VRc (decades) and Bz (days), may correlate with some geological events, as the lithosphere-atmosphere-ionosphere coupling (LAIC).

  6. Anomalous changes of vertical geomagnetic field in Kamchatka

    Directory of Open Access Journals (Sweden)

    Moroz Yuriy

    2016-01-01

    Full Text Available Secular variations of the vertical geomagnetic field at Paratunka (Kamchatka, Kakioka (Honshu, Mamambetsu (Hokkaido and Patrony (Irkutsk are considered from 1968 to 2014. Comparative analysis of secular variations showed that from 1968 to 2001, similar variations with the intensity of first hundreds on nT are obvious at four observatories. For the following period from 2001 to 2014, the secular variation at Paratunka observatory differs from other observatories. This disagreement of the secular geomagnetic variation at Paratunka observatory is timed to the increase of seismicity at the depth of 400-700 km in South Kamchatka region. It is suggested that in the result of increase of the seismicity in the region of transition from the upper to lower mantle, physical and chemical processes became more active. That caused formation of a large geo-electrical inhomogeneity which affected the behavior of the vertical component of geomagnetic field.

  7. Analysis of Geomagnetic Field Variations during Total Solar Eclipses Using INTERMAGNET Data

    Science.gov (United States)

    KIM, J. H.; Chang, H. Y.

    2017-12-01

    We investigate variations of the geomagnetic field observed by INTERMAGNET geomagnetic observatories over which the totality path passed during a solar eclipse. We compare results acquired by 6 geomagnetic observatories during the 4 total solar eclipses (11 August 1999, 1 August 2008, 11 July 2010, and 20 March 2015) in terms of geomagnetic and solar ecliptic parameters. These total solar eclipses are the only total solar eclipse during which the umbra of the moon swept an INTERMAGNET geomagnetic observatory and simultaneously variations of the geomagnetic field are recorded. We have confirmed previous studies that increase BY and decreases of BX, BZ and F are conspicuous. Interestingly, we have noted that variations of geomagnetic field components observed during the total solar eclipse at Isla de Pascua Mataveri (Easter Island) in Chile (IPM) in the southern hemisphere show distinct decrease of BY and increases of BX and BZ on the contrary. We have found, however, that variations of BX, BY, BZ and F observed at Hornsund in Norway (HRN) seem to be dominated by other geomagnetic occurrence. In addition, we have attempted to obtain any signatures of influence on the temporal behavior of the variation in the geomagnetic field signal during the solar eclipse by employing the wavelet analysis technique. Finally, we conclude by pointing out that despite apparent success a more sophisticate and reliable algorithm is required before implementing to make quantitative comparisons.

  8. International Geomagnetic Reference Field

    DEFF Research Database (Denmark)

    Finlay, Chris; Maus, S.; Beggan, C. D.

    2010-01-01

    The eleventh generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2009 by the International Association of Geomagnetism and Aeronomy Working Group V‐MOD. It updates the previous IGRF generation with a definitive main field model for epoch 2005.0, a main field...... model for epoch 2010.0, and a linear predictive secular variation model for 2010.0–2015.0. In this note the equations defining the IGRF model are provided along with the spherical harmonic coefficients for the eleventh generation. Maps of the magnetic declination, inclination and total intensity...

  9. High-resolution chronology of sediment below CCD based on Holocene paleomagnetic secular variations in the Tohoku-oki earthquake rupture zone

    Science.gov (United States)

    Kanamatsu, Toshiya; Usami, Kazuko; McHugh, Cecilia M. G.; Ikehara, Ken

    2017-08-01

    Using high-resolution paleomagnetic data, we examined the potential for obtaining precise ages from sediment core samples recovered from deep-sea basins close to rupture zones of the 2011 and earlier earthquakes off Tohoku, Japan. Obtaining detailed stratigraphic ages from deep-sea sediments below the calcium compensation depth (CCD) is difficult, but we found that the samples contain excellent paleomagnetic secular variation records to constrain age models. Variations in paleomagnetic directions obtained from the sediments reveal systematic changes in the cores. A stacked paleomagnetic profile closely matches the Lake Biwa data sets in southwest Japan for the past 7000 years, one can establish age models based on secular variations of the geomagnetic field on sediments recovered uniquely below the CCD. Comparison of paleomagnetic directions near a tephra and a paleomagnetic direction of contemporaneous pyroclastic flow deposits acquired by different magnetization processes shows precise depositional ages reflecting the magnetization delay of the marine sediment record.Plain Language SummaryGenerally obtaining detailed ages from deep-sea sediments is difficult, because available dating method is very limited. We found that the deep-see sediment off North Japan recorded past sequential geomagnetic directions. If those records correlate well with the reference record in past 7000 years, then we could estimate age of sediment by pattern matching. Additionally a volcanic ash emitted in 915 A.D., which was intercalated in our samples, indicates a time lag in our age model. This observation makes our age model more precise.

  10. Solar and lunar daily geomagnetic variations at Dourbes

    International Nuclear Information System (INIS)

    De Meyer, F.

    1980-01-01

    Spectral analysis of the Dourbes H component hourly data from the period 1960-1978 revealed the existence of a number of minor terms, in addition to the main solar and lunar peaks. The relative amplitudes of oscillations in the geomagnetic spectrum are unrelated with those predicted through lunar tide theory. The minor terms agree more closely with the 27-day amplitude modulation mechanism. A high frequency resolution power spectrum clearly shows the splitting of the solar diurnal and semi-diurnal line, and even of the lunar semi-diurnal line by the annual variation and its harmonics. The correlation between the amplitude of the M 2 wave and the mean sunspot number is of no significance. (author)

  11. Latitudinal variation of the polar cusp during a geomagnetic storm

    International Nuclear Information System (INIS)

    Meng, C.

    1982-01-01

    Large amplitude latitudinal variation of the polar cusp position was observed during the intense geomagnetic storm of 15--16 February 1980. The observation of the polar cusp, identified as the region of intense but extremely soft electron precipitation, was made by two nearly noon-midnight orbit DMSP satellites over both northern and southern hemispheres. The latitudinal shift of the polar cusp is observed to be related to the intensity variation of the ring current indicated by the hourly Dst values. The polar cusp region moved from its normal location at approx.76 0 gm lat down to approx.62 0 gm lat at the peak of this storm. This movement took about 5 hours and was detected over both hemispheres. A drastic variation in the width of the cusp region was also observed; it is very narrow (approx.1 0 ) during the equatorial shift and expands to > or approx. =5 0 during the poleward recovery. Variation of the polar cusp latitude with that of the Dst index was also seen during the period before the intense storm

  12. Proper Motion and Secular Variations of Keplerian Orbital Elements

    Directory of Open Access Journals (Sweden)

    Alexey G. Butkevich

    2018-05-01

    Full Text Available High-precision observations require accurate modeling of secular changes in the orbital elements in order to extrapolate measurements over long time intervals, and to detect deviation from pure Keplerian motion caused, for example, by other bodies or relativistic effects. We consider the evolution of the Keplerian elements resulting from the gradual change of the apparent orbit orientation due to proper motion. We present rigorous formulae for the transformation of the orbit inclination, longitude of the ascending node and argument of the pericenter from one epoch to another, assuming uniform stellar motion and taking radial velocity into account. An approximate treatment, accurate to the second-order terms in time, is also given. The proper motion effects may be significant for long-period transiting planets. These theoretical results are applicable to the modeling of planetary transits and precise Doppler measurements as well as analysis of pulsar and eclipsing binary timing observations.

  13. An upper limit to the secular variation of the gravitational constant from white dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    García-Berro, Enrique; Lorén-Aguilar, Pablo; Torres, Santiago [Departament de Física Aplicada, Universitat Politècnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels (Spain); Althaus, Leandro G. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, (1900) La Plata (Argentina); Isern, Jordi, E-mail: garcia@fa.upc.edu, E-mail: loren@fa.upc.edu, E-mail: santi@fa.upc.edu, E-mail: althaus@fcaglp.fcaglp.unlp.edu.ar, E-mail: isern@ieec.cat [Institut de Ciències de l' Espai (CSIC), Campus UAB, 08193 Bellaterra (Spain)

    2011-05-01

    A variation of the gravitational constant over cosmological ages modifies the main sequence lifetimes and white dwarf cooling ages. Using an state-of-the-art stellar evolutionary code we compute the effects of a secularly varying G on the main sequence ages and, employing white dwarf cooling ages computed taking into account the effects of a running G, we place constraints on the rate of variation of Newton's constant. This is done using the white dwarf luminosity function and the distance of the well studied open Galactic cluster NGC 6791. We derive an upper bound Ġ/G ∼ −1.8 × 10{sup −12} yr{sup −1}. This upper limit for the secular variation of the gravitational constant compares favorably with those obtained using other stellar evolutionary properties, and can be easily improved if deep images of the cluster allow to obtain an improved white dwarf luminosity function.

  14. Transit Duration Variations due to Secular Interactions in Systems with Tightly-packed Inner Planets

    Science.gov (United States)

    Boley, Aaron; Van Laerhoven, Christa; Granados Contreras, A. Paula

    2018-04-01

    Secular interactions among planets in multi-planet systems will lead to variations in orbital inclinations and to the precession of orbital nodes. Taking known system architectures at face value, we calculate orbital precession rates for planets in tightly-packed systems using classical second-order secular theory, in which the orientation of the orbits can be described as a vector sum of eigenmodes and the eigenstructure is determined only by the masses and semi-major axes of the planets. Using this framework, we identify systems that have fast precession frequencies, and use those systems to explore the range of transit duration variation that could occur using amplitudes that are consistent with tightly-packed planetary systems. We then further assess how transit duration variations could be used in practice.

  15. Characteristics of seasonal variation and solar activity dependence of the geomagnetic solar quiet daily variation

    Science.gov (United States)

    Shinbori, A.; Koyama, Y.; Nose, M.; Hori, T.

    2017-12-01

    Characteristics of seasonal variation and solar activity dependence of the X- and Y-components of the geomagnetic solar quiet (Sq) daily variation at Memanbetsu in mid-latitudes and Guam near the equator have been investigated using long-term geomagnetic field data with 1-h time resolution from 1957 to 2016. In this analysis, we defined the quiet day when the maximum value of the Kp index is less than 3 for that day. In this analysis, we used the monthly average of the adjusted daily F10.7 corresponding to geomagnetically quiet days. For identification of the monthly mean Sq variation in the X and Y components (Sq-X and Sq-Y), we first determined the baseline of the X and Y components from the average value from 22 to 2 h (LT: local time) for each quiet day. Next, we calculated a deviation from the baseline of the X- and Y-components of the geomagnetic field for each quiet day, and computed the monthly mean value of the deviation for each local time. As a result, Sq-X and Sq-Y shows a clear seasonal variation and solar activity dependence. The amplitude of seasonal variation increases significantly during high solar activities, and is proportional to the solar F10.7 index. The pattern of the seasonal variation is quite different between Sq-X and Sq-Y. The result of the correlation analysis between the solar F10.7 index and Sq-X and Sq-Y shows almost the linear relationship, but the slope and intercept of the linear fitted line varies as function of local time and month. This implies that the sensitivity of Sq-X and Sq-Y to the solar activity is different for different local times and seasons. The local time dependence of the offset value of Sq-Y at Guam and its seasonal variation suggest a magnetic field produced by inter-hemispheric field-aligned currents (FACs). From the sign of the offset value of Sq-Y, it is infer that the inter-hemispheric FACs flow from the summer to winter hemispheres in the dawn and dusk sectors and from the winter to summer hemispheres in

  16. Secular variations in carbon-14 and their geophysical implications

    CSIR Research Space (South Africa)

    Vogel

    2002-03-01

    Full Text Available . The identification of the causes and magnitudes of these deviations has created a new too that is contributing to the investigation of different geophysical: phenomena. Variations in the activity of the Sun produce fluctuations of the C-14 level in the atmosphere...

  17. Secular trends in seasonal variation in birth weight

    DEFF Research Database (Denmark)

    Jensen, Camilla Bjørn; Gamborg, M; Raymond, K

    2015-01-01

    and phase of the yearly cycles to change. RESULTS: There was a clear seasonal pattern in BW which, however, changed gradually across the study period. The highest BWs were seen during fall (September - October) from 1936 to 1963, but a new peak gradually grew from the early 1940s during early summer (May...... again. Sunshine did not explain the seasonal variation in BW. CONCLUSION: There was a clear seasonal pattern in BW in Denmark 1936-1989, which however changed across the study period. Throughout the study period we observed a peak in BW during the fall, but gradually, starting in the early 1940s...

  18. Paleosecular variations from lake sediments

    International Nuclear Information System (INIS)

    Lund, S.P.; Banerjee, S.K.

    1979-01-01

    Data are presented on the secular variations of the magnetization of wet and dry lake sediments for 17 North American locations. The usefullness of this data in terms of the geomagnetic field is discussed

  19. Long-term trends of foE and geomagnetic activity variations

    Directory of Open Access Journals (Sweden)

    A. V. Mikhailov

    2003-03-01

    Full Text Available A relationship between foE trends and geomagnetic activity long-term variations has been revealed for the first time. By analogy with earlier obtained results on the foF2 trends it is possible to speak about the geomagnetic control of the foE long-term trends as well. Periods of increasing geomagnetic activity correspond to negative foE trends, while these trends are positive for the decreasing phase of geomagnetic activity. This "natural" relationship breaks down around 1970 (on some stations later when pronounced positive foE trends have appeared on most of the stations considered. The dependence of foE trends on geomagnetic activity can be related with nitric oxide variations at the E-layer heights. The positive foE trends that appeared after the "break down" effect may also be explained by the [NO] decrease which is not related to geomagnetic activity variations. But negative trends or irregular foE variations on some stations for the same time period require some different mechanism. Chemical pollution of the lower thermosphere due to the anthropogenic activity may be responsible for such abnormal foE behavior after the end of the 1960s.Key words. Ionosphere (ionosphere-atmosphere interactions; ionospheric disturbances

  20. Geophysical variables and behavior: XXI. Geomagnetic variation as possible enhancement stimuli for UFO reports preceding earthtremors.

    Science.gov (United States)

    Persinger, M A

    1985-02-01

    The contribution of geomagnetic variation to the occurrence of UFORs (reports of UFOs) within the New Madrid States during the 6-mo. increments before increases in the numbers of IV-V or less intensity earthquakes within the central USA was determined. Although statistically significant zero-order correlations existed between measures of earthquakes, UFORs and geomagnetic variability, the association between the latter two deteriorated markedly when their shared variance with earthquakes was held constant. These outcomes are compatible with the hypothesis that geomagnetic variability (or phenomena associated with it) may enhance UFORs but only if tectonic stress and strain are increasing within the region.

  1. Crustal concealing of small-scale core-field secular variation

    DEFF Research Database (Denmark)

    Hulot, G.; Olsen, Nils; Thebault, E.

    2009-01-01

    of internal origin happen to be detectable now in spherical harmonic degrees up to, perhaps, 16. All of these changes are usually attributed to changes in the core field itself, the secular variation, on the ground that the lithospheric magnetization cannot produce such signals. It has, however, been pointed...... out, on empirical grounds, that temporal changes in the field of internal origin produced by the induced part of the lithospheric magnetization could dominate the core field signal beyond degree 22. This short note revisits this issue by taking advantage of our improved knowledge of the small...... cause of the observed changes in the field of internal origin up to some critical degree, N-C, is indeed likely to be the secular variation of the core field, but that the signal produced by the time-varying lithospheric field is bound to dominate and conceal the time-varying core signal beyond...

  2. Possible relationship between the Earth's rotation variations and geomagnetic field reversals over the past 510 Myr

    OpenAIRE

    Pacca, Igor G.; Frigo, Everton; Hartmann, Gelvam A.

    2015-01-01

    The Earth's rotation can change as a result of several internal and external processes, each of which is at a different timescale. Here, we present some possible connections between the Earth's rotation variations and the geomagnetic reversal frequency rates over the past 120 Myr. In addition, we show the possible relationship between the geomagnetic field reversal frequency and the δ18O oscillations. Because the latter reflects the glacial and interglacial periods, we hypothesize that it can...

  3. Modeling of Thermospheric Neutral Density Variations in Response to Geomagnetic Forcing using GRACE Accelerometer Data

    Science.gov (United States)

    Calabia, A.; Matsuo, T.; Jin, S.

    2017-12-01

    The upper atmospheric expansion refers to an increase in the temperature and density of Earth's thermosphere due to increased geomagnetic and space weather activities, producing anomalous atmospheric drag on LEO spacecraft. Increased drag decelerates satellites, moving their orbit closer to Earth, decreasing the lifespan of satellites, and making satellite orbit determination difficult. In this study, thermospheric neutral density variations due to geomagnetic forcing are investigated from 10 years (2003-2013) of GRACE's accelerometer-based estimates. In order to isolate the variations produced by geomagnetic forcing, 99.8% of the total variability has been modeled and removed through the parameterization of annual, LST, and solar-flux variations included in the primary Empirical Orthogonal Functions. The residual disturbances of neutral density variations have been investigated further in order to unravel their relationship to several geomagnetic indices and space weather activity indicators. Stronger fluctuations have been found in the southern polar cap, following the dipole-tilt angle variations. While the parameterization of the residual disturbances in terms of Dst index results in the best fit to training data, the use of merging electric field as a predictor leads to the best forecasting performance. An important finding is that modeling of neutral density variations in response geomagnetic forcing can be improved by accounting for the latitude-dependent delay. Our data-driven modeling results are further compared to modeling with TIEGCM.

  4. Fourteen years of geomagnetic daily variation at Mario Zucchelli Station (Antarctica

    Directory of Open Access Journals (Sweden)

    A. Meloni

    2007-06-01

    Full Text Available During the 1986-87 austral summer a geomagnetic observatory was installed at the Italian Antarctic Base Mario Zucchelli Station. In the first three years continuous time variation monitoring and absolute measurements of the geomagnetic field were carried out only during summer expeditions. Starting 1991 an automatic acquisition system, operating through all the year, was put in operation. We present here some peculiarities of the daily variation as observed for fourteen years (1987-2000. The availability of a long series of data has allowed the definition of seasonal, as well as solar cycle effects, on short time variations as observed at a cusp-cap observatory. In particular, contrary to mid latitude behaviour, a clear dependence of the daily variation amplitude on the global geomagnetic K index was well defined.

  5. Qualitative and quantitative estimations of the effect of geomagnetic field variations on human brain functional state

    International Nuclear Information System (INIS)

    Belisheva, N.K.; Popov, A.N.; Petukhova, N.V.; Pavlova, L.P.; Osipov, K.S.; Tkachenko, S.Eh.; Baranova, T.I.

    1995-01-01

    The comparison of functional dynamics of human brain with reference to qualitative and quantitative characteristics of local geomagnetic field (GMF) variations was conducted. Steady and unsteady states of human brain can be determined: by geomagnetic disturbances before the observation period; by structure and doses of GMF variations; by different combinations of qualitative and quantitative characteristics of GMF variations. Decrease of optimal GMF activity level and the appearance of aperiodic disturbances of GMF can be a reason of unsteady brain's state. 18 refs.; 3 figs

  6. What do we mean by accuracy in geomagnetic measurements?

    Science.gov (United States)

    Green, A.W.

    1990-01-01

    High accuracy is what distinguishes measurements made at the world's magnetic observatories from other types of geomagnetic measurements. High accuracy in determining the absolute values of the components of the Earth's magnetic field is essential to studying geomagnetic secular variation and processes at the core mantle boundary, as well as some magnetospheric processes. In some applications of geomagnetic data, precision (or resolution) of measurements may also be important. In addition to accuracy and resolution in the amplitude domain, it is necessary to consider these same quantities in the frequency and space domains. New developments in geomagnetic instruments and communications make real-time, high accuracy, global geomagnetic observatory data sets a real possibility. There is a growing realization in the scientific community of the unique relevance of geomagnetic observatory data to the principal contemporary problems in solid Earth and space physics. Together, these factors provide the promise of a 'renaissance' of the world's geomagnetic observatory system. ?? 1990.

  7. Secular Variation and Physical Characteristics Determination of the HADS Star EH Lib

    Science.gov (United States)

    Pena, J. H.; Villarreal, C.; Pina, D. S.; Renteria, A.; Soni, A., Guillen, J. Calderon, J.

    2017-12-01

    Physical parameters of EH Lib have been determined based on observations carried out in 2015 with photometry. They have also served, along with samples from the years 1969 and 1986, to analyse the frequency content of EH Lib with Fourier Transforms. Recent CCD observations increased the times of maximum with twelve new times which helped us study the secular variation of the period with a method based on the minimization of the standard deviation of the O-C residuals. It is concluded that there may be a long-term period change.

  8. Geomagnetic imprinting predicts spatio-temporal variation in homing migration of pink and sockeye salmon.

    Science.gov (United States)

    Putman, Nathan F; Jenkins, Erica S; Michielsens, Catherine G J; Noakes, David L G

    2014-10-06

    Animals navigate using a variety of sensory cues, but how each is weighted during different phases of movement (e.g. dispersal, foraging, homing) is controversial. Here, we examine the geomagnetic and olfactory imprinting hypotheses of natal homing with datasets that recorded variation in the migratory routes of sockeye (Oncorhynchus nerka) and pink (Oncorhynchus gorbuscha) salmon returning from the Pacific Ocean to the Fraser River, British Columbia. Drift of the magnetic field (i.e. geomagnetic imprinting) uniquely accounted for 23.2% and 44.0% of the variation in migration routes for sockeye and pink salmon, respectively. Ocean circulation (i.e. olfactory imprinting) predicted 6.1% and 0.1% of the variation in sockeye and pink migration routes, respectively. Sea surface temperature (a variable influencing salmon distribution but not navigation, directly) accounted for 13.0% of the variation in sockeye migration but was unrelated to pink migration. These findings suggest that geomagnetic navigation plays an important role in long-distance homing in salmon and that consideration of navigation mechanisms can aid in the management of migratory fishes by better predicting movement patterns. Finally, given the diversity of animals that use the Earth's magnetic field for navigation, geomagnetic drift may provide a unifying explanation for spatio-temporal variation in the movement patterns of many species. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  9. Geomagnetic imprinting predicts spatio-temporal variation in homing migration of pink and sockeye salmon

    Science.gov (United States)

    Putman, Nathan F.; Jenkins, Erica S.; Michielsens, Catherine G. J.; Noakes, David L. G.

    2014-01-01

    Animals navigate using a variety of sensory cues, but how each is weighted during different phases of movement (e.g. dispersal, foraging, homing) is controversial. Here, we examine the geomagnetic and olfactory imprinting hypotheses of natal homing with datasets that recorded variation in the migratory routes of sockeye (Oncorhynchus nerka) and pink (Oncorhynchus gorbuscha) salmon returning from the Pacific Ocean to the Fraser River, British Columbia. Drift of the magnetic field (i.e. geomagnetic imprinting) uniquely accounted for 23.2% and 44.0% of the variation in migration routes for sockeye and pink salmon, respectively. Ocean circulation (i.e. olfactory imprinting) predicted 6.1% and 0.1% of the variation in sockeye and pink migration routes, respectively. Sea surface temperature (a variable influencing salmon distribution but not navigation, directly) accounted for 13.0% of the variation in sockeye migration but was unrelated to pink migration. These findings suggest that geomagnetic navigation plays an important role in long-distance homing in salmon and that consideration of navigation mechanisms can aid in the management of migratory fishes by better predicting movement patterns. Finally, given the diversity of animals that use the Earth's magnetic field for navigation, geomagnetic drift may provide a unifying explanation for spatio-temporal variation in the movement patterns of many species. PMID:25056214

  10. A kinematic model of vertical geomagnetic field variation resulting from a steady convective flow

    Czech Academy of Sciences Publication Activity Database

    Marsenić, Alexandra

    2014-01-01

    Roč. 108, č. 2 (2014), s. 191-212 ISSN 0309-1929 Grant - others:VEGA(SK) 2/0137/12 Institutional support: RVO:67985530 Keywords : magnetohydrodynamics * induction equation * geomagnetic variation * reversed flux patches Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.924, year: 2013

  11. Diurnal and Seasonal Variations in Mid-Latitude Geomagnetic Field During International Quiet Days: BOH Magnetometer

    Directory of Open Access Journals (Sweden)

    Junga Hwang

    2012-12-01

    Full Text Available Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Bohyunsan Observatory to measure the Earth's magnetic field variations in South Korea. In 2007, we installed a fluxgate magnetometer (RFP-523C to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we use the H, D, Z components of fluxgate magnetometer data to investigate the characteristics of mid-latitude geomagnetic field variation. To remove the temporary changes in Earth’s geomagnetic filed by space weather, we use the international quiet days’ data only. In other words, we performed a superposed epoch analysis using five days per each month during 2008-2011. We find that daily variations of H, D, and Z shows similar tendency compared to previous results using all days. That is, H, D, Z all three components’ quiet intervals terminate near the sunrise and shows maximum 2-3 hours after the culmination and the quiet interval start from near the sunset. Seasonal variations show similar dependences to the Sun. As it becomes hot season, the geomagnetic field variation’s amplitude becomes large and the quiet interval becomes shortened. It is well-known that these variations are effects of Sq current system in the Earth’s atmosphere. We confirm that the typical mid-latitude geomagnetic field variations due to the Sq current system by excluding all possible association with the space weather.

  12. The steady part of the secular variation of the Earth's magnetic field

    Science.gov (United States)

    Bloxham, Jeremy

    1992-01-01

    The secular variation of the Earth's magnetic field results from the effects of magnetic induction in the fluid outer core and from the effects of magnetic diffusion in the core and the mantle. Adequate observations to map the magnetic field at the core-mantle boundary extend back over three centuries, providing a model of the secular variation at the core-mantle boundary. Here we consider how best to analyze this time-dependent part of the field. To calculate steady core flow over long time periods, we introduce an adaptation of our earlier method of calculating the flow in order to achieve greater numerical stability. We perform this procedure for the periods 1840-1990 and 1690-1840 and find that well over 90 percent of the variance of the time-dependent field can be explained by simple steady core flow. The core flows obtained for the two intervals are broadly similar to each other and to flows determined over much shorter recent intervals.

  13. A New View of Long-Term Geomagnetic Field Secular Variation

    Directory of Open Access Journals (Sweden)

    Steve P. Lund

    2018-05-01

    Full Text Available This study carries out a statistical analysis of high-resolution PSV records for the last ~70 ka from three different regions of the Earth. We consider directional and intensity variability in each region on time scales of 103-105 years in order to evaluate long-term PSV. We then compare those results with more traditional long-term PSV statistical studies averaged over ~106 years. Three replicate PSV records from one region (subtropical North Atlantic Ocean were averaged at overlapping 3 and 9 ka intervals. Variability in both scalar inclination and declination variability and vector angular dispersion are significant and coherent among the three records. The vector dispersion is relatively low for most of the time but contains two relatively narrow intervals (~30–42 and 60–65 ka of high dispersion. (Vector dispersion in all records was calculated after removing directions with true excursional VGPs, VGPs < 45° N. We have carried out a comparable statistical analysis on two other PSV records from other parts of the Earth (Chile margin; Philippines/Indonesia. The results for these three regions are comparable in their overall style of variability. The scalar directional variability from the Philippines/Indonesia is quite different in detail from the other two regions, as might be expected, but the scalar directional variability between the Western Hemisphere regions is remarkably consistent considering their distance from one another. This may be associated with them being on the same longitude swath and having some coherent dynamo activity occurring along that path. Three magnetic field excursions occur in the study interval. All three excursions are associated with the two highest vector dispersion intervals. Paleointensity records from the three regions were subjected to the same statistical analysis as the directions. These records are all coherent in their pattern of variability. The similarity in paleointensity variability on a global scale is expected even though the detailed scalar directional variability is not coherent on a global scale. The pattern of intensity variability is strongly correlated with the pattern of vector dispersion and excursions on a global scale—high (low intensity is associated with low (high plus excursions vector dispersion. The fact that regional directional variability is always larger than “normal” during low intensity/excursional intervals, even though the effect of true excursional directions was removed, suggests that we need to reevaluate what field variability was like during low intensity/excursional intervals on a global scale and how/why it was different from today's field (last 104 years.

  14. Solar and Geomagnetic Activity Variations Correlated to Italian M6+ Earthquakes Occurred in 2016

    Science.gov (United States)

    Cataldi, Gabriele; Cataldi, Daniele; Straser, Valentino

    2017-04-01

    Between August 2016 and October 2016 in Italy were recorded three strong earthquakes: M6.2 on August 2016 at 01:36:32 UTC; M6.1 on October 26, 2016 at 19:18:08 UTC and M6,6 on October 30, 2016 at 06:40:18 UTC. The authors of this study wanted to verify the existence of a correlation between these earthquakes and solar/geomagnetic activity. To confirming or not the presence of this kind of correlation, the authors analyzed the conditions of Spaceweather "near Earth" and the characteristics of the Earth's geomagnetic field in the hours that preceded the three earthquakes. The data relating to the three earthquakes were provided by the United States Geological Survey (USGS). The data on ion density used to realize the correlation study are represented by: solar wind ion density variation detected by ACE (Advanced Composition Explorer) Satellite, in orbit near the L1 Lagrange point, at 1.5 million of km from Earth, in direction of the Sun. The instrument used to perform the measurement of the solar wind ion density is the Electron, Proton, and Alpha Monitor (EPAM) instrument, equipped on the ACE Satellite. To conduct the study, the authors have taken in consideration the variation of the solar wind protons density of three different energy fractions: differential proton flux 1060-1900 keV (p/cm^2-sec-ster-MeV); differential proton flux 761-1220 keV (p/cm^2-sec-ster-MeV); differential proton flux 310-580 keV (p/cm^2-sec-ster-MeV). Geomagnetic activity data were provided by Tromsø Geomagnetic Observatory (TGO), Norway; by Scoresbysund Geomagnetic Observatory (SCO), Greenland, Denmark; Dikson Geomagnetic Observatory (DIK), Russia and by Pushkov Institute of terrestrial magnetism, ionosphere and radio wave propagation (IZMIRAN), Troitsk, Moscow Region. The results of the study, in agreement with what already ascertained by authors from 2012, have confirmed that the three strong Italian earthquakes were preceded by a clear increase of the solar wind proton density which

  15. Seasonal variations of the high-latitude geomagnetic field intensity in the northern hemisphere

    International Nuclear Information System (INIS)

    Rivin, Yu.R.; Chkhaidze, Z.Sh.

    1994-01-01

    Seasonal variation of the geomagnetic field three components is investigated using the data of the USA observatories chain separately for polar region, auroral zone and middle latitudes beginning from 1950. The variation consists of an annual and half-yearly waves. main attention is paid to time variability of the annual wave phase in the auroral zone, that is connected with superposition of waves of western and eastern jets

  16. Modelling the quiet-time geomagnetic daily variations using observatory data

    OpenAIRE

    Hamilton, Brian; Macmillan, Susan

    2008-01-01

    We present on-going work towards building a global model of the quiet-time geomagnetic daily variation using bservatory data. We select hourly mean data during June 2006 (solar minimum). We fit Fourier series in time, with a fundamental period of 24 hours, to the data at each observatory. We then use global spherical harmonic expansions to separate the daily variation signal, as characterised by the Fourier coefficients in time, into external and induced internal contributions. The mode...

  17. Solar cycle 22 control on daily geomagnetic variation at Terra Nova Bay (Antarctica

    Directory of Open Access Journals (Sweden)

    P. Palangio

    1998-06-01

    Full Text Available Nine summer geomagnetic observatory data (1986-1995 from Terra Nova Bay Base, Antarctica (Lat.74.690S, Long. 164.120E, 80.040S magnetic latitude are used to investigate the behaviour of the daily variation of the geomagnetic field at polar latitude. The instrumentation includes a proton precession magnetometer for total intensity |F| digital recordings; DI magnetometers for absolute measuring of the angular elements D and I and a three axis flux-gate system for acquiring H,D Z time variation data. We find that the magnetic time variation amplitude follows the solar cycle evolution and that the ratio between minimum solar median and maximum solar median is between 2-3 for intensive elements (H and Z and 1.7 for declination(D. The solar cycle effect on geomagnetic daily variation elements amplitude in Antarctica, in comparison with previous studies, is then probably larger than expected. As a consequence, the electric current system that causes the daily magnetic field variation reveals a quite large solar cycle effect at Terra Nova Bay.

  18. Natural variations in the geomagnetically trapped electron population

    Science.gov (United States)

    Vampola, A. L.

    1972-01-01

    Temporal variations in the trapped natural electron flux intensities and energy spectra are discussed and demonstrated using recent satellite data. These data are intended to acquaint the space systems engineer with the types of natural variations that may be encountered during a mission and to augment the models of the electron environment currently being used in space system design and orbit selection. An understanding of the temporal variations which may be encountered should prove helpful. Some of the variations demonstrated here which are not widely known include: (1) addition of very energetic electrons to the outer zone during moderate magnetic storms: (2) addition of energetic electrons to the inner zone during major magnetic storms; (3) inversions in the outer zone electron energy spectrum during the decay phase of a storm injection event and (4) occasional formation of multiple maxima in the flux vs altitude profile of moderately energetic electrons.

  19. Statistical analysis of geomagnetic field variations during the partial solar eclipse on 2011 January 4 in Turkey

    International Nuclear Information System (INIS)

    Ateş, Abdullah; Levent Ekinci, Yunus; Buyuksarac, Aydin; Aydemir, Attila; Demirci, Alper

    2015-01-01

    Some geophysical parameters, such as those related to gravitation and the geomagnetic field, could change during solar eclipses. In order to observe geomagnetic fluctuations, geomagnetic measurements were carried out in a limited time frame during the partial solar eclipse that occurred on 2011 January 4 and was observed in Canakkale and Ankara, Turkey. Additionally, records of the geomagnetic field spanning 24 hours, obtained from another observatory (in Iznik, Turkey), were also analyzed to check for any peculiar variations. In the data processing stage, a polynomial fit, following the application of a running average routine, was applied to the geomagnetic field data sets. Geomagnetic field data sets indicated there was a characteristic decrease at the beginning of the solar eclipse and this decrease can be well-correlated with previous geomagnetic field measurements that were taken during the total solar eclipse that was observed in Turkey on 2006 March 29. The behavior of the geomagnetic field is also consistent with previous observations in the literature. As a result of these analyses, it can be suggested that eclipses can cause a shielding effect on the geomagnetic field of the Earth. (paper)

  20. Diurnal changes of earthquake activity and geomagnetic Sq-variations

    Directory of Open Access Journals (Sweden)

    G. Duma

    2003-01-01

    Full Text Available Statistic analyses demonstrate that the probability of earthquake occurrence in many earthquake regions strongly depends on the time of day, that is on Local Time (e.g. Conrad, 1909, 1932; Shimshoni, 1971; Duma, 1997; Duma and Vilardo, 1998. This also applies to strong earthquake activity. Moreover, recent observations reveal an involvement of the regular diurnal variations of the Earth’s magnetic field, commonly known as Sq-variations, in this geodynamic process of changing earthquake activity with the time of day (Duma, 1996, 1999. In the article it is attempted to quantify the forces which result from the interaction between the induced Sq-variation currents in the Earth’s lithosphere and the regional Earth’s magnetic field, in order to assess the influence on the tectonic stress field and on seismic activity. A reliable model is obtained, which indicates a high energy involved in this process. The effect of Sq-induction is compared with the results of the large scale electromagnetic experiment "Khibiny" (Velikhov, 1989, where a giant artificial current loop was activated in the Barents Sea.

  1. A 20-15 ka high-resolution paleomagnetic secular variation record from Black Sea sediments - no evidence for the 'Hilina Pali excursion'?

    Science.gov (United States)

    Liu, Jiabo; Nowaczyk, Norbert R.; Frank, Ute; Arz, Helge W.

    2018-06-01

    A comprehensive magnetostratigraphic investigation on sixteen sediment cores from the southeastern Black Sea yielded a very detailed high-quality paleosecular variation (PSV) record spanning from 20 to 15 ka. The age models are based on radiocarbon dating, stratigraphic correlation, and tephrochronology. Further age constraints were obtained by correlating four meltwater events, described from the western Black Sea, ranging in age from about 17 to 15 ka, with maxima in K/Ti ratios, obtained from X-ray fluorescence (XRF) scanning, and minima in S-ratios, reflecting increased hematite content, in the studied cores. Since the sedimentation rates in the investigated time window are up to 50 cm ka-1, the obtained PSVs records enabled a stacking using 50-yr bins. A directional anomaly at 18.5 ka, associated with pronounced swings in inclination and declination, as well as a low in relative paleointensity (rPI), is probably contemporaneous with the Hilina Pali excursion, originally reported from Hawaiian lava flows. However, virtual geomagnetic poles (VGPs) calculated from Black Sea sediments are not located at latitudes lower than 60°N, which denotes normal, though pronounced secular variations. During the postulated Hilina Pali excursion, the VGPs calculated from Black Sea data migrated clockwise only along the coasts of the Arctic Ocean from NE Canada (20.0 ka), via Alaska (18.6 ka) and NE Siberia (18.0 ka) to Svalbard (17.0 ka), then looping clockwise through the Eastern Arctic Ocean.

  2. Possible relationship between the Earth’s rotation variations and geomagnetic field reversals over the past 510 Myr

    Directory of Open Access Journals (Sweden)

    Igor Gil Pacca

    2015-04-01

    Full Text Available The Earth’s rotation can change as a result of several internal and external processes, each of which is at a different timescale. Here, we present some possible connections between the Earth’s rotation variations and the geomagnetic reversal frequency rates over the past 120 Myr. In addition, we show the possible relationship between the geomagnetic field reversal frequency and the δ18O oscillations. Because the latter reflects the glacial and interglacial periods, we hypothesize that it can be used as a possible indicator to explain the length of day (LOD variations and consequently the reversal field frequency over the past 510 Myr. Therefore, our analysis suggests that the relationships between the geomagnetic reversal frequency rates and the Earth’s rotation changes during the Phanerozoic. However, more reversal data are required for periods before the KRS to strengthen the perspective of using the geomagnetic reversal data as a marker for the LOD variations through geological times.

  3. Geomagnetic, ionospheric and cosmic ray variations around the passages of different magnetic clouds

    International Nuclear Information System (INIS)

    Maercz, F.

    1992-01-01

    Thirty-four interplanetary magnetic clouds have been divided into two groups on the basis of Wilson's (J.geophys. Res. 95, 215, 1990) classification: NS clouds (whose B z near cloud onset at Earth is directed northward, and soon after B z is turning southward) and SN clouds (those with an opposite behaviour with respect to B z ). Using the days of cloud onsets as key days, geomagnetic, ionospheric and cosmic ray data have been analysed by the superposed epoch analysis method for passages of both NS and SN clouds. On the basis of the daily ΣK p values, geomagnetic activity is found to suddenly increase in the vicinity of both types of cloud passages. Afterwards, the variation shown by the geomagnetic indices is found to differ for NS clouds in comparison with SN clouds. Namely, on average the recovery to a normal activity level is much slower for NS clouds. Similarly, the enhancements in the ionospheric absorption of radio waves (the so-called ''after-effects'') are found to show different signatures according to cloud type, an interpretation also valid for variations in cosmic ray intensity. The latter results are based on analyses of neutron monitor counts observed at two stations (Apatity: 67 N; and Moscow: 55 o N). (author)

  4. The Egyptian geomagnetic reference field to the Epoch, 2010.0

    Science.gov (United States)

    Deebes, H. A.; Abd Elaal, E. M.; Arafa, T.; Lethy, A.; El Emam, A.; Ghamry, E.; Odah, H.

    2017-06-01

    The present work is a compilation of two tasks within the frame of the project ;Geomagnetic Survey & Detailed Geomagnetic Measurements within the Egyptian Territory; funded by the ;Science and Technology Development Fund agency (STDF);. The National Research Institute of Astronomy and Geophysics (NRIAG), has conducted a new extensive land geomagnetic survey that covers the whole Egyptian territory. The field measurements have been done at 3212 points along all the asphalted roads, defined tracks, and ill-defined tracks in Egypt; with total length of 11,586 km. In the present work, the measurements cover for the first time new areas as: the southern eastern borders of Egypt including Halayeb and Shlatin, the Quattara depresion in the western desert, and the new roads between Farafra and Baharia oasis. Also marine geomagnetic survey have been applied for the first time in Naser lake. Misallat and Abu-Simble geomagnetic observatories have been used to reduce the field data to the Epoch 2010. During the field measurements, whenever possible, the old stations occupied by the previous observers have been re-occupied to determine the secular variations at these points. The geomagnetic anomaly maps, the normal geomagnetic field maps with their corresponding secular variation maps, the normal geomagnetic field equations of the geomagnetic elements (EGRF) and their corresponding secular variations equations, are outlined. The anomalous sites, as discovered from the anomaly maps are, only, mentioned. In addition, a correlation between the International Geomagnetic Reference Field (IGRF) 2010.0 and the Egyptian Geomagnetic Reference Field (EGRF) 2010 is indicated.

  5. Origins of the semiannual variation of geomagnetic activity in 1954 and 1996

    Directory of Open Access Journals (Sweden)

    L. Svalgaard

    Full Text Available We investigate the cause of the unusually strong semiannual variation of geomagnetic activity observed in the solar minimum years of 1954 and 1996. For 1996 we separate the contributions of the three classical modulation mechanisms (axial, equinoctial, and Russell-McPherron to the six-month wave in the aam index and find that all three contribute about equally. This is in contrast to the longer run of geomagnetic activity (1868-1998 over which the equinoctial effect accounts for ∼70% of the semiannual variation. For both 1954 and 1996, we show that the Russell-McPherron effect was enhanced by the Rosenberg-Coleman effect (an axial polarity effect which increased the amount of the negative (toward Sun [positive (away from Sun] polarity field observed during the first [second] half of the year; such fields yield a southward component in GSM coordinates. Because this favourable condition occurs only for alternate solar cycles, the marked semiannual variation in 1954 and 1996 is a manifestation of the 22-year cycle of geomagnetic activity. The 11-year evolution of the heliospheric current sheet (HCS also contributes to the strong six-month wave during these years. At solar minimum, the streamer belt at the base of the HCS is located near the solar equator, permitting easier access to high speed streams from polar coronal holes when the Earth is at its highest heliographic latitudes in March and September. Such an axial variation in solar wind speed was observed for 1996 and is inferred for 1954. Key words. Magnetosphere (solar wind – magnetosphere interactions; storms and substorms

  6. Origins of the semiannual variation of geomagnetic activity in 1954 and 1996

    Directory of Open Access Journals (Sweden)

    E. W. Cliver

    2004-01-01

    Full Text Available We investigate the cause of the unusually strong semiannual variation of geomagnetic activity observed in the solar minimum years of 1954 and 1996. For 1996 we separate the contributions of the three classical modulation mechanisms (axial, equinoctial, and Russell-McPherron to the six-month wave in the aam index and find that all three contribute about equally. This is in contrast to the longer run of geomagnetic activity (1868-1998 over which the equinoctial effect accounts for ∼70% of the semiannual variation. For both 1954 and 1996, we show that the Russell-McPherron effect was enhanced by the Rosenberg-Coleman effect (an axial polarity effect which increased the amount of the negative (toward Sun [positive (away from Sun] polarity field observed during the first [second] half of the year; such fields yield a southward component in GSM coordinates. Because this favourable condition occurs only for alternate solar cycles, the marked semiannual variation in 1954 and 1996 is a manifestation of the 22-year cycle of geomagnetic activity. The 11-year evolution of the heliospheric current sheet (HCS also contributes to the strong six-month wave during these years. At solar minimum, the streamer belt at the base of the HCS is located near the solar equator, permitting easier access to high speed streams from polar coronal holes when the Earth is at its highest heliographic latitudes in March and September. Such an axial variation in solar wind speed was observed for 1996 and is inferred for 1954. Key words. Magnetosphere (solar wind – magnetosphere interactions; storms and substorms

  7. Relation of geomagnetic activity index variations with parameters of interplanetary scintillations

    International Nuclear Information System (INIS)

    Vlasov, V.I.; Shishov, V.I.; Shishova, T.D.

    1985-01-01

    A correlation between the Asub(p)-index of geomagnetic activity, index of interplanetary scintillations and solar wind velocity, has been considered depending on the spatial position of the interplanetary plasma (IPP) regions under study. It is shown, that the scintillation index can be used to forecast the geomagnetic activity, whereas the solar wind velocity can not be used for the purpose. Heliolongitudinal dependence of geoeffectiveness of IPP sreading perturbations agrees well with their structure in the heliolongitudinal cross section (and, on the whole, with the angular structure and direction of IPP perturbation spread). To use interplanetary scintillations in forecasting the geomagnetic activity (on the level of correlation not below 0.5), the angular distance of the investigated IPP regions relative to the Sun-Earth line on the average should not exceed 30-40 deg. The time of delay between the moments of observation of variations in the scintillation index the time of passage of the corresponding heliocentric distances at an average rate of the interplanetary perturbation spread approximately 500 km/s

  8. Geomagnetic field variations at the equatorial electrojet station in Sri Lanka, Peredinia

    Directory of Open Access Journals (Sweden)

    R. G. Rastogi

    2004-09-01

    Full Text Available The paper discusses the variations of the horizontal (H, vertical (Z and eastward (Y components of the geomagnetic field at Peredinia (PRD, an electrojet station in Sri Lanka, with the time of the day, season, sudden commencement (SSC and during geomagnetic storms. The daily variation of H showed a large peak around midday. The daily variation of Z appeared to be almost a time gradient curve of the daily variation of H, showing a maximum around 09:00 LT (75° EMT when the H field was increasing fastest and not at noon when Δ H was the maximum. Storm time variation of H resembled the variation of the Dst index but that of Z showed a large minimum about 2-3h before the time of minimum Dst or at the time of maximum time gradient of Dst variation. These features are compared with corresponding variations at the equatorial stations Trivandrum (TRD in India, and remarkable similarity in all observations is noticed at PRD and TRD. It is suggested that the observed abnormal features of Z variations at electrojet stations in India-Sri Lanka are due to (i direct effect of the ionospheric electrojet current (ii the induction effect of the image current by the average spatially extended conductivity region and (iii the induction current in the local subsurface conductor. It is suggested that the conductor responsible for the observed features in Z in India and Sri Lanka has to have extended spatial domain to latitudes well south of India, rather than confined to narrow Palk Strait.

  9. Prospects of hydrocarbon deposits exploration using the method of induced polarization during geomagnetic-variation profiling

    Directory of Open Access Journals (Sweden)

    К. М. Ермохин

    2017-10-01

    Full Text Available Traditionally it is believed that the effect of induced polarization is an interfering factor for the measurement of electromagnetic fields and their interpretation during conducting works using magnetotelluric sounding and geomag-netic-variation profiling methods. A new method is proposed for isolating the effects of induced polarization during geomagnetic-variation profiling aimed at searching for hydrocarbon deposits on the basis of phase measurements during the conduct of geomagnetic-variation profiling. The phenomenon of induced polarization is proposed to be used as a special exploration mark for deep-lying hydrocarbon deposits. The traditional method of induced polarization uses artificial field sources, the powers of which are principally insufficient to reach depths of 3-5 km, which leads to the need to search for alternative - natural sources in the form of telluric and magnetotelluric fields. The proposed method makes it possible to detect and interpret the effects of induced polarization from deep-seated oil and gas reservoirs directly, without relying on indirect signs.

  10. Spatial power spectrum of the geomagnetic field since 1945

    International Nuclear Information System (INIS)

    Senanayake, W.E.

    1987-04-01

    The Geomagnetic field for the period 1945-1990 has been analyzed in terms of Spatial Power Spectra of the Main Field and its Secular Variation. It is observed that for the above interval, the magnetic energy density at the core-mantle boundary is almost conserved. This supports the idea that an exchange of energy between different spherical harmonic constituents could occur. The distinctive behaviour of the first two terms (Dipole and Quadrupole), as seen from the spectra of the main field and secular variation, probably indicates somewhat different feature associated with the field origin. (author). 28 refs, 3 figs, 1 tab

  11. Cosmogenic 10Be signature of geomagnetic dipole moment variations over the last 2 Ma

    Science.gov (United States)

    Simon, Q.; Thouveny, N.; Bourlès, D. L.; Valet, J. P.; Bassinot, F. C.; Savranskaia, T.; Duvivier, A.; Choy, S.; Gacem, L.; Villedieu, A.

    2017-12-01

    Long-term variations of the geomagnetic dipole moment (GDM) during periods of stable polarity and in transitional states (reversals and excursions) provide key information for understanding the geodynamo regime. Authigenic 10Be/9Be ratios (Be-ratio, proxy of atmospheric 10Be production) from marine sedimentary cores give independent and additional insights on the evolution of the geomagnetic intensity, completing information from absolute and relative paleointensity (RPI) records. Here we present new Be-ratio results obtained on several marine cores from the North Atlantic, Indian and Pacific Oceans which permit to extent into the Matuyama chron our previous 10Be-derived GDM reconstructions (Simon et al., 2016 JGR 121). Stratigraphic offsets measured between Be-ratio peaks and the corresponding RPI minima in each studied cores are assigned to (post-) detrital remanent magnetization (pDRM) effects leading to magnetization locking-in delays varying from 0 to 16 cm (up to 12 ka). All these results were compiled in order to obtain a continuous Be-ratio record covering the last 2 Ma. 10Be overproduction episodes triggered by geomagnetic dipole moment lows (GDL) linked to polarity reversals and excursions confirm the global control exerted by the GDM on cosmogenic radionuclides production. A dipole moment reconstruction derived from the Be-ratio stack (BeDiMo2Ma) was calibrated using absolute paleointensity data. This independent record completes the available paleomagnetic RPI records and permits: 1) to confront and increase the robustness and precision of GDM reconstructions; and, 2) to better constrain geomagnetic field instabilities during the mid- to late- Matuyama chron. Our new 10Be derived inventory is fully compatible with the GDL series linked to polarity reversals (Matuyama-Brunhes transition, Jaramillo and Olduvai boundaries), geomagnetic events (Cobb Mountain, Réunion) and Brunhes' excursions (e.g. Laschamp, Blake, Iceland-Basin, Big Lost). It further

  12. Anomalous short period geomagnetic variations at two stations in Sri Lanka

    International Nuclear Information System (INIS)

    Kunaratnam, K.

    1986-08-01

    An analysis of the rates of change in the geomagnetic field components in the period range 20-600 sec recorded at Kondavil and Hikkaduwa, two stations in the equatorial electrojet belt near the northern and south western coasts respectively of Sri Lanka, shows anomalous variations. The results confirm induced current concentration in the Palk Strait and deflection of induced currents around the southerncoast of Sri Lanka postulated by earlier workers from observations of SSC and Bay events at Indian stations and from analogue and numerical model studies. At Kondavil, which is situated close to the geomagnetic equator, no appreciable difference in the night-time and day-time values of ΔZ/ΔH and ΔD/ΔH ratios was noticed while at Hikkaduwa, a station situated under the edge of the equatorial electrojet belt, a day-time enhancement of ΔZ/ΔH ratios was found at all periods in the observed range. An enhancement of the H component at Colombo over that at Hikkaduwa was also found at short periods, the enhancement being greater at day-time. The day-time enhancement in the ΔZ/ΔH ratios at Hikkaduwa and in the ratio of the H components at Colombo and Hikkaduwa could be due to the effect of the equatorial electrojet on the short period variations. (author)

  13. Time variations of geomagnetic activity indices Kp and Ap: an update

    Directory of Open Access Journals (Sweden)

    G. K. Rangarajan

    1997-10-01

    Full Text Available Kp and Ap indices covering the period 1932 to 1995 are analysed in a fashion similar to that attempted by Bartels for the 1932–1961 epoch to examine the time variations in their characteristics. Modern analysis techniques on the extended data base are used for further insight. The relative frequencies of occurrence of Kp with different magnitudes and the seasonal and solar cycle dependences are seen to be remarkably consistent despite the addition of 35 years of observations. Many of the earlier features seen in the indices and special intervals are shown to be replicated in the present analysis. Time variations in the occurrence of prolonged periods of geomagnetic calm or of enhanced activity are presented and their relation to solar activity highlighted. It is shown that in the declining phase the occurrence frequencies of Kp = 4–5 (consecutively over 4 intervals can be used as a precursor for the maximum sunspot number to be expected in the next cycle. The semi-annual variation in geomagnetic activity is re-examined utilising not only the Ap index but also the occurrence frequencies of Kp index with different magnitudes. Lack of dependence of the amplitude of semi-annual variation on sunspot number is emphasised. Singular spectrum analysis of the mean monthly Ap index shows some distinct periodic components. The temporal evolution of ~44 month, ~21 month and ~16 month oscillations are examined and it is postulated that while QBO and the 16 month oscillations could be attributed to solar wind and IMF oscillations with analogous periodicity, the 44 month variation is associated with a similar periodicity in recurrent high speed stream caused by sector boundary passage. It is reconfirmed that there could have been only one epoch around 1940 when solar wind speed could have exhibited a 1.3-year periodicity comparable to that seen during the post-1986 period.

  14. Time variations of geomagnetic activity indices Kp and Ap: an update

    Directory of Open Access Journals (Sweden)

    G. K. Rangarajan

    Full Text Available Kp and Ap indices covering the period 1932 to 1995 are analysed in a fashion similar to that attempted by Bartels for the 1932–1961 epoch to examine the time variations in their characteristics. Modern analysis techniques on the extended data base are used for further insight. The relative frequencies of occurrence of Kp with different magnitudes and the seasonal and solar cycle dependences are seen to be remarkably consistent despite the addition of 35 years of observations. Many of the earlier features seen in the indices and special intervals are shown to be replicated in the present analysis. Time variations in the occurrence of prolonged periods of geomagnetic calm or of enhanced activity are presented and their relation to solar activity highlighted. It is shown that in the declining phase the occurrence frequencies of Kp = 4–5 (consecutively over 4 intervals can be used as a precursor for the maximum sunspot number to be expected in the next cycle. The semi-annual variation in geomagnetic activity is re-examined utilising not only the Ap index but also the occurrence frequencies of Kp index with different magnitudes. Lack of dependence of the amplitude of semi-annual variation on sunspot number is emphasised. Singular spectrum analysis of the mean monthly Ap index shows some distinct periodic components. The temporal evolution of ~44 month, ~21 month and ~16 month oscillations are examined and it is postulated that while QBO and the 16 month oscillations could be attributed to solar wind and IMF oscillations with analogous periodicity, the 44 month variation is associated with a similar periodicity in recurrent high speed stream caused by sector boundary passage. It is reconfirmed that there could have been only one epoch around 1940 when solar wind speed could have exhibited a 1.3-year periodicity comparable to that seen during the post-1986 period.

  15. Marine sediments and Beryllium-10 record of the geomagnetic moment variations during the Brunhes period.

    Science.gov (United States)

    Ménabréaz, Lucie; Thouveny, Nicolas; Bourlès, Didier; Demory, François

    2010-05-01

    Over millennial time scales, the atmospheric production of the cosmonuclid 10Be (half-life 1.387 ± 0.012 Ma [Shmeleff et al., 2009; Korschinek et al., 2009]) is modulated by the geomagnetic field strength, following a negative power law (e.g. Lal, 1988; Masarik and Beer, 2009). With respect to paleomagnetic reconstructions, 10Be-derived paleointensity records can therefore constitute an alternative, global and independent reading of the dipole moment variations. During the last years, efforts have been made to extract a geomagnetic signal from single and stacked 10Be records in natural archives such as ice and marine sediments (e.g. Carcaillet et al., 2004; Christl et al., 2007; Muscheler et al., 2005). In marine sediments, the 10Be concentration results from complex interplay of several processes: cosmogenic production, adsorption on sediment particles, redistribution by fluviatile and oceanic transport, and deposition. Therefore, a correction procedure is required to consider both sediment redistribution and enhanced scavenging, which can alter the primary signatures. To reconstruct the succession of field intensity lows accompanying excursions during the Brunhes chron, we investigated authigenic 10Be/9Be record of marine sequences also studied for paleomagnetism and oxygen isotopes. Mid and low latitude sites were preferred in order to benefit from the most efficient modulation by the magnetospheric shielding. We present a high resolution authigenic 10Be/9Be record of the last 50 ka recovered from the Portuguese Margin, that deciphers the cosmonuclide 10Be overproduction created by the geomagnetic dipole low associated with the Laschamp excursion. This record is compared to other proxy records of the geomagnetic field variations for the same time interval: (1) the relative paleointensity (RPI) reconstructed from the same sediments and the GLOPIS-75 record (Laj et al., 2004), (2) the absolute VDM record based on absolute paleointensities measured on lava flows

  16. Characteristic features of the geomagnetic field of the Earth

    International Nuclear Information System (INIS)

    Petrova, G.N.

    1978-01-01

    The laws of the earth magnetism permitting to make a model of the earth magnetic field are popularly investigated. The modern methods of investigations used in the development of geomagnetism and determining the quantity and direction of the earth magnetic field from the moment of rock formation are described. Considered are the characteristic peculiarities of geomagnetic field: the inclination of the magnetic axis to the rotational axis of the Earth, the western drift of the geomagnetic field, the magnetic field asymmetry, its pole exchange and secular variations. The sources of the continuous magnetic field are investigated. The theory of hydromagnatic dinamo operating in the earth core is described. According to the invariance of the geomagnetic field characteristics it is possible to assume that the core has not significantly evolved for milliard years

  17. Improving geomagnetic observatory data in the South Atlantic Anomaly

    Science.gov (United States)

    Matzka, Jürgen; Morschhauser, Achim; Brando Soares, Gabriel; Pinheiro, Katia

    2016-04-01

    The Swarm mission clearly proofs the benefit of coordinated geomagnetic measurements from a well-tailored constellation in order to recover as good as possible the contributions of the various geomagnetic field sources. A similar truth applies to geomagnetic observatories. Their scientific value can be maximised by properly arranging the position of individual observatories with respect to the geometry of the external current systems in the ionosphere and magnetosphere, with respect to regions of particular interest for secular variation, and with respect to regions of anomalous electric conductivity in the ground. Here, we report on our plans and recent efforts to upgrade geomagnetic observatories and to recover unpublished data from geomagnetic observatories at low latitudes in the South Atlantic Anomaly. In particular, we target the magnetic equator with the equatorial electrojet and low latitudes to characterise the Sq- and ring current. The observatory network that we present allows also to study the longitudinal structure of these external current systems. The South Atlantic Anomaly region is very interesting due to its secular variation. We will show newly recovered data and comparisons with existing data sets. On the technical side, we introduce low-power data loggers. In addition, we use mobile phone data transfer, which is rapidly evolving in the region and allows timely data access and quality control at remote sites that previously were not connected to the internet.

  18. Evaluation of candidate geomagnetic field models for IGRF-12

    OpenAIRE

    Erwan Thébault; Christopher C. Finlay; Patrick Alken; Ciaran D. Beggan; Elisabeth Canet; Arnaud Chulliat; Benoit Langlais; V. Lesur; Frank J. Lowes; Chandrasekharan Manoj; Martin Rother; Reyko Schachtschneider

    2015-01-01

    Background: The 12th revision of the International Geomagnetic Reference Field (IGRF) was issued in December 2014 by the International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group V-MOD (http://www.ngdc.noaa.gov/IAGA/vmod/igrf.html). This revision comprises new spherical harmonic main field models for epochs 2010.0 (DGRF-2010) and 2015.0 (IGRF-2015) and predictive linear secular variation for the interval 2015.0-2020.0 (SV-2010-2015). Findings: The models were deri...

  19. International Geomagnetic Reference Field: the 12th generation

    OpenAIRE

    Thébault , Erwan; Finlay , Christopher ,; Beggan , Ciarán ,; Alken , Patrick; Aubert , Julien ,; Barrois , Olivier; Bertrand , François; Bondar , Tatiana; Boness , Axel; Brocco , Laura; Canet , Elisabeth ,; Chambodut , Aude; Chulliat , Arnaud ,; Coïsson , Pierdavide ,; Civet , François

    2015-01-01

    International audience; The 12th generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2014 by the Working Group V-MOD appointed by the International Association of Geomagnetism and Aeronomy (IAGA). It updates the previous IGRF generation with a definitive main field model for epoch 2010.0, a main field model for epoch 2015.0, and a linear annual predictive secular variation model for 2015.0-2020.0. Here, we present the equations defining the IGRF model, p...

  20. Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, J. R.

    2003-01-01

    It has frequently been suggested that only the geomagnetic dipole, rather than higher order poles, reverse during a geomagnetic field reversal. Under this assumption the geomagnetic field strength has been calculated for the surface of the Earth for various steps of the reversal process. Even without an eminent a reversal of the field, extrapolation of the present secular change (although problematic) shows that the field strength may become zero in some geographic areas within a few hundred years.

  1. Correlations between the geomagnetic field variations, the fluctuations of the earth`s rotation and climate change

    Energy Technology Data Exchange (ETDEWEB)

    Greiner-Mai, H; Jochmann, H

    1995-03-01

    The amplitude spectra of global geophysical phenomena were investigated to motivate research of physical connections between them. The suggested causality was derived from comparison of the spectra, and from cross correlation functions. The following global parameters were discussed: For the earth rotation by the variations of the length of day, for the geomagnetic variation by the global field intensity, changes of the dipole axis and the westward drift, and for climate change by the atmospheric excitation function derived from air pressure variations, and temperature variations. The model of atmospheric excitation, which can be proved most exactly for the annual variations of length of day, is responsible for the 11 and 22 years periods, too. It failed for longer periods, e.g. partially for the 30 years periods and completely for the 60 to 80 years periods, which were also discovered in the mean temperature and geomagnetic field variations. Therefore, it was suggested that longer periods in climate change and in the variations of the earth`s rotation are caused independently by the same process in the earth core, provided that a physical influence of the geomagnetic field on climate will be accepted in future. The investigation was completed by comparison with the spectra of some local temperature variations in Europe. (orig.)

  2. Geomagnetic fluctuations during a polarity transition

    Science.gov (United States)

    Audunsson, Haraldur; Levi, Shaul

    1997-01-01

    The extensive Roza Member of the Columbia River Basalt Group (Washington State) has intermediate paleomagnetic directions, bracketed by underlying normal and overlying reverse polarity flows. A consistent paleomagnetic direction was measured at 11 widely distributed outcrops; the average direction has a declination of 189° and an inclination of -5°, with greater variation in the inclination [Rietman, 1966]. In this study the Roza Member was sampled in two Pasco Basin drillcores, where it is a single cooling unit and its thickness exceeds 50 m. Excellent core recovery allowed uniform and dense sampling of the drillcores. During its protracted cooling, the Roza flow in the drillcores recorded part of a 15.5 Ma geomagnetic polarity transition. The inclination has symmetric, quasicyclic intraflow variation, while the declination is nearly constant, consistent with the results from the outcrops. Thermal models of the cooling flow provide the timing for remanence acquisition. The inclination is inferred to have progressed from 0° to -15° and back to -3°over a period of 15 to 60 years, at rates of 1.6° to 0.5°/yr. Because the geomagnetic intensity was probably weak during the transition, these apparently high rates of change are not significantly different from present-day secular variation. These results agree with the hypothesis that normal secular variation persists through geomagnetic transitions. The Iow-amplitude quasicyclical fluctuations of the field over tens of years, recorded by Roza, suggest that the geomagnetic field reverses in discrete steps, and that more than 15-60 years were required to complete this reversal.

  3. Analysis of geomagnetic storm variations and count-rate of cosmic ray muons recorded at the Brazilian southern space observatory

    International Nuclear Information System (INIS)

    Frigo, Everton; Savian, Jairo Francisco; Silva, Marlos Rockenbach da; Lago, Alisson dal; Trivedi, Nalin Babulal; Schuch, Nelson Jorge

    2007-01-01

    An analysis of geomagnetic storm variations and the count rate of cosmic ray muons recorded at the Brazilian Southern Space Observatory -OES/CRS/INPE-MCT, in Sao Martinho da Serra, RS during the month of November 2004, is presented in this paper. The geomagnetic measurements are done by a three component low noise fluxgate magnetometer and the count rates of cosmic ray muons are recorded by a muon scintillator telescope - MST, both instruments installed at the Observatory. The fluxgate magnetometer measures variations in the three orthogonal components of Earth magnetic field, H (North-South), D (East-West) and Z (Vertical), with data sampling rate of 0.5 Hz. The muon scintillator telescope records hourly count rates. The arrival of a solar disturbance can be identified by observing the decrease in the muon count rate. The goal of this work is to describe the physical morphology and phenomenology observed during the geomagnetic storm of November 2004, using the H component of the geomagnetic field and vertical channel V of the multi-directional muon detector in South of Brazil. (author)

  4. Analysis of geomagnetic storm variations and count-rate of cosmic ray muons recorded at the Brazilian southern space observatory

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, Everton [University of Sao Paulo, USP, Institute of Astronomy, Geophysics and Atmospheric Sciences, IAG/USP, Department of Geophysics, Sao Paulo, SP (Brazil); Savian, Jairo Francisco [Space Science Laboratory of Santa Maria, LACESM/CT, Southern Regional Space Research Center, CRS/INPE, MCT, Santa Maria, RS (Brazil); Silva, Marlos Rockenbach da; Lago, Alisson dal; Trivedi, Nalin Babulal [National Institute for Space Research, INPE/MCT, Division of Space Geophysics, DGE, Sao Jose dos Campos, SP (Brazil); Schuch, Nelson Jorge, E-mail: efrigo@iag.usp.br, E-mail: savian@lacesm.ufsm.br, E-mail: njschuch@lacesm.ufsm.br, E-mail: marlos@dge.inpe.br, E-mail: dallago@dge.inpe.br, E-mail: trivedi@dge.inpe.br [Southern Regional Space Research Center, CRS/INPE, MCT, Santa Maria, RS (Brazil)

    2007-07-01

    An analysis of geomagnetic storm variations and the count rate of cosmic ray muons recorded at the Brazilian Southern Space Observatory -OES/CRS/INPE-MCT, in Sao Martinho da Serra, RS during the month of November 2004, is presented in this paper. The geomagnetic measurements are done by a three component low noise fluxgate magnetometer and the count rates of cosmic ray muons are recorded by a muon scintillator telescope - MST, both instruments installed at the Observatory. The fluxgate magnetometer measures variations in the three orthogonal components of Earth magnetic field, H (North-South), D (East-West) and Z (Vertical), with data sampling rate of 0.5 Hz. The muon scintillator telescope records hourly count rates. The arrival of a solar disturbance can be identified by observing the decrease in the muon count rate. The goal of this work is to describe the physical morphology and phenomenology observed during the geomagnetic storm of November 2004, using the H component of the geomagnetic field and vertical channel V of the multi-directional muon detector in South of Brazil. (author)

  5. Comment on ``Annual variation of geomagnetic activity'' by Alicia L. Clúa de Gonzales et al.

    Science.gov (United States)

    Sonnemann, G. R.

    2002-10-01

    Clúa de Gonzales et al. (J. Atmos. Terr. Phys. 63 (2001) 367) analyzed the monthly means of the geomagnetic /aa-index available since 1868 and found enhanced geomagnetic activity in July outside of the known seasonal course of semiannual variation. They pointed out that this behavior is mainly caused by the high values of the geomagnetic activity. Their analysis confirmed results obtained from an analysis of Ap-values nearly 30 years ago but widely unknown to the scientific community. At that time the entire year was analyzed using running means of the activity values averaged to the same date. Aside from the July period, the calculations revealed distinct deviations from the seasonal course-called geomagnetic singularities. The most marked singularity occurs from the middle of March to the end of March characterized by a strong increase from, on average, relatively calm values to the actually strongest ones during the entire year. Some typical time patterns around and after equinox are repeated half a year later. An analysis in 1998 on the basis of the available /aa-values confirmed the findings derived from Ap-values and the local activity index Ak from Niemegk, Germany available since 1890. The new results will be presented and discussed. Special attention is paid to the statistical problem of the persistence of geomagnetic perturbations. The main problem under consideration is that the variation of the mean activity is not caused by an accidental accumulation of strong perturbations occurring within certain intervals of days. We assume that the most marked variations of the mean value are not accidental and result from internal processes within the earth's atmosphere but different, particularly small-scale features, are most probably accidental.

  6. Statistical study of interplanetary condition effect on geomagnetic storms: 2. Variations of parameters

    Science.gov (United States)

    Yermolaev, Yu. I.; Lodkina, I. G.; Nikolaeva, N. S.; Yermolaev, M. Yu.

    2011-02-01

    We investigate the behavior of mean values of the solar wind’s and interplanetary magnetic field’s (IMF) parameters and their absolute and relative variations during the magnetic storms generated by various types of the solar wind. In this paper, which is a continuation of paper [1], we, on the basis of the OMNI data archive for the period of 1976-2000, have analyzed 798 geomagnetic storms with D st ≤ -50 nT and their interplanetary sources: corotating interaction regions CIR, compression regions Sheath before the interplanetary CMEs; magnetic clouds MC; “Pistons” Ejecta, and an uncertain type of a source. For the analysis the double superposed epoch analysis method was used, in which the instants of the magnetic storm onset and the minimum of the D st index were taken as reference times. It is shown that the set of interplanetary sources of magnetic storms can be sub-divided into two basic groups according to their slowly and fast varying characteristics: (1) ICME (MC and Ejecta) and (2) CIR and Sheath. The mean values, the absolute and relative variations in MC and Ejecta for all parameters appeared to be either mean or lower than the mean value (the mean values of the electric field E y and of the B z component of IMF are higher in absolute value), while in CIR and Sheath they are higher than the mean value. High values of the relative density variation sN/ are observed in MC. At the same time, the high values for relative variations of the velocity, B z component, and IMF magnitude are observed in Sheath and CIR. No noticeable distinctions in the relationships between considered parameters for moderate and strong magnetic storms were observed.

  7. How does the predicted geomagnetic main field variation alter the thermosphere-ionosphere storm-time response?

    Science.gov (United States)

    Maute, A. I.; Lu, G.; Richmond, A. D.

    2017-12-01

    Earth's magnetic main field plays an important role in the thermosphere-ionosphere (TI) system, as well as its coupling to Earth's magnetosphere. The ionosphere consists of a weakly ionized plasma strongly influenced by the main field and embedded in the thermosphere. Therefore, ion-neutral coupling and ionospheric electrodynamics can influence the plasma distribution and neutral dynamics. There are strong longitude variations of the TI storm response. At high latitude magnetosphere-ionosphere coupling is organized by the geomagnetic main field, leading in general to stronger northern middle latitude storm time response in the American sector due to the geomagnetic dipole location. In addition, the weak geomagnetic main field in the American sector leads to larger local ExB drift and can alter the plasma densities. During geomagnetic storms the intense energy input into the high latitude region is redistributed globally, leading to thermospheric heating, wind circulation changes and alterations of the ionospheric electrodynamics. The storm time changes are measurable in the plasma density, ion drift, temperature, neutral composition, and other parameters. All these changes depend, to some degree, on the geomagnetic main field which changes on decadal time scales. In this study, we employ a forecast model of the geomagnetic main field based on data assimilation and geodynamo modeling [Aubert et al., 2015]. The main field model predicts that in 50 years the South Atlantic Anomaly is further weakened by 2 mT and drifts westward by approximately 10o. The dipole axis moves northward and westward by 2o and 6o, respectively. Simulating the March 2015 geomagnetic storm with the Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIE-GCM) driven by the Assimilative Mapping of Ionospheric Electrodynamics (AMIE), we evaluate the thermosphere-ionosphere response using the geomagnetic main field of 2015, 2065, and 2115. We compare the TI response for 2015 with

  8. Long-term variations in the geomagnetic activity level Part II: Ascending phases of sunspot cycles

    Directory of Open Access Journals (Sweden)

    V. Mussino

    1994-08-01

    Full Text Available Monthly averages of the Helsinki Ak-values have been reduced to the equivalent aa-indices to extend the aa-data set back to 1844. A periodicity of about five cycles was found for the correlation coefficient (r between geomagnetic indices and sunspot numbers for the ascending phases of sunspot cycles 9 to 22, confirming previous findings based on a minor number of sunspot cycles. The result is useful to researchers in topics related to solar-terrestrial physics, particularly for the interpretation of long-term trends in geomagnetic activity during the past, and to forecast geomagnetic activity levels in the future.

  9. Anomaly of the geomagnetic Sq variation in Japan: effect from 3-D subterranean structure or the ocean effect?

    OpenAIRE

    Kuvshinov, Alexei; Utada, Hisashi

    2017-01-01

    Many years ago Rikitake et al. described the anomalous behaviour of the vertical component Z of the geomagnetic solar quiet (Sq) daily variation field at observatories in central and northern Japan - namely about 2 hr shift of the local noontime peak towards morning hours. They suggested that this anomaly is associated with the anomalous distribution of electrical conductivity in the mantle beneath central Japan. Although a few works have been done to confirm or argue this explanation, no cle...

  10. Geomagnetic Paleointensity Variations as a Cheap, High-Resolution Geochronometer for Recent Mid-Ocean Ridge Processes

    Science.gov (United States)

    DYMENT, J.; HEMOND, C.

    2001-12-01

    The sequence of geomagnetic field reversals is widely used to date events younger than 160 Ma, with a resolution of a million years. In oceanic domains, Vine and Matthews (1963) magnetic anomalies have been successfully used for more than 35 years. The major limitation of this chronometer is its low temporal resolution, especially for the recent times: the youngest polarity reversal, between Brunhes normal and Matuyama reversed periods, is dated ~800 ka. Studies of pelagic sedimentary cores have shown the existence of consistent variations of the geomagnetic field intensity within this period. If accurately dated, these variations may refine the magnetic geochronometer to a much higher resolution of 10-100 ka. Recent studies have demonstrated that the "tiny wiggles" of lower amplitude and shorter wavelength superimposed to the Vine and Matthews anomalies are of geomagnetic origin and correspond to the paleointensity variations identified on sediment cores. Using a large set of magnetic data acquired in 1996 on the Mid-Atlantic Ridge at 21° N (surface and submersible magnetic anomalies, natural remanent magnetization and absolute paleointensities measured on samples), we have shown that the oceanic crust confidently records the geomagnetic intensity variations. It was unfortunately impossible to date the samples, made of basalt too depleted in K2O and in trace elements required by the various methods of radiochronology. In 2000 we have collected a similar data set at the Central Indian Ridge axis at 19° S (surface, deep-tow, and submersible magnetic anomalies, natural remanent magnetization and absolute paleointensities measured on samples). This area offers the advantages of 1) a faster spreading rate, and therefore a higher temporal resolution of the geomagnetic signal, and 2) the presence of moderately enriched basalt as a consequence of the interaction of the ridge with the nearby Reunion hotspot, making possible radiochronologic dating. Our first evaluation

  11. Rapid geomagnetic field intensity variations in the Near East during the 6th millennium BC: New archeointensity data from Halafian site Yarim Tepe II (Northern Iraq)

    Science.gov (United States)

    Yutsis-Akimova, Stanislava; Gallet, Yves; Amirov, Shahmardan

    2018-01-01

    further suggests that the intensity secular variation in the Near East and in Eastern Europe during the 6th millennium BC was in fact principally punctuated by two successive short-lasting intensity peaks, the first around 5800 BC and the second around 5500 BC. The scarcity of the intensity data available worldwide, however, prevents us constraining the geomagnetic dipole or non-dipole origin of these features. The variation rates associated with the rapid intensity fluctuations observed in Yarim Tepe II are of ∼0.15-0.25 μT/yr. This range of values appears similar to that of rapid intensity variations that sporadically occurred in more recent times, such as in Western Europe around 700 BC and 1000 AD. In contrast, it is lower than the variation rates that were proposed for geomagnetic spikes. Our results also have interesting implications on Halafian archeology; in particular, they suggest that the Late Halaf-HUT boundary was older by ∼ one century than previously considered.

  12. Paleomagnetic Secular Variation Constraints on the Rapid Eruption of the Emeishan Continental Flood Basalts in Southwestern China and Northern Vietnam

    Science.gov (United States)

    Xu, Yingchao; Yang, Zhenyu; Tong, Ya-Bo; Jing, Xianqing

    2018-04-01

    Estimating the duration of magma eruptions using isotopic dating methods is difficult because of the intrinsic errors of the technique regarding the dated materials (such as zircon). However, the long-term variation of the geomagnetic field recorded by lava flows can be used to estimate the net duration of an eruption sequence. The Emeishan basalts at Dongchuan, with a thickness of 630 m, yielded a reliable characteristic remanent magnetization of normal polarity and which passed the fold test (Tauxe & Watson, 1994, https://doi.org/10.1016/0012-821X(94)90006-X). Stratigraphic and magnetostratigraphic correlations of the Emeishan basalts in the Dongchuan section with other sections indicate that the eruption of the Emeishan basalts at Dongchuan spans the entire normal polarity zone in the early stage of the Emeishan large igneous province. A flow-by-flow analysis of geomagnetic directions of the Emeishan basalts at Dongchuan indicates that four directional groups and fifteen individual lava directions were recorded, with a net duration (excluding quiescent intervals) of no more than 3100 years. The averaged site directions from the Emeishan basalts with normal polarity conforming to a geocentric axial dipole direction indicate that this interval is longer than 104-105 years. In addition, a magnetostratigraphic study indicates that the normal polarity interval recorded by the Emeishan basalts was shorter than 2-20 × 104 years. Thus, the total duration of the normal polarity stage of the Emeishan large igneous province was roughly 105 years. There is a possible relationship between the rapid eruption and the Late Capitanian mass extinction (259.8 ± 0.4 Ma, Henderson et al., 2012).

  13. Stochastic forecasting of the geomagnetic field from the COV-OBS.x1 geomagnetic field model, and candidate models for IGRF-12

    DEFF Research Database (Denmark)

    Gillet, Nicolas; Barrois, Olivier; Finlay, Chris

    2015-01-01

    the ‘observations’ uncertainties in data assimilation schemes for the study of the outer core dynamics.We also present and illustrate a stochastic algorithm designed to forecast the geomagnetic field. The radial field at the outer core surface is advected by core motions governed by an auto-regressive process...... filter algorithm. We show that the envelope of forecasts includes the observed secular variation of the geomagnetic field over 5-year intervals, even in the case of rapid changes. In a purpose of testing hypotheses about the core dynamics, this prototype method could be implemented to build the ‘state...

  14. Relationship between human physiological parameters and geomagnetic variations of solar origin

    Science.gov (United States)

    Dimitrova, S.

    Results presented concern influence of increased geomagnetic activity on some human physiological parameters. The blood pressure and heart rate of 86 volunteers were measured on working days in autumn 2001 (01/10 09/11) and in spring 2002 (08/04 28/05). These periods were chosen because of maximal expected geomagnetic activity. Altogether 2799 recordings were obtained and analysed. Questionnaire information about subjective psycho-physiological complaints was also gathered. MANOVA was employed to check the significance of the influence of three factors on the physiological parameters under consideration. The factors were the following: (1) planetary geomagnetic activity level estimated by Ap-index and divided into five levels; (2) gender males and females; (3) blood pressure degree persons in the group examined were divided into hypotensive, normotensive and hypertensive. Post hoc analysis was performed to elicit the significance of differences in the factors’ levels. The average arterial blood pressure of the group was found to increase significantly with the increase of geomagnetic activity level. The average increment of systolic and diastolic blood pressure of the group examined reached 9%. This effect was present irrespectively of gender. Results obtained suppose that hypertensive persons have the highest sensitivity and the hypotensive persons have the lowest sensitivity of the arterial blood pressure to increase of geomagnetic activity. The results did not show significant changes in the heart rate. The percentage of the persons who reported subjective psycho-physiological complaints was also found to increase significantly with the geomagnetic activity increase and the highest sensitivity was revealed for the hypertensive females.

  15. The influence of ENSO, PDO and PNA on secular rainfall variations in Hawai‘i

    Science.gov (United States)

    Abby G. Frazier; Oliver Elison Timm; Thomas W. Giambelluca; Henry F. Diaz

    2017-01-01

    Over the last century, significant declines in rainfall across the state of Hawai‘i have been observed, and it is unknown whether these declines are due to natural variations in climate, or manifestations of human-induced climate change. Here, a statistical analysis of the observed rainfall variability was applied as first step towards better understanding causes for...

  16. [Seasonal variations in the myocardial infarction incidence and possible effects of geomagnetic micropulsations on the cardiovascular system in humans].

    Science.gov (United States)

    Kleĭmenova, N G; Kozyreva, O V; Breus, T K; Rapoport, S I

    2007-01-01

    The analysis of the ambulance calls in Moscow, related to myocardial infarction (85.000 events), sudden death (71.700 events), and hypertension crises (165.500 events) over the period of 1979-1981 demonstrated their clear seasonal variations with a profound summer minimum and a winter maximum. The same results were obtained in the analysis of statistical monthly data on sudden death from infarction in Bulgaria over the period of 15 years (1970-1985). However, there are a great number of clinical and statistical studies confirming the rises in the incidence of myocardial infarction, hypertension crise, and sudden death during geomagnetic disturbances, which have maximum occurrence near equinox, not in winter. In order to explain this contradiction, we suggested that one of critical factors that affect the human cardiovascular system is geomagnetic micropulsations Pc1 having the frequency comparable with the frequency of heart rate beatings and winter maximum in their occurrence. The results of a comparative analysis of data of ambulance calls in Moscow related to myocardial infarction and sudden death and the catalog of Pc1 observations at the geophysical observatory "Borok" (Yaroslavl region) are presented. It is shown that in approximately 70% of days with an anomalously large number of ambulance calls related to myocardial infarction, Pc1 micropulsations have been registered. The probability of simultaneous occurrence of myocardial infarction and Pc1 in the winter season was 1.5 times greater than their accidental coincidence. Moreover, it was found that in winter the effects of magnetic storms and Pc1 IM(A) were much higher than in summer. We suggested that one of possible reasons for the seasonal variations in the occurrence of myocardial infarction is an increase in the production of the pineal hormone melatonin in winter which leads to an unstable state of the human organism and an increase in its sensitivity to the effect of geomagnetic pulsations.

  17. Longitudinal distribution of recurrent solar activity sources and its reflection in geomagnetic variations

    International Nuclear Information System (INIS)

    Letfus, V.; Apostolov, E.M.

    1980-01-01

    By analysing the autocorrelation function of the geomagnetic Asup(p)-index, a series of subsidiary maxima were found which seem to indicate that they correspond to periods considerably different from the solar rotation period. It was found that these subsidiary maxima are located symmetrically around the maxima of the first and second recurrences of the solar rotation period (and probably also around the subsequent ones). This fact leads to a model of two or more geoactive longitudes on the Sun. (author)

  18. Seasonal latitudinal and secular variations in temperature trend - evidence for influence of anthropogenic sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, D E; Schwartz, S E; Wagener, R; Benkovitz, C M [University of California at San Diego, La Jolla, CA (United States). Scripps Institute of Oceanography

    1993-11-19

    Tropospheric aerosols increase the shortwave reflectivity of the Earth-atmosphere system both by scattering light directly, in the absence of clouds, and by enhancing cloud reflectivity. The radiative forcing of climate exerted by anthropogenic sulfate aerosols, derived mainly from SO[sub 2] emitted from fossil fuel combustion, is opposite that due to anthropogenic greenhouse gases and is estimated to be of comparable average magnitude in Northern Hemisphere midlatitudes. However, persuasive evidence of climate response to this forcing has thus far been lacking. Here we examine patterns of seasonal and latitudinal variations in temperature anomaly trend for evidence of such a response. Pronounced minima in the rate of temperature increase in summer months in Northern Hemisphere midlatitudes are consistent with the latitudinal distribution of anthropogenic sulfate and changes in the rate of SO[sub 2] emissions over the industrial era.

  19. Secular variations in composition of the solar wind - Evidence and causes

    International Nuclear Information System (INIS)

    Kerridge, J.F.

    1980-01-01

    Variations in the composition of the regolith due to irradiation by the solar wind are examined by categorizing the exposure history recorded in each sample. The history can be defined by two parameters: the duration of solar wind exposure (maturity) and a measure of how long the exposure took place (antiquity). Three partially successful methods for determining antiquity are described: the regolith contains small amounts of unsupported, trapped radiogenic noble gases, the most common being Ar-40. Assuming relatively prompt outgassing of the lunar interior, the amount of Ar-40 implanted per unit time should be proportional to the lunar content of K-40, and thus should have decayed exponentially over the lifetime of the moon. Normalization to constant exposure duration is achieved by taking the ratio Ar-40/Ar-36 in trapped gas, Ar-36 being an efficiently trapped solar wind species. The second method involves the interaction between galactic cosmic rays and lunar material producing certain spallogenic nuclides which may be analyzed in terms of a cosmic ray exposure age. The third method deals with the fact that there is a general tendency for depth within a core to be related to time deposition; two variants of this method are presented

  20. Secular variation of the amount of nuclear information and its interpretation by a media-public interaction model

    International Nuclear Information System (INIS)

    Ohnishi, Teruaki

    1998-01-01

    Time dependent characteristics of the amount of nuclear information fed by the Japanese press are explained by a nonlinear model with mutual interaction between the media and the public. In the secular variation of that amount since the early 1950s, there appears semicyclicly oscillating fine structure of that amount with a period of several months superposed on a background having a feature of slowly varying wave of information with a period of around ten years. A model is proposed such that an individual media determines its reportorial stance using the response of the public to the preceding information and the general tendency of the other media as measures of judgement. Since the structure of this model resembles to that of an evolving ecosystem, the paradigm shift in nuclear information can be interpreted by analogy with the succession of facies in an ecological system. Moreover, the slowly time-varying waves of information associated with the paradigm shift is found to be grasped as a resultant of prevalence phenomenon if the nuclear paradigm is regarded as a sort of prevalence. The oscillation of the amount of information in a short time scale, on the other hand, is found to appear as a result of the competition between the extent of reflection of the present amount of information to the next information and the extent of reflection of the reportorial state of the other media also to the next information under the existence of public response. Those characteristics regarding the amount of nuclear information are found to come out as necessary consequences of the society with mutual stimulation between the media and the public. (author)

  1. The temporal and spatial variations of low frequency geomagnetic pulsations at polar cusp and cap latitudes

    International Nuclear Information System (INIS)

    Kleimenova, N.; Kozyreva, O.V.; Francia, P.; Villante, U.

    1999-01-01

    Geomagnetic field measurements at two Antarctic are compared during two weeks in the local summer (January 1-15, 1992). Low frequency (0.6 mHz) pulsations are observed at each station near local magnetic noon. The same wave packets appear in some case also at the other station, although with a significant attenuation, more clearly in the morning sector; the wave show a near noon reversal of the polarization sense from counterclockwise in the morning to clockwise in the afternoon indicating a westward and an eastward propagation, respectively

  2. The temporal and spatial variations of low frequency geomagnetic pulsations at polar cusp and cap latitudes

    Directory of Open Access Journals (Sweden)

    J. Bitterly

    1999-06-01

    Full Text Available Geomagnetic field measurements at two Antarctic stations are compared during two weeks in the local summer (January 1-15, 1992. Low frequency (0.6-6 mHz pulsations are observed at each station near local magnetic noon. The same wave packets appear in some cases also at the other station, although with a significant attenuation, more clearly in the morning sector; the waves show a near noon reversal of the polarization sense from counter-clockwise in the morning to clockwise in the afternoon indicating a westward and an eastward propagation, respectively.

  3. Domino model for geomagnetic field reversals.

    Science.gov (United States)

    Mori, N; Schmitt, D; Wicht, J; Ferriz-Mas, A; Mouri, H; Nakamichi, A; Morikawa, M

    2013-01-01

    We solve the equations of motion of a one-dimensional planar Heisenberg (or Vaks-Larkin) model consisting of a system of interacting macrospins aligned along a ring. Each spin has unit length and is described by its angle with respect to the rotational axis. The orientation of the spins can vary in time due to spin-spin interaction and random forcing. We statistically describe the behavior of the sum of all spins for different parameters. The term "domino model" in the title refers to the interaction among the spins. We compare the model results with geomagnetic field reversals and dynamo simulations and find strikingly similar behavior. The aggregate of all spins keeps the same direction for a long time and, once in a while, begins flipping to change the orientation by almost 180 degrees (mimicking a geomagnetic reversal) or to move back to the original direction (mimicking an excursion). Most of the time the spins are aligned or antialigned and deviate only slightly with respect to the rotational axis (mimicking the secular variation of the geomagnetic pole with respect to the geographic pole). Reversals are fast compared to the times in between and they occur at random times, both in the model and in the case of the Earth's magnetic field.

  4. Feeding secularism

    DEFF Research Database (Denmark)

    Fischer, Johan

    2005-01-01

    life. He shows how Islamic organizations in Britain claim authority through halal in the interfaces of expanding markets, secularism, and the rights and demands of a growing group of Muslim consumers. These claims emerge in a society where powerful political discourses identify the veiling of Muslim...

  5. Fearing Secularism

    DEFF Research Database (Denmark)

    Sheikh, Mona Kanwal

    Secularism and Beyond - Comparative Perspectives: International og interdisciplinær konference, 29. maj-1. juni, 2007Arrangeret af Anders Berg-Sørensen for "Religion i det 21. århundrede" i samarbejde med kolleger fraKøbenhavns Universitet og universiteterne i Wien og Birmingham...

  6. The Holocene Geomagnetic Field: Spikes, Low Field Anomalies, and Asymmetries

    Science.gov (United States)

    Constable, C.

    2017-12-01

    Our understanding of the Holocene magnetic field is constrained by individual paleomagnetic records of variable quality and resolution, composite regional secular variation curves, and low resolution global time-varying geomagnetic field models. Although spatial and temporal data coverages have greatly improved in recent years, typical views of millennial-scale secular variation and the underlying physical processes continue to be heavily influenced by more detailed field structure and short term variability inferred from the historical record and modern observations. Recent models of gyre driven decay of the geomagnetic dipole on centennial time scales, and studies of the evolution of the South Atlantic Anomaly provide one prominent example. Since 1840 dipole decay has largely been driven by meridional flux advection, with generally smaller fairly steady contributions from magnetic diffusion. The decay is dominantly associated with geomagnetic activity in the Southern Hemisphere. In contrast to the present decay, dipole strength generally grew between 1500 and 1000 BC, sustaining high but fluctuating values around 90-100 ZAm2 until after 1500 AD. Thus high dipole moments appear to have been present shortly after 1000 AD at the time of the Levantine spikes, which represent extreme variations in regional geomagnetic field strength. It has been speculated that the growth in dipole moment originated from a strong flux patch near the equatorial region at the core-mantle boundary that migrated north and west to augment the dipole strength, suggesting the presence of a large-scale anticyclonic gyre in the northern hemisphere, not totally unlike the southern hemisphere flow that dominates present day dipole decay. The later brief episodes of high field strength in the Levant may have contributed to prolonged values of high dipole strength until the onset of dipole decay in the late second millennium AD. This could support the concept of a large-scale stable flow

  7. Summary of daily observational results of solar phenomena, cosmic ray, geomagnetic variation, ionosphere, radio wave propagation and airglow

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    The diagrams in this section of the publication illustrate the summary of daily observational results of solar phenomena, cosmic ray, geomagnetic variation, ionosphere, radio wave propagation and airglow observed in Japan. For convenience, the observational results are arranged by the solar rotation number. The aim of this illustration is to disseminate an outline of daily events observed in Japan for the benefit of active research workers who plan to make detailed study of the specific solar and terrestrial events. Therefore, the illustrations do not show all observational results in Japan but only representative ones at some key stations in Japan. They will suffice for the present purpose. The method of illustration shown in the instruction on the next page is still a preliminary one, and it is subject to change resulting from the kind advice of the users of this part of the publication. We welcome any advice for making the data arrangement and expression better and more convenient. (auth.)

  8. Solar activity effects on cosmic ray intensity and geomagnetic field variation

    International Nuclear Information System (INIS)

    Shukla, A.K.; Shukla, J.P.; Sharma, S.M.; Singh, R.L.; Agrawal, S.P.

    1978-01-01

    An analysis has been performed to statistically correlate the date of solar flare occurrence and its importance with the short term cosmic ray intensity decreases (observed by the high latitude neutron monitors) as well as with the geomagnetic field fluctuation indices (Asub(p) and Dsub(st)), during the period 1973-1976. This period has the particular advantage of being close to a solar minimum to avoid the ambiguity due to closely spaced solar flares. It is found that the intensity decrease starts at least 2-3 days after the date of bright solar flares of Imp 1B, 2B or 3B and the amplitude of the decrease increases with the importance of the solar flare. (author)

  9. Geomagnetism 4

    CERN Document Server

    Jacobs, John A

    2013-01-01

    Geomagnetism, Volume 4 focuses on the processes, methodologies, technologies, and approaches involved in geomagnetism, including electric fields, solar wind plasma, pulsations, and gravity waves.The selection first offers information on solar wind, magnetosphere, and the magnetopause of the Earth. Discussions focus on magnetopause structure and transfer processes, magnetosphere electric fields, geomagnetically trapped radiation, microstructure of the solar wind plasma, and hydro magnetic fluctuations and discontinuities. The text then examines geomagnetic tail, neutral upper atmosphere, and ge

  10. Toward constructing a time-series of geomagnetic field variations from thermal remanence in slowly cooled igneous rocks

    Science.gov (United States)

    Burns, Z.; Gee, J. S.

    2017-12-01

    Analysis of paleomagnetic data can not only help us to understand the behavior of the ancient magnetic field but may also further our understanding of the current field, as well as of the mechanisms and constraints of the geodynamo and geomagnetic reversals. A question of particular interest is the possible relationship between reversal frequency and geomagnetic field intensity. Some research appears to indicate a correlation between low intensity and high reversal frequency, seeming to support the theory that low field intensity is what makes reversals possible. In order to study this correlation, we obtained several hundred samples from the 182 Ma Dufek Massif, in Antarctica. This intrusion was cooled slowly, at depth, during the high reversal frequency era of the early Jurassic, and most of our samples record multiple polarity intervals. This, combined with their particularly homogeneous magnetic characteristics, makes them ideally suited for recovering a record of geomagnetic field variations. On approximately 300 samples from the lower portion of the intrusion, we performed step-wise thermal demagnetization of the natural remanent magnetization (NRM), followed by thermal demagnetization of a laboratory thermoremance (TRM), imparted as partial TRMs in three orthogonal directions to assess the reliability of the remanence. These two sets of measurements can tell us about the amount and direction of magnetization acquired at each temperature step and the sample's capacity to acquire a remanence. Corrected for anisotropy, the ratio of the NRM/TRM values at each step multiplied by the value of the lab field can give us an estimate of the paleofield intensity. When convolved with a thermal cooling model for the intrusion, this yields a model of the time-varying ancient field during the intrusion's cooling period. Initial analysis of our data shows average field values of around 20 µT and a minimum of four reversals. The average at this high-latitude site is lower

  11. Explanation of observable secular variations of gravity and alternative methods of determination of drift of the center of mass of the Earth

    Science.gov (United States)

    Barkin, Yury

    2010-05-01

    The summary. On the basis of geodynamic model of the forced relative displacement of the centers of mass of the core and the mantle of the Earth the secular variations of a gravity and heights of some gravimetry stations on a surface of the Earth have ben studied. At the account of secular drift of the center of mass of the Earth which on our geodynamic model is caused by the unidirectional drift of the core of the Earth relatively to the mantle, the full explanation is given to observable secular variations of a gravity at stations Ny-Alesund (Norway), Churchill (Canada), Medicine (Italy), Sayowa (Antarctica), Strastburg (France), Membach (Belgium), Wuhan (China) and Metsahovi (Finland). Two new methods of determination of secular drift of the center of mass of the Earth, alternative to classical method of a space geodesy are offered: 1) on the basis of gravimetry data about secular trends of a gravity at the stations located on all basic regions of the Earth; 2) on the basis of the comparative analysis of altimetry and coastal data about secular changes of sea level also in basic regions of ocean. 1. Secular drift of the center of mass of the core and the center of mass of the Earth. A secular drift of the center of mass of the Earth to the North relatively to special center O on an axis of rotation of the Earth for which the coefficient of third zonal harmonic J3' = 0, has been predicted in the author work [1]. A drift in a direction to a geographical point (pole P) 70°0 N and 104°3 E has been established for the first time theoretically - as a result of the analysis of the global directed redistribution of masses of the Earth, explaining the observed secular drift of the pole of an axis of rotation of the Earth and not tidal acceleration of its axial rotation [2]. In [1] velocity of drift it has been estimated in 1-2 cm/yr. For specified center O the figure of a planet is as though deprived of pure-shaped form (J3' = 0). And in this sense the point O can be

  12. Authigenic 10Be/9Be ratio signatures of the cosmogenic nuclide production linked to geomagnetic dipole moment variation since the Brunhes/Matuyama boundary.

    Science.gov (United States)

    Simon, Quentin; Thouveny, Nicolas; Bourlès, Didier L; Valet, Jean-Pierre; Bassinot, Franck; Ménabréaz, Lucie; Guillou, Valéry; Choy, Sandrine; Beaufort, Luc

    2016-11-01

    Geomagnetic dipole moment variations associated with polarity reversals and excursions are expressed by large changes of the cosmogenic nuclide beryllium-10 ( 10 Be) production rates. Authigenic 10 Be/ 9 Be ratios (proxy of atmospheric 10 Be production) from oceanic cores therefore complete the classical information derived from relative paleointensity (RPI) records. This study presents new authigenic 10 Be/ 9 Be ratio results obtained from cores MD05-2920 and MD05-2930 collected in the west equatorial Pacific Ocean. Be ratios from cores MD05-2920, MD05-2930 and MD90-0961 have been stacked and averaged. Variations of the authigenic 10 Be/ 9 Be ratio are analyzed and compared with the geomagnetic dipole low series reported from global RPI stacks. The largest 10 Be overproduction episodes are related to dipole field collapses (below a threshold of 2 × 10 22  Am 2 ) associated with the Brunhes/Matuyama reversal, the Laschamp (41 ka) excursion, and the Iceland Basin event (190 ka). Other significant 10 Be production peaks are correlated to geomagnetic excursions reported in literature. The record was then calibrated by using absolute dipole moment values drawn from the Geomagia and Pint paleointensity value databases. The 10 Be-derived geomagnetic dipole moment record, independent from sedimentary paleomagnetic data, covers the Brunhes-Matuyama transition and the whole Brunhes Chron. It provides new and complementary data on the amplitude and timing of millennial-scale geomagnetic dipole moment variations and particularly on dipole moment collapses triggering polarity instabilities.

  13. Anomaly of the geomagnetic Sq variation in Japan: effect from 3-D subterranean structure or the ocean effect?

    Science.gov (United States)

    Kuvshinov, Alexei; Utada, Hisashi

    2010-12-01

    Many years ago Rikitake et al. described the anomalous behaviour of the vertical component Z of the geomagnetic solar quiet (Sq) daily variation field at observatories in central and northern Japan - namely about 2 hr shift of the local noontime peak towards morning hours. They suggested that this anomaly is associated with the anomalous distribution of electrical conductivity in the mantle beneath central Japan. Although a few works have been done to confirm or argue this explanation, no clear answer has been obtained so far. The goal of this work is to understand the nature of this anomaly using our 3-D forward solution. The conductivity model of the Earth includes oceans of laterally variable conductance and conducting mantle either spherically symmetric or 3-D underneath. Data from six Japanese observatories at four seasons for two different years of the solar cycle are analysed. As an inducing ionospheric (Sq) current system, we use those provided by the Comprehensive Model (CM4) of Sabaka et al. Our analysis clearly demonstrates that 3-D induction in the ocean is responsible for the anomalous behaviour of Z daily variations in this region. We also show that the effects from a suite of 3-D mantle models that include mantle wedge and subducting slab are minor compared with the ocean effect.

  14. Variations of plasmaspheric field-aligned electron and ion densities (90-4000 km) during quiet to moderately active (Kp < 4) geomagnetic conditions

    Science.gov (United States)

    Sonwalkar, V. S.; Reddy, A.

    2017-12-01

    Variation in field-aligned electron and ion densities as a function of geomagnetic activity are important parameters in the physics of the thermosphere-ionosphere-magnetosphere coupling. Using whistler mode sounding from IMAGE, we report variations in field-aligned electron density and O+/H+ transition height (HT) during two periods (16-23 Aug 2005; 24 Sep-06 Oct 2005) when geomagnetic conditions were quiet (maximum Kp in the past 24 hours, Kpmax,24 ≤ 2) to moderately active (2 quiet time, during moderate geomagnetic activity: (1) O+/H+ transition height was roughly same; (2) electron density variations below HT showed no trend; (3) electron density above HT increased ( 10-40 %). The measured electron density is in agreement with in situ measurements from CHAMP (350 km) and DMSP (850 km) and past space borne (e. g., ISIS) measurements but the F2 peak density is a factor of 2 lower relative to that measured by ground ionosondes and that predicted by IRI-2012 empirical model. The measured transition height is consistent with OGO 4, Explorer 31, and C/NOFS measurements but is lower than that from IRI-2012. The observed variations in electron density at F2 peak are consistent with past work and are attributed to solar, geomagnetic, and meteorological causes [e. g. Risibeth and Mendillo, 2001; Forbes et al., 2000]. To the best of our knowledge, variations in field-aligned electron density above transition height at mid-latitudes during quiet to moderately active periods have not been reported in the past. Further investigation using physics based models (e. g., SAMI3) is required to explain the observed variations.

  15. 85 SECULARISM, SECULAR STATE AND RELIGIOUS FREEDOM ...

    African Journals Online (AJOL)

    finds that, although more feasible within secular states, religious freedom and human rights are possibilities ... and values, nor uses its powers and offices to persecute religion.” According to ... Secularism is in fact an expression of humanism.

  16. A Study on the Model of Detecting the Variation of Geomagnetic Intensity Based on an Adapted Motion Strategy

    Directory of Open Access Journals (Sweden)

    Hong Li

    2017-12-01

    Full Text Available By simulating the geomagnetic fields and analyzing thevariation of intensities, this paper presents a model for calculating the objective function ofan Autonomous Underwater Vehicle (AUVgeomagnetic navigation task. By investigating the biologically inspired strategies, the AUV successfullyreachesthe destination duringgeomagnetic navigation without using the priori geomagnetic map. Similar to the pattern of a flatworm, the proposed algorithm relies on a motion pattern to trigger a local searching strategy by detecting the real-time geomagnetic intensity. An adapted strategy is then implemented, which is biased on the specific target. The results show thereliabilityandeffectivenessofthe proposed algorithm.

  17. Linkage between the Biosphere and Geomagnetic field: Knowns and Unknowns

    Science.gov (United States)

    Pan, Y.; Zhu, R.

    2017-12-01

    The geomagnetic field extends from Earth's interior into space, and protects our planets habitability by shielding the planet from solar winds and cosmic rays. Recently, single zircon paleomagnetic study provides evidence of the field to ages as old as 4.2 Ga. Many great questions remain, including whether the emergence of life on Earth was a consequence of the field's protection, how organisms utilize the field, and if field variations (polarity reversal, excursion and secular variation) impact the evolution of the biosphere. In the past decade, great efforts have been made to probe these very complex and great challenging questions through the inter-disciplinary subject of biogeomagnetism. Numerous birds, fish, sea turtles, bats and many other organisms utilize the geomagnetic field during orientation and long-distance navigation. We recently found that bats, the second most abundant order of mammals, can use the direction of magnetic field with a weak strength comparable to polarity transitions/excursions, which is indicative of advanced magnetoreception developed in bats co-evolving with the geomagnetic field since the Eocene. Magnetotactic bacteria swim along the geomagnetic field lines by synthesizing intracellular nano-sized and chain-arranged magnetic minerals (magnetosomes). Recent field surveys in China, Europe, America and Australia have shown that these microbes are ubiquitous in aqueous habitats. Both their biogeography distribution and magnetotactic swimming speed are field intensity dependent. On the other hand, it is increasingly accepted that the geomagnetic field influences life through several indirect pathways. For example, it has been discovered that solar wind erosion enhanced the atmospheric oxygen escape during periods of weak magnetic field and global mean ionospheric electron density profiles can be affected by geomagnetic field strength variation. In addition, depletion of the ozone layer during a weak magnetic field could result in

  18. Geomagnetically conjugate observations of ionospheric and thermospheric variations accompanied by a midnight brightness wave at low latitudes

    Science.gov (United States)

    Fukushima, D.; Shiokawa, K.; Otsuka, Y.; Kubota, M.; Yokoyama, T.; Nishioka, M.; Komonjinda, S.; Yatini, C. Y.

    2017-08-01

    We conducted geomagnetically conjugate observations of 630-nm airglow for a midnight brightness wave (MBW) at Kototabang, Indonesia [geomagnetic latitude (MLAT): 10.0°S], and Chiang Mai, Thailand (MLAT: 8.9°N), which are geomagnetically conjugate points at low latitudes. An airglow enhancement that was considered to be an MBW was observed in OI (630-nm) airglow images at Kototabang around local midnight from 2240 to 2430 LT on February 7, 2011. This MBW propagated south-southwestward, which is geomagnetically poleward, at a velocity of 290 m/s. However, a similar wave was not observed in the 630-nm airglow images at Chiang Mai. This is the first evidence of an MBW that does not have geomagnetic conjugacy, which also implies generation of MBW only in one side of the hemisphere from the equator. We simultaneously observed thermospheric neutral winds observed by a co-located Fabry-Perot interferometer at Kototabang. The observed meridional winds turned from northward (geomagnetically equatorward) to southward (geomagnetically poleward) just before the wave was observed. This indicates that the observed MBW was generated by the poleward winds which push ionospheric plasma down along geomagnetic field lines, thereby increasing the 630-nm airglow intensity. The bottomside ionospheric heights observed by ionosondes rapidly decreased at Kototabang and slightly increased at Chiang Mai. We suggest that the polarization electric field inside the observed MBW is projected to the northern hemisphere, causing the small height increase observed at Chiang Mai. This implies that electromagnetic coupling between hemispheres can occur even though the original disturbance is caused purely by the neutral wind.[Figure not available: see fulltext.

  19. Geomagnetically conjugate observations of ionospheric and thermospheric variations accompanied with a midnight brightness wave at low latitudes

    Science.gov (United States)

    Fukushima, D.; Shiokawa, K.; Otsuka, Y.; Kubota, M.; Yokoyama, T.; Nishioka, M.; Komonjinda, S.; Yatini, C. Y.

    2014-12-01

    A midnight brightness wave (MBW) is the phenomenon that the OI (630-nm) airglow enhancement propagates poleward once at local midnight. In this study, we first conducted geomagnetically conjugate observations of 630nm airglow for an MBW at conjugate stations. An airglow enhancement which is considered to be an MBW was observed in the 630-nm airglow images at Kototabang, Indonesia (geomagnetic latitude (MLAT): 10.0S) at around local midnight from 1540 to 1730 UT (from 2240 to 2430 LT) on 7 February 2011. This MBW was propagating south-southwestward, which is geomagnetically poleward, with a velocity of 290 m/s. However, similar wave was not observed in the 630-nm airglow images at Chiang Mai, Thailand (MLAT: 8.9N), which is close to being conjugate point of Kototabang. This result indicates that the MBW does not have geomagnetic conjugacy. We simultaneously observed thermospheric neutral winds observed by a co-located Fabry-Perot interferometer at Kototabang. The observed meridional winds turned from northward (geomagnetically equatorward) to southward (geomagnetically poleward) just before the MBW was observed. The bottomside ionospheric heights observed by ionosondes rapidly decreased at Kototabang and slightly increased at Chiang Mai simultaneously with the MBW passage. In the presentation, we discuss the MBW generation by the observed poleward neutral winds at Kototabang, and the cause of the coinciding small height increase at Chiang Mai by the polarization electric field inside the observed MBW at Kototabang.

  20. Variations in the geomagnetic and gravitational background associated with two strong earthquakes of the May 2012 sequence in the Po Valley Plain (Italy).

    Science.gov (United States)

    Straser, Valentino

    2013-04-01

    Reawakening of seismic activity in the Emilian Po Valley Plain (Italy) resulted in 2,492 earthquakes over five and a half months: 2,270 with M= 7. The mainshock was recorded during the night of 20 May 2012, at 04:03:52 Italian time (02:03:52 UTC) with epicentre in Finale Emilia, at a depth of 6.3km, by the Italian National Institute of Geophysics and Vulcanology (INGV). A long sequence of telluric shocks occurred in the same seismic district in the areas between the provinces of Modena, Ferrara, Mantua, Reggio Emilia, Bologna and Rovigo. In addition to the general devastation plus damage to civil and industrial buildings and the historical heritage, the earthquakes resulted in a total of 27 victims. Concomitant with the two strongest quakes, recorded on 20 and 29 May 2012, respectively, as in the case of others, variations were noted in the geomagnetic background by the LTPA monitoring station in Rome (Italy). The geomagnetic background variations were associated with the appearance of radio-anomalies in a frequency range from 0.1 to 3.0Hz, as well as gravimetric variations found around 60km from the epicentre. The peak accelerations, detected in correspondence with the strongest shocks on 20 and 29 May 2012, were respectively 0.31g and 0.29g. The appearance of the radio-anomalies coincided, from a temporal point of view, with average gravimetric variations of approximately 30µGal around the epicentre areas, concurrent with the mainshock. In this study, both the appearance of radio-anomalies and the gravitational variations recorded before strong earthquakes were related to the dynamics of the fault and a progressive reduction in granulometry in the core of the fracture, until the point of dislocation was reached. The intense friction in the fault and the damping factors produced before the shock are hypothesized as being proportional to the number of radio-anomalies measured. The radio anomaly is an unknown radio emission that has no characteristics (duration

  1. Long periods (1 -10 mHz) geomagnetic pulsations variation with solar cycle in South Atlantic Magnetic Anomaly

    Science.gov (United States)

    Rigon Silva, Willian; Schuch, Nelson Jorge; Guimarães Dutra, Severino Luiz; Babulal Trivedi, Nalin; Claudir da Silva, Andirlei; Souza Savian, Fernando; Ronan Coelho Stekel, Tardelli; de Siqueira, Josemar; Espindola Antunes, Cassio

    The occurrence and intensity of the geomagnetic pulsations Pc-5 (2-7 mHz) and its relationship with the solar cycle in the South Atlantic Magnetic Anomaly -SAMA is presented. The study of geomagnetic pulsations is important to help the understanding of the physical processes that occurs in the magnetosphere region and help to predict geomagnetic storms. The fluxgate mag-netometers H, D and Z, three axis geomagnetic field data from the Southern Space Observatory -SSO/CRS/INPE -MCT, São Martinho da Serra (29.42° S, 53.87° W, 480m a.s.l.), RS, Brasil, a were analyzed and correlated with the solar wind parameters (speed, density and temperature) from the ACE and SOHO satellites. A digital filtering to enhance the 2-7 mHz geomagnetic pulsations was used. Five quiet days and five perturbed days in the solar minimum and in the solar maximum were selected for this analysis. The days were chosen based on the IAGA definition and on the Bartels Musical Diagrams (Kp index) for 2001 (solar maximum) and 2008 (solar minimum). The biggest Pc-5 amplitude averages differences between the H-component is 78,35 nT for the perturbed days and 1,60nT for the quiet days during the solar maximum. For perturbed days the average amplitude during the solar minimum is 8,32 nT, confirming a direct solar cycle influence in the geomagnetic pulsations intensity for long periods.

  2. Review: geological and experimental evidence for secular variation in seawater Mg/Ca (calcite-aragonite seas and its effects on marine biological calcification

    Directory of Open Access Journals (Sweden)

    J. B. Ries

    2010-09-01

    Full Text Available Synchronized transitions in the polymorph mineralogy of the major reef-building and sediment-producing calcareous marine organisms and abiotic CaCO3 precipitates (ooids, marine cements throughout Phanerozoic time are believed to have been caused by tectonically induced variations in the Mg/Ca ratio of seawater (molar Mg/Ca>2="aragonite seas", <2="calcite seas". Here, I assess the geological evidence in support of secular variation in seawater Mg/Ca and its effects on marine calcifiers, and review a series of recent experiments that investigate the effects of seawater Mg/Ca (1.0–5.2 on extant representatives of calcifying taxa that have experienced variations in this ionic ratio of seawater throughout the geologic past.

    Secular variation in seawater Mg/Ca is supported by synchronized secular variations in (1 the ionic composition of fluid inclusions in primary marine halite, (2 the mineralogies of late stage marine evaporites, abiogenic carbonates, and reef- and sediment-forming marine calcifiers, (3 the Mg/Ca ratios of fossil echinoderms, molluscs, rugose corals, and abiogenic carbonates, (4 global rates of tectonism that drive the exchange of Mg2+ and Ca2+ along zones of ocean crust production, and (5 additional proxies of seawater Mg/Ca including Sr/Mg ratios of abiogenic carbonates, Sr/Ca ratios of biogenic carbonates, and Br concentrations in marine halite.

    Laboratory experiments have revealed that aragonite-secreting bryopsidalean algae and scleractinian corals and calcite-secreting coccolithophores exhibit higher rates of calcification and growth in experimental seawaters formulated with seawater Mg/Ca ratios that favor their skeletal mineral. These results support the assertion that seawater Mg/Ca played an important role in determining which hypercalcifying marine organisms were the major reef-builders and sediment-producers throughout Earth history. The observation that primary

  3. The International Geomagnetic Reference Field (IGRF) generation 12: BGS candidates and final models

    OpenAIRE

    Beggan, Ciaran D.; Hamilton, Brian; Taylor, Victoria; Macmillan, Susan; Thomson, Alan

    2015-01-01

    The International Geomagnetic Reference Field (IGRF) model is a reference main field magnetic model updated on a quinquennial basis. The latest revision (generation 12) was released in January 2015. The IGRF-12 consists of a definitive model (DGRF2010) of the main field for 2010.0, a model for the field at 2015.0 (IGRF2015) and a prediction of secular variation (IGRF-12 SV) for the forthcoming five years until 2020.0. The remaining coefficients of IGRF-12 are unchanged from IGRF-11. Nin...

  4. Global Distribution and Variations of NO Infrared Radiative Flux and Its Responses to Solar Activity and Geomagnetic Activity in the Thermosphere

    Science.gov (United States)

    Tang, Chaoli; Wei, Yuanyuan; Liu, Dong; Luo, Tao; Dai, Congming; Wei, Heli

    2017-12-01

    The global distribution and variations of NO infrared radiative flux (NO-IRF) are presented during 2002-2016 in the thermosphere covering 100-280 km altitude based on Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) data set. For investigating the spatial variations of the mutual relationship between NO-IRF and solar activity, the altitude ranges from 100 km to 280 km are divided into 90 altitude bins, and the latitude regions of 83°S-83°N are divided into 16 latitude bins. By processing about 1.8E9 NO-IRF observation values from about 5E6 vertical nighttime profiles recorded in SABER data set, we obtained more than 4.1E8 samples of NO-IRF. The annual-mean values of NO-IRF are then calculated by all available NO-IRF samples within each latitude and altitude bin. Local latitudinal maxima in NO-IRF are found between 120 and 145 km altitude, and the maximum NO-IRF located at polar regions are 3 times more than that of the minimum at equatorial region. The influences of solar and geomagnetic activity on the spatial variations of NO-IRF are investigated. Both the NO-IRF and its response to solar and geomagnetic activity show nearly symmetric distribution between the two hemispheres. It is demonstrated that the observed changes in NO-IRF at altitudes between 100 and 225 km correlate well with the changes in solar activity. The NO-IRF at solar maximum is about 4 times than that at solar minimum, and the current maximum of NO-IRF in 2014 is less than 70% of the prior maximum in 2001. For the first time, the response ranges of the NO-IRF to solar and geomagnetic activity at different altitudes and latitudes are reported.

  5. Secular spirituality versus secular dualism: Towards postsecular ...

    African Journals Online (AJOL)

    The term “secular spirituality” is meant to convey the contemporary phenomenon of spirituality as experienced in different spheres not associated with structured, institutionalised religion. An outline is given of the relation between secular reality (the natural realm) and religious/spiritual reality (the supernatural realm), as it ...

  6. Dynamical similarity of geomagnetic field reversals.

    Science.gov (United States)

    Valet, Jean-Pierre; Fournier, Alexandre; Courtillot, Vincent; Herrero-Bervera, Emilio

    2012-10-04

    No consensus has been reached so far on the properties of the geomagnetic field during reversals or on the main features that might reveal its dynamics. A main characteristic of the reversing field is a large decrease in the axial dipole and the dominant role of non-dipole components. Other features strongly depend on whether they are derived from sedimentary or volcanic records. Only thermal remanent magnetization of lava flows can capture faithful records of a rapidly varying non-dipole field, but, because of episodic volcanic activity, sequences of overlying flows yield incomplete records. Here we show that the ten most detailed volcanic records of reversals can be matched in a very satisfactory way, under the assumption of a common duration, revealing common dynamical characteristics. We infer that the reversal process has remained unchanged, with the same time constants and durations, at least since 180 million years ago. We propose that the reversing field is characterized by three successive phases: a precursory event, a 180° polarity switch and a rebound. The first and third phases reflect the emergence of the non-dipole field with large-amplitude secular variation. They are rarely both recorded at the same site owing to the rapidly changing field geometry and last for less than 2,500 years. The actual transit between the two polarities does not last longer than 1,000 years and might therefore result from mechanisms other than those governing normal secular variation. Such changes are too brief to be accurately recorded by most sediments.

  7. Secular Religious Establishment

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2013-01-01

    Secularism as a political doctrine claims that religion and politics should be separated. The compatibility question is whether secularism can accept some forms of religious establishment in the form of institutional linkages between state and organised religion. I argue that the answer...... to the compatibility question is not obvious and requires a systematic analysis of secularism. Based on a distinction between a general concept and specific conceptions of secularism I offer a general structure for conceptions of secularism that incorporates both a) basic values, e.g. political equality and freedom...

  8. Geomagnetic storms

    International Nuclear Information System (INIS)

    McNamara, A.G.

    1980-01-01

    Disturbances due to geomagnetic storms can affect the functioning of communications satellites and of power lines and other long conductors. Two general classes of geomagnetic activity can be distinguished: ionospheric current flow (the auroral electrojet), and magnetospheric compression. Super magnetic storms, such as the one of August 1972, can occur at any time and average about 17 occurrences per century. Electrical transmission systems can be made more tolerant of such events at a price, but the most effective way to minimize damage is by better operator training coupled with effective early warning systems. (LL)

  9. Secular bathymetric variations of the North Channel in the Changjiang (Yangtze) Estuary, China, 1880-2013: Causes and effects

    Science.gov (United States)

    Mei, Xuefei; Dai, Zhijun; Wei, Wen; Li, Weihua; Wang, Jie; Sheng, Hao

    2018-02-01

    As the interface between the fluvial upland system and the open coast, global estuaries are facing serious challenges owing to various anthropogenic activities, especially to the Changjiang Estuary. Since the establishment of the Three Gorges Dam (TGD), currently the world's largest hydraulic structure, and certain other local hydraulic engineering structures, the Changjiang Estuary has experienced severe bathymetric variations. It is urgent to analyze the estuarine morphological response to the basin-wide disturbance to enable a better management of estuarine environments. North Channel (NC), the largest anabranched estuary in the Changjiang Estuary, is the focus of this study. Based on the analysis of bathymetric data between 1880 and 2013 and related hydrological data, we developed the first study on the centennial bathymetric variations of the NC. It is found that the bathymetric changes of NC include two main modes, with the first mode representing 64% of the NC variability, which indicates observable deposition in the mouth bar and its outer side area (lower reach); the second mode representing 11% of the NC variability, which further demonstrates channel deepening along the inner side of the mouth bar (upper reach) during 1970-2013. Further, recent erosion observed along the inner side of the mouth bar is caused by riverine sediment decrease, especially in relation to TGD induced sediment trapping since 2003, while the deposition along the lower reach since 2003 can be explained by the landward sediment transport because of flood-tide force strengthen under the joint action of TGD induced seasonal flood discharge decrease and land reclamation induced lower reach narrowing. Generally, the upper and lower NC reach are respectively dominated by fluvial and tidal discharge, however, episodic extreme floods can completely alter the channel morphology by smoothing the entire channel. The results presented herein for the NC enrich our understanding of bathymetric

  10. Secular Variations of Soil CO2 Efflux at Santa Ana-Izalco-Coatepeque Volcanic Complex, El Salvador, Central America

    Science.gov (United States)

    Olmos, R.; Barahona, F.; Cartagena, R.; Soriano, T.; Salazar, J.; Hernandez, P.; Perez, N.; Lopez, D.

    2002-12-01

    The Santa Ana-Izalco-Coatepeque volcanic complex (2,365 m elevation), located 40 Km west of San Salvador, consists of the Coatepeque collapse caldera (a 6.5 x 10.5 Km elliptical depression), the Santa Ana and Izalco stratovolcanoes, as well as numerous cinder cones and explosion craters. The summit of the Santa Ana volcano contains an acid lake where hot springs, gas bubbling and intense fumarolic emissions occur. A volcanic plume, usually driven by the NE trades, may be seen rising up to 500 m from the summit crater of the Santa Ana volcano. The goal of this study is to provide a multidisciplinary approach for the volcanic surveillance by means of performing geochemical continuous monitoring of diffuse CO2 emission rate in addition to seismic monitoring. Temporal variations of soil CO2 efflux measured at Cerro Pacho dome, Coatepeque caldera, by means of the accumulation chamber method and using a CO2 efflux continuous monitoring station developed by WEST Systems (Italy). From May 2001 till May 2002, CO2 efflux ranged from 4.3 to 327 gm-2d-1, with a median value of 98 and a quartile range of 26 gm-2d-1. Two distinct diffuse CO2 degassing periods have been observed: (1) an increasing trend from May to July 2001, and (2) a stationary period from November 2001 to May 2002. The increasing-trend period may be due to the anomalous plume degassing at the Santa Ana volcano during 2001 and soon after the January and February 2001 earthquakes. Temporal variations of CO2 efllux during the second period seem to be coupled with those of barometric pressure and wind speed at different time scales, though most of the variance is contained at diurnal and semi-diurnal frequencies. These observations can help to explain the existence of a persistent behavior (Hurst exponent, H=0.934 +/- 0.0039) within the diffuse CO2 degassing phenomena. However, further observations are in progress to understand the long-term memory of diffuse CO2 degassing at the Santa Ana volcanic complex.

  11. Geomagnetism and paleomagnetism 1979-1983

    Science.gov (United States)

    Fuller, M.

    My function, in writing these notes, is to bring you up to date in Geomagnetism and Paleomagnetism, in as painless a manner as possible—without tears, as the French language texts for tourists used to promise. In writing this account of progress in the past quadrennium, I must first acknowledge that it is a personal and subjective viewpoint;; another reporter would surely emphasize other developments. Yet, there is some virture in writing of things, about which one knows something, so I leave to future reporters the task of redresssing the balance in matters covered.At the outset, one very sad event must be recorded. On April 3, 1981, Sir Edward Bullard died. His published work alone marks him as one of the leaders of geomagnetism in our times. Yet his contribution was much greater; many an American geophysicist, as well as a whole generation of British colleagues, have felt the benefit of his perceptive advice on their research. To those who saw him in the last few months of his life, his courage in the face of his illness was a remarkable example of fortitude. It is by now well known that the definitive paper, which he wrote with Malin, on secular variation at London, was only completed immediately before his death. The transmittal letter had been typed, but death prevented him from signing it. Bullard returned in this final paper to a topic to which he had contributed much. In it, he notes the role of Halley, who first described the phenomenon of westward drift, to which Bullard gave a new numerical precision, two and a half centuries later. I seem to remember Bullard saying in a lecture years ago that, while the Newtons of this world seem other than mortal, Halley was a scientist whose life and acheivements could encourage one's own efforts. Bullard, like Halley, inspires and encourages us.

  12. Geomagnetic effects caused by rocket exhaust jets

    Directory of Open Access Journals (Sweden)

    Lipko Yu.V.

    2016-09-01

    Full Text Available In the space experiment Radar–Progress, we have made 33 series of measurements of geomagnetic variations during ignitions of engines of Progress cargo spacecraft in low Earth orbit. We used magneto-measuring complexes, installed at observatories of the Institute of Solar-Terrestrial Physics of Siberian Branch of the Russian Academy of Sciences, and magnetotelluric equipment of a mobile complex. We assumed that engine running can cause geomagnetic disturbances in field tubes crossed by the spacecraft. When analyzing experimental data, we took into account the following space weather factors: solar wind parameters, total daily mid-latitude geomagnetic activity index Kр, geomagnetic auroral electrojet index AE, global geomagnetic activity. The empirical data we obtained indicate that 18 of the 33 series showed geomagnetic variations with various periods.

  13. A model for solar constant secular changes

    Science.gov (United States)

    Schatten, Kenneth H.

    1988-01-01

    In this paper, contrast models for solar active region and global photospheric features are used to reproduce the observed Active Cavity Radiometer and Earth Radiation Budget secular trends in reasonably good fashion. A prediction for the next decade of solar constant variations is made using the model. Secular trends in the solar constant obtained from the present model support the view that the Maunder Minimum may be related to the Little Ice Age of the 17th century.

  14. Summary of daily observational results of solar phenomena, cosmic ray, geomagnetic variation, ionosphere, radio wave propagation and airglow. During October 1973 through September 1975

    Energy Technology Data Exchange (ETDEWEB)

    1976-12-01

    The diagrams in this section of the publication illustrate the summary of daily observational results of solar phenomena, cosmic ray, geomagnetic variation, ionosphere, radio wave propagation and airglow observed in Japan. For convenience, the observational results are arranged by the solar rotation number. The aim of this illustration is to disseminate an outline of daily events observed in Japan for the benefit of active research workers who plan to make detailed study of the specific solar and terrestrial events. Therefore, the illustrations do not show all observational results in Japan but only representative ones at some key stations in Japan. They will suffice for the present purpose. The method of illustration shown in the instruction on the next page is still a preliminary one, and it is subject to change resulting from the kind advice of the users of this part of the publication.

  15. Northern hemisphere mid-latitude geomagnetic anomaly revealed from Levantine Archaeomagnetic Compilation (LAC).

    Science.gov (United States)

    Shaar, R.; Tauxe, L.; Agnon, A.; Ben-Yosef, E.; Hassul, E.

    2015-12-01

    The rich archaeological heritage of Israel and nearby Levantine countries provides a unique opportunity for archaeomagnetic investigation in high resolution. Here we present a summary of our ongoing effort to reconstruct geomagnetic variations of the past several millennia in the Levant at decadal to millennial resolution. This effort at the Southern Levant, namely the "Levantine Archaeomagnetic Compilation" (LAC), presently consists of data from over 650 well-dated archaeological objects including pottery, slag, ovens, and furnaces. In this talk we review the methodological challenges in achieving a robust master secular variation curve with realistic error estimations from a large number of different datasets. We present the current status of the compilation, including the southern and western Levant LAC data (Israel, Cyprus, and Jordan) and other published north-eastern Levant data (Syria and southern Turkey), and outline the main findings emerging from these data. The main feature apparent from the new compilation is an extraordinary intensity high that developed over the Levant region during the first two millennia BCE. The climax of this event is a double peak intensity maximum starting at ca. 1000 BCE and ending at ca. 735 BCE, accompanied with at least two events of geomagnetic spikes. Paleomagnetic directions from this period demonstrate anomalies of up to 20 degrees far from the averaged GAD field. This leads us to postulate that the maximum in the intensity is a manifestation of an intense mid-latitude local positive geomagnetic anomaly that persisted for over two centuries.

  16. Variations of the Geomagnetic Field During the Holocene-Pleistocene: Relative Paleointensity Records From South-Western Argentina

    Science.gov (United States)

    Gogorza, C. S.

    2008-05-01

    I present a review of the research carried out by the Group of Geomagnetism at Universidad Nacional del Centro (Argentina) on paleointensity records from bottom sediments from three lakes: Escondido (Gogorza et al., 2004), Moreno (Gogorza et al., 2006) and El Trébol (Gogorza et al., 2007; Irurzun et al., 2008) (South-Western Argentina, 41° S, 71° 30'W). Based on these studies, we construct a first relative (RPI) stack for South-Western Argentina covering the last 21,000 14C years BP. The degree of down-core homogeneity of magnetic mineral content as well as magnetic mineral concentration and grain sizes vary between all lakes and are quantified by high-resolution rock magnetic measurements. Rock magnetic studies suggest that the main carriers of magnetization are ferrimagnetic minerals, predominantly pseudo-single domain magnetite The remanent magnetization at 20 mT (NRM20mT) was normalized using the anhysteric remanent magnetization at 20mT (ARM20mT), the saturation of the isothermal remanent at 20 mT (SIRM20mT) and the low field magnetic susceptibility {k}. Coherence function analysis indicates that the normalised records are free of environmental influences. Our paleointensity (NRM20mT/ ARM20mT) versus age curve shows a good agreement with published records from other parts of the world suggesting that, in suitable sediments, paleointensity of the geomagnetic field can give a globally coherent, dominantly dipolar signal. References Gogorza, C.S.G., Irurzun, M.A., Chaparro, M.A.E., Lirio, J.M., Nuñez, H., Bercoff, P.G., Sinito, A.M. Relative Paleointensity of the Geomagnetic Field over the last 21,000 years bp from Sediment Cores, Lake El Trébol, (Patagonia, Argentina). Earth, Planets and Space. V58(10), 1323-1332. 2006. Gogorza, C.S.G., Sinito, A.M., Lirio, J.M., Nuñez, H., Chaparro, M.A.E., Bertorello, H.R. Paleointensity Studies on Holocene-Pleistocene Sediments from Lake Escondido, Argentina. Physical of the Earth and Planetary Interiors, Elsevier, ISSN

  17. Secularism, secular state and religious freedom | Nweke | Journal of ...

    African Journals Online (AJOL)

    The historic separation of the Church and the State, as an immediate product of secularism, informs the reality of secular state, a state without official religion. This paper attempts to understudy the extent to which secularism enhances religious freedom within the frame of secular state. With the tools of phenomenological ...

  18. Archeomagnetic Intensity Spikes: Global or Regional Geomagnetic Field Features?

    Directory of Open Access Journals (Sweden)

    Monika Korte

    2018-03-01

    Full Text Available Variations of the geomagnetic field prior to direct observations are inferred from archeo- and paleomagnetic experiments. Seemingly unusual variations not seen in the present-day and historical field are of particular interest to constrain the full range of core dynamics. Recently, archeomagnetic intensity spikes, characterized by very high field values that appear to be associated with rapid secular variation rates, have been reported from several parts of the world. They were first noted in data from the Levant at around 900 BCE. A recent re-assessment of previous and new Levantine data, involving a rigorous quality assessment, interprets the observations as an extreme local geomagnetic high with at least two intensity spikes between the 11th and 8th centuries BCE. Subsequent reports of similar features from Asia, the Canary Islands and Texas raise the question of whether such features might be common occurrences, or whether they might even be part of a global magnetic field feature. Here we use spherical harmonic modeling to test two hypotheses: firstly, whether the Levantine and other potential spikes might be associated with higher dipole field intensity than shown by existing global field models around 1,000 BCE, and secondly, whether the observations from different parts of the world are compatible with a westward drifting intense flux patch. Our results suggest that the spikes originate from intense flux patches growing and decaying mostly in situ, combined with stronger and more variable dipole moment than shown by previous global field models. Axial dipole variations no more than 60% higher than observed in the present field, probably within the range of normal geodynamo behavior, seem sufficient to explain the observations.

  19. Multiculturalism and secularism

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2017-01-01

    . Secularism denotes what such principles imply for the relationship between politics and religion. Such formal understandings provide theoretical frameworks for specifying different conceptions of multiculturalism and secularism and for determining in precisely which respects conflicts might arise......Multiculturalism in a European context increasingly has come to denote a concern with religious minorities. Claims for multicultural accommodation of minorities therefore potentially conflict with secularist requirements of separation of politics and religion. Whether there is a conflict depends...... on the general understandings of multiculturalism and secularism. The paper therefore distinguishes and examines different general understandings. Both multiculturalism and secularism can be understood as sets of policies, or as forms of minority accommodation or views about the relationship between religion...

  20. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade....... The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites....

  1. Geomagnetic Principal Magnetic Storms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The abbreviations used for observatory names are as follows: GEOMAGNETIC OBSERVATORIES Code Station Geomagnetic Latitude ABG Alibag AMS Martin de Vivie. These data...

  2. Combining virtual observatory and equivalent source dipole approaches to describe the geomagnetic field with Swarm measurements

    Science.gov (United States)

    Saturnino, Diana; Langlais, Benoit; Amit, Hagay; Civet, François; Mandea, Mioara; Beucler, Éric

    2018-03-01

    A detailed description of the main geomagnetic field and of its temporal variations (i.e., the secular variation or SV) is crucial to understanding the geodynamo. Although the SV is known with high accuracy at ground magnetic observatory locations, the globally uneven distribution of the observatories hampers the determination of a detailed global pattern of the SV. Over the past two decades, satellites have provided global surveys of the geomagnetic field which have been used to derive global spherical harmonic (SH) models through some strict data selection schemes to minimise external field contributions. However, discrepancies remain between ground measurements and field predictions by these models; indeed the global models do not reproduce small spatial scales of the field temporal variations. To overcome this problem we propose to directly extract time series of the field and its temporal variation from satellite measurements as it is done at observatory locations. We follow a Virtual Observatory (VO) approach and define a global mesh of VOs at satellite altitude. For each VO and each given time interval we apply an Equivalent Source Dipole (ESD) technique to reduce all measurements to a unique location. Synthetic data are first used to validate the new VO-ESD approach. Then, we apply our scheme to data from the first two years of the Swarm mission. For the first time, a 2.5° resolution global mesh of VO time series is built. The VO-ESD derived time series are locally compared to ground observations as well as to satellite-based model predictions. Our approach is able to describe detailed temporal variations of the field at local scales. The VO-ESD time series are then used to derive global spherical harmonic models. For a simple SH parametrization the model describes well the secular trend of the magnetic field both at satellite altitude and at the surface. As more data will be made available, longer VO-ESD time series can be derived and consequently used to

  3. Eliminating large-scale magnetospheric current perturbations from long-term geomagnetic observatory data

    Science.gov (United States)

    Pick, L.; Korte, M. C.

    2016-12-01

    Magnetospheric currents generate the largest external contribution to the geomagnetic field observed on Earth. Of particular importance is the solar-driven effect of the ring current whose fluctuations overlap with internal field secular variation (SV). Recent core field models thus co-estimate this effect but their validity is limited to the last 15 years offering satellite data. We aim at eliminating magnetospheric modulation from the whole geomagnetic observatory record from 1840 onwards in order to obtain clean long-term SV that will enhance core flow and geodynamo studies.The ring current effect takes form of a southward directed external dipole field aligned with the geomagnetic main field axis. Commonly the Dst index (Sugiura, 1964) is used to parametrize temporal variations of this dipole term. Because of baseline instabilities, the alternative RC index was derived from hourly means of 21 stations spanning 1997-2013 (Olsen et al., 2014). We follow their methodology based on annual means from a reduced station set spanning 1960-2010. The absolute level of the variation so determined is "hidden" in the static lithospheric offsets taken as quiet-time means. We tackle this issue by subtracting crustal biases independently calculated for each observatory from an inversion of combined Swarm satellite and observatory data.Our index reproduces the original annual RC index variability with a reasonable offset of -10 nT in the reference time window 2000-2010. Prior to that it depicts a long-term trend consistent with the external dipole term from COV-OBS (Gillet et al., 2013), being the only long-term field model available for comparison. Sharper variations that are better correlated with the Ap index than the COV-OBS solution lend support to the usefulness of our initial modeling approach. Following a detailed sensitivity study of station choice future work will focus on increasing the resolution from annual to hourly means.

  4. BLASPHEMY IN A SECULAR STATE:

    African Journals Online (AJOL)

    MLR

    altogether the religious basis of secular authority'.2 Accordingly, it 'terminated the Pope's claim to universal authority and confirmed the diplomatic independence of secular rulers'.3 However, the meaning of the secular is itself in a continuous state of articulation and re-articulation, casting doubts also on its attributes.

  5. Thermospheric mass density variations during geomagnetic storms and a prediction model based on the merging electric field

    Directory of Open Access Journals (Sweden)

    R. Liu

    2010-09-01

    Full Text Available With the help of four years (2002–2005 of CHAMP accelerometer data we have investigated the dependence of low and mid latitude thermospheric density on the merging electric field, Em, during major magnetic storms. Altogether 30 intensive storm events (Dstmin<−100 nT are chosen for a statistical study. In order to achieve a good correlation Em is preconditioned. Contrary to general opinion, Em has to be applied without saturation effect in order to obtain good results for magnetic storms of all activity levels. The memory effect of the thermosphere is accounted for by a weighted integration of Em over the past 3 h. In addition, a lag time of the mass density response to solar wind input of 0 to 4.5 h depending on latitude and local time is considered. A linear model using the preconditioned Em as main controlling parameter for predicting mass density changes during magnetic storms is developed: ρ=0.5 Em + ρamb, where ρamb is based on the mean density during the quiet day before the storm. We show that this simple relation predicts all storm-induced mass density variations at CHAMP altitude fairly well especially if orbital averages are considered.

  6. Thermospheric mass density variations during geomagnetic storms and a prediction model based on the merging electric field

    Science.gov (United States)

    Liu, R.; Lühr, H.; Doornbos, E.; Ma, S.-Y.

    2010-09-01

    With the help of four years (2002-2005) of CHAMP accelerometer data we have investigated the dependence of low and mid latitude thermospheric density on the merging electric field, Em, during major magnetic storms. Altogether 30 intensive storm events (Dstmineffect in order to obtain good results for magnetic storms of all activity levels. The memory effect of the thermosphere is accounted for by a weighted integration of Em over the past 3 h. In addition, a lag time of the mass density response to solar wind input of 0 to 4.5 h depending on latitude and local time is considered. A linear model using the preconditioned color: #000;">Em as main controlling parameter for predicting mass density changes during magnetic storms is developed: ρ=0.5 color: #000;">Em + ρamb, where ρamb is based on the mean density during the quiet day before the storm. We show that this simple relation predicts all storm-induced mass density variations at CHAMP altitude fairly well especially if orbital averages are considered.

  7. Decadal variability in core surface flows deduced from geomagnetic observatory monthly means

    DEFF Research Database (Denmark)

    Whaler, K. A.; Olsen, Nils; Finlay, Chris

    2016-01-01

    . On the annual to decadal timescale, the SV is generated primarily by advection in the fluid outer core. We demonstrate the utility of the revised monthly means by calculating models of the core surface advective flow between 1997 and 2013 directly from the SV data. One set of models assumes flow......Monthly means of the magnetic field measurements at ground observatories are a key data source for studying temporal changes of the core magnetic field. However, when they are calculated in the usual way, contributions of external (magnetospheric and ionospheric) origin may remain, which make them...... less favourable for studying the field generated by dynamo action in the core. We remove external field predictions, including a new way of characterising the magnetospheric ring current, from the data and then calculate revised monthly means using robust methods. The geomagnetic secular variation (SV...

  8. Moderate Secularism and Multicultural Equality

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2008-01-01

    Tariq Modood argues that European states are only ‘moderately secular' and that this kind of secularism is compatible with public accommodation of religious groups and provides a model of Muslim integration appropriate for European states. Although attention to the fact of moderate secularism...... provides a response to a prominent argument against multicultural accommodation of religious minorities, what is really at stake in discussions of multiculturalism and secularism are political principles. Modood's case for accommodation of Muslims along the lines of moderate secularism presupposes...

  9. Quickly erupted volcanic sections of the Steens Basalt, Columbia River Basalt Group: Secular variation, tectonic rotation, and the Steens Mountain reversal

    Science.gov (United States)

    Jarboe, Nicholas A.; Coe, Robert S.; Renne, Paul R.; Glen, Jonathan M. G.; Mankinen, Edward A.

    2008-01-01

    The Steens Basalt, now considered part of the Columbia River Basalt Group (CRBG), contains the earliest eruptions of this magmatic episode. Lava flows of the Steens Basalt cover about 50,000 km2 of the Oregon Plateau in sections up to 1000 m thick. The large number of continuously exposed, quickly erupted lava flows (some sections contain over 200 flows) allows for small loops in the magnetic field direction paths to be detected. For volcanic rocks, this detail and fidelity are rarely found outside of the Holocene and yield estimates of eruption durations at our four sections of ∼2.5 ka for 260 m at Pueblo Mountains, 0.5 to 1.5 ka for 190 m at Summit Springs, 1–3 ka for 170 m at North Mickey, and ∼3 ka for 160 m at Guano Rim. That only one reversal of the geomagnetic field occurred during the eruption of the Steens Basalt (the Steens reversal at approximately 16.6 Ma) is supported by comparing 40Ar/39Ar ages and magnetic polarities to the geomagnetic polarity timescale. At Summit Springs two 40Ar/39Ar ages from normal polarity flows (16.72 ± ± 0.29 Ma (16.61) and 16.92 ± ± 0.52 Ma (16.82); ± ± equals 2σ error) place their eruptions after the Steens reversal, while at Pueblo Mountains an 40Ar/39Ar age of 16.72 ± ± 0.21 Ma (16.61) from a reverse polarity flow places its eruption before the Steens reversal. Paleomagnetic field directions yielded 50 nontransitional directional-group poles which, combined with 26 from Steens Mountain, provide a paleomagnetic pole for the Oregon Plateau of 85.7°N, 318.4°E, K = 15.1, A95 = 4.3. Comparison of this new pole with a reference pole derived from CRBG flows from eastern Washington and a synthetic reference pole for North America derived from global data implies relative clockwise rotation of the Oregon Plateau of 7.4 ± 5.0° or 14.5 ± 5.4°, respectively, probably due to northward decreasing extension of the basin and range.

  10. The timing of normal puberty and the age limits of sexual precocity: variations around the world, secular trends, and changes after migration.

    Science.gov (United States)

    Parent, Anne-Simone; Teilmann, Grete; Juul, Anders; Skakkebaek, Niels E; Toppari, Jorma; Bourguignon, Jean-Pierre

    2003-10-01

    During the past decade, possible advancement in timing of puberty has been reported in the United States. In addition, early pubertal development and an increased incidence of sexual precocity have been noticed in children, primarily girls, migrating for foreign adoption in several Western European countries. These observations are raising the issues of current differences and secular trends in timing of puberty in relation to ethnic, geographical, and socioeconomic background. None of these factors provide an unequivocal explanation for the earlier onset of puberty seen in the United States. In the formerly deprived migrating children, refeeding and catch-up growth may prime maturation. However, precocious puberty is seen also in some nondeprived migrating children. Attention has been paid to the changing milieu after migration, and recently, the possible role of endocrine- disrupting chemicals from the environment has been considered. These observations urge further study of the onset of puberty as a possible sensitive and early marker of the interactions between environmental conditions and genetic susceptibility that can influence physiological and pathological processes.

  11. Geomagnetic field of earth

    International Nuclear Information System (INIS)

    Delipetrev, Marjan; Delipetrev, Blagoj; Panovska, Sanja

    2008-01-01

    In this paper is introduced the theory of geomagnetic field of the Earth. A homogenous and isotropic sphere is taken for a model of Earth with a bar magnet at its center as a magnetic potential. The understanding of the real origin of geomagnetic field produced from differential rotation of inner core with respect to the outer core of Earth is here presented. Special attention is given to the latest observed data of the established net of geomagnetic repeat stations in the Republic of Macedonia. Finally, the maps of elements of geomagnetic field and the equation for calculation of normal magnetic field of Earth are provided. (Author)

  12. Beyond comparing secularisms: a critique of religio-secularism

    NARCIS (Netherlands)

    Jansen, Y.; Zuckerman, P.; Shook, J.R.

    2017-01-01

    “Religio-secularism” denotes the tendency to understand specific cultural and political conflicts in terms an opposition between religion on the one hand and secularism on the other. Religio-secularism as a cultural-political paradigm tends to obscure the intricacies of political, socioeconomic,

  13. Inner Core Rotation from Geomagnetic Westward Drift and a Stationary Spherical Vortex in Earth's Core

    Science.gov (United States)

    Voorhies, C. V.

    1999-01-01

    The idea that geomagnetic westward drift indicates convective leveling of the planetary momentum gradient within Earth's core is pursued in search of a differentially rotating mean state, upon which various oscillations and secular effects might be superimposed. The desired state conforms to roughly spherical boundary conditions, minimizes dissipative interference with convective cooling in the bulk of the core, yet may aide core cooling by depositing heat in the uppermost core and lower mantle. The variational calculus of stationary dissipation applied to a spherical vortex within the core yields an interesting differential rotation profile akin to spherical Couette flow bounded by thin Hartmann layers. Four boundary conditions are required. To concentrate shear induced dissipation near the core-mantle boundary, these are taken to be: (i) no-slip at the core-mantle interface; (ii) geomagnetically estimated bulk westward flow at the base of the core-mantle boundary layer; (iii) no-slip at the inner-outer core interface; and, to describe magnetic locking of the inner core to the deep outer core, (iv) hydrodynamically stress-free at the inner-outer core boundary. By boldly assuming the axial core angular momentum anomaly to be zero, the super-rotation of the inner core is calculated to be at most 1.5 degrees per year.

  14. Electromagnetic core-mantle coupling associated with changes in the geomagnetic dipole field

    International Nuclear Information System (INIS)

    Watanabe, Hidehumi; Yukutake, Takesi.

    1975-01-01

    On a shelluar earth model electromagnetic coupling between the mantle and the core is investigated when the geomagnetic dipole field changes its intensity. Besides electromagnetic interaction between the dipole change and the relative slip of the mantle to the core, coupling of the dipole change with shear motions within the core is considered. If, in the core, the dipole change is limited within a surface layer shallower than a few hundred kilometers, the electromagnetic interaction gives the same order of magnitudes and phases of mantle oscillation as suggested from observation for three different periods, 8000, 400 and 65 years, provided that the electrical conductivity of the bottom part of the mantle is 10 -9 to 10 -8 emu. It is shown that mean motion of the surface shells of the core thus calculated is compatible with the observed variations in the drift velocity of the geomagnetic secular change. Except for surface shells, those in the deep interior is confirmed to oscillate almost with the same angular velocity, like a rigid rotation, for all the periods. (auth.)

  15. Craniofacial Secular Change in Recent Mexican Migrants.

    Science.gov (United States)

    Spradley, Katherine; Stull, Kyra E; Hefner, Joseph T

    2016-01-01

    Research by economists suggests that recent Mexican migrants are better educated and have higher socioeconomic status (SES) than previous migrants. Because factors associated with higher SES and improved education can lead to positive secular changes in overall body form, secular changes in the craniofacial complex were analyzed within a recent migrant group from Mexico. The Mexican group represents individuals in the act of migration, not yet influenced by the American environment, and thus can serve as a starting point for future studies of secular change in this population group. The excavation of a historic Hispanic cemetery in Tucson, Arizona, also allows for a comparison between historic Hispanics and recent migrants to explore craniofacial trends over a broad time period, as both groups originate from Mexico. The present research addresses two main questions: (1) Are cranial secular changes evident in recent Mexican migrants? (2) Are historic Hispanics and recent Mexican migrants similar? By studying secular changes within a migrant population group, secular trends may be detected, which will be important for understanding the biological variation of the migrants themselves and will serve as a preliminary investigation of secular change within Mexican migrants. The comparison of a sample of recent Mexican migrants with a historic Hispanic sample, predominantly of Mexican origin, allows us to explore morphological similarities and differences between early and recent Mexicans within the United States. Vault and face size and a total of 82 craniofacial interlandmark distances were used to explore secular changes within the recent Mexican migrants (females, n = 38; males, n = 178) and to explore the morphological similarities between historic Hispanics (females, n = 54; males, n = 58) and recent migrants. Sexes were separated, and multivariate adaptive regression splines and basis splines (quadratic with one knot) were used to assess the direction and magnitude

  16. Large geomagnetic field anomalies revealed in Bronze to Iron Age archeomagnetic data from Tel Megiddo and Tel Hazor, Israel

    Science.gov (United States)

    Shaar, Ron; Tauxe, Lisa; Ron, Hagai; Ebert, Yael; Zuckerman, Sharon; Finkelstein, Israel; Agnon, Amotz

    2016-05-01

    Geomagnetic field measurements from the past few centuries show heightened secular variation activity in the southern hemisphere associated with the south Atlantic anomaly (SAA). It is uncertain whether geomagnetic anomalies at a similar scale have existed in the past owing to limited coverage and uncertainties in the paleomagnetic database. Here we provide new evidence from archaeological sources in the Levant suggesting a large positive northern hemisphere anomaly, similar in magnitude to the SAA during the 9th-8th centuries BCE, called ;Levantine Iron Age anomaly;. We also report an additional geomagnetic spike in the 8th century. The new dataset comprises 73 high precision paleointensity estimates from ca. 3000 BCE to 732 BCE, and five directional measurements between the 14th and the 9th centuries BCE. Well-dated pottery and cooking ovens were collected from twenty archaeological strata in two large contemporaneous stratigraphical mounds (tells) in Israel: Tel Megiddo and Tel Hazor. The new data are combined with previously published data and interpreted automatically using the PmagPy Thellier GUI program. The Tel Megiddo and Tel Hazor data sets demonstrate excellent internal consistency and remarkable agreement with published data from Mesopotamia (Syria). The data illustrate the evolution of an extreme geomagnetic high that culminated in at least two spikes between the 11th and the 8th centuries BCE (Iron Age in the Levant). The paleomagnetic directional data of the 9th century BCE show positive inclination anomalies, and deviations of up to 22° from the averaged geocentric axial dipole (GAD) direction. From comparison of the Levantine archaeomagnetic data with IGRF model for 2015 we infer the ;Levantine Iron Age anomaly; between the 10th and the 8th centuries BCE is a local positive anomaly. The eastward extent of the anomaly is currently unknown.

  17. Metaphysical Concept of Secularization versus Islamic Concept of Secularization

    Directory of Open Access Journals (Sweden)

    Volkan ERTİT

    2017-12-01

    Full Text Available In early 21st century, the question “Is Turkey becoming secularized contrary to popular belief?” was one of the discussions occupying Turkish public opinion. These discussions led to the encounter of two different concepts of secularization, “theological (Islamic” and "metaphysical", and to put forward different claims using the same concept. Hence, it became evidentwas understood that a discussion was necessary to understand what secularization is and what it is not before starting any debate on Turkey's secularization. That is because the metaphysical discussion that defines secularization as the decline in the social influence of metaphysical realm (religion, religion-like mechanisms, folk religions, superstitious beliefs, etc. is overshadowed by the Islamic definition describing secularization as "irreligiousness" or "non-Islamism". Therefore, discussingTo understand the social transformation in Turkey, this article attempts to explain that metaphysical rather than theological definition of secularization is necessary for understanding the social implications of the process of modernization.

  18. Sensitivity of the Geomagnetic Octupole to a Stably Stratified Layer in the Earth's Core

    Science.gov (United States)

    Yan, C.; Stanley, S.

    2017-12-01

    The presence of a stably stratified layer at the top of the core has long been proposed for Earth, based on evidence from seismology and geomagnetic secular variation. Geodynamo modeling offers a unique window to inspect the properties and dynamics in Earth's core. For example, numerical simulations have shown that magnetic field morphology is sensitive to the presence of stably stratified layers in a planet's core. Here we use the mMoSST numerical dynamo model to investigate the effects of a thin stably stratified layer at the top of the fluid outer core in Earth on the resulting large-scale geomagnetic field morphology. We find that the existence of a stable layer has significant influence on the octupolar component of the magnetic field in our models, whereas the quadrupole doesn't show an obvious trend. This suggests that observations of the geomagnetic field can be applied to provide information of the properties of this plausible stable layer, such as how thick and how stable this layer could be. Furthermore, we have examined whether the dominant thermal signature from mantle tomography at the core-mantle boundary (CMB) (a degree & order 2 spherical harmonic) can influence our results. We found that this heat flux pattern at the CMB has no outstanding effects on the quadrupole and octupole magnetic field components. Our studies suggest that if there is a stably stratified layer at the top of the Earth's core, it must be limited in terms of stability and thickness, in order to be compatible with the observed paleomagnetic record.

  19. Geomagnetic field, global pattern

    OpenAIRE

    Macmillan, Susan

    2011-01-01

    The geomagnetic field is generated in the fluid outer core region of the Earth by electrical currents flowing in the slowly moving molten iron. In addition to sources in the Earth’s core, the geomagnetic field observable on the Earth’s surface has sources in the crust and in the ionosphere and magnetosphere. The signal from the core dominates, accounting for over 95% of the field at the Earth’s surface. The geomagnetic field varies on a range of scales, both temporal and spatial; the...

  20. Secular Variation in the Storage and Dissipation of Elastic Strain Energy Along the Central Altyn Tagh Fault (86-88.5°E), NW China

    Science.gov (United States)

    Cowgill, E.; Gold, R. D.; Arrowsmith, R.; Friedrich, A. M.

    2015-12-01

    In elastic rebound theory, hazard increases as interseismic strain rebuilds after rupture. This model is challenged by the temporal variation in the pacing of major earthquakes that is both predicted by mechanical models and suggested by some long paleoseismic records (e.g., 1-3). However, the extent of such behavior remains unclear due to a lack of long (5-25 ky) records of fault slip. Using Monte Carlo analysis of 11 offset landforms, we determined a 16-ky record of fault slip for the active, left-lateral Altyn Tagh fault, which bounds the NW margin of the Tibetan Plateau. This history reveals a pulse of accelerated slip between 6.4 and 6.0 ka, during which the fault slipped 9 +14/-2 m at a rate of 23 +35/-5 mm/y, or ~3x the 16 ky average of 8.1 +1.2/-0.9mm/y. These two modes of earthquake behavior suggest temporal variation in the rates of stress storage and release. The simplest explanation for the pulse is a cluster of 2-8 Mw > 7.5 earthquakes. Such supercyclicity has been reported for the Sunda (4) and Cascadia (3) megathrusts, but contrasts with steady slip along the strike-slip Alpine fault (5), for example. A second possibility is that the pulse reflects a single, unusually large rupture. However, this Black Swan event is unlikely: empirical scaling relationships require a Mw 8.2 rupture of the entire 1200-km-long ATF to produce 7 m of average slip. Likewise, Coulomb stress change from rupture on the adjacent North Altyn fault is of modest magnitude and overlap with the ATF. Poor temporal correlation between precipitation and the slip pulse argues against climatically modulated changes in surface loading (lakes/ice) or pore-fluid pressure. "Paleoslip" studies such as this sacrifice the single-event resolution of paleoseismology in exchange for long records that quantify both the timing and magnitude of fault slip averaged over multiple ruptures, and are essential for documenting temporal variations in fault slip as we begin to use calibrated physical

  1. Geomagnetic Storm Sudden Commencements

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Storm Sudden Commencements (ssc) 1868 to present: STORM1 and STORM2 Lists: (Some text here is taken from the International Association of Geomagnetism and Aeronomy...

  2. Geomagnetic Indices Bulletin (GIB)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Geomagnetic Indices Bulletin is a one page sheet containing the magnetic indices Kp, Ap, Cp, An, As, Am and the provisional aa indices. The bulletin is published...

  3. Geomagnetic aa Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The geomagnetic aa indices are the continuation of the series beginning in the year 1868. A full description of these indices is given in the International...

  4. Secular Evolution of Spiral Galaxies

    Science.gov (United States)

    2003-01-01

    recombination (z=1000). Furthermore, the BigBang nucleosynthesis model also requires a signi cantamount of non- baryonic dark matter (Primack 1999) ifthe universe...momentum (as well as energy) outward. Associ-ated with this outward angular momentum transport isan expected secular redistribution of disk matter , co...mode, a secular transfer of energy andangular momentum between the disk matter and thedensity wave. The existence of the phase shift betweenthe

  5. Secular humanism and "scientific psychiatry"

    OpenAIRE

    Szasz, Thomas

    2006-01-01

    Abstract The Council for Secular Humanism identifies Secular Humanism as a "way of thinking and living" committed to rejecting authoritarian beliefs and embracing "individual freedom and responsibility ... and cooperation." The paradigmatic practices of psychiatry are civil commitment and insanity defense, that is, depriving innocent persons of liberty and excusing guilty persons of their crimes: the consequences of both are confinement in institutions ostensibly devoted to the treatment of m...

  6. Celebrating the Secular

    Directory of Open Access Journals (Sweden)

    Amanda Lohrey

    2013-08-01

    Full Text Available On 4 November 2004 I read a report in the Sydney Morning Herald that I found genuinely shocking, a statement by Cardinal George Pell, of the Catholic diocese of Sydney, on what’s wrong with democracy. This report was of a speech given to the Acton Institute for the Study of Religion and Liberty in the United States. In it, Dr Pell told his audience that liberal democracy is a world of ‘empty secularism’ that is over-focused on ‘individual autonomy’. The problem with democracy, said the Cardinal, quoting John Paul II, is that it is not a good thing in itself; its value depends on the moral vision that it serves, and a secular democracy is lacking in moral vision. If democracy is not a good thing in and of itself, then why have we sent troops to Iraq to enable it? And what about the principle of equality before the law? Freedom of conscience? Freedom of speech and of action? Responsibility for community? Sounds like a moral vision to me.

  7. Atmospheric helium and geomagnetic field reversals.

    Science.gov (United States)

    Sheldon, W. R.; Kern, J. W.

    1972-01-01

    The problem of the earth's helium budget is examined in the light of recent work on the interaction of the solar wind with nonmagnetic planets. It is proposed that the dominant mode of helium (He4) loss is ion pumping by the solar wind during geomagnetic field reversals, when the earth's magnetic field is very small. The interaction of the solar wind with the earth's upper atmosphere during such a period is found to involve the formation of a bow shock. The penetration altitude of the shock-heated solar plasma is calculated to be about 700 km, and ionization rates above this level are estimated for a cascade ionization (electron avalanche) process to average 10 to the 9th power ions/sq cm/sec. The calculated ionization rates and the capacity of the solar wind to remove ionized helium (He4) from the upper atmosphere during geomagnetic dipole reversals are sufficient to yield a secular equilibrium over geologic time scales. The upward transport of helium from the lower atmosphere under these conditions is found to be adequate to sustain the proposed loss rate.

  8. Re-Evaluation of Geomagnetic Field Observation Data at Syowa Station, Antarctica

    Directory of Open Access Journals (Sweden)

    K Takahashi

    2013-05-01

    Full Text Available The Japanese Antarctic Research Expedition has conducted geomagnetic observations at Syowa Station, Antarctica, since 1966. Geomagnetic variation data measured with a fluxgate magnetometer are not absolute but are relative to a baseline and show drift. To enhance the importance of the geomagnetic data at Syowa Station, therefore, it is necessary to correct the continuous variation data by using absolute baseline values acquired by a magnetic theodolite and proton magnetometer. However, the database of baseline values contains outliers. We detected outliers in the database and then converted the geomagnetic variation data to absolute values by using the reliable baseline values.

  9. Secular humanism and "scientific psychiatry"

    Directory of Open Access Journals (Sweden)

    Szasz Thomas

    2006-04-01

    Full Text Available Abstract The Council for Secular Humanism identifies Secular Humanism as a "way of thinking and living" committed to rejecting authoritarian beliefs and embracing "individual freedom and responsibility ... and cooperation." The paradigmatic practices of psychiatry are civil commitment and insanity defense, that is, depriving innocent persons of liberty and excusing guilty persons of their crimes: the consequences of both are confinement in institutions ostensibly devoted to the treatment of mental diseases. Black's Law Dictionary states: "Every confinement of the person is an 'imprisonment,' whether it be in a common prison, or in private house, or in the stocks, or even by forcibly detaining one in the public streets." Accordingly, I maintain that Secular Humanism is incompatible with the principles and practices of psychiatry.

  10. Secular humanism and "scientific psychiatry".

    Science.gov (United States)

    Szasz, Thomas

    2006-04-25

    The Council for Secular Humanism identifies Secular Humanism as a "way of thinking and living" committed to rejecting authoritarian beliefs and embracing "individual freedom and responsibility ... and cooperation." The paradigmatic practices of psychiatry are civil commitment and insanity defense, that is, depriving innocent persons of liberty and excusing guilty persons of their crimes: the consequences of both are confinement in institutions ostensibly devoted to the treatment of mental diseases. Black's Law Dictionary states: "Every confinement of the person is an 'imprisonment,' whether it be in a common prison, or in private house, or in the stocks, or even by forcibly detaining one in the public streets." Accordingly, I maintain that Secular Humanism is incompatible with the principles and practices of psychiatry.

  11. Varieties of Secularism in Asia

    DEFF Research Database (Denmark)

    of the North Atlantic rim. This anthology seeks to begin that task. It does so by suggesting that the kind of secularity described by Taylor is only one amongst others. By attending to the shifting relationship between proper religion and ‘bad faiths’; between politically valorised and embarrassing spiritual...... phenomena; between the new visibilities and silences of magic, ancestors, and religion in democratic politics, this book seeks to outline the particular formations of secularism that have become possible in Asia from China to Indonesia and from Bahrain to Timor-Leste....

  12. Properties of Pliocene sedimentary geomagnetic reversal records from the Mediterranean

    OpenAIRE

    Linssen, J.H.

    1991-01-01

    In the history of the Earth the dipolar geomagnetic field has frequently reversed polarity. Though this property was already known early this century (Brunhes, 1906), nowadays the characteristics and the origin of polarity transitions are still largely unknown. The geomagnetic field and its variations are recorded in rocks as a natural remanent magnetization (NRM) during the formation of these rocks. The study of the NRM in sedimentary reversal records is the subject of this dissertation.

  13. The geomagnetic cutoff rigidities at high latitudes for different solar wind and geomagnetic conditions

    International Nuclear Information System (INIS)

    Chu, W.; Univ. of Chinese Academy of Sciences, Beijing; Qin, G.

    2016-01-01

    Studying the access of the cosmic rays (CRs) into the magnetosphere is important to understand the coupling between the magnetosphere and the solar wind. In this paper we numerically studied CRs' magnetospheric access with vertical geomagnetic cutoff rigidities using the method proposed by Smart and Shea (1999). By the study of CRs' vertical geomagnetic cutoff rigidities at high latitudes we obtain the CRs' window (CRW) whose boundary is determined when the vertical geomagnetic cutoff rigidities drop to a value lower than a threshold value. Furthermore, we studied the area of CRWs and found out they are sensitive to different parameters, such as the z component of interplanetary magnetic field (IMF), the solar wind dynamic pressure, AE index, and Dst index. It was found that both the AE index and Dst index have a strong correlation with the area of CRWs during strong geomagnetic storms. However, during the medium storms, only AE index has a strong correlation with the area of CRWs, while Dst index has a much weaker correlation with the area of CRWs. This result on the CRW can be used for forecasting the variation of the cosmic rays during the geomagnetic storms.

  14. Modeling the ocean effect of geomagnetic storms

    DEFF Research Database (Denmark)

    Olsen, Nils; Kuvshinov, A.

    2004-01-01

    At coastal sites, geomagnetic variations for periods shorter than a few days are strongly distorted by the conductivity of the nearby sea-water. This phenomena, known as the ocean (or coast) effect, is strongest in the magnetic vertical component. We demonstrate the ability to predict the ocean...... if the oceans are considered. Our analysis also indicates a significant local time asymmetry (i.e., contributions from spherical harmonics other than P-I(0)), especially during the main phase of the storm....

  15. Evaluation of candidate geomagnetic field models for IGRF-11

    DEFF Research Database (Denmark)

    Finlay, Chris; Maus, S.; Beggan, C. D.

    2010-01-01

    variations between candidates originate. A retrospective analysis of IGRF-10 main field candidates for epoch 2005.0 and predictive secular variation candidates for 2005.0–2010.0 using the new IGRF-11 models as a reference is also reported. The high quality and consistency of main field models derived using...

  16. Geomagnetic field evolution during the Laschamp excursion

    Science.gov (United States)

    Leonhardt, Roman; Fabian, Karl; Winklhofer, Michael; Ferk, Annika; Laj, Carlo; Kissel, Catherine

    2009-02-01

    Since the last geomagnetic reversal, 780,000 years ago, the Earth's magnetic field repeatedly dropped dramatically in intensity. This has often been associated with large variations in local field direction, but without a persistent global polarity flip. The structure and dynamics of geomagnetic excursions, and especially the difference between excursions and polarity reversals, have remained elusive so far. For the best documented excursion, the Laschamp event at 41,000 years BP, we have reconstructed the evolution of the global field morphology by using a Bayesian inversion of several high-resolution palaeomagnetic records. We have obtained an excursion scenario in which inverse magnetic flux patches at the core-mantle boundary emerge near the equator and then move poleward. Contrary to the situation during the last reversal (Leonhardt, R., Fabian, K., 2007. Paleomagnetic reconstruction of the global geomagnetic field evolution during the Matuyama/Brunhes transition: Iterative Bayesian inversion and independent verification. Earth Planet. Sci. Lett. 253, 172-195), these flux patches do not cross the hydrodynamic boundary of the inner-core tangent cylinder. While the last geomagnetic reversal began with a substantial increase in the strength of the non-dipolar field components, prior to the Laschamp excursion, both dipolar and non-dipolar field decay at the same rate. This result suggests that the nature of an upcoming geomagnetic field instability can be predicted several hundred years in advance. Even though during the Laschamp excursion the dipolar field at the Earth's surface was dominant, the reconstructed dynamic non-dipolar components lead to considerable deviations among predicted records at different locations. The inverse model also explains why at some locations no directional change during the Laschamp excursion is observed.

  17. Long-term rise in geomagnetic activity - A close connection between quiet days and storms

    DEFF Research Database (Denmark)

    Vennerstrøm, Susanne

    2000-01-01

    Geomagnetic quiet days and magnetic storms are naturally believed to be due to very different solar wind conditions. In this study we however demonstrate that the long-term variation of geomagnetic quiet and disturbed days are surprisingly similar. By the use of daily averages of the geomagnetic.......7. The results indicate that the longterm,increase is due to an increase in the background solar wind parameters, rather than in the number of solar wind disturbances....

  18. Geomagnetic radioflash unfold (GRUF)

    International Nuclear Information System (INIS)

    Malik, J.S.

    1975-08-01

    A method of inverting the geomagnetic component of the radioflash signal from a nuclear explosion to obtain the gamma-ray time history was proposed by E. D. Dracott of the Atomic Weapons Research Establishment. A simplified development of an elaboration by B. R. Suydam has been programmed for small calculators in a form suitable for interim field analysis of such data. The development of the program is contained in the report

  19. Research on Stealthy Headphone Detector Based on Geomagnetic Sensor

    Directory of Open Access Journals (Sweden)

    Liu Ya

    2016-01-01

    Full Text Available A kind of stealth headphone detector based on geomagnetic sensor has been developed to deal with the stealth headphones which are small, extremely stealthy and hard to detect. The U.S. PNI geomagnetic sensor is chosen to obtain magnetic field considering the strong magnetic performance of stealth headphones. The earth’s magnetic field at the geomagnetic sensor is eliminated by difference between two geomagnetic sensors, and then weak variations of magnetic field is detected. STM8S103K2 is chosen as the central controlling chip, which is connected to LED, buzzer and LCD 1602. As shown by the experimental results, the probe is not liable to damage by the magnetic field and the developed device has high sensitivity, low False Positive Rate (FAR and satisfactory reliability.

  20. Automated detection of geomagnetic storms with heightened risk of GIC

    Science.gov (United States)

    Bailey, Rachel L.; Leonhardt, Roman

    2016-06-01

    Automated detection of geomagnetic storms is of growing importance to operators of technical infrastructure (e.g., power grids, satellites), which is susceptible to damage caused by the consequences of geomagnetic storms. In this study, we compare three methods for automated geomagnetic storm detection: a method analyzing the first derivative of the geomagnetic variations, another looking at the Akaike information criterion, and a third using multi-resolution analysis of the maximal overlap discrete wavelet transform of the variations. These detection methods are used in combination with an algorithm for the detection of coronal mass ejection shock fronts in ACE solar wind data prior to the storm arrival on Earth as an additional constraint for possible storm detection. The maximal overlap discrete wavelet transform is found to be the most accurate of the detection methods. The final storm detection software, implementing analysis of both satellite solar wind and geomagnetic ground data, detects 14 of 15 more powerful geomagnetic storms over a period of 2 years.

  1. The post-secular city

    DEFF Research Database (Denmark)

    Greve, Anni

    ) elements in ritual and ceremonies. Second, emergent spaces of post-secular practices are not only connected to traditional religious sites. With Schmautz (1998) it is necessary to understand a sacred site in its original social and cultural setting, and in the present experience of it. With a point...... in research on trans-national identity making (Fortier 2002). This paper suggests a displacement of focus from trans-national to international identity making and the possible role of religious societies. It is argued that an international culture is not mainstream culture however there are (universal......’ the paper argues for a possible potential of storytelling and mutual recognition. Third, it offers an argument for detecting ‘post-secular sites’ at the urban level from two angles: From architecture (the iconic consciousness) and from performance (the sacred drama). Fourth, the paper closes with a case...

  2. Secular stability of rotating stars

    International Nuclear Information System (INIS)

    Imamura, J.N.; Friedman, J.L.; Durisen, R.H.

    1984-01-01

    In this work, we calculate the secular stability limits of rotating polytropes to nonaxisymmetric perturbations of low m. We consider polytropic indices ranging from 1 to 3 and several angular momentum distributions. Results are most conveniently presented in terms of the t-parameter, defined as the ratio of the rotational kinetic energy to the absolute value of the gravitational energy of the fluid. Previous work on polytropes considered only the m = 2 mode, which is unstable for values of the t-parameter greater than 0.14 +- 0.01 for the n values n = 1.5 and 3 and the angular momentum distributions tested (see Durisen and Imamura 1981). The GRR secular stability limit of the m = 2 mode for the Maclaurin spheroids (n = O) was determined by Chandrasekhar (1970). GRR stability limits of higher m modes for the Maclaurin spheroids were located approximately by Comins (1979a,b) and more precisely by Friedman (1983)

  3. The national geomagnetic initiative

    Science.gov (United States)

    1993-01-01

    The Earth's magnetic field, through its variability over a spectrum of spatial and temporal scales, contains fundamental information on the solid Earth and geospace environment (the latter comprising the atmosphere, ionosphere, and magnetosphere). Integrated studies of the geomagnetic field have the potential to address a wide range of important processes in the deep mantle and core, asthenosphere, lithosphere, oceans, and the solar-terrestrial environment. These studies have direct applications to important societal problems, including resource assessment and exploration, natural hazard mitigation, safe navigation, and the maintenance and survivability of communications and power systems on the ground and in space. Studies of the Earth's magnetic field are supported by a variety of federal and state agencies as well as by private industry. Both basic and applied research is presently supported by several federal agencies, including the National Science Foundation (NSF), U.S. Geological Survey (USGS), U.S. Department of Energy (DOE), National Oceanic and Atmospheric Administration (NOAA), National Aeronautics and Space Administration (NASA), and U.S. Department of Defense (DOD) (through the Navy, Air Force, and Defense Mapping Agency). Although each agency has a unique, well-defined mission in geomagnetic studies, many areas of interest overlap. For example, NASA, the Navy, and USGS collaborate closely in the development of main field reference models. NASA, NSF, and the Air Force collaborate in space physics. These interagency linkages need to be strengthened. Over the past decade, new opportunities for fundamental advances in geomagnetic research have emerged as a result of three factors: well-posed, first-order scientific questions; increased interrelation of research activities dealing with geomagnetic phenomena; and recent developments in technology. These new opportunities can be exploited through a national geomagnetic initiative to define objectives and

  4. Secular Love number of Phobos

    International Nuclear Information System (INIS)

    Bursa, M.

    1988-01-01

    The secular Love number of Phobos was estimated k s =10.4. It only deviates by one order of magnitude from that corresponding to the ideal equilibrium state. It is not in contradiction with the theory of the origin of Phobos as a result of the accretion around Mars. In its early history, the rotation period of Phobos had been estimated to be approx. 2.4 hours. (author). 1 tab., 4 refs

  5. Geomagnetic imprinting: A unifying hypothesis of long-distance natal homing in salmon and sea turtles.

    Science.gov (United States)

    Lohmann, Kenneth J; Putman, Nathan F; Lohmann, Catherine M F

    2008-12-09

    Several marine animals, including salmon and sea turtles, disperse across vast expanses of ocean before returning as adults to their natal areas to reproduce. How animals accomplish such feats of natal homing has remained an enduring mystery. Salmon are known to use chemical cues to identify their home rivers at the end of spawning migrations. Such cues, however, do not extend far enough into the ocean to guide migratory movements that begin in open-sea locations hundreds or thousands of kilometers away. Similarly, how sea turtles reach their nesting areas from distant sites is unknown. However, both salmon and sea turtles detect the magnetic field of the Earth and use it as a directional cue. In addition, sea turtles derive positional information from two magnetic elements (inclination angle and intensity) that vary predictably across the globe and endow different geographic areas with unique magnetic signatures. Here we propose that salmon and sea turtles imprint on the magnetic field of their natal areas and later use this information to direct natal homing. This novel hypothesis provides the first plausible explanation for how marine animals can navigate to natal areas from distant oceanic locations. The hypothesis appears to be compatible with present and recent rates of field change (secular variation); one implication, however, is that unusually rapid changes in the Earth's field, as occasionally occur during geomagnetic polarity reversals, may affect ecological processes by disrupting natal homing, resulting in widespread colonization events and changes in population structure.

  6. Geomagnetic imprinting: A unifying hypothesis of long-distance natal homing in salmon and sea turtles

    Science.gov (United States)

    Lohmann, Kenneth J.; Putman, Nathan F.; Lohmann, Catherine M. F.

    2008-01-01

    Several marine animals, including salmon and sea turtles, disperse across vast expanses of ocean before returning as adults to their natal areas to reproduce. How animals accomplish such feats of natal homing has remained an enduring mystery. Salmon are known to use chemical cues to identify their home rivers at the end of spawning migrations. Such cues, however, do not extend far enough into the ocean to guide migratory movements that begin in open-sea locations hundreds or thousands of kilometers away. Similarly, how sea turtles reach their nesting areas from distant sites is unknown. However, both salmon and sea turtles detect the magnetic field of the Earth and use it as a directional cue. In addition, sea turtles derive positional information from two magnetic elements (inclination angle and intensity) that vary predictably across the globe and endow different geographic areas with unique magnetic signatures. Here we propose that salmon and sea turtles imprint on the magnetic field of their natal areas and later use this information to direct natal homing. This novel hypothesis provides the first plausible explanation for how marine animals can navigate to natal areas from distant oceanic locations. The hypothesis appears to be compatible with present and recent rates of field change (secular variation); one implication, however, is that unusually rapid changes in the Earth's field, as occasionally occur during geomagnetic polarity reversals, may affect ecological processes by disrupting natal homing, resulting in widespread colonization events and changes in population structure. PMID:19060188

  7. Secular change in 13 metabolic phenotypes: A Chinese longitudinal twin study

    DEFF Research Database (Denmark)

    Li, Shuxia; Pang, Zengchang; Zhang, Dongfeng

    in prospective investigations. Based on Chinese twin data collected from Danish-Chinese collaboration research, we perform twin modeling on 13 metabolic phenotypes (total cholesterol; triglyceride; high density lipoprotein (HDL); low density lipoprotein (LDL); urine acid (UA); glucose; weight; body mass index...... fitted to the secular changes in each of the 13 phenotypes with best fitting model selected based on model performance. Age and sex were included as covariates in the models to adjust for their effects on secular trend. Results: Variations in secular change in 3 lipids (total cholesterol; triglyceride...

  8. Geomagnetic and ionospheric data analysis over Antarctica: a contribution to the long term trends investigation

    Directory of Open Access Journals (Sweden)

    L. Alfonsi

    2008-05-01

    Full Text Available 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 magneto-ionospheric conditions, highlights the role of the geomagnetic activity in the secular change of the ionosphere and confirms the latitudinal dependence of the trends. These results suggest interesting relations with some recent findings on the rapid decrease of some important physical and statistical quantities related to the geomagnetic field over the whole globe and mainly in Antarctica. In this paper we discuss the possibility of a connection between the ionospheric trends and a possible imminent geomagnetic reversal or excursion.

  9. Geomagnetic and ionospheric data analysis over Antarctica: a contribution to the long term trends investigation

    Directory of Open Access Journals (Sweden)

    L. Alfonsi

    2008-05-01

    Full Text Available 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 magneto-ionospheric conditions, highlights the role of the geomagnetic activity in the secular change of the ionosphere and confirms the latitudinal dependence of the trends. These results suggest interesting relations with some recent findings on the rapid decrease of some important physical and statistical quantities related to the geomagnetic field over the whole globe and mainly in Antarctica. In this paper we discuss the possibility of a connection between the ionospheric trends and a possible imminent geomagnetic reversal or excursion.

  10. Magnetic local time dependence of geomagnetic disturbances contributing to the AU and AL indices

    DEFF Research Database (Denmark)

    Tomita, S; Nose´, M; Iyemori, T

    2010-01-01

    activity in the auroral zone. In the present study, we examine magnetic local time (MLT) dependence of geomagnetic field variations contributing to the AU and AL indices. We use 1-min geomagnetic field data obtained in 2003. It is found that both AU and AL indices have two ranges of MLT (AU: 15:00-22:00MLT...

  11. Climatic influence in NRM and 10 Be-derived geomagnetic paleointensity data

    NARCIS (Netherlands)

    1999-01-01

    One can determine geomagnetic paleointensities from natural remanent magnetizations (NRM) and by inverting production rates of cosmogenic isotopes such as 10 Be and 14 C. Recently, two independently derived 200-kyr stacks [Y. Guyodo, J.-P. Valet, Relative variations in geomagnetic intensity from

  12. The response of the 11 August 1999 total solar eclipse in the geomagnetic field

    Czech Academy of Sciences Publication Activity Database

    Střeštík, Jaroslav

    85-86, 1/3 (2001), s. 561-566 ISSN 0167-9295 R&D Projects: GA ČR GA205/99/0915 Institutional research plan: CEZ:AV0Z3012916 Keywords : geomagnetic pulsations * geomagnetic variations * total solar eclipse Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.457, year: 2001

  13. HAS ROMANIA BECOME A SECULAR SOCIETY?

    Directory of Open Access Journals (Sweden)

    IRINA STAHL

    2016-04-01

    Full Text Available The article examines the question of secularization of Europe, and in particular of Romania, by using multiple international data sets. Secularization has been defined separation of the state government and religious authority resulting in a decrease in church attendance, a diminished trust in religious institutions, a lessening of religions’ importance in society, an increase in religious diversity with a concomitant decrease in group cohesiveness, and the rise of situational ethics and moral relativism. Several theories of secularization are explored in an effort to determine the presence of a secular continuum. Although there may be an increase of secular behaviours in member states of the European Union, a claim of growing secularism in Romania is not supported by an examination of the multiple data sets

  14. Geomagnetic Reversals during the Phanerozoic.

    Science.gov (United States)

    McElhinny, M W

    1971-04-09

    An antalysis of worldwide paleomagnetic measurements suggests a periodicity of 350 x 10(6) years in the polarity of the geomagnetic field. During the Mesozoic it is predominantly normal, whereas during the Upper Paleozoic it is predominantly reversed. Although geomagnetic reversals occur at different rates throughout the Phanerozoic, there appeaars to be no clear correlation between biological evolutionary rates and reversal frequency.

  15. Reconstruction of geomagnetic activity and near-Earth interplanetary conditions over the past 167 yr - Part 1: A new geomagnetic data composite

    Science.gov (United States)

    Lockwood, M.; Barnard, L.; Nevanlinna, H.; Owens, M. J.; Harrison, R. G.; Rouillard, A. P.; Davis, C. J.

    2013-11-01

    We present a new composite of geomagnetic activity which is designed to be as homogeneous in its construction as possible. This is done by only combining data that, by virtue of the locations of the source observatories used, have similar responses to solar wind and IMF (interplanetary magnetic field) variations. This will enable us (in Part 2, Lockwood et al., 2013a) to use the new index to reconstruct the interplanetary magnetic field, B, back to 1846 with a full analysis of errors. Allowance is made for the effects of secular change in the geomagnetic field. The composite uses interdiurnal variation data from Helsinki for 1845-1890 (inclusive) and 1893-1896 and from Eskdalemuir from 1911 to the present. The gaps are filled using data from the Potsdam (1891-1892 and 1897-1907) and the nearby Seddin observatories (1908-1910) and intercalibration achieved using the Potsdam-Seddin sequence. The new index is termed IDV(1d) because it employs many of the principles of the IDV index derived by Svalgaard and Cliver (2010), inspired by the u index of Bartels (1932); however, we revert to using one-day (1d) means, as employed by Bartels, because the use of near-midnight values in IDV introduces contamination by the substorm current wedge auroral electrojet, giving noise and a dependence on solar wind speed that varies with latitude. The composite is compared with independent, early data from European-sector stations, Greenwich, St Petersburg, Parc St Maur, and Ekaterinburg, as well as the composite u index, compiled from 2-6 stations by Bartels, and the IDV index of Svalgaard and Cliver. Agreement is found to be extremely good in all cases, except two. Firstly, the Greenwich data are shown to have gradually degraded in quality until new instrumentation was installed in 1915. Secondly, we infer that the Bartels u index is increasingly unreliable before about 1886 and overestimates the solar cycle amplitude between 1872 and 1883 and this is amplified in the proxy data used

  16. Reconstruction of geomagnetic activity and near-Earth interplanetary conditions over the past 167 yr – Part 1: A new geomagnetic data composite

    Directory of Open Access Journals (Sweden)

    M. Lockwood

    2013-11-01

    Full Text Available We present a new composite of geomagnetic activity which is designed to be as homogeneous in its construction as possible. This is done by only combining data that, by virtue of the locations of the source observatories used, have similar responses to solar wind and IMF (interplanetary magnetic field variations. This will enable us (in Part 2, Lockwood et al., 2013a to use the new index to reconstruct the interplanetary magnetic field, B, back to 1846 with a full analysis of errors. Allowance is made for the effects of secular change in the geomagnetic field. The composite uses interdiurnal variation data from Helsinki for 1845–1890 (inclusive and 1893–1896 and from Eskdalemuir from 1911 to the present. The gaps are filled using data from the Potsdam (1891–1892 and 1897–1907 and the nearby Seddin observatories (1908–1910 and intercalibration achieved using the Potsdam–Seddin sequence. The new index is termed IDV(1d because it employs many of the principles of the IDV index derived by Svalgaard and Cliver (2010, inspired by the u index of Bartels (1932; however, we revert to using one-day (1d means, as employed by Bartels, because the use of near-midnight values in IDV introduces contamination by the substorm current wedge auroral electrojet, giving noise and a dependence on solar wind speed that varies with latitude. The composite is compared with independent, early data from European-sector stations, Greenwich, St Petersburg, Parc St Maur, and Ekaterinburg, as well as the composite u index, compiled from 2–6 stations by Bartels, and the IDV index of Svalgaard and Cliver. Agreement is found to be extremely good in all cases, except two. Firstly, the Greenwich data are shown to have gradually degraded in quality until new instrumentation was installed in 1915. Secondly, we infer that the Bartels u index is increasingly unreliable before about 1886 and overestimates the solar cycle amplitude between 1872 and 1883 and this is

  17. Letter to the Editor: Geomagnetic storm effects at low latitudes

    OpenAIRE

    R. G. Rastogi; R. G. Rastogi

    1999-01-01

    The geomagnetic horizontal (H) field from the chain of nine observatories in India are used to study the storm-time and disturbance daily variations. The peak decrease in storm-time variation in H showed significant enhancements at the equatorial electrojet stations over and above the normally expected decrease due to the ring current effects corrected for geomagnetic latitudes. The disturbance daily variation of H at equatorial stations showed a large decrease around midday...

  18. Geomagnetic control of polar mesosphere summer echoes

    Directory of Open Access Journals (Sweden)

    J. Bremer

    2000-02-01

    Full Text Available Using observations with the ALOMAR SOUSY radar near Andenes (69.3°N, 16.0°E from 1994 until 1997 polar mesosphere summer echoes (PMSE have been investigated in dependence on geomagnetic K indices derived at the Auroral Observatory Tromsø (69.66°N, 18.94°E. During night-time and morning hours a significant correlation between the signal-to-noise ratio (SNR of the radar results and the geomagnetic K indices could be detected with a maximum correlation near midnight. The correlation becomes markedly smaller in the afternoon and early evening hours with a minimum near 17 UT. This diurnal variation is in reasonable agreement with riometer absorption at Ivalo (68.55°N, 27.28°E and can be explained by the diurnal variation of ionization due to precipitating high energetic particles. Therefore, a part of the diurnal PMSE variation is caused by this particle precipitation. The variability of the solar EUV variation, however, has no significant influence on the PMSE during the observation period.Keywords: Ionosphere (auroral ionosphere - Magnetospheric physics (energetic particles, precipitating - Radio science (remote sensing

  19. Zonal wind observations during a geomagnetic storm

    Science.gov (United States)

    Miller, N. J.; Spencer, N. W.

    1986-01-01

    In situ measurements taken by the Wind and Temperature Spectrometer (WATS) onboard the Dynamics Explorer 2 spacecraft during a geomagnetic storm display zonal wind velocities that are reduced in the corotational direction as the storm intensifies. The data were taken within the altitudes 275 to 475 km in the dusk local time sector equatorward of the auroral region. Characteristic variations in the value of the Dst index of horizontal geomagnetic field strength are used to monitor the storm evolution. The detected global rise in atmospheric gas temperature indicates the development of thermospheric heating. Concurrent with that heating, reductions in corotational wind velocities were measured equatorward of the auroral region. Just after the sudden commencement, while thermospheric heating is intense in both hemispheres, eastward wind velocities in the northern hemisphere show reductions ranging from 500 m/s over high latitudes to 30 m/s over the geomagnetic equator. After 10 hours storm time, while northern thermospheric heating is diminishing, wind velocity reductions, distinct from those initially observed, begin to develop over southern latitudes. In the latter case, velocity reductions range from 300 m/s over the highest southern latitudes to 150 m/s over the geomagnetic equator and extend into the Northern Hemisphere. The observations highlight the interhemispheric asymmetry in the development of storm effects detected as enhanced gas temperatures and reduced eastward wind velocities. Zonal wind reductions over high latitudes can be attributed to the storm induced equatorward spread of westward polar cap plasma convection and the resulting plasma-neutral collisions. However, those collisions are less significant over low latitudes; so zonal wind reductions over low latitudes must be attributed to an equatorward extension of a thermospheric circulation pattern disrupted by high latitude collisions between neutrals transported via eastward winds and ions

  20. Secular stability of rotating stars

    International Nuclear Information System (INIS)

    Imamura, J.N.; Friedman, J.L.; Durisen, R.H.

    1984-01-01

    In this work, the authors calculate the secular stability limits of rotating polytropes to nonaxisymmetric perturbations of low m. Polytropic indices ranging from 1 to 3 and several angular momentum distributions are considered. Results are most conveniently presented in terms of the t-parameter, defined as the ratio of the rotational kinetic energy to the absolute value of the gravitational energy of the fluid. Previous work on polytropes considered only the m = 2 mode, which is unstable for values of the t-parameter greater than 0.14 +- 0.01 for the n values n = 1.5 and 3 and the angular momentum distributions tested (see Durisen and Imamura 1981). The GRR secular stability limit of the m - 2 mode for the Maclaurin spheroids (n = 0) was determined by Chandrasekhar (1970). GRR stability limits of higher m modes for the Maclaurin spheroids were located approximately by Comins (1979a,b) and more precisely by Friedman (1983). 16 references, 2 tables

  1. The Geomagnetic Control Concept of The Ionospheric Long- Term Trends

    Science.gov (United States)

    Mikhailov, A. V.

    The geomagnetic control concept has been developed to explain long-term trends of the electron concentration in the F2 and E ionospheric regions. Periods with negative and positive foF2, hmF2 and foE trends correspond to the periods of increasing or decreasing geomagnetic activity with the turning points around the end of 1950s, 1960s, and 1980s where trends change their signs. Strong latitudinal and diurnal variations revealed for the foF2 and hmF2 trends can be explained by neutral composition, temperature and thermospheric wind changes. Particle precipitation is important in the auroral zone. The newly proposed concept proceeds from a natural origin of the F2-layer trends rather than an artificial one related to the greenhouse effect. Using the proposed method a very long-term foF2 and foE trends related with general increase of geomagnetic activity in the 20th century has been revealed for the first time. The firstly revealed relationship of the foE trends with geomagnetic activity is due to nitric oxide variations at the E-region heights. This "natural" relationship of the foE trends with geomagnetic activity breaks down around 1970 on many stations presumably due to chemical polution of the upper atmosphere. The increasing rate of rocket and satellite launchings in the late 1960s is considered as a reason.

  2. The Swarm Initial Field Model for the 2014 geomagnetic field

    DEFF Research Database (Denmark)

    Olsen, Nils; Hulot, Gauthier; Lesur, Vincent

    2015-01-01

    agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for East...

  3. Out of time : the limits of secular critique

    Directory of Open Access Journals (Sweden)

    Randell-Moon, Holly

    2011-01-01

    Full Text Available A review of Talal Asad, Wendy Brown, Judith Butler, Saba Mahmood, 'Is critique secular? Blasphemy, injury, and free speech' and Michael Warner, Jonathan Vanantwerpen, and Craig Calhoun (eds, 'Varieties of secularism in a secular age'.

  4. Moderate Secularism, Difference Sensitivity and Contextualism

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2009-01-01

    The article is a rejoinder to Tariq Modood's reply (Politics, Vol. 29, No. 1, 2009) to my article 'Moderate Secularism and Multicultural Equality' (Politics, Vol 28, No. 3, 2008).......The article is a rejoinder to Tariq Modood's reply (Politics, Vol. 29, No. 1, 2009) to my article 'Moderate Secularism and Multicultural Equality' (Politics, Vol 28, No. 3, 2008)....

  5. Unsafe Gods: Security, Secularism and Schooling

    Science.gov (United States)

    Davies, Lynn

    2014-01-01

    This book makes the compelling argument that religion can be complicit in conflict and that a new secularism is vital to foster security. Using insights from complexity science, it shows how dynamic secularism can be used to accommodate diverse faiths and beliefs within worldly politics. Exploration of the interplay of religion and education in…

  6. Concept and Indications of Secular State

    Directory of Open Access Journals (Sweden)

    Philina N. V.

    2014-10-01

    Full Text Available The article deals with the elaborate analysis of the concept and indications of a secular state. The paper has the interdisciplinary character and it is written on the verge of constitutional law, theory of state administration, philosophy, political science. The comparative analysis between the constitutional indicators of a secular state and democracy realia has been conducted

  7. Evidence in the auroral record for secular solar variability

    International Nuclear Information System (INIS)

    Sicoe, G.L.

    1980-01-01

    The historial record of aurorae is continuous and usefully dense for at least the 2000 years. Revival of interest in the secular variability in solar activity motivates a review of the auroral record. The existence of secular variations in the auroral occurrence frequency has been known since the early 1700's, including the existence of a significant attenuation of auroral activity during the Maunder Minimum. Investigation of secular variations prior to the Maunder Minimum is now possible based on six auroral catalogs that have been published within the last 20 years. The catalogs cover the time period from the fifth century B.C. to the seventeenth century A.D. and combine both oriental and European obsertions. Features corresponding to the previously recognized Medieval Minimum, Medieval Maximum, and the Spoerer Minimum are clearly evident in both oriental and European records. The global synchronicity of anomalies in the auroral occurrence frequency is used to argue that they are caused by changes in the level or state of solar activity. The combined catalogs provide a sufficient number of events in the Middle Ages to resolve a quasi-80-year periodicity in the recorded auroral occurrence frequency. Also in the unusually rich intervals of the Middle Ages, clear quasi-10-year periodicities appear in the recorded occurrence frequency wave from. These are most reasonably interpreted as manifestations of the 11-year solar cycle and indicate that the solar cycle was then operative

  8. Plasmaspheric noise radiation during geomagnetic storms

    International Nuclear Information System (INIS)

    Larkina, V.I.; Likhter, Ya.I.

    1981-01-01

    Variations of plasmospheric background radiations during geomagnetic storms of different intensity are investigated. Used are results of ELF and VLF radiation measurements as well as electron fluxes of energies Esub(e)>40 keV carried out by Intercosmos 3 and Intercosmos 5 satellites. Dependences of radiation amplitude variations at 1.6 and 25 kHz frequencies on L shell for various geomagnetic activity in the day-time as well as data on variations of quasicaptured electron fluxes at Esub(e)>40 keV, are given. It is shown that experimental data agree with the existing theories of plasmospheric noise excitation. It is concluded that the plasmospheric noise excitation area Lsub(max) is always in the region of gap between radiation belts and inner slope of external radiation belt during magnetic storms. During magnetic storms Lsub(max) area moves simultaneously with the area, where particle flux of the external radiation belt is the most intensive [ru

  9. The Ranges Of Subauroral Geomagnetic Field Elements | Rabiu ...

    African Journals Online (AJOL)

    Nigeria Journal of Pure and Applied Physics ... An anomaly in seasonal response of range at high solar activity is observed on disturbed condition. ... apart from the anomaly - maintain the order e>j>d of seasonal variation which is in agreement with the popular equinoctial maximum observed in geomagnetic activity.

  10. Geomagnetic Observatory Database February 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) maintains an active database of worldwide geomagnetic observatory...

  11. Contemplative Science and Secular Ethics

    Directory of Open Access Journals (Sweden)

    Brendan Ozawa-de Silva

    2016-08-01

    Full Text Available This article argues that the emerging project of contemplative science will be best served if it is informed by two perspectives. First, attention should be paid not only to non-analytical and/or mindfulness-based practices, but to a fuller range of contemplative practices, including analytical styles of meditation. Second, the issue of ethics must be addressed as a framework within which to understand contemplative practice: both theoretically in order to understand better the practices themselves and the traditions they come from, and practically in order to understand the ways in which contemplative practices are deployed in contemporary societies. The Tibetan Buddhist Lojong (blo sbyong tradition and secularized practices derived from it, which are now an area of study in contemplative science, are examined as a kind of case study in order to make these two points and illustrate their importance and relevance for the future of this emerging field.

  12. Secular Evolution in Disk Galaxies

    Science.gov (United States)

    Kormendy, John

    2013-10-01

    Self-gravitating systems evolve toward the most tightly bound configuration that is reachable via the evolution processes that are available to them. They do this by spreading -- the inner parts shrink while the outer parts expand -- provided that some physical process efficiently transports energy or angular momentum outward. The reason is that self-gravitating systems have negative specific heats. As a result, the evolution of stars, star clusters, protostellar and protoplanetary disks, black hole accretion disks and galaxy disks are fundamentally similar. How evolution proceeds then depends on the evolution processes that are available to each kind of self-gravitating system. These processes and their consequences for galaxy disks are the subjects of my lectures and of this Canary Islands Winter School. I begin with a review of the formation, growth and death of bars. Then I review the slow (`secular') rearrangement of energy, angular momentum, and mass that results from interactions between stars or gas clouds and collective phenomena such as bars, oval disks, spiral structure and triaxial dark haloes. The `existence-proof' phase of this work is largely over: we have a good heuristic understanding of how nonaxisymmetric structures rearrange disk gas into outer rings, inner rings and stuff dumped onto the centre. The results of simulations correspond closely to the morphology of barred and oval galaxies. Gas that is transported to small radii reaches high densities. Observations confirm that many barred and oval galaxies have dense central concentrations of gas and star formation. The result is to grow, on timescales of a few Gyr, dense central components that are frequently mistaken for classical (elliptical-galaxy-like) bulges but that were grown slowly out of the disk (not made rapidly by major mergers). The resulting picture of secular galaxy evolution accounts for the richness observed in galaxy structure. We can distinguish between classical and pseudo

  13. Interplanetary magnetic field associated changes in cosmic ray intensity and geomagnetic field during 1973-75

    International Nuclear Information System (INIS)

    Singh, R.L.; Shukla, J.P.; Shukla, A.K.; Sharma, S.M.; Agrawal, S.P.

    1979-01-01

    The effects of interplanetary magnetic field (IMF) B and its Bsub(z) component on cosmic ray intensity and geomagnetic field variations have been examined for the period 1973-75. It is observed that: (1) B >= 10γ (magnetic blobs) is pre-requisite in producing cosmic ray intensity and geomagnetic field variations of varying magnitudes, (2) the longer existence of magnetic blobs on successive days produces larger decreases in cosmic ray intensity and geomagnetic field and (3) the southward component (Bsub(z)) of IMF generally gives rise to large Asub(p) changes, though it is not effective in producing cosmic ray intensity decreases. (auth.)

  14. Insights into pre-reversal paleosecular variation from stochastic models

    Directory of Open Access Journals (Sweden)

    Klaudio ePeqini

    2015-09-01

    Full Text Available To provide insights on the paleosecular variation of the geomagnetic field and the mechanism of reversals, long time series of the dipolar magnetic moment are generated by two different stochastic models, known as the domino model and the inhomogeneous Lebovitz disk dynamo model, with initial values taken from the from paleomagnetic data. The former model considers mutual interactions of N macrospins embedded in a uniformly rotating medium, where random forcing and dissipation act on each macrospin. With an appropriate set of the model’s parameters values, the series generated by this model have similar statistical behaviour to the time series of the SHA.DIF.14K model. The latter model is an extension of the classical two-disk Rikitake model, considering N dynamo elements with appropriate interactions between them.We varied the parameters set of both models aiming at generating suitable time series with behaviour similar to the long time series of recent secular variation (SV. Such series are then extended to the near future, obtaining reversals in both cases of models. The analysis of the time series generated by simulating the models show that the reversals appears after a persistent period of low intensity geomagnetic field, as it is occurring in the present times.

  15. Midlatitude cooling caused by geomagnetic field minimum during polarity reversal.

    Science.gov (United States)

    Kitaba, Ikuko; Hyodo, Masayuki; Katoh, Shigehiro; Dettman, David L; Sato, Hiroshi

    2013-01-22

    The climatic effects of cloud formation induced by galactic cosmic rays (CRs) has recently become a topic of much discussion. The CR-cloud connection suggests that variations in geomagnetic field intensity could change climate through modulation of CR flux. This hypothesis, however, is not well-tested using robust geological evidence. Here we present paleoclimate and paleoenvironment records of five interglacial periods that include two geomagnetic polarity reversals. Marine oxygen isotope stages 19 and 31 contain both anomalous cooling intervals during the sea-level highstands and the Matuyama-Brunhes and Lower Jaramillo reversals, respectively. This contrasts strongly with the typical interglacial climate that has the temperature maximum at the sea-level peak. The cooling occurred when the field intensity dropped to 40% increase in CR flux. The climate warmed rapidly when field intensity recovered. We suggest that geomagnetic field intensity can influence global climate through the modulation of CR flux.

  16. Secular schools in Zaragoza (1885-1917

    Directory of Open Access Journals (Sweden)

    Alfonso HEREDIA MANRIQUE

    2016-07-01

    Full Text Available This research has a very specific goal that is to know how many and which were secular schools that took place in Zaragoza city, in the period that goes from the first established at the end of the 19th century until the dictatorship of Miguel Primo de Rivera in 1923. Secular schools identified are described by the educational aspects most relevant to that appear in the scarce and scattered remains of them information, and mainly related to the urban location, organization and didactics, teachers and students. All these aspects allow us to glimpse something of how trying to implement his project of secular, rational, scientific education.

  17. Letter to the Editor: Geomagnetic storm effects at low latitudes

    Directory of Open Access Journals (Sweden)

    R. G. Rastogi

    Full Text Available The geomagnetic horizontal (H field from the chain of nine observatories in India are used to study the storm-time and disturbance daily variations. The peak decrease in storm-time variation in H showed significant enhancements at the equatorial electrojet stations over and above the normally expected decrease due to the ring current effects corrected for geomagnetic latitudes. The disturbance daily variation of H at equatorial stations showed a large decrease around midday hours over and above the usual dawn-maximum and dusk-minimum seen at any mid-latitude stations around the world. These slow and persistent additional decreases of H of disturbance daily variation at equatorial latitudes could be the effect of a westward electric field due to the Disturbance Ionospheric dynamo coupled with abnormally large electrical conductivities in the E region over the equator.Key words. Ionosphere (electric fields and currents · Magnetospheric physics (electric fields; storms and substorms

  18. Letter to the Editor: Geomagnetic storm effects at low latitudes

    Directory of Open Access Journals (Sweden)

    R. G. Rastogi

    1999-03-01

    Full Text Available The geomagnetic horizontal (H field from the chain of nine observatories in India are used to study the storm-time and disturbance daily variations. The peak decrease in storm-time variation in H showed significant enhancements at the equatorial electrojet stations over and above the normally expected decrease due to the ring current effects corrected for geomagnetic latitudes. The disturbance daily variation of H at equatorial stations showed a large decrease around midday hours over and above the usual dawn-maximum and dusk-minimum seen at any mid-latitude stations around the world. These slow and persistent additional decreases of H of disturbance daily variation at equatorial latitudes could be the effect of a westward electric field due to the Disturbance Ionospheric dynamo coupled with abnormally large electrical conductivities in the E region over the equator.Key words. Ionosphere (electric fields and currents · Magnetospheric physics (electric fields; storms and substorms

  19. (Post Secular Discomforts: Religio-Secular Disclosures in the Indian Context

    Directory of Open Access Journals (Sweden)

    Goldie Osuri

    2012-09-01

    Full Text Available The post-secular turn at the intersection of the fields of political philosophy, anthropology, religious, postcolonial and cultural studies has highlighted theological political formations which have informed differential histories of the secular. This essay examines how debates around the secular and the post-secular play out in the Indian context. Some questions that the essay addresses are: What does a reconsideration of the secular, a probing of its discomforts, offer in the Indian context? And what are the limits of a post-secular turn—in the sense of a reconsideration of spiritual belief or theological conventions as a resource for co-existence—if we think through the forms of power generated by this turn?

  20. Post-Secularism or Liberal-Democratic Constitutionalism?

    NARCIS (Netherlands)

    Bader, V.

    2012-01-01

    The increasingly fashionable concept and framing of post-secularism aims to construct simplistic dichotomies and clear-cut ruptures between pre-secular, secular and post-secular ages or epochs, in order to paint generalised and homogenised pictures of societies and their inevitable evolution. This

  1. Post-Secularism or Liberal-Democratic Constitutionalism?

    NARCIS (Netherlands)

    V. Bader (Veit)

    2012-01-01

    markdownabstract__Abstract__ The increasingly fashionable concept and framing of post-secularism aims to construct simplistic dichotomies and clear-cut ruptures between pre-secular, secular and post-secular ages or epochs, in order to paint generalised and homogenised pictures of societies and

  2. Secular Examination of Spirituality-Prosociality Association

    NARCIS (Netherlands)

    Dong, Mengchen; Wu, Song; Zhu, Yijie; Jin, Shenghua; Zhang, Yanjun

    2017-01-01

    Religious beliefs in Chinese cultural background, especially in Chinese secular society, have rarely been systematically investigated. The nonreligious-based population in China endorses certain supernatural beliefs or has related transcendent experience, even though they usually claim themselves as

  3. Effect of geomagnetic storms on VHF scintillations observed at low latitude

    Science.gov (United States)

    Singh, S. B.; Patel, Kalpana; Singh, A. K.

    2018-06-01

    A geomagnetic storm affects the dynamics and composition of the ionosphere and also offers an excellent opportunity to study the plasma dynamics. In the present study, we have used the VHF scintillations data recorded at low latitude Indian station Varanasi (Geomag. latitude = 14^{°}55^' }N, long. = 154^{°}E) which is radiated at 250 MHz from geostationary satellite UFO-02 during the period 2011-2012 to investigate the effects of geomagnetic storms on VHF scintillation. Various geomagnetic and solar indices such as Dst index, Kp index, IMF Bz and solar wind velocity (Vx) are used to describe the geomagnetic field variation observed during geomagnetic storm periods. These indices are very helpful to find out the proper investigation and possible interrelation between geomagnetic storms and observed VHF scintillation. The pre-midnight scintillation is sometimes observed when the main phase of geomagnetic storm corresponds to the pre-midnight period. It is observed that for geomagnetic storms for which the recovery phase starts post-midnight, the probability of occurrence of irregularities is enhanced during this time and extends to early morning hours.

  4. THEORY OF SECULAR CHAOS AND MERCURY'S ORBIT

    International Nuclear Information System (INIS)

    Lithwick, Yoram; Wu Yanqin

    2011-01-01

    We study the chaotic orbital evolution of planetary systems, focusing on secular (i.e., orbit-averaged) interactions, which dominate on long timescales. We first focus on the evolution of a test particle that is forced by multiple planets. To linear order in eccentricity and inclination, its orbit precesses with constant frequencies. But nonlinearities modify the frequencies, and can shift them into and out of resonance with either the planets' eigenfrequencies (forming eccentricity or inclination secular resonances), or with linear combinations of those frequencies (forming mixed high-order secular resonances). The overlap of these nonlinear secular resonances drives secular chaos. We calculate the locations and widths of nonlinear secular resonances, display them together on a newly developed map (the 'map of the mean momenta'), and find good agreement between analytical and numerical results. This map also graphically demonstrates how chaos emerges from overlapping secular resonances. We then apply this newfound understanding to Mercury to elucidate the origin of its orbital chaos. We find that since Mercury's two free precession frequencies (in eccentricity and inclination) lie within ∼25% of two other eigenfrequencies in the solar system (those of the Jupiter-dominated eccentricity mode and the Venus-dominated inclination mode), secular resonances involving these four modes overlap and cause Mercury's chaos. We confirm this with N-body integrations by showing that a slew of these resonant angles alternately librate and circulate. Our new analytical understanding allows us to calculate the criterion for Mercury to become chaotic: Jupiter and Venus must have eccentricity and inclination of a few percent. The timescale for Mercury's chaotic diffusion depends sensitively on the forcing. As it is, Mercury appears to be perched on the threshold for chaos, with an instability timescale comparable to the lifetime of the solar system.

  5. The Incidence and Management of Conflicts in Secular and Non-Secular Tertiary Institutions in South West Nigeria

    Science.gov (United States)

    Ayodele, Joseph Babatola; Adewumi, Joseph Olukayode

    2007-01-01

    This paper compared the incidence and management of conflicts in secular and non-secular tertiary institutions in Nigeria. The sample of this study was made of sixty staff, and two hundred and forty students randomly selected each from two secular and two non-secular tertiary institutions in south western Nigeria. A validated questionnaire was…

  6. Mid-latitude Geomagnetic Field Analysis Using BOH Magnetometer: Preliminary Results

    Directory of Open Access Journals (Sweden)

    Junga Hwang

    2011-09-01

    Full Text Available Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Mt. Bohyun Observatory to measure the Earth's magnetic field variations in South Korea. We, in 2007, installed a fluxgate magnetometer (RFP-523C to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we provide the preliminary and the first statistical analysis using the BOH magnetometer installed at Mt. Bohyun Observatory. By superposed analysis, we find that daily variations of H, D, and Z shows similar tendency, that is, about 30 minutes before the meridian (11:28 a minimum appears and the time after about 3 hours and 30 minutes (15:28 a maximum appears. Also, a quiet interval start time (19:06 is near the sunset time, and a quiet interval end time (06:40 is near the sunrise time. From the sunset to the sunrise, the value of H has a nearly constant interval, that is, the sun affects the changes in H values. Seasonal variations show similar dependences to the sun. Local time variations show that noon region has the biggest variations and midnight region has the smallest variations. We compare the correlations between geomagnetic variations and activity indices as we expect the geomagnetic variation would contain the effects of geomagnetic activity variations. As a result, the correlation coefficient between H and Dst is the highest (r = 0.947, and other AL, AE, AU index and showed a high correlation. Therefore, the effects of geomagnetic storms and geomagnetic substorms might contribute to the geomagnetic changes significantly.

  7. Mechanism of the relations between the changes of the geomagnetic field, solar corpuscular radiation, atmospheric circulation, and climate

    International Nuclear Information System (INIS)

    Bucha, Vaclav

    1980-01-01

    The correlations between geomagnetic, climatic, and meteorological phenomena were investigated with the object of demonstrating the function of the geomagnetic pole and changes of its position in controlling the climate and weather. A tentative model has been proposed to enable one to understand the causes of the generation of glacial and interglacial periods, as well as the causes which effect changes of climate (Bucha, 1976a). The analyses of various types of geomagnetic and atmospheric manifestations have disclosed certain associations. The coincidence in the occurrence of increased spectral densities with regard to geomagnetic activity and the variations of atmospheric pressure over the geomagnetic pole shows the relation between their periodicities. The results imply that the changes in the intensity of corpuscular radiation, indicated by geomagnetic activity, affect the temperature and pressure patterns over the geomagnetic pole and polar region significantly, so that a pronounced modification of the general circulation may take place, as shown schematically (Bucha, 1976b). As a result of investigating the relations between the variations of geomagnetic activity and meteorological factors a mechanism of solar-terrestrial relationships and a model of the changes of atmospheric circulation in the Northern Hemisphere are proposed; this provides a probable explanation of the causes of the fluctuation of the climate, of dry and cold periods and of differing vegetation conditions in various years in dependence on the intensity of geomagnetic activity (Bucha, 1976b, 1977a). (author)

  8. Paleomagnetic reconstruction of the global geomagnetic field evolution during the Matuyama/Brunhes transition: Iterative Bayesian inversion and independent verification

    Science.gov (United States)

    Leonhardt, Roman; Fabian, Karl

    2007-01-01

    The Earth's magnetic field changed its polarity from the last reversed into today's normal state approximately 780 000 years ago. While before and after this so called Matuyama/Brunhes reversal, the Earth magnetic field was essentially an axial dipole, the details of its transitional structure are still largely unknown. Here, a Bayesian inversion method is developed to reconstruct the spherical harmonic expansion of this transitional field from paleomagnetic data. This is achieved by minimizing the total variational power at the core-mantle boundary during the transition under paleomagnetic constraints. The validity of the inversion technique is proved in two ways. First by inverting synthetic data sets from a modeled reversal. Here it is possible to reliably reconstruct the Gauss coefficients even from noisy records. Second by iteratively combining four geographically distributed high quality paleomagnetic records of the Matuyama/Brunhes reversal into a single geometric reversal scenario without assuming an a priori common age model. The obtained spatio-temporal reversal scenario successfully predicts most independent Matuyama/Brunhes transitional records. Therefore, the obtained global reconstruction based on paleomagnetic data invites to compare the inferred transitional field structure with results from numerical geodynamo models regarding the morphology of the transitional field. It is found that radial magnetic flux patches form at the equator and move polewards during the transition. Our model indicates an increase of non-dipolar energy prior to the last reversal and a non-dipolar dominance during the transition. Thus, the character and information of surface geomagnetic field records is strongly site dependent. The reconstruction also offers new answers to the question of existence of preferred longitudinal bands during the transition and to the problem of reversal duration. Different types of directional variations of the surface geomagnetic field

  9. Biological effects of geomagnetic storms

    International Nuclear Information System (INIS)

    Chibisov, S.M.; Breus, T.K.; Levitin, A.E.; Drogova, G.M.; AN SSSR, Moscow; AN SSSR, Moscow

    1995-01-01

    Six physiological parameters of cardio-vascular system of rabbits and ultrastructure of cardiomyocytes were investigated during two planetary geomagnetic storms. At the initial and main phase of the storm the normal circadian structure in each cardiovascular parameter was lost. The disynchronozis was growing together with the storm and abrupt drop of cardia activity was observed during the main phase of storm. The main phase of storm followed by the destruction and degradation of cardiomyocytes. Parameters of cardia activity became substantially synchronized and characterized by circadian rhythm structure while the amplitude of deviations was still significant at the recovery stage of geomagnetic storm. 3 refs.; 7 figs

  10. Striking Seasonality in the Secular Warming of the Northern Continents: Structure and Mechanisms

    Science.gov (United States)

    Nigam, S.; Thomas, N. P.

    2017-12-01

    The linear trend in twentieth-century surface air temperature (SAT)—a key secular warming signal— exhibits striking seasonal variations over Northern Hemisphere continents; SAT trends are pronounced in winter and spring but notably weaker in summer and fall. The SAT trends in historical twentieth-century climate simulations informing the Intergovernmental Panel for Climate Change's Fifth Assessment show varied (and often unrealistic) strength and structure, and markedly weaker seasonal variation. The large intra-ensemble spread of winter SAT trends in some historical simulations was surprising, especially in the context of century-long linear trends, with implications for the detection of the secular warming signal. The striking seasonality of observed secular warming over northern continents warrants an explanation and the representation of related processes in climate models. Here, the seasonality of SAT trends over North America is shown to result from land surface-hydroclimate interactions and, to an extent, also from the secular change in low-level atmospheric circulation and related thermal advection. It is argued that the winter dormancy and summer vigor of the hydrologic cycle over middle- to high-latitude continents permit different responses to the additional incident radiative energy from increasing greenhouse gas concentrations. The seasonal cycle of climate, despite its monotony, provides an expanded phase space for the exposition of the dynamical and thermodynamical processes generating secular warming, and an exceptional cost-effective opportunity for benchmarking climate projection models.

  11. Research on meaning-making and health in secular society: Secular, spiritual and religious existential orientations

    DEFF Research Database (Denmark)

    Hvidt, Niels Christian; La Cour, Peter

    2010-01-01

    cultural basis for research in secular society. Reviewing the literature, three main domains of existential meaning-making emerge: Secular, spiritual, and religious. In reconfirming these three domains, we propose to couple them with the three dimensions of cognition (knowing), practice (doing...

  12. Latitude dependence of long-term geomagnetic activity and its solar wind drivers

    Energy Technology Data Exchange (ETDEWEB)

    Myllys, M. [Helsinki Univ. (Finland). Dept. of Physics; Partamies, N. [Finnish Meteorological Institute, Helsinki (Finland); University Centre in Svalbard, Longyearbyen (Norway). Dept. of Arctic Geophysics; Juusola, L. [Finnish Meteorological Institute, Helsinki (Finland)

    2015-09-01

    To validate the usage of global indices in studies of geomagnetic activity, we have examined the latitude dependence of geomagnetic variations in Fennoscandia and Svalbard from 1994 to 2010. Daily standard deviation (SD) values of the horizontal magnetic field have been used as a measure of the ground magnetic disturbance level.We found that the timing of the geomagnetic minimum depends on the latitude region: corresponding to the minimum of sunspot cycle 22 (in 1996), the geomagnetic minimum occurred between the geomagnetic latitudes 57-61 in 1996 and at the latitudes 64-67 in 1997, which are the average auroral oval latitudes. During sunspot cycle 23, all latitude regions experienced the minimum in 2009, a year after the sunspot minimum. These timing differences are due to the latitude dependence of the 10 s daily SD on the different solar wind drivers. In the latitude region of 64-67 , the impact of the high-speed solar wind streams (HSSs) on the geomagnetic activity is the most pronounced compared to the other latitude groups, while in the latitude region of 57-61 , the importance of the coronal mass ejections (CMEs) dominates. The geomagnetic activity maxima during ascending solar cycle phases are typically caused by CME activity and occur especially in the oval and sub-auroral regions. The strongest geomagnetic activity occurs during the descending solar cycle phases due to a mixture of CME and HSS activity. Closer to the solar minimum, less severe geomagnetic activity is driven by HSSs and mainly visible in the poleward part of the auroral region. According to our study, however, the timing of the geomagnetic activity minima (and maxima) in different latitude bands is different, due to the relative importance of different solar wind drivers at different latitudes.

  13. Latitude dependence of long-term geomagnetic activity and its solar wind drivers

    International Nuclear Information System (INIS)

    Myllys, M.

    2015-01-01

    To validate the usage of global indices in studies of geomagnetic activity, we have examined the latitude dependence of geomagnetic variations in Fennoscandia and Svalbard from 1994 to 2010. Daily standard deviation (SD) values of the horizontal magnetic field have been used as a measure of the ground magnetic disturbance level.We found that the timing of the geomagnetic minimum depends on the latitude region: corresponding to the minimum of sunspot cycle 22 (in 1996), the geomagnetic minimum occurred between the geomagnetic latitudes 57-61 in 1996 and at the latitudes 64-67 in 1997, which are the average auroral oval latitudes. During sunspot cycle 23, all latitude regions experienced the minimum in 2009, a year after the sunspot minimum. These timing differences are due to the latitude dependence of the 10 s daily SD on the different solar wind drivers. In the latitude region of 64-67 , the impact of the high-speed solar wind streams (HSSs) on the geomagnetic activity is the most pronounced compared to the other latitude groups, while in the latitude region of 57-61 , the importance of the coronal mass ejections (CMEs) dominates. The geomagnetic activity maxima during ascending solar cycle phases are typically caused by CME activity and occur especially in the oval and sub-auroral regions. The strongest geomagnetic activity occurs during the descending solar cycle phases due to a mixture of CME and HSS activity. Closer to the solar minimum, less severe geomagnetic activity is driven by HSSs and mainly visible in the poleward part of the auroral region. According to our study, however, the timing of the geomagnetic activity minima (and maxima) in different latitude bands is different, due to the relative importance of different solar wind drivers at different latitudes.

  14. Mantle superplumes induce geomagnetic superchrons

    Directory of Open Access Journals (Sweden)

    Peter eOlson

    2015-07-01

    Full Text Available We use polarity reversal systematics from numerical dynamos to quantify the hypothesis that the modulation of geomagnetic reversal frequency, including geomagnetic superchrons, results from changes in core heat flux related to growth and collapse of lower mantle superplumes. We parameterize the reversal frequency sensitivity from numerical dynamos in terms of average core heat flux normalized by the difference between the present-day core heat flux and the core heat flux at geomagnetic superchron onset. A low-order polynomial fit to the 0-300 Ma Geomagnetic Polarity Time Scale (GPTS reveals that a decrease in core heat flux relative to present-day of approximately 30% can account for the Cretaceous Normal Polarity and Kiaman Reverse Polarity Superchrons, whereas the hyper-reversing periods in the Jurassic require a core heat flux equal to or higher than present-day. Possible links between GPTS transitions, large igneous provinces (LIPs, and the two lower mantle superplumes are explored. Lower mantle superplume growth and collapse induce GPTS transitions by increasing and decreasing core heat flux, respectively. Age clusters of major LIPs postdate transitions from hyper-reversing to superchron geodynamo states by 30-60 Myr, suggesting that superchron onset may be contemporaneous with LIP-forming instabilities produced during collapses of lower mantle superplumes.

  15. Explaining Global Secularity: Existential Security or Education?

    Directory of Open Access Journals (Sweden)

    Claude M. J. Braun

    2012-11-01

    Full Text Available At the time of data analysis for this report there were 193 countries in the world. Various institutions – the United Nations, the World Health Organization, the CIA, the World Values Survey, Gallup, and many others – have performed sophisticated statistical analyses on cross-national data. The present investigation demonstrates that valid and reliable data concerning religiosity and secularity exist for most countries and that these data are comparable. Cross-national data relating to social, political, economic and cultural aspects of life were tested for correlation with religiosity/secularity. In contrast to the most widely accepted general account of secularity, the Existential Security Framework (ESF; Norris & Inglehart, 2004, secularity was not most highly related to material security, though these were highly related. Rather, secularity was most strongly related to the degree of formal education attained. Material security explained no significant variance beyond education. Thus, religion’s primary function in the world today is being replaced, not so much by the pseudo-materialistic supplication for better living conditions as posited by the ESF, but by contemporary education – extensive knowledge of contemporary cultures, philosophy, modes of thought or processes of reasoning.

  16. Statistical Properties of Geomagnetic Activity Indices and Solar Wind Parameters

    Directory of Open Access Journals (Sweden)

    Jung-Hee Kim

    2014-06-01

    Full Text Available As the prediction of geomagnetic storms is becoming an important and practical problem, conditions in the Earth’s magnetosphere have been studied rigorously in terms of those in the interplanetary space. Another approach to space weather forecast is to deal with it as a probabilistic geomagnetic storm forecasting problem. In this study, we carry out detailed statistical analysis of solar wind parameters and geomagnetic indices examining the dependence of the distribution on the solar cycle and annual variations. Our main findings are as follows: (1 The distribution of parameters obtained via the superimposed epoch method follows the Gaussian distribution. (2 When solar activity is at its maximum the mean value of the distribution is shifted to the direction indicating the intense environment. Furthermore, the width of the distribution becomes wider at its maximum than at its minimum so that more extreme case can be expected. (3 The distribution of some certain heliospheric parameters is less sensitive to the phase of the solar cycle and annual variations. (4 The distribution of the eastward component of the interplanetary electric field BV and the solar wind driving function BV2, however, appears to be all dependent on the solar maximum/minimum, the descending/ascending phases of the solar cycle and the equinoxes/solstices. (5 The distribution of the AE index and the Dst index shares statistical features closely with BV and BV2 compared with other heliospheric parameters. In this sense, BV and BV2 are more robust proxies of the geomagnetic storm. We conclude by pointing out that our results allow us to step forward in providing the occurrence probability of geomagnetic storms for space weather and physical modeling.

  17. Christian identity of secular Europe

    Directory of Open Access Journals (Sweden)

    Malešević Miroslava

    2006-01-01

    Full Text Available The Jyllands-Posten Muhammad cartoons controversy began after twelve editorial cartoons, most of which depicted the Islamic prophet Muhammad, were published in the Danish newspaper Jyllands-Posten on September 30, 2005. The newspaper explained that this publication was a contribution to debate regarding criticism of Islam and self-censorship. In response, Danish Muslim organizations held public protests and spread knowledge of Jyllands-Postens publication. As the controversy grew, some or all of the cartoons were reprinted in newspapers in more than fifty other countries, which led to violent protests, particularly in the Muslim world. Critics of the cartoons describe them as islamophobic and argue that they are blasphemous, intended to humiliate a marginalized Danish minority, and a manifestation of ignorance about the history of western imperialism, from colonialism to the current conflicts in the Middle East. Supporters of the cartoons claim they illustrate an important issue in an age of Islamic extremist terrorism and that their publication is a legitimate exercise of the right of free speech. They also note that similar cartoons about other religions are frequently printed, arguing that the followers of Islam were not targeted in a discriminatory way. The dispute has again pointed out to the relevance of religion and religious differences in the contemporary world. Again, several questions presented themselves as significant: citizen freedom, values and the rights to exercise them, secularism, tolerance, multiculturalism majority-minority relationships and so on. The resolution to these issues appears as of the outmost importance, considering the existing tendencies of united Europe to even more firmly establish cultural, economic, and political associations, in order to launch a one, joined European identity with vanishing national, ethnic and religious differences. Therefore, the question becomes: what could serve as a foundation for

  18. Methodology for simulation of geomagnetically induced currents in power systems

    Directory of Open Access Journals (Sweden)

    Boteler David

    2014-07-01

    Full Text Available To assess the geomagnetic hazard to power systems it is useful to be able to simulate the geomagnetically induced currents (GIC that are produced during major geomagnetic disturbances. This paper examines the methodology used in power system analysis and shows how it can be applied to modelling GIC. Electric fields in the area of the power network are used to determine the voltage sources or equivalent current sources in the transmission lines. The power network can be described by a mesh impedance matrix which is combined with the voltage sources to calculate the GIC in each loop. Alternatively the power network can be described by a nodal admittance matrix which is combined with the sum of current sources into each node to calculate the nodal voltages which are then used to calculate the GIC in the transmission lines and GIC flowing to ground at each substation. Practical calculations can be made by superposition of results calculated separately for northward and eastward electric fields. This can be done using magnetic data from a single observatory to calculate an electric field that is a uniform approximation of the field over the area of the power system. It is also shown how the superposition of results can be extended to use data from two observatories: approximating the electric field by a linear variation between the two observatory locations. These calculations provide an efficient method for simulating the GIC that would be produced by historically significant geomagnetic storm events.

  19. Surface electric fields for North America during historical geomagnetic storms

    Science.gov (United States)

    Wei, Lisa H.; Homeier, Nichole; Gannon, Jennifer L.

    2013-01-01

    To better understand the impact of geomagnetic disturbances on the electric grid, we recreate surface electric fields from two historical geomagnetic storms—the 1989 “Quebec” storm and the 2003 “Halloween” storms. Using the Spherical Elementary Current Systems method, we interpolate sparsely distributed magnetometer data across North America. We find good agreement between the measured and interpolated data, with larger RMS deviations at higher latitudes corresponding to larger magnetic field variations. The interpolated magnetic field data are combined with surface impedances for 25 unique physiographic regions from the United States Geological Survey and literature to estimate the horizontal, orthogonal surface electric fields in 1 min time steps. The induced horizontal electric field strongly depends on the local surface impedance, resulting in surprisingly strong electric field amplitudes along the Atlantic and Gulf Coast. The relative peak electric field amplitude of each physiographic region, normalized to the value in the Interior Plains region, varies by a factor of 2 for different input magnetic field time series. The order of peak electric field amplitudes (largest to smallest), however, does not depend much on the input. These results suggest that regions at lower magnetic latitudes with high ground resistivities are also at risk from the effect of geomagnetically induced currents. The historical electric field time series are useful for estimating the flow of the induced currents through long transmission lines to study power flow and grid stability during geomagnetic disturbances.

  20. Periodic and secular changes in SS 433

    International Nuclear Information System (INIS)

    Collins, G.W.; Newsom, G.H.

    1983-01-01

    The recent history of SS 433 is reviewed with particular attention being given to the discovery of the periodic phenomena displayed by this object. Several periods ranging from days to months are established as being present in the spectrum of the ''moving'' lines as well as in other aspects of the emission from the object. In addition evidence for secular change in some of the defining parameters of the system is presented. Although these secular changes may eventually prove to be periodic on a rather long time scale, some interpretation of both the periodic and secular phenomena is possible. It is shown that it is possible to interpret all the known periodic phenomena in terms of a processing object responding to the time-varying torques that one would expect in a binary system

  1. Geomagnetic activity effects on plasma sheet energy conversion

    Directory of Open Access Journals (Sweden)

    M. Hamrin

    2010-10-01

    Full Text Available In this article we use three years (2001, 2002, and 2004 of Cluster plasma sheet data to investigate what happens to localized energy conversion regions (ECRs in the plasma sheet during times of high magnetospheric activity. By examining variations in the power density, E·J, where E is the electric field and J is the current density obtained by Cluster, we have studied the influence on Concentrated Load Regions (CLRs and Concentrated Generator Regions (CGRs from variations in the geomagnetic disturbance level as expressed by the Kp, the AE, and the Dst indices. We find that the ECR occurrence frequency increases during higher magnetospheric activities, and that the ECRs become stronger. This is true both for CLRs and for CGRs, and the localized energy conversion therefore concerns energy conversion in both directions between the particles and the fields in the plasma sheet. A higher geomagnetic activity hence increases the general level of energy conversion in the plasma sheet. Moreover, we have shown that CLRs live longer during magnetically disturbed times, hence converting more electromagnetic energy. The CGR lifetime, on the other hand, seems to be unaffected by the geomagnetic activity level. The evidence for increased energy conversion during geomagnetically disturbed times is most clear for Kp and for AE, but there are also some indications that energy conversion increases during large negative Dst. This is consistent with the plasma sheet magnetically mapping to the auroral zone, and therefore being more tightly coupled to auroral activities and variations in the AE and Kp indices, than to variations in the ring current region as described by the Dst index.

  2. Secular Islam and the Rhetoric of Humanity

    OpenAIRE

    Kharputly, Nadeen Sh B

    2017-01-01

    Secular Islam and the Rhetoric of Humanity” examines competing notions of humanity in representations of Islam in the United States from the Civil Rights period to the present. In post-9/11 representations, Islam is rhetorically “humanized” by the dominant culture in attempts to determine Islam’s role in the United States. This humanizing framework not only presumes an inherent lack of humanity in Islam; it establishes the ideal of the human as white, rational, and secular. To critique this ...

  3. Prediction of secular acceleration of axial rotation of Mars

    Science.gov (United States)

    Barkin, Yu. V.

    2009-04-01

    Secular motion of the Earth pole and non-tidal acceleration of its diurnal rotation have obtained rather precise explanation with the help of simple one-point model of the directed transport of fluid masses from a southern hemisphere in northern hemisphere with the general direction, given by geocentric axis OP directed to pole P with coordinates 700N, 10403 E[1]. The another generalized model represents a system of two material points with masses m2 and m1, located on surface of the Earth at poles of geocentric axis OP. Masses are linearly changed in the time with velocities [2]: ṁ2 = 0.179 × 1015kg/yrand ṁ1 = 0.043 × 1015kg/yr. A reduction of fluid masses of the appropriate thin spherical layer of the Earth correspond to secular increasing of masses of model points. The specified model has allowed to explain values of fundamental geodynamic parameters observably and determined during decades: a direction and velocity of drift of a pole of the Earth; value of non-tidal acceleration of axial rotation; to explain a secular variations of coefficients of the second, third, fourth, sixth and eighth zonal harmonics of a geopotential; coefficients of secular changes of a surface of ocean for the last approximately 150 years; a direction of secular drift of a geocenter and other planetary phenomena [3]. The role of the angular momentum of redistributed masses of the Earth in rotation of the Earth appeared not essential at the given stage of researches. On the essence the offered model has semi-empirical character as it bases on values of velocities of change of masses of points and the given position of axis OP. For their determination and estimations the part of the observant data was used, and other parameters were designed under analytical formulas. The obtained results have precisely confirmed competency and affectivity of geodynamic model [4] about existence of secular drift of a liquid core along radial direction OP with velocity about 2.6 cm/yr in the

  4. Day-to-Day Variability of H and Z Components of the Geomagnetic Field at the African Longitudes

    OpenAIRE

    Obiekezie, T. N.; Obiadazie, S. C.; Agbo, G. A.

    2013-01-01

    The Day-to-day variability of the geomagnetic field elements at the African longitudes has been studied for the year 1987 using geomagnetic data obtained from four different African observatories. The analysis was carried out on solar quiet days using hourly values of the Horizontal, , and vertical, , geomagnetic field values. The results of this study confirm that Sq is a very changeable phenomenon, with a strong day-to-day variation. This day-to-day variation is seen to be superimposed on m...

  5. Ice ages and geomagnetic reversals

    Science.gov (United States)

    Wu, Patrick

    1992-01-01

    There have been speculations on the relationship between climatic cooling and polarity reversals of the earth's magnetic field during the Pleistocene. Two of the common criticisms on this relationship have been the reality of these short duration geomagnetic events and the accuracy of their dates. Champion et al. (1988) have reviewed recent progress in this area. They identified a total of 10 short-duration polarity events in the last 1 Ma and 6 of these events have been found in volcanic rocks, which also have K-Ar dates. Supposing that the speculated relationship between climatic cooling and geomagnetic reversals actually exist, two mechanisms that assume climatic cooling causes short period magnetic reversals will be investigated. These two methods are core-mantle boundary topography and transfer of the rotational energy to the core.

  6. Calling in Work: Secular or Sacred?

    Science.gov (United States)

    Steger, Michael F.; Pickering, N. K.; Shin, J. Y.; Dik, B. J.

    2010-01-01

    Recent scholarship indicates that people who view their work as a calling are more satisfied with their work and their lives. Historically, calling has been regarded as a religious experience, although modern researchers frequently have adopted a more expansive and secular conceptualization of calling, emphasizing meaning and personal fulfillment…

  7. Religion, Education, and Secularism in International Agencies

    Science.gov (United States)

    Stambach, Amy; Marshall, Katherine; Nelson, Matthew J.; Andreescu, Liviu; Kwayu, Aikande C.; Wexler, Philip; Hotam, Yotam; Fischer, Shlomo; El Bilawi, Hassan

    2011-01-01

    During the interwar years of the early twentieth century, and through at least the 1980s, education was seen by scholars, state leaders, and international agency representatives alike as a way to modernize and secularize underdeveloped communities. Arguments about the modernizing power of education did not erase or discount the presence of…

  8. Public debt, secular stagnation and functional finance

    DEFF Research Database (Denmark)

    Skott, Peter

    2016-01-01

    Fiscal policy and public debt may be required to maintain full employment and avoid secular stagnation. This conclusion emerges from a range of different models, including OLG specifications and stock-flow consistent (post-) Keynesian models. One of the determinants of the required long-run debt ...

  9. Aggregate demand, functional finance and secular stagnation

    DEFF Research Database (Denmark)

    Skott, Peter

    2016-01-01

    This paper makes three main points. Fiscal policy, first, may be needed in the long run to maintain full employment and avoid secular stagnation. If fiscal policy is used in this way, second, the long-run debt ratio depends (i) inversely on the rate of growth, (ii) inversely on government consump...

  10. Religious Globalisms in the Post-Secular Age

    NARCIS (Netherlands)

    Wilson, E.K.; B. Steger, Manfred

    2013-01-01

    This article explores the interconnections between mounting global crises and the emergence of the post-secular. Specifically, the article argues that the post-secular is both a description of and a response to shifting global realities in the twenty-first century. It describes the crisis of secular

  11. Paleointensity Behavior and Intervals Between Geomagnetic Reversals in the Last 167 Ma

    Science.gov (United States)

    Kurazhkovskii, A. Yu.; Kurazhkovskaya, N. A.; Klain, B. I.

    2018-01-01

    The results of comparative analysis of the behavior of paleointensity and polarity (intervals between reversals) of the geomagnetic field for the last 167 Ma are presented. Similarities and differences in the behavior of these characteristics of the geomagnetic field are discussed. It is shown that bursts of paleointensity and long intervals between reversals occurred at high mean values of paleointensity in the Cretaceous and Paleogene. However, there are differences between the paleointensity behavior and the reversal regime: (1) the characteristic times of paleointensity variations are less than the characteristic times of the frequency of geomagnetic reversals, (2) the achievement of maximum values of paleointensity at the Cretaceous-Paleogene boundary and the termination of paleointensity bursts after the boundary of 45-40 Ma are not marked by explicit features in the geomagnetic polarity behavior.

  12. Geomagnetic Observations for Main Field Studies

    DEFF Research Database (Denmark)

    Matzka, Jürgen; Chulliat, A.; Mandea, M.

    2010-01-01

    Direct measurements of the geomagnetic field have been made for more than 400 years, beginning with individual determinations of the angle between geographic and magnetic North. This was followed by the start of continuous time series of full vector measurements at geomagnetic observatories...... and the beginning of geomagnetic repeat stations surveys in the 19th century. In the second half of the 20th century, true global coverage with geomagnetic field measurements was accomplished by magnetometer payloads on low-Earth-orbiting satellites. This article describes the procedures and instruments...... for magnetic field measurements on ground and in space and covers geomagnetic observatories, repeat stations, automatic observatories, satellites and historic observations. Special emphasis is laid on the global network of geomagnetic observatories....

  13. The Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, James R.

    2003-01-01

    By modifying the IGRF it is possible to learn what may happen to the geomagnetic field during a geomagnetic reversal. If the entire IGRF reverses then the declination and inclination only reverse when the field strength is zero. If only the dipole component of the IGRF reverses a large geomagnetic field remains when the dipole component is zero and he direction of the field at the end of the reversal is not exactly reversed from the directions at the beginning of the reversal.

  14. The church and the secular: The effect of the post-secular on Christianity

    Directory of Open Access Journals (Sweden)

    Jaco Beyers

    2014-07-01

    Full Text Available Paradigms determine relationships. During the Enlightenment period Emile Durkheim proposed a relationship between the sacred and the profane. Religion, which is concerned with the sacred, was defined in terms of being different from the profane. The profane came to denote the secular. The organic character of religion caused some scholars to predict the end of the church at the hand of modernisation and rationalisation. Some scholars instead envisaged a new form and function of the church. Some scholars anticipated the growth of Christianity. Reality shows that Christianity has not died out but seems to be growing. The new era we are currently in (identified as the postmodern has been described as the post-secular age where a process of re-sacralisation takes place. How will the post-secular influence the church? What will the relationship between the church and the secular be like under a new paradigm? This article suggests that within a postmodern paradigm, the post-secular will emphasise the place of the individual in the church. Fragmentation of society will also be the result of the post-secular. Religiosity in future will have to contend with fundamentalism and civil religion.

  15. The Mono Lake geomagnetic excursion recorded in loess: Its application as time marker and implications for its geomagnetic nature

    Science.gov (United States)

    Hambach, U.; Hark, M.; Zeeden, C.; Reddersen, B.; Zöller, L.; Fuchs, M.

    2009-04-01

    . The directional palaeomagnetic record is of high quality and shows variations in the bandwidth of secular variation in the upper and in the lower part of the section, whereas in the central part shallow (? 30˚ ) and oversteep inclinations reveal the record of a geomagnetic excursion just above the find horizon. The shallow inclinations are preceded by and go along with westerly declinations, whereas the steep inclinations are preceded by easterly declinations. This directional pattern is similar to what was found at the Mono Lake in California (e.g. Liddicoat and Coe, 1979; Lund et al., 1988). A relative palaeointensity (RPI) record was constructed by using MS and ARM as normalisers. This record corresponds quite well to the GLOPIS (Laj et al., 2004) and thus provides additional dating. The peak of the directional excursion coincides with a relative minimum of RPI. The average RPI during the excursional interval, however, is significantly higher than during normal periods, contrary to what is usually reported. Furthermore, just before and after the directional excursion the highest values of RPI occur. The largest amplitude of the directional excursion does not correspond to the well defined minimum in RPI preceding this interval which is usually taken for the MLE in the marine RPI records. This offset between the RPI and the directional record may indicate the presence of strong non-dipole components and may also explain the blur in dating of the MLE. The calculated VGPs of the directional excursion lie over North America but do not correspond to the looping behaviour as reported from the Mono Lake VGPs itself (Liddicoat and Coe, 1979). The cultural layer at the Krems-Wachtberg site is located in the centre of the RPI minimum which is slightly older than the peak of the directional excursion. The radiocarbon ages from the cultural layer (~27 ka 14C age BP = ~32 ka calendric age calBP) fit well to the age estimates of the MLE at the Mono Lake based on radiocarbon

  16. Low-altitude trapped protons at the geomagnetic equator

    Science.gov (United States)

    Guzik, T. G.; Miah, M. A.; Mitchell, J. M.; Wefel, J. P.

    1989-01-01

    Geomagnetically trapped protons in the 0.6- to 9-MeV energy range were measured at latitudes near the geomagnetic equator by the Phoenix 1 experiment on board the S81-1 mission from May to November 1982. The protons show a distribution in latitude along the line of minimum magnetic field strength with a full width at half maximum of about 10 deg but with no appreciable longitudinal variation. Between 170 and 290 Km the peak proton flux shows a fifth-power altitude dependence, in contrast to previous measurements at higher altitudes, possibly demonstrating source attenuation. The efficiency of the telescope is calculated as a function of particle pitch angle and used to investigate the time dependence (1969-1982) of the intensity.

  17. Low-altitude trapped protons at the geomagnetic equator

    International Nuclear Information System (INIS)

    Guzik, T.G.; Miah, M.A.; Mitchell, J.W.; Wefel, J.P.

    1989-01-01

    Geomagnetically trapped protons in the 0.6- to 9-MeV energy range were measured at latitudes near the geomagnetic equator by the Phoenix 1 experiment on board the S81-1 mission from May to November 1982. The protons show a distribution in latitude along the line of minimum magnetic field strength with a full width at half maximum of ∼10 0 but with no appreciable longitudinal variation. Between 170 and 290 km the peak proton flux shows a fifth-power altitude dependence, in contrast to previous measurements at higher altitudes, possibly demonstrating source attenuation. The efficiency of the telescope is calculated as a function of particle pitch angle and used to investigate the time dependence (1969--1982) of the intensity. copyright American Geophysical Union 1989

  18. Forecasting intense geomagnetic activity using interplanetary magnetic field data

    Science.gov (United States)

    Saiz, E.; Cid, C.; Cerrato, Y.

    2008-12-01

    Southward interplanetary magnetic fields are considered traces of geoeffectiveness since they are a main agent of magnetic reconnection of solar wind and magnetosphere. The first part of this work revises the ability to forecast intense geomagnetic activity using different procedures available in the literature. The study shows that current methods do not succeed in making confident predictions. This fact led us to develop a new forecasting procedure, which provides trustworthy results in predicting large variations of Dst index over a sample of 10 years of observations and is based on the value Bz only. The proposed forecasting method appears as a worthy tool for space weather purposes because it is not affected by the lack of solar wind plasma data, which usually occurs during severe geomagnetic activity. Moreover, the results obtained guide us to provide a new interpretation of the physical mechanisms involved in the interaction between the solar wind and the magnetosphere using Faraday's law.

  19. Pilgrimage as post-secular therapy

    Directory of Open Access Journals (Sweden)

    Lisbeth Mikaelsson

    2012-01-01

    Full Text Available This article describes the institutionalized pilgrim role and then turns to the therapeutic discourse which is so prominent in the modern pilgrimage to Santiago de Compostela. Both the role and the discourse can be related to the concept of post-secularity, demonstrating that complex cultural fields such as religion and therapy, become intertwined in new ways through modern pilgrimage. This article also shows that churches cooperating in this type of pilgrimage are adapting to the post-secular age, finding a new sort of raison d’être in a multi-religious, international world. Here the author refers to the Church of Norway and its role in Norwegian pilgrimage. The latter is modelled upon the Santiago example.

  20. Kosovar Society through Secularism and Religion

    OpenAIRE

    MSc. Dritero Arifi; Dr.Sc. Ylber Sela

    2013-01-01

    This paper will analyze the importance and the effects of religion, in Kosovar society. A great part of the paper, will analyze the social and the political relations in Post-War Kosovo. Initially it will elaborate religion and secularism, especially in theoreticall aspect, what impact have these definitions in modern societies. In order to explain what the importance of the religion in Kosovo is, we will focus on analyzing ethnical, social and political relations within Kosovo society. A...

  1. Fuzzy Law and the Boundaries of Secularism

    Directory of Open Access Journals (Sweden)

    W Menski

    2010-12-01

    Full Text Available The author delivered a speech at a Religare Conference. Showing his distaste for fuzzy law, he argues that "moderate secularism" is not merely another fuzzy concept, but it is "super-fuzzy", and that lawyers claiming to love certainty "have a tendency to sit in judgment over matters and even pre-judge things they know little about, including legal pluralism" leading to much irritation.

  2. Morphology in the total electron content under geomagnetic disturbed conditions: results from global ionosphere maps

    Directory of Open Access Journals (Sweden)

    Zhao Biqiang

    2007-07-01

    Full Text Available Using 8-year global ionosphere maps (GIMs of TEC products from the Jet Propulsion Laboratory (JPL, we make a statistical study on the morphology of the global ionospheric behaviors with respect to the geomagnetic disturbances. Results show that the behaviors of TEC during geomagnetic storm present clear seasonal and local time variations under geomagnetic control in a similar way as those of NmF2 (Field and Rishbeth, 1997. A negative phase of TEC occurs with high probability in the summer hemisphere and most prominent near the geomagnetic poles, while a positive phase is obvious in the winter hemisphere and in the far pole region. A negative storm effect toward lower latitudes tends to occur from post-midnight to the morning sector and recedes to high latitude in the afternoon. A positive storm effect is separated by geomagnetic latitudes and magnetic local time. Furthermore, ionospheric responses at different local time sectors with respect to the storm commencement shows very different developing processes corresponding to the evolution of the geomagnetic storm. A daytime positive storm effect is shown to be more prominent in the American region than those in the Asian and European regions, which may suggest a longitudinal effect of the ionospheric storm.

  3. Morphology in the total electron content under geomagnetic disturbed conditions: results from global ionosphere maps

    Directory of Open Access Journals (Sweden)

    Z. Biqiang

    2007-07-01

    Full Text Available Using 8-year global ionosphere maps (GIMs of TEC products from the Jet Propulsion Laboratory (JPL, we make a statistical study on the morphology of the global ionospheric behaviors with respect to the geomagnetic disturbances. Results show that the behaviors of TEC during geomagnetic storm present clear seasonal and local time variations under geomagnetic control in a similar way as those of NmF2 (Field and Rishbeth, 1997. A negative phase of TEC occurs with high probability in the summer hemisphere and most prominent near the geomagnetic poles, while a positive phase is obvious in the winter hemisphere and in the far pole region. A negative storm effect toward lower latitudes tends to occur from post-midnight to the morning sector and recedes to high latitude in the afternoon. A positive storm effect is separated by geomagnetic latitudes and magnetic local time. Furthermore, ionospheric responses at different local time sectors with respect to the storm commencement shows very different developing processes corresponding to the evolution of the geomagnetic storm. A daytime positive storm effect is shown to be more prominent in the American region than those in the Asian and European regions, which may suggest a longitudinal effect of the ionospheric storm.

  4. Fast directional changes in the geomagnetic field recovered from archaeomagnetism of ancient Israel

    Science.gov (United States)

    Shaar, R.; Hassul, E.; Raphael, K.; Ebert, Y.; Marco, S.; Nowaczyk, N. R.; Ben-Yosef, E.; Agnon, A.

    2017-12-01

    Recent archaeomagnetic intensity data from the Levant revealed short-term sub-centennial changes in the geomagnetic field such as `archaeomagnetic jerks' and `geomagnetic spikes'. To fully understand the nature of these fast variations a complementary high-precision time-series of geomagnetic field direction is required. To this end we investigated 35 heat impacted archaeological objects from Israel, including cooking ovens, furnaces, and burnt walls. We combine the new dataset with previously unpublished data and construct the first archaeomagnetic compilation of Israel which, at the moment, consists of a total of 57 directions. Screening out poor quality data leaves 30 acceptable archaeomagnetic directions, 25 of which spanning the period between 1700 BCE to 400 BCE. The most striking result of this dataset is a large directional anomaly with deviation of 20°-25° from geocentric axial dipole direction during the 9th century BCE. This anomaly in field direction is contemporaneous with the Levantine Iron Age Anomaly (LIAA) - a local geomagnetic anomaly over the Levant that was characterized by a high averaged geomagnetic field (nearly twice of today's field) and short decadal-scale geomagnetic spikes.

  5. Kosovar Society through Secularism and Religion

    Directory of Open Access Journals (Sweden)

    MSc. Dritero Arifi

    2013-12-01

    Full Text Available This paper will analyze the importance and the effects of religion, in Kosovar society. A great part of the paper, will analyze the social and the political relations in Post-War Kosovo. Initially it will elaborate religion and secularism, especially in theoreticall aspect, what impact have these definitions in modern societies. In order to explain what the importance of the religion in Kosovo is, we will focus on analyzing ethnical, social and political relations within Kosovo society. A considerable component of the paper is also, the elaboration of secularism in Kosovo conditions. This implies that the formulation of the problem and the objective of this research, are the substance of the paper’s theme, which is, religion in Kosovo; its definition and the outlook of the Kosovar society on religion. Is Kosovo post-war society more or less religious? That means the elements of Religions and Secularism will be part of the analysis of developments in post-war Kosovo.

  6. VLF Wave Properties During Geomagnetic Storms

    Science.gov (United States)

    Blancarte, J.; Artemyev, A.; Mozer, F.; Agapitov, O. V.

    2017-12-01

    Whistler-mode chorus is important for the global dynamics of the inner magnetosphere electron population due to its ability to scatter and accelerate electrons of a wide energy range in the outer radiation belt. The parameters of these VLF emissions change dynamically during geomagnetic storms. Presented is an analysis of four years of Van Allen probe data, utilizing electric and magnetic field in the VLF range focused on the dynamics of chorus wave properties during the enhancement of geomagnetic activity. It is found that VLF emissions respond to geomagnetic storms in more complicated ways than just by affecting the waves' amplitude growth or depletion. Oblique wave amplitudes grow together with parallel waves during periods of intermediate geomagnetic activity, while the occurrence rate of oblique waves decreases during larger geomagnetic storms.

  7. Archaeomagnetic Dating in Europe Using a Global Geomagnetic Field Model

    Science.gov (United States)

    Lodge, A.; Suttie, N.; Holme, R.; Shaw, J.; Hill, M. J.; Linford, P.

    2009-12-01

    Using up-to-date archaeomagnetic data from Europe and CALS7K.2 as an apriori model, we produce a global geomagnetic field model to be used for archaeomagnetic dating in Europe. More details on the modelling process will be presented elsewhere (in session GP12, abstract: Geophysical insights from archaeomagnetic dating). Here we apply the global geomagnetic field model to a series of test cases from both recently published data and unpublished data to demonstrate its application to archaeomagnetic dating. We compare the results produced using our model with those from the spherical cap harmonic model, SCHA.DIF.3K (Pavón-Carrasco et al., 2009), the global geomagnetic field model, ARCH3K.1 (Korte et al., 2009) and those produced using the palaeosecular variation curves generated using Bayesian statistics (Lanos, 2004). We include examples which emphasise the importance of using three component data (declination, inclination and intensity) to produce an improved archaeomagnetic date. In addition to the careful selection of an appropriate model for archaeomagnetic dating, the choice of errors on the model curves is vital for providing archaeologists with an age range of possible dates. We discuss how best to constrain the errors on the model curves and alternative ways to the mathematical method of Lanos (2004) for producing an archaeomagnetic date for archaeologists.

  8. Core surface flow modelling from high-resolution secular variation

    DEFF Research Database (Denmark)

    Holme, R.; Olsen, Nils

    2006-01-01

    -flux hypothesis, but the spectrum of the SV implies that a conclusive test of frozen-flux is not possible. We parametrize the effects of diffusion as an expected misfit in the flow prediction due to departure from the frozen-flux hypothesis; at low spherical harmonic degrees, this contribution dominates...... the expected departure of the SV predictions from flow to the observed SV, while at high degrees the SV model uncertainty is dominant. We construct fine-scale core surface flows to model the SV. Flow non-uniqueness is a serious problem because the flows are sufficiently small scale to allow flow around non......-series of magnetic data and better parametrization of the external magnetic field....

  9. Secular variations in sperm quality: fact or science fiction?

    Directory of Open Access Journals (Sweden)

    Luc Multigner

    Full Text Available The debate concerning the possible degradation in human sperm quality began in the 1970s, was revived at the beginning of the 1990s and has continued to mobilize the scientific community ever since. After the meta-analysis by Carlsen et al. (1992 showing a decline in human semen quality over the last 50 years, several groups investigated the sperm characteristics of more or less homogeneous groups of men who had provided semen at the same center for 10 to 20 years. A significant decrease in sperm concentration was reported in some studies, but not in others. Meanwhile, there is an increasing number of reports suggesting that physical and chemical factors introduced and spread by human activity in the environment may have contributed to sperm decline. At the end of the 20th century the debate on declining semen quality is not closed. The lack of certainty and the serious consequences that such a decline would have on the fertility of human populations make this an important public health issue at the start of the 21st century. For this reason, intensive research should be developed in both fundamental and epidemiological domains, particularly in South America, where industrial and agricultural pollution pose a serious threat to the population.

  10. Space Weather Monitoring for ISS Geomagnetic Storm Studies

    Science.gov (United States)

    Minow, Joseph I.; Parker, Linda Neergaard

    2013-01-01

    The International Space Station (ISS) space environments community utilizes near real time space weather data to support a variety of ISS engineering and science activities. The team has operated the Floating Potential Measurement Unit (FPMU) suite of plasma instruments (two Langmuir probes, a floating potential probe, and a plasma impedance probe) on ISS since 2006 to obtain in-situ measurements of plasma density and temperature along the ISS orbit and variations in ISS frame potential due to electrostatic current collection from the plasma environment (spacecraft charging) and inductive (vxB) effects from the vehicle motion across the Earth s magnetic field. An ongoing effort is to use FPMU for measuring the ionospheric response to geomagnetic storms at ISS altitudes and investigate auroral charging of the vehicle as it passes through regions of precipitating auroral electrons. This work is challenged by restrictions on FPMU operations that limit observation time to less than about a third of a year. As a result, FPMU campaigns ranging in length from a few days to a few weeks are typically scheduled weeks in advance for ISS engineering and payload science activities. In order to capture geomagnetic storm data under these terms, we monitor near real time space weather data from NASA, NOAA, and ESA sources to determine solar wind disturbance arrival times at Earth likely to be geoeffective (including coronal mass ejections and high speed streams associated with coronal holes) and activate the FPMU ahead of the storm onset. Using this technique we have successfully captured FPMU data during a number of geomagnetic storm periods including periods with ISS auroral charging. This presentation will describe the strategies and challenges in capturing FPMU data during geomagnetic storms, the near real time space weather resources utilized for monitoring the space weather environment, and provide examples of auroral charging data obtained during storm operations.

  11. Really not god: Secularization and pragmatism in Gamblers Anonymous.

    Science.gov (United States)

    Browne, B R

    1994-09-01

    The paper argues that despite maintaining the image of a twelve-step organization, the central theme of the history of Gamblers Anonymous (GA) in the United States is the increasing secularization of the program of the recovery. The paper documents the increasing secularization and pragmatism of Gamblers Anonymous, as reflected in key documents, despite the spiritual vision of its founding member. The author speculates on why Gamblers Anonymous took a secularized development path. Further research is called for.

  12. Kinematic reversal schemes for the geomagnetic dipole.

    Science.gov (United States)

    Levy, E. H.

    1972-01-01

    Fluctuations in the distribution of cyclonic convective cells, in the earth's core, can reverse the sign of the geomagnetic field. Two kinematic reversal schemes are discussed. In the first scheme, a field maintained by cyclones concentrated at low latitude is reversed by a burst of cyclones at high latitude. Conversely, in the second scheme, a field maintained predominantly by cyclones in high latitudes is reversed by a fluctuation consisting of a burst of cyclonic convection at low latitude. The precise fluid motions which produce the geomagnetic field are not known. However, it appears that, whatever the details are, a fluctuation in the distribution of cyclonic cells over latitude can cause a geomagnetic reversal.

  13. The geomagnetic field gradient tensor

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Olsen, Nils

    2012-01-01

    We develop the general mathematical basis for space magnetic gradiometry in spherical coordinates. The magnetic gradient tensor is a second rank tensor consisting of 3 × 3 = 9 spatial derivatives. Since the geomagnetic field vector B is always solenoidal (∇ · B = 0) there are only eight independent...... tensor elements. Furthermore, in current free regions the magnetic gradient tensor becomes symmetric, further reducing the number of independent elements to five. In that case B is a Laplacian potential field and the gradient tensor can be expressed in series of spherical harmonics. We present properties...... of the magnetic gradient tensor and provide explicit expressions of its elements in terms of spherical harmonics. Finally we discuss the benefit of using gradient measurements for exploring the Earth’s magnetic field from space, in particular the advantage of the various tensor elements for a better determination...

  14. PEDIATRIC FITNESS: SECULAR TRENDS AND GEOGRAPHIC VARIABILITY

    Directory of Open Access Journals (Sweden)

    Grant R. Tomkinson

    2007-06-01

    Full Text Available DESCRIPTION This book describes and discusses children's physical capacity in terms of aerobic and anaerobic power generation according to secular trends and geographic variability. PURPOSE To discuss the controversial issue of whether present day's children and adolescents are fitter than their equals of the past and whether they are fitter if they live in the more prosperous countries. AUDIENCE Pediatricians, medical practitioners, physical educators, exercise and/or sport scientists, exercise physiologists, personal trainers and graduate students in relevant fields will find this book helpful when dealing with contemporary trends and geographic variability in pediatric fitness. FEATURES The volume starts by examining the general picture on children fitness by the editors. The individual chapter's authors discuses the data gathered since the late 1950s on secular trends and geographic changeability in aerobic and anaerobic pediatric fitness performances of children and adolescents from 23 countries in Africa, Asia, Australasia, Europe, the Middle East and North America. There are chapters proposing that there is proof that there has been a world-wide decline in pediatric aerobic performance in recent decades, relative stability in anaerobic performance, and that the best performing children come from northern and central Europe. In final chapters possible causes to that end are considered, including whether weakening in aerobic performance are the result of distributional or widespread declines, and whether increases in obesity alone can explain the failure in aerobic performance. ASSESSMENT The editors have assembled a volume of Medicine and Sports Science that is necessary and essential reading for all who are interested in understanding and improving the fitness of children. The readers will find useful information in this book on secular trends and geographic variability in pediatric fitness. I believe, the book will serve as a first

  15. A new regard about Surlari National Geomagnetic Observatory

    Science.gov (United States)

    Asimopolos, Laurentiu; Asimopolos, Natalia-Silvia; Pestina, Agata-Monica

    2010-05-01

    Geomagnetic field study in Romanian stations has started with irregular measurements in late XIXth century. In 1943, the foundation of Surlari National Geomagnetic Observatory (SNGO) marks the beginning of a new era in the systematic study of geomagnetic field by a continuous registration of its variations and by carrying out standard absolute measurements in a fundamental station. The location of the observatory meets the highest exigencies, being situated in physical-geological conditions of a uniform local field, at a reasonably long distance from human activities. Its laboratories observe strict conditions of non-magnetism, ensuring the possibility of absolute standard measurements (national magnetic standards) for all the units in the country, civil or military, which are endowed with equipment based on geomagnetic metrology. These basic conditions have allowed the observatory to become by developing its initial preoccupations a centre of complex geomagnetic research, constantly involved in national and international issues, promoting new themes in our country and bringing significant contributions. During the last two decades, infrastructure and equipment used in monitoring geomagnetic field at European and planetary level have experienced a remarkable development. New registering techniques have allowed a complete to automate of data acquisition, and sampling step and their precision increased by two classes of size. Systems of transmitting these data in real time to world collecting centres have resulted in the possibility of approaching globalize studies, suitable for following some phenomena at planetary scale. At the same time, a significant development in the procedures of processing primary data has been registered, based on standardized programmes. The new stage of this fundamental research, largely applicable in various fields, is also marked by the simultaneous observation of space-time distribution of terrestrial electromagnetic field by means of

  16. Solar wind and geomagnetism: toward a standard classification of geomagnetic activity from 1868 to 2009

    Directory of Open Access Journals (Sweden)

    J. L. Zerbo

    2012-02-01

    Full Text Available We examined solar activity with a large series of geomagnetic data from 1868 to 2009. We have revisited the geomagnetic activity classification scheme of Legrand and Simon (1989 and improve their scheme by lowering the minimum Aa index value for shock and recurrent activity from 40 to 20 nT. This improved scheme allows us to clearly classify about 80% of the geomagnetic activity in this time period instead of only 60% for the previous Legrand and Simon classification.

  17. The sacred, the secular, and the profane

    DEFF Research Database (Denmark)

    Tsinovoi, Alexei

    2017-01-01

    types of power relations, which can provide a basis for critical re-formulation of the concepts of securitisation and desecuritisation. The article illustrates the analytical purchase of these ideal types through an analysis of the politics of Israel’s natural gas discoveries. Due to neoliberal reforms......In security studies, the dichotomy between ‘security’ and ‘regular’ politics has been effectively challenged in recent years, both theoretically and empirically. To address this challenge, the article develops Giorgio Agamben’s concepts of the sacred, the profane and the secular into three ideal...

  18. Secular trends in menarcheal age in India-evidence from the Indian human development survey.

    Directory of Open Access Journals (Sweden)

    Praveen Kumar Pathak

    Full Text Available Evidence from a number of countries in Europe and North America point towards the secular declining trend in menarcheal age with considerable spatial variations over the past two centuries. Similar trends were reported in several developing countries from Asia, Africa and Latin America. However, data corroborating any secular trend in the menarcheal age of the Indian population remained sparse and inadequately verified.We examined secular trends, regional heterogeneity and association of socioeconomic, anthropometric and contextual factors with menarcheal age among ever-married women (15-49 years in India. Using the pseudo cohort data approach, we fit multiple linear regression models to estimate secular trends in menarcheal age of 91394 ever-married women using the Indian Human Development Survey.The mean age at menarche among Indian women was 13.76 years (95 % CI: 13.75, 13.77 in 2005. It declined by three months from 13.83 years (95% CI: 13.81, 13.85 among women born prior to 1955-1964, to nearly 13.62 years (95% CI: 13.58, 13.67 among women born during late 1985-1989. However, these aggregate national figures mask extensive spatial heterogeneity as mean age at menarche varied from 15.0 years in Himachal Pradesh during 1955-1964 (95% CI: 14.89-15.11 to about 12.1 years in Assam (95% CI: 11.63-12.56 during 1985-1989.The regression analysis established a reduction of nearly one month per decade, suggesting a secular decline in age at menarche among Indian women. Notably, the menarcheal age was significantly associated with the area of residence, geographic region, linguistic groups, educational attainment, wealth status, caste and religious affiliations among Indian women.

  19. Change of the radiocarbon natural level in the Earth atmosphere and geomagnetic field

    International Nuclear Information System (INIS)

    Vasil'ev, S.S.; Dergachev, V.A.

    1995-01-01

    Harmonic spectral analysis of change of radiocarbon concentration on the Earth atmosphere during the last 7000 years, including time intervals of both high and low intensity of the Earth magnetic field, was conducted. The effect of geomagnetic field on a harmonic amplitudes and frequencies in variations of radiocarbon concentration, conditioned by solar activity, was shown

  20. Modelling geomagnetically induced currents in midlatitude Central Europe using a thin-sheet approach

    Science.gov (United States)

    Bailey, Rachel L.; Halbedl, Thomas S.; Schattauer, Ingrid; Römer, Alexander; Achleitner, Georg; Beggan, Ciaran D.; Wesztergom, Viktor; Egli, Ramon; Leonhardt, Roman

    2017-06-01

    Geomagnetically induced currents (GICs) in power systems, which can lead to transformer damage over the short and the long term, are a result of space weather events and geomagnetic variations. For a long time, only high-latitude areas were considered to be at risk from these currents, but recent studies show that considerable GICs also appear in midlatitude and equatorial countries. In this paper, we present initial results from a GIC model using a thin-sheet approach with detailed surface and subsurface conductivity models to compute the induced geoelectric field. The results are compared to measurements of direct currents in a transformer neutral and show very good agreement for short-period variations such as geomagnetic storms. Long-period signals such as quiet-day diurnal variations are not represented accurately, and we examine the cause of this misfit. The modelling of GICs from regionally varying geoelectric fields is discussed and shown to be an important factor contributing to overall model accuracy. We demonstrate that the Austrian power grid is susceptible to large GICs in the range of tens of amperes, particularly from strong geomagnetic variations in the east-west direction.

  1. The effect of the August 11, 1999 total solar eclipse on the geomagnetic field

    Czech Academy of Sciences Publication Activity Database

    Střeštík, Jaroslav

    2001-01-01

    Roč. 31, č. 1 (2001), s. 331-334 ISSN 1335-2806. [IAGA Workshop /9./. Hurbanovo, 12.06.2000-18.06.2000] R&D Projects: GA ČR GA205/99/0915 Institutional research plan: CEZ:AV0Z3012916 Keywords : solar eclipse * diurnal variation * geomagnetic field Subject RIV: DE - Earth Magnetism, Geodesy, Geography

  2. Geomagnetism solid Earth and upper atmosphere perspectives

    CERN Document Server

    Basavaiah, Nathani

    2011-01-01

    This volume elaborates several important aspects of solid Earth geomagnetism. It covers all the basics of the subject, including biomagnetism and instrumentation, and offers a number of practical applications with carefully selected examples and illustrations.

  3. A secular technetium–molybdenum generator

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Wagner L., E-mail: wagnerleite@ufmg.br; Campos, Tarcisio P.R., E-mail: tprcampos@pq.cnpq.br

    2015-05-11

    A compact secular molybdenium generator is subject of this paper. This generator represents a nuclear system that comprises a hydrogen-isotopes fusor, moderator, reflector and shield. Deuterium fusion reactions in a tritiated or deuterated target provide the neutron source. A moderation fluid slowdown the neutron energy which increases {sup 98}Mo(n,γ){sup 99}Mo capture reaction rates. Neutron reflection minimizes the neutron escape and the radiation shield encloses the device. The neutron yield calculation along with electromagnetic and nuclear simulations were addressed. Results revealed the accelerator equipotential surfaces ranging from −30 to 150 kV, the ion trajectories and the energy beam profile define a deuteron current of 1 A with energy of 180 keV at the target, the spatial distribution of the neutron flux, and the {sup 99}Mo and {sup 99m}Tc activities in function of transmuter operation time. The kinetics of the {sup 99m}Tc correlated to its precursor activity demonstrates a secular equilibrium providing 2 Ci in a operational time of 150 h. As conclusion, the investigated nuclear and electromagnetic features have demonstrated that such generator shall have a notable potential for feeding the {sup 99m}Tc clinical application.

  4. Analysis of Total Electron Content and Electron Density Profile during Different Geomagnetic Storms

    Science.gov (United States)

    Chapagain, N. P.; Rana, B.; Adhikari, B.

    2017-12-01

    Total Electron content (TEC) and electron density are the key parameters in the mitigation of ionospheric effects on radio communication system. Detail study of the TEC and electron density variations has been carried out during geomagnetic storms, with longitude and latitude, for four different locations: (13˚N -17˚N, 88˚E -98˚E), (30˚N-50˚N, 120˚W -95˚W), (29˚S-26˚S, 167˚W-163˚W,) and (60˚S-45˚S, 120˚W-105˚W) using the Gravity Recovery and Climate Experiment (GRACE) satellite observations. In order to find the geomagnetic activity, the solar wind parameters such as north-south component of inter planetary magnetic field (Bz), plasma drift velocity (Vsw), flow pressure (nPa), AE, Dst and Kp indices were obtained from Operating Mission as Nodes on the Internet (OMNI) web system. The data for geomagnetic indices have been correlated with the TEC and electron density for four different events of geomagnetic storms on 6 April 2008, 27 March 2008, 4 September 2008, and 11 October 2008. The result illustrates that the observed TEC and electron density profile significantly vary with longitudes and latitudes. This study illustrates that the values of TEC and the vertical electron density profile are influenced by the solar wind parameters associated with solar activities. The peak values of electron density and TEC increase as the geomagnetic storms become stronger. Similarly, the electron density profile varies with altitudes, which peaks around the altitude range of about 250- 350 km, depending on the strength of geomagnetic storms. The results clearly show that the peak electron density shifted to higher altitude (from about 250 km to 350 km) as the geomagnetic disturbances becomes stronger.

  5. Magnetotactic bacteria at the geomagnetic equator

    International Nuclear Information System (INIS)

    Frankel, R.B.; Blakemore, R.P.; Araujo, F.F.T. de; Esquivel, D.M.S.; Danon, J.

    1981-01-01

    Magnetotatic bacteria are observed in freshwater and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments. (Author) [pt

  6. Toward a possible next geomagnetic transition?

    OpenAIRE

    A. De Santis; E. Qamili; L. Wu

    2013-01-01

    The geomagnetic field is subject to possible reversals or excursions of polarity during its temporal evolution. Considering that: (a) the typical average time between one reversal and the next (the so-called chron) is around 300 000 yr, (b) the last reversal occurred around 780 000 yr ago, (c) more excursions (rapid changes of polarity) can occur within the same chron and (d) the geomagnetic field dipole is currently decreasing, a possible imminent geomagne...

  7. How the geomagnetic field vector reverses polarity

    Science.gov (United States)

    Prevot, M.; Mankinen, E.A.; Gromme, C.S.; Coe, R.S.

    1985-01-01

    A highly detailed record of both the direction and intensity of the Earth's magnetic field as it reverses has been obtained from a Miocene volcanic sequence. The transitional field is low in intensity and is typically non-axisymmetric. Geomagnetic impulses corresponding to astonishingly high rates of change of the field sometimes occur, suggesting that liquid velocity within the Earth's core increases during geomagnetic reversals. ?? 1985 Nature Publishing Group.

  8. Secular tolerance? : Anti‐Muslim sentiment in Western Europe

    NARCIS (Netherlands)

    Ribberink, E.C.; Achterberg, P.H.J.; Houtman, D.

    2017-01-01

    he literature about secularization proposes two distinct explanations of anti-Muslim sentiment in secularized societies. The first theory understands it in terms of religious competition between Muslims and the remaining minority of orthodox Protestants; the second understands it as resulting from

  9. Post-secular religious practices entering traditional religion

    Directory of Open Access Journals (Sweden)

    Urszula Pękala

    2012-01-01

    Full Text Available Nowadays we can observe complex interactions between the religious and secular spheres. Several different processes take place simultaneously: the traditionally religious elements function in the secular sphere as if they were part of secular culture; elements of the secular sphere build a specific kind of post-secular religiosity; finally, this post-secular religiosity influences traditional religions. This article focuses on the last stage of these changes. The author's purpose is to describe and interpret the practices we can observe. Because of the complexity of this issue, the analyses are limited to examples taken from the Catholic Church in Germany, where this process seems to be as popular as it is paradoxical. Catholicism realises that the post-secular forms of religiosity are very popular and that many people choose them instead of the traditional Church. It could offer them spirituality based on ages of experience. But instead of making its own spiritual tradition competitive on the spiritual market, Catholicism seems to offer Christianised post-secular goods, or its own traditional elements represented in a secularised form. It seems difficult to predict how it will all end. However, we observe an interesting encounter and interaction between an ‘old’ religion and a new religiosity, which will certainly have impact on further presence of the Church in the society.

  10. The Jesuit Imaginary: Higher Education in a Secular Age

    Science.gov (United States)

    Hendrickson, Daniel Scott

    2012-01-01

    The philosopher Charles Taylor argues in "A Secular Age" (2007) that people who live in secular cultures are losing the capacity to experience genuine "fullness." Described by Taylor as a philosophical-anthropological conception of human flourishing that corresponds with existential senses of meaning and purpose, fullness is…

  11. Human Rights Education and the Post Secular Turn

    Science.gov (United States)

    Bowie, Bob

    2012-01-01

    This article questions whether human rights education (HRE) scholarship is responding adequately to the post secular turn in thinking about the place and nature of religion in society. Here the post secular turn is used to describe the discrediting of secularisation theory, the recognition of religion as an enduring and pervasive global cultural…

  12. A synoptic study of geomagnetic storms and related solar phenomena during 1976 through 1978

    International Nuclear Information System (INIS)

    Marubashi, K.

    1979-01-01

    An attempt has been made to identify the causes of geomagnetic storms which occurred during the three year period from 1976 through 1978. Of the 114 storms with D sub(st) = 25 investigated in this paper, 52 storms are found to be caused by corotating streams, 16 storms by solar flares, and 19 storms by compound effects of both corotating streams and flares. The causes of the remaining 27 storms could not be identified. By examining the characteristics of those solar flares which were taken to be responsible for geomagnetic storms, a semiquantitative conclusion has been obtained about the criteria for the flares which can produce magnetic storms. In addition, clear semiannual variation has been found in geomagnetic activity caused by flare-free corotating streams. (author)

  13. The effect of geomagnetic storm on GPS derived total electron content (TEC) at Varanasi, India

    International Nuclear Information System (INIS)

    Kumar, Sanjay; Singh, A K

    2010-01-01

    In this paper we studied the effect of geomagnetic storm on Global Positioning System (GPS) derived total electron content (TEC) at low latitude Varanasi (Geomagnetic lat 14 0 , 55' N, geomagnetic long 154 0 E) during the period of May 2007 to April 2008. During this period 2 storms were found, which were occurred on 20 November 2007 and 9 March 2008. In this study vertical total electron content (VTEC) of single Pseudorandom Noise (PRN) and average of VTEC of same PRN before 10 days of storm, which is called background TEC, were used to see the effect of these storms on the variation of TEC. From this study this is found that during the storm of March 2008 the TEC increases in main phase of storm while in the case of November 2007 storm, TEC decreases during the main phase of storm but increases in the recovery phase (next day) of storm.

  14. Impact of the Lower Atmosphere on the Ionosphere Response to a Geomagnetic Superstorm

    Science.gov (United States)

    Pedatella, N. M.

    2016-12-01

    Numerical simulations in the National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) are performed to elucidate the impacts of lower atmosphere forcing on the ionosphere response to a geomagnetic superstorm. In particular, how the ionosphere variability due to the October 2003 Halloween storm would be different if it occurred in January coincident with a major sudden stratosphere warming (SSW) event is investigated. The TIE-GCM simulations reveal that the E x B vertical drift velocity and total electron content (TEC) respond differently to the geomagnetic disturbance when the lower atmosphere forcing is representative of SSW conditions compared to climatological lower atmosphere forcing conditions. Notably, the storm time variations in the E x B vertical drift velocity differ when the effects of the SSW are considered, and this is in part due to effects of the SSW on the equatorial ionosphere being potentially misinterpreted as being of geomagnetic origin. Differences in the TEC response to the geomagnetic storm can be up to 100% ( 30 TECU) of the storm induced TEC change, and the temporal variability of the TEC during the storm recovery phase is considerably different if SSW effects are considered. The results demonstrate that even during periods of extreme geomagnetic forcing it is important to consider the effects of lower atmosphere forcing on the ionosphere variability.

  15. The Coming of Secular Buddhism: a Synoptic View

    Directory of Open Access Journals (Sweden)

    Winton Higgins

    2015-02-01

    Full Text Available Secular Buddhism is coalescing today in response to two main factors. First, it rejects the incoherence of Buddhist modernism, a protean formation that accommodates elements as far afield as ancestral Buddhism and psychotherapies claiming the Buddhist brand. Second, it absorbs the cultural influence of modern secularity in the West. Historically understood, secularity has constituted a centuries-long religious development, not a victory of "science" over "religion." Today's secularity marks a further stage in the cultural decline of "enchanted" truth-claims and the intellectual eclipse of metaphysics, especially under the aegis of phenomenology. In Buddhism as in Christianity, secularity brings forth a new humanistic approach to ethical-spiritual life and creative this-worldly practices.

  16. SECULAR CHAOS AND THE PRODUCTION OF HOT JUPITERS

    International Nuclear Information System (INIS)

    Wu Yanqin; Lithwick, Yoram

    2011-01-01

    In a planetary system with two or more well-spaced, eccentric, inclined planets, secular interactions may lead to chaos. The innermost planet may gradually become very eccentric and/or inclined as a result of the secular degrees of freedom drifting toward equipartition of angular momentum deficit. Secular chaos is known to be responsible for the eventual destabilization of Mercury in our own solar system. Here we focus on systems with three giant planets. We characterize the secular chaos and demonstrate the criterion for it to occur, but leave a detailed understanding of secular chaos to a companion paper. After an extended period of eccentricity diffusion, the inner planet's pericenter can approach the star to within a few stellar radii. Strong tidal interactions and ensuing tidal dissipation extract orbital energy from the planet and pull it inward, creating a hot Jupiter. In contrast to other proposed channels for the production of hot Jupiters, such a scenario (which we term 'secular migration') explains a range of observations: the pile-up of hot Jupiters at 3 day orbital periods, the fact that hot Jupiters are in general less massive than other radial velocity planets, that they may have misaligned inclinations with respect to stellar spin, and that they have few easily detectable companions (but may have giant companions in distant orbits). Secular migration can also explain close-in planets as low in mass as Neptune; and an aborted secular migration can explain the 'warm Jupiters' at intermediate distances. In addition, the frequency of hot Jupiters formed via secular migration increases with stellar age. We further suggest that secular chaos may be responsible for the observed eccentricities of giant planets at larger distances and that these planets could exhibit significant spin-orbit misalignment.

  17. Secularization and de-secularization processes under the light of Max Weber’s rationalization sociology

    Directory of Open Access Journals (Sweden)

    Eduardo Weisz

    2017-10-01

    Full Text Available This article starts posing a number of problems with which the classical understanding of the end of religions in Modernity has been confronted. This allows for a framework from which Max Weber’s theory of secularization can be addressed. From 1904 onwards, this author was engaged in the understanding of the historical-universal process of rationalization, and it is in this analysis where his prospective of secularization has to be looked for. His sociology of religion is therefore deconstructed from this point of view, so as to grasp why he understood that religions were displaced in the constitution of modern life conducts. After this analysis, the article poses the importance of this author’s legacy for the understanding of different issues concerning the present process of rebirth of religions.

  18. Investigation of the Effects of Solar and Geomagnetic Changes on the Total Electron Content: Mid-Latitude Region

    Science.gov (United States)

    Ulukavak, Mustafa; Yalcinkaya, Mualla

    2016-04-01

    The Global Positioning System (GPS) is used as an important tool for ionosphere monitoring and obtaining the Total Electron Content (TEC). GPS satellites, positioned in the Earth's orbit, are used as sensors to investigate the space weather conditions. In this study, solar and geomagnetic activity variations were investigated between the dates 1 March-30 June 2015 for the mid-latitude region. GPS-TEC variations were calculated for each selected International GNSS Service (IGS) station in Europe. GNSS data was obtained from Crustal Dynamics Data and Information System (CDDIS) archive. Solar and geomagnetic activity indices (Kp, F10.7 ve Dst) were obtained from the Oceanic and Atmospheric Administration (NOAA), the Canadian Space Weather Forecast Centre (CSWFC) and Data Analysis Center for geomagnetism and Space Magnetism Graduate School of Science, Kyoto University (WDC) archives. GPS-TEC variations were determined for the quiet periods of the solar and geomagnetic activities. GPS-TEC changes were then compared with respect to the quiet periods of the solar and geomagnetic activities. Global Ionosphere Maps (GIM) IONEX files, obtained from the IGS analysis center, was used to check the robustness of the GPS-TEC variations. The investigations revealed that it is possible to use the GPS-TEC data for monitoring the ionospheric disturbances.

  19. Defining and Distinguishing Secular and Religious Terrorism

    Directory of Open Access Journals (Sweden)

    Heather S. Gregg

    2014-04-01

    Full Text Available Religious terrorism is typically characterised as acts of unrestrained, irrational and indiscriminant violence, thus offering few if any policy options for counterterrorism measures. This assumption about religious terrorism stems from two challenges in the literature: disproportionate attention to apocalyptic terrorism, and a lack of distinction between religious terrorism and its secular counterpart. This article, therefore, aims to do four things: define and differentiate religiously motivated terrorism from traditional terrorism; investigate three goals of religious terrorism (fomenting the apocalypse, creating a religious government, and establishing a religiously pure state; consider the role of leadership and target selection of religious terrorists; and, finally, suggest a range of counterterrorism strategies based on these observations.

  20. Access to abortion and secular liberties

    Directory of Open Access Journals (Sweden)

    Roberto Arriada Lorea

    2007-01-01

    Full Text Available In Brazil, facing an issue like abortion requires a secular perspective since the freedom of conscience assured by the Federal Constitution places upon the State the need to regard not only different viewpoints of different religions, but more specifically assure the right to diversity existing within a same religion, as well as the right to exercise different views from those of the hierarchy of his/her own religion. As such, there is no legal barrier for the decriminalization of abortion in the country. It is up to legislators to reform the present law and decriminalize abortion, assuming the commitments Brazil has assumed with international human-rights organizations, thus assuring the efficacy of civil liberties.

  1. Tendencia secular da amamentacao no Brasil

    Directory of Open Access Journals (Sweden)

    Sonia Isoyama Venancio

    2013-12-01

    Full Text Available Com o objetivo de documentar a tendência secular da amamentação no Brasil, foram reanalisadas as bases de dados de sete pesquisas nacionais realizadas de 1975 a 2008. Para obter dados comparáveis entre os diferentes inquéritos, foram analisadas as mesmas faixas etárias e indicadores, e utilizadas as mesmas técnicas estatísticas. A duração mediana da amamentação aumentou de 2,5 para 11,3 meses e a prevalência da amamentação exclusiva em menores de seis meses passou de 3,1% para 41,0% no período. Os resultados apontam importantes desafios no sentido de acelerar o ritmo de crescimento dessa prática no País, rumo às recomendações internacionais.

  2. [Adolphe Quetelet and biopolitics as secularized theology].

    Science.gov (United States)

    Pich, Santiago

    2013-01-01

    The article recaptures the work of an author who has been forgotten by the contemporary social sciences, that is, the Belgium polymath Adolphe Quetelet. Focusing on his main work, Sur l'homme et le développement de ses facultés, ou Essai de physique sociale, the study underscores how the secularization of theological principles within the realm of science was important to the construction of Quetelet's work. His dual engagement in science and politics is pertinent here, as he was the main nineteenth-century force behind the incorporation of statistics as a science essential to the State's ability to govern its people. He also played a relevant role in the realization of the hegemonic political project of modernity, biopolitics, and its influence in the field of biomedicine in the nineteenth and twentieth centuries.

  3. The Swarm Initial Field Model for the 2014 Geomagnetic Field

    Science.gov (United States)

    Olsen, Nils; Hulot, Gauthier; Lesur, Vincent; Finlay, Christopher C.; Beggan, Ciaran; Chulliat, Arnaud; Sabaka, Terence J.; Floberghagen, Rune; Friis-Christensen, Eigil; Haagmans, Roger

    2015-01-01

    Data from the first year of ESA's Swarm constellation mission are used to derive the Swarm Initial Field Model (SIFM), a new model of the Earth's magnetic field and its time variation. In addition to the conventional magnetic field observations provided by each of the three Swarm satellites, explicit advantage is taken of the constellation aspect by including east-west magnetic intensity gradient information from the lower satellite pair. Along-track differences in magnetic intensity provide further information concerning the north-south gradient. The SIFM static field shows excellent agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for east-west intensity differences between the lower satellite pair being only 0.12 nT.

  4. Geometric effects of ICMEs on geomagnetic storms

    Science.gov (United States)

    Cho, KyungSuk; Lee, Jae-Ok

    2017-04-01

    It has been known that the geomagnetic storm is occurred by the interaction between the Interplanetary Coronal Mass Ejection (ICME) and the Earth's magnetosphere; especially, the southward Bz component of ICME is thought as the main trigger. In this study, we investigate the relationship between Dst index and solar wind conditions; which are the southward Bz, electric field (VBz), and time integral of electric field as well as ICME parameters derived from toroidal fitting model in order to find what is main factor to the geomagnetic storm. We also inspect locations of Earth in ICMEs to understand the geometric effects of the Interplanetary Flux Ropes (IFRs) on the geomagnetic storms. Among 59 CDAW ICME lists, we select 30 IFR events that are available by the toroidal fitting model and classify them into two sub-groups: geomagnetic storms associated with the Magnetic Clouds (MCs) and the compression regions ahead of the MCs (sheath). The main results are as follows: (1) The time integral of electric field has a higher correlation coefficient (cc) with Dst index than the other parameters: cc=0.85 for 25 MC events and cc=0.99 for 5 sheath events. (2) The sheath associated intense storms (Dst ≤-100nT) having usually occur at flank regions of ICMEs while the MC associated intense storms occur regardless of the locations of the Earth in ICMEs. The strength of a geomagnetic storm strongly depends on electric field of IFR and durations of the IFR passages through the Earth.

  5. Secular instability of axisymmetric rotating stars to gravitational radiation reaction

    International Nuclear Information System (INIS)

    Managan, R.A.

    1985-01-01

    A generalization of the Eulerian variational principle derived by Ipser and Managan, for nonaxisymmetric neutral modes of axisymmetric fluid configurations, is developed. The principle provides a variational basis for calculating the frequencies of nonaxisymmetric normal modes proportional to e/sup i/(sigmat + mphi). A modified form of this principle, valid for sigma near 0, is also developed. The latter principle is used to locate the points where the frequency of a nonaxisymmetric normal mode of an axisymmetric rotating fluid configuration passes through zero. lt is at these points that the configuration becomes secularly unstable to gravitational radiation reaction (GRR). This is demonstrated directly by including the GRR potential and showing that the imaginary part of sigma passes through zero and becomes negative at these points. The imaginary part of the frequency is used to estimate the e-folding time of the mode. This variational principle is applied to sequences of rotating polytropes. The sequences are constructed using four rotation laws at each value of the polytropic index n = 0.5, 1.0, 1.5, 2.0, and 3.0. The values of (T/W)/sub m/, the ratio of the rotational kinetic energy to the magnitude of the gravitational potential energy at the onset of instability, and timescales for the modes with m = 2, 3, and 4 are estimated for each sequence. The value of (T/W) 2 is largely independent of the equation of state and rotation law. For m > 2, (T/W)/sub m/ decreases as the equation of state becomes softer, i.e., as the polytropic index n increases, and increases as the amount of differential rotation increases. The most striking result of this behavior occurs for uniform rotation

  6. Geomagnetic response to sudden expansions of the magnetosphere

    International Nuclear Information System (INIS)

    Araki, Tohru; Nagano, Hiroshi

    1988-01-01

    The geomagnetic response to five successive sudden expansions of the magnetosphere was examined by the use of magnetic data observed on the ground and by satellites. At the geosynchronous orbit between 0800 and 1100 LT the magnetic field component parallel to Earth's rotation axis decreased successively. The amplitude and the fall time of each decrease were 20-30 nT and 2.5-3.5 min, respectively. The decrease was propagated about 10 min later to the distance of about 31 R E from Earth in the antisunward direction, indicating propagation speed of about 300 km/s. The H component of ground magnetograms from low-latitude stations showed decreases with waveform similar to that at the geosynchronous orbit, but each decrease at the dayside equator was greatly enhanced and preceded by a short small positive impulse. Each of the corresponding geomagnetic variations at high latitude stations consisted of two successive sharp pulses of opposite sense with 2-3 min duration. The dominant component and the sense of these high-latitude pulses were highly dependent upon local time and latitude. The distribution of equivalent ionospheric current arrows for each high-latitude pulse showed clear twin vortices centered at 70-76 degree geomagnetic latitude in the dayside and was approximately symmetric with respect to the noon meridian. The current direction of the vortices was reversed from the first pulse to the second. it suggests successive appearance of a dawn-to-dusk and then a dusk-to-dawn electric field, both of which were transmitted from the magnetosphere to the polar ionosphere. The effect of ionospheric currents due to these polar electric fields was superposed on the simple magnetic decrease produced by an expansion of the whole magnetosphere and produced the complex waveform distribution on the ground

  7. K-type geomagnetic index nowcast with data quality control

    Directory of Open Access Journals (Sweden)

    René Warnant

    2011-07-01

    Full Text Available

    A nowcast system for operational estimation of a proxy K-type geomagnetic index is presented. The system is based on a fully automated computer procedure for real-time digital magnetogram data acquisition that includes screening of the dataset and removal of the outliers, estimation of the solar regular variation (SR of the geomagnetic field, calculation of the index, and issuing of an alert if storm-level activity is indicated. This is a time-controlled (rather than event-driven system that delivers the regular output of: the index value, the estimated quality flag, and eventually, an alert. The novel features provided are first, the strict control of the data input and processing, and second, the increased frequency of production of the index (every 1 h. Such quality control and increased time resolution have been found to be of crucial importance for various applications, e.g. ionospheric monitoring, that are of particular interest to us and to users of our service. The nowcast system operability, accuracy and precision have been tested with instantaneous measurements from recent years. A statistical comparison between the nowcast and the definitive index values shows that the average root-mean-square error is smaller than 1 KU. The system is now operational at the site of the Geophysical Centre of the Royal Meteorological Institute in Dourbes (50.1ºN, 4.6ºE, and it is being used for alerting users when geomagnetic storms take place.

  8. Effect of geomagnetic storms on the daytime low-latitude thermospheric wave dynamics

    Science.gov (United States)

    Karan, Deepak K.; Pallamraju, Duggirala

    2018-05-01

    The equatorial- and low-latitude thermospheric dynamics is affected by both equatorial electrodynamics and neutral wave dynamics, the relative variation of which is dependent on the prevalent background conditions, which in turn has a seasonal dependence. Depending on the ambient thermospheric conditions, varying effects of the geomagnetic disturbances on the equatorial- and low-latitude thermosphere are observed. To investigate the effect of these disturbances on the equatorial- and low-latitude neutral wave dynamics, daytime airglow emission intensities at OI 557.7 nm, OI 630.0 nm, and OI 777.4 nm are used. These emissions from over a large field-of-view (FOV∼1000) have been obtained using a high resolution slit spectrograph, MISE (Multiwavelength Imaging Spectrograph using Echelle grating), from a low-latitude location, Hyderabad (17.50N, 78.40E; 8.90N MLAT), in India. Variations of the dayglow emission intensities are investigated during three geomagnetic disturbance events that occurred in different seasons. It is seen that the neutral dayglow emission intensities at all the three wavelengths showed different type of variations with the disturbance storm time (Dst) index in different seasons. Even though the dayglow emission intensities over low-latitude regions are sensitive to the variation in the equatorial electric fields, during periods of geomagnetic disturbances, especially in solstices, these are dependent on thermospheric O/N2 values. This shows the dominance of neutral dynamics over electrodynamics in the low-latitude upper atmosphere during geomagnetic disturbances. Further, spectral analyses have been carried out to obtain the zonal scale sizes in the gravity wave regime and their diurnal distributions are compared for geomagnetic quiet and disturbed days. Broadly, the zonal scales seem to be breaking into various scale sizes on days of geomagnetic disturbances when compared to those on quiet days. This contrast in the diurnal distribution of the

  9. Social Boundaries and Secularism in the Lebanese Left

    DEFF Research Database (Denmark)

    Haugbølle, Sune

    2013-01-01

    This article explores the social meaning of boundaries in Lebanon through debates about secularism in and around the Lebanese Left. The aim is to elucidate the political and social meaning of ‘Left’ in a Lebanese context, and the positioning of liminal political subjectivity in a system organized...... along sectarian boundaries. Based on readings of debates about secularism in 1975 and 1976, the article proposes that the Left has since that year been forced to embrace secularism as its primary ideological marker. This experience in turn has become constitutive for what it means to be a leftist...

  10. Coronal mass ejections and large geomagnetic storms

    International Nuclear Information System (INIS)

    Gosling, J.T.; Bame, S.J.; McComas, D.J.; Phillips, J.L.

    1990-01-01

    Previous work indicates that coronal mass ejection (CME) events in the solar wind at 1 AU can be identified by the presence of a flux of counterstreaming solar wind halo electrons (above about 80 eV). Using this technique to identify CMEs in 1 AU plasma data, the authors find that most large geomagnetic storms during the interval surrounding the last solar maximum (Aug. 1978-Oct. 1982) were associated with Earth-passage of interplanetary disturbances in which the Earth encountered both a shock and the CME driving the shock. However, only about one CME in six encountered by Earth was effective in causing a large geomagnetic storm. Slow CMEs which did not interact strongly with the ambient solar wind ahead were particularly ineffective in a geomagnetic sense

  11. Recent Activities Of The World Data Centre For Geomagnetism (Edinburgh)

    OpenAIRE

    Reay, Sarah; Humphries, Tom; Macmillan, Susan; Flower, Simon; Stevenson, Peter; Clarke, Ellen

    2015-01-01

    For almost 50 years the World Data Centre for Geomagnetism (Edinburgh) has been a custodian of geomagnetic data. In particular, over recent years the scope of the data holdings has been increased, quality control measures introduced and better interfaces to make the data more accessible to users are being developed. The WDC hold geomagnetic time-series data from around 280 observatories worldwide at a number of time resolutions along with various magnetic survey, model, and geomagnetic ac...

  12. Lower thermosphere (80-100 km) dynamics response to solar and geomagnetic activity: Overview

    International Nuclear Information System (INIS)

    Kazimirovsky, E.S.

    1989-01-01

    The variations of solar and geomagnetic activity may affect the thermosphere circulation via plasma heating and electric fields, especially at high latitudes. The possibility exists that the energy involved in auroral and magnetic storms can produce significant changes of mesosphere and lower thermosphere wind systems. A study of global radar measurements of winds at 80 to 100 km region revealed the short term effects (correlation between wind field and geomagnetic storms) and long term variations over a solar cycle. It seems likely that the correlation results from a modification of planetary waves and tides propagated from below, thus altering the dynamical regime of the thermosphere. Sometimes the long term behavior points rather to a climatic variation with the internal atmospheric cause than to a direct solar control

  13. Space weather and dangerous phenomena on the Earth: principles of great geomagnetic storms forcasting by online cosmic ray data

    Directory of Open Access Journals (Sweden)

    L. I. Dorman

    2005-11-01

    Full Text Available According to NOAA space weather scales, geomagnetic storms of scales G5 (3-h index of geomagnetic activity Kp=9, G4 (Kp=8 and G3 (Kp=7 are dangerous for satellites, aircrafts, and even for technology on the ground (influence on power systems, on spacecraft operations, on HF radio-communications and others. We show on the basis of statistical data, that these geomagnetic storms, mostly accompanied by cosmic ray (CR Forbush-decreases, are also dangerous for people's health on spacecraft and on the ground (increasing the rate of myocardial infarctions, brain strokes and car accident road traumas. To prevent these serious damages it is very important to forecast dangerous geomagnetic storms. Here we consider the principles of using CR measurements for this aim: to forecast at least 10-15h before the sudden commencement of great geomagnetic storms accompanied by Forbush-decreases, by using neutron monitor muon telescope worldwide network online hourly data. We show that for this forecast one may use the following features of CR intensity variations connected with geomagnetic storms accompanied by Forbush-decreases: 1 CR pre-increase, 2 CR pre-decrease, 3 CR fluctuations, 4 change in the 3-D CR anisotropy.

  14. Improvements in geomagnetic observatory data quality

    DEFF Research Database (Denmark)

    Reda, Jan; Fouassier, Danielle; Isac, Anca

    2011-01-01

    between observatories and the establishment of observatory networks has harmonized standards and practices across the world; improving the quality of the data product available to the user. Nonetheless, operating a highquality geomagnetic observatory is non-trivial. This article gives a record...... of the current state of observatory instrumentation and methods, citing some of the general problems in the complex operation of geomagnetic observatories. It further gives an overview of recent improvements of observatory data quality based on presentation during 11th IAGA Assembly at Sopron and INTERMAGNET...

  15. A simple statistical model for geomagnetic reversals

    Science.gov (United States)

    Constable, Catherine

    1990-01-01

    The diversity of paleomagnetic records of geomagnetic reversals now available indicate that the field configuration during transitions cannot be adequately described by simple zonal or standing field models. A new model described here is based on statistical properties inferred from the present field and is capable of simulating field transitions like those observed. Some insight is obtained into what one can hope to learn from paleomagnetic records. In particular, it is crucial that the effects of smoothing in the remanence acquisition process be separated from true geomagnetic field behavior. This might enable us to determine the time constants associated with the dominant field configuration during a reversal.

  16. Geomagnetic Storm Impact On GPS Code Positioning

    Science.gov (United States)

    Uray, Fırat; Varlık, Abdullah; Kalaycı, İbrahim; Öǧütcü, Sermet

    2017-04-01

    This paper deals with the geomagnetic storm impact on GPS code processing with using GIPSY/OASIS research software. 12 IGS stations in mid-latitude were chosen to conduct the experiment. These IGS stations were classified as non-cross correlation receiver reporting P1 and P2 (NONCC-P1P2), non-cross correlation receiver reporting C1 and P2 (NONCC-C1P2) and cross-correlation (CC-C1P2) receiver. In order to keep the code processing consistency between the classified receivers, only P2 code observations from the GPS satellites were processed. Four extreme geomagnetic storms October 2003, day of the year (DOY), 29, 30 Halloween Storm, November 2003, DOY 20, November 2004, DOY 08 and four geomagnetic quiet days in 2005 (DOY 92, 98, 99, 100) were chosen for this study. 24-hour rinex data of the IGS stations were processed epoch-by-epoch basis. In this way, receiver clock and Earth Centered Earth Fixed (ECEF) Cartesian Coordinates were solved for a per-epoch basis for each day. IGS combined broadcast ephemeris file (brdc) were used to partly compensate the ionospheric effect on the P2 code observations. There is no tropospheric model was used for the processing. Jet Propulsion Laboratory Application Technology Satellites (JPL ATS) computed coordinates of the stations were taken as true coordinates. The differences of the computed ECEF coordinates and assumed true coordinates were resolved to topocentric coordinates (north, east, up). Root mean square (RMS) errors for each component were calculated for each day. The results show that two-dimensional and vertical accuracy decreases significantly during the geomagnetic storm days comparing with the geomagnetic quiet days. It is observed that vertical accuracy is much more affected than the horizontal accuracy by geomagnetic storm. Up to 50 meters error in vertical component has been observed in geomagnetic storm day. It is also observed that performance of Klobuchar ionospheric correction parameters during geomagnetic storm

  17. Geomagnetic spikes on the core-mantle boundary

    Science.gov (United States)

    Davies, C. J.; Constable, C.

    2017-12-01

    Extreme variations of Earth's magnetic field occurred in the Levantine region around 1000 BC, where the field intensity rose and fell by a factor of 2-3 over a short time and confined spatial region. There is presently no coherent link between this intensity spike and the generating processes in Earth's liquid core. Here we test the attribution of a surface spike to a flux patch visible on the core-mantle boundary (CMB), calculating geometric and energetic bounds on resulting surface geomagnetic features. We show that the Levantine intensity high must span at least 60 degrees in longitude. Models providing the best trade-off between matching surface spike intensity, minimizing L1 and L2 misfit to the available data and satisfying core energy constraints produce CMB spikes 8-22 degrees wide with peak values of O(100) mT. We propose that the Levantine spike grew in place before migrating northward and westward, contributing to the growth of the axial dipole field seen in Holocene field models. Estimates of Ohmic dissipation suggest that diffusive processes, which are often neglected, likely govern the ultimate decay of geomagnetic spikes. Using these results, we search for the presence of spike-like features in geodynamo simulations.

  18. Sex, secularism and religious influence in US politics.

    Science.gov (United States)

    Bernstein, Elizabeth; Jakobsen, Janet R

    2010-01-01

    Through an analysis of alliances between secular and religious actors in US politics and a specific case study on anti-trafficking policy, we show that the intertwining of religion and politics in the US comes from two sources: 1) the secular political and cultural institutions of American public life that have developed historically out of Protestantism, and which predominantly operate by presuming Protestant norms and values; and 2) the direct influence on US politics of religious groups and organisations, particularly in the past quarter-century of lobby groups and political action committees identified with conservative evangelical Christianity. The sources of policies that promote gender and sexual inequality in the US are both secular and religious and we conclude that it is inaccurate to assume that religious influence in politics is necessarily conservative or that more secular politics will necessarily be more progressive than the religious varieties.

  19. Secular instabilities of Keplerian stellar discs

    Science.gov (United States)

    Kaur, Karamveer; Kazandjian, Mher V.; Sridhar, S.; Touma, Jihad R.

    2018-05-01

    We present idealized models of a razor-thin, axisymmetric, Keplerian stellar disc around a massive black hole, and study non-axisymmetric secular instabilities in the absence of either counter-rotation or loss cones. These discs are prograde mono-energetic waterbags, whose phase-space distribution functions are constant for orbits within a range of eccentricities (e) and zero outside this range. The linear normal modes of waterbags are composed of sinusoidal disturbances of the edges of distribution function in phase space. Waterbags that include circular orbits (polarcaps) have one stable linear normal mode for each azimuthal wavenumber m. The m = 1 mode always has positive pattern speed and, for polarcaps consisting of orbits with e normal modes for each m, which can be stable or unstable. We derive analytical expressions for the instability condition, pattern speeds, growth rates, and normal mode structure. Narrow bands are unstable to modes with a wide range in m. Numerical simulations confirm linear theory and follow the non-linear evolution of instabilities. Long-time integration suggests that instabilities of different m grow, interact non-linearly, and relax collisionlessly to a coarse-grained equilibrium with a wide range of eccentricities.

  20. Polar cap geomagnetic field responses to solar sector changes

    International Nuclear Information System (INIS)

    Campbell, W.H.

    1976-01-01

    I made a computerized analysis of digitized magnetograms from Alert, Thule, Resolute Bay, Mould Bay, and Godhavn for 1965 and from Thule and Vostok for 1967 to determine the characteristic features of the day-to-day geomagnetic field variations related to the interplanetary solar sector field direction. Higher invariant latitude stations showed the sector effects most clearly. A sector-related phase shift in the characteristic diurnal variation of the field occurred principally for the dayside vertical geomagnetic component. The amplitude of this diurnal variation was related to Ap and could not be used to identify the sector direction. The quiet nighttime level of field Z component rose and fell on days when the interplanetary magnetic field was directed toward or away from the sun, respectively. When a station's base level field was determined from quiet magnetospheric conditions by using days with low values of Dst and AE indices, the mean field level of the Z component for the whole day increased or decreased (often over 100 γ) from this level as the solar sector direction was toward or away, respectively. With respect to the earth's main field direction the souther polar station field level changes were opposite those at the northern stations. This level shift corresponded with the two solar field directions during the summer months at polar stations for about 70% of the days in 1965 and 88% of the days in 1967. In 1967 the standoff locations of the magnetopause and magnetoshock boundaries were abotu 1 R/sub E/ more distant from the earth for the average toward sector days than for the away sector days

  1. GDS (Geomagnetic Depth Sounding in Italy: applications and perspectives

    Directory of Open Access Journals (Sweden)

    M. Gambetta

    1998-06-01

    Full Text Available The analysis of geomagnetic field variations is a useful tool to detect electrical conductivity contrasts within the Earth. Lateral resolution of outlined patterns depends on the array dimensions and density of measurement sites over the investigated area. The inspection depth is constrained by the period of geomagnetic variations considered in data processing. Regions with significant geological features such as boundaries of continental plates, marginal areas of contact between tectonic units or other geodynamical processes, are of primary interest for the application of the MagnetoVariational (MV method. In the last ten years, in the frame of the ElectroMagnetic (EM sounding techniques in applied geophysics, this method has been applied in Italy by researchers of the Istituto Nazionale di Geofisica, Rome, the Dipartimento di Scienze della Terra, Universitá di Genova and the Czech Science Academy of Prague. The Ivrea body in the Northwestern Alps and their junction with the Apennine chain, the micro-plate of the Sardinian-Corsican system and, recently, the central part of the peninsula along Tyrrhenian-Adriatic lithospheric transects were investigated. Studies in time and frequency-domain used in the first investigations, have been followed by more refined analysis involving tests on the induced EM field dimension, computations of single site Transfer Functions (TFs through Parkinson arrows' and Fourier maps in the Hypothetical Event technique (HE. It was possible to describe the electrical conductivity distribution in the inner part of the SW Alpine arc and to confirm the presence of lithospheric and asthenospheric anomalies obtained by other geophysical methods. For the Sardinia-Corsica system, 2D and 3D inversion models highlighted the existence of two major conducting bodies, one north of Corsica, and the other south of Sardinia. In Central Italy, the regional electrical conductivity distribution pointed out a deep conductive structure

  2. Geomagnetic activity and the North Atlantic Oscillation

    Czech Academy of Sciences Publication Activity Database

    Bucha, Václav

    2014-01-01

    Roč. 58, č. 3 (2014), s. 461-472 ISSN 0039-3169 Institutional support: RVO:67985530 Keywords : geomagnetic activity * solar wind * polar vortex intensification * downward winds Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.806, year: 2014

  3. Geomagnetic activity and the global temperature

    Czech Academy of Sciences Publication Activity Database

    Bucha, Václav

    2009-01-01

    Roč. 53, č. 4 (2009), s. 571-573 ISSN 0039-3169 Institutional research plan: CEZ:AV0Z30120515 Keywords : global warming * Southern Oscillation * geomagnetic storms Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.000, year: 2009

  4. Some aspects of geomagnetically conjugate phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Rycroft, M.J.

    1987-12-01

    Both charged particles and waves convey information about the thermosphere, ionosphere and magnetosphere from the Northern to the Southern Hemisphere and vice versa, along geomagnetic flux tubes.The interhemispheric travel time of electrons or ions, being dependent upon L-value , pitch angle and energy (which may lie between less than or equal to 1 eV and greater than or equal to 1 MeV) may be many hours, ranging down to less than or equal to 1 s. However, the one-hop propagation time for magnetohydrodynamic or whistler mode waves generally lies between 10/sup 2/s and 1 s. Such times, therefore, give the time scales of transient phenomena that are geomagnetically conjugate and of changes in steady-state plasma processes occurring in geomagnetically conjugate regions. Contrasting examples are presented of conjugate physical phenomena, obtained using satellite, rocket, aircraft and ground-based observations; the latter capitalise upon the rather rare disposition of land - rather than ocean - at each end of a geophysically interesting flux tube. Particular attention is paid to the interactions between whistler mode waves and energetic electrons. Geomagnetic, radio, optical and plasma observations, taken together with model computations, provide a wealth of knowledge on conjugate phenomena and their dependence on conditions in the solar wind, substorms, L-value, etc... Finally, some suggestions are made for future lines of research.

  5. On the problem of secular variability in the stellar initial mass function

    International Nuclear Information System (INIS)

    Meusinger, H.

    1987-01-01

    The hypothesis of secular variations in the stellar initial mass function (IMF) is studied. It is found that neither the present-day mass function of the nearby main sequence field stars nor the velocity distribution of these stars are contradictory with this hypothesis. The luminosity functions of unbiased kinematically defined age-groups of the nearby stars also provide no strong constraints. Simple evoluion models with time-dependent IMF and star formation rate enable to fit the data of blue irregular galaxies. Some problems with an universal IMF are pointed out. (author)

  6. Applying inversion techniques to derive source currents and geoelectric fields for geomagnetically induced current calculations

    Directory of Open Access Journals (Sweden)

    J. S. de Villiers

    2014-10-01

    Full Text Available This research focuses on the inversion of geomagnetic variation field measurement to obtain source currents in the ionosphere. During a geomagnetic disturbance, the ionospheric currents create magnetic field variations that induce geoelectric fields, which drive geomagnetically induced currents (GIC in power systems. These GIC may disturb the operation of power systems and cause damage to grounded power transformers. The geoelectric fields at any location of interest can be determined from the source currents in the ionosphere through a solution of the forward problem. Line currents running east–west along given surface position are postulated to exist at a certain height above the Earth's surface. This physical arrangement results in the fields on the ground having the magnetic north and down components, and the electric east component. Ionospheric currents are modelled by inverting Fourier integrals (over the wavenumber of elementary geomagnetic fields using the Levenberg–Marquardt technique. The output parameters of the inversion model are the current strength, height and surface position of the ionospheric current system. A ground conductivity structure with five layers from Quebec, Canada, based on the Layered-Earth model is used to obtain the complex skin depth at a given angular frequency. This paper presents preliminary and inversion results based on these structures and simulated geomagnetic fields. The results show some interesting features in the frequency domain. Model parameters obtained through inversion are within 2% of simulated values. This technique has applications for modelling the currents of electrojets at the equator and auroral regions, as well as currents in the magnetosphere.

  7. Secular changes in Earth's shape and surface mass loading derived from combinations of reprocessed global GPS networks

    Science.gov (United States)

    Booker, David; Clarke, Peter J.; Lavallée, David A.

    2014-09-01

    The changing distribution of surface mass (oceans, atmospheric pressure, continental water storage, groundwater, lakes, snow and ice) causes detectable changes in the shape of the solid Earth, on time scales ranging from hours to millennia. Transient changes in the Earth's shape can, regardless of cause, be readily separated from steady secular variation in surface mass loading, but other secular changes due to plate tectonics and glacial isostatic adjustment (GIA) cannot. We estimate secular station velocities from almost 11 years of high quality combined GPS position solutions (GPS weeks 1,000-1,570) submitted as part of the first international global navigation satellite system service reprocessing campaign. Individual station velocities are estimated as a linear fit, paying careful attention to outliers and offsets. We remove a suite of a priori GIA models, each with an associated set of plate tectonic Euler vectors estimated by us; the latter are shown to be insensitive to the a priori GIA model. From the coordinate time series residuals after removing the GIA models and corresponding plate tectonic velocities, we use mass-conserving continental basis functions to estimate surface mass loading including the secular term. The different GIA models lead to significant differences in the estimates of loading in selected regions. Although our loading estimates are broadly comparable with independent estimates from other satellite missions, their range highlights the need for better, more robust GIA models that incorporate 3D Earth structure and accurately represent 3D surface displacements.

  8. Feminist Practice and Solidarity in Secular Societies : Case Studies on Feminists Crossing Religious–Secular Divides in Politics and Practice in Antwerp, Belgium

    NARCIS (Netherlands)

    van den Brandt, H.P.

    2015-01-01

    In west European countries, public debates on migration, integration, and diversity are informed by particular understandings of secularism and the secular society. In our increasingly diverse societies, so the story goes, it is needed to implement a certain type of secularism and/or support

  9. Galaxy Zoo: Observing secular evolution through bars

    International Nuclear Information System (INIS)

    Cheung, Edmond; Faber, S. M.; Koo, David C.; Athanassoula, E.; Bosma, A.; Masters, Karen L.; Nichol, Robert C.; Melvin, Thomas; Bell, Eric F.; Lintott, Chris; Schawinski, Kevin; Skibba, Ramin A.; Willett, Kyle W.

    2013-01-01

    In this paper, we use the Galaxy Zoo 2 data set to study the behavior of bars in disk galaxies as a function of specific star formation rate (SSFR) and bulge prominence. Our sample consists of 13,295 disk galaxies, with an overall (strong) bar fraction of 23.6% ± 0.4%, of which 1154 barred galaxies also have bar length (BL) measurements. These samples are the largest ever used to study the role of bars in galaxy evolution. We find that the likelihood of a galaxy hosting a bar is anticorrelated with SSFR, regardless of stellar mass or bulge prominence. We find that the trends of bar likelihood and BL with bulge prominence are bimodal with SSFR. We interpret these observations using state-of-the-art simulations of bar evolution that include live halos and the effects of gas and star formation. We suggest our observed trends of bar likelihood with SSFR are driven by the gas fraction of the disks, a factor demonstrated to significantly retard both bar formation and evolution in models. We interpret the bimodal relationship between bulge prominence and bar properties as being due to the complicated effects of classical bulges and central mass concentrations on bar evolution and also to the growth of disky pseudobulges by bar evolution. These results represent empirical evidence for secular evolution driven by bars in disk galaxies. This work suggests that bars are not stagnant structures within disk galaxies but are a critical evolutionary driver of their host galaxies in the local universe (z < 1).

  10. Technological Progress, Globalization, and Secular Stagnation

    Directory of Open Access Journals (Sweden)

    Popović Milenko

    2018-01-01

    Full Text Available After the 2008 crisis, despite economic recovery that started in 2009, the world economy has experienced a downward shift of its growth path and a consequent decline. As shown at the beginning of this paper, this shift and growth rate stagnation are totally attributable to the economic dynamics in developed economies, the USA and the EU. Explanations of this phenomenon can be divided into two large groups: explanations that belong to the demand side and those that belong to the supply side. The aim of this paper is to give a critical survey of the most important explanations for the ongoing growth stagnation in developed countries and consequently in the entire world economy. This ongoing prolonged stagnation can only be explained by looking at both, the demand and supply sides of the explanation, and particularly by taking a closer look at the interaction between aggregate demand and aggregate supply. In other words, secular stagnation manifests itself as a problem of the limitation of long run growth of aggregate demand. However, in order to explain the causes of those demand limitations, we have to undertake a careful analysis of the supply side dynamics, especially the dynamics of innovations, which bring us to circular and cumulative causation. In order to explain the numerous consequences of this stagnation and to solve some important puzzles, like the productivity paradox for example, a special emphasis is given to the analysis of deindustrialization and the consequent strange reoccurrence of a dual economy within most developed countries during the period of the IT revolution and hyper-globalization. It will also be shown that this new dual economy presents serious limitations for further technological advancement and economic development, quite contrary to the old dualism which contributed to an acceleration of economic growth.

  11. Natural variability of atmospheric temperatures and geomagnetic intensity over a wide range of time scales.

    Science.gov (United States)

    Pelletier, Jon D

    2002-02-19

    The majority of numerical models in climatology and geomagnetism rely on deterministic finite-difference techniques and attempt to include as many empirical constraints on the many processes and boundary conditions applicable to their very complex systems. Despite their sophistication, many of these models are unable to reproduce basic aspects of climatic or geomagnetic dynamics. We show that a simple stochastic model, which treats the flux of heat energy in the atmosphere by convective instabilities with random advection and diffusive mixing, does a remarkable job at matching the observed power spectrum of historical and proxy records for atmospheric temperatures from time scales of one day to one million years (Myr). With this approach distinct changes in the power-spectral form can be associated with characteristic time scales of ocean mixing and radiative damping. Similarly, a simple model of the diffusion of magnetic intensity in Earth's core coupled with amplification and destruction of the local intensity can reproduce the observed 1/f noise behavior of Earth's geomagnetic intensity from time scales of 1 (Myr) to 100 yr. In addition, the statistics of the fluctuations in the polarity reversal rate from time scales of 1 Myr to 100 Myr are consistent with the hypothesis that reversals are the result of variations in 1/f noise geomagnetic intensity above a certain threshold, suggesting that reversals may be associated with internal fluctuations rather than changes in mantle thermal or magnetic boundary conditions.

  12. Towards a fully self-consistent inversion combining historical and paleomagnetic data for geomagnetic field reconstructions

    Science.gov (United States)

    Arneitz, P.; Leonhardt, R.; Fabian, K.; Egli, R.

    2017-12-01

    Historical and paleomagnetic data are the two main sources of information about the long-term geomagnetic field evolution. Historical observations extend to the late Middle Ages, and prior to the 19th century, they consisted mainly of pure declination measurements from navigation and orientation logs. Field reconstructions going back further in time rely solely on magnetization acquired by rocks, sediments, and archaeological artefacts. The combined dataset is characterized by a strongly inhomogeneous spatio-temporal distribution and highly variable data reliability and quality. Therefore, an adequate weighting of the data that correctly accounts for data density, type, and realistic error estimates represents the major challenge for an inversion approach. Until now, there has not been a fully self-consistent geomagnetic model that correctly recovers the variation of the geomagnetic dipole together with the higher-order spherical harmonics. Here we present a new geomagnetic field model for the last 4 kyrs based on historical, archeomagnetic and volcanic records. The iterative Bayesian inversion approach targets the implementation of reliable error treatment, which allows different record types to be combined in a fully self-consistent way. Modelling results will be presented along with a thorough analysis of model limitations, validity and sensitivity.

  13. Modeling the secular evolution of migrating planet pairs

    Science.gov (United States)

    Michtchenko, T. A.; Rodríguez, A.

    2011-10-01

    The secular regime of motion of multi-planetary systems is universal; in contrast with the 'accidental' resonant motion, characteristic only for specific configurations of the planets, secular motion is present everywhere in phase space, even inside the resonant region. The secular behavior of a pair of planets evolving under dissipative forces is the principal subject of this study, particularly, the case when the dissipative forces affect the planetary semi-major axes and the planets move inward/outward the central star, the process known as planet migration. Based on the fundamental concepts of conservative and dissipative dynamics of the three-body problem, we develop a qualitative model of the secular evolution of the migrating planetary pair. Our approach is based on analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces is invoked. We show that, under assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the Mode I and Mode II stationary solutions of the conservative secular problem. The ultimate convergence and the evolution of the system along one of these secular modes of motion is determined uniquely by the condition that the dissipation rate is sufficiently smaller than the proper secular frequency of the system. We show that it is possible to reassemble the starting configurations and migration history of the systems on the basis of their final states and consequently to constrain the parameters of the physical processes involved.

  14. Role of the Hermanus Magnetic Observatory in geomagnetic-field research

    CSIR Research Space (South Africa)

    Sutcliffe, PR

    1995-08-01

    Full Text Available supplemented by induction magnetometer data from the low latitude Hermanus Magnetic Obser- vatory and fluxgate magnetometer data from the EISCAT Magnetometer Cross (Liihr et al., 1984) which is located below the STARE field... the removal of the Sq variation when processing satel~te magnetometer data over Southern Africa and be usefully incorporated into a navigation system based on magnetometer technology. 2.1 GEOMAGNETIC Pi 2 PULSATIONS Pi 2...

  15. A study of Sq(H) variations over equatorial electrojet regions | Okeke ...

    African Journals Online (AJOL)

    The newly established geomagnetic field observations in Japan, have enabled us to analyse the 1998 data of Huancayo, Kiritimati (Christmas Island) and Pohnpei where the geomagnetic Sq(H) variations of equatorial electrojet have been studied. The diurnal variation of the monthly means of Sq(H) on the five international ...

  16. Editorial: Topical Volume on Earth's Magnetic Field - Understanding Geomagnetic Sources from the Earth's Interior and its Environment

    DEFF Research Database (Denmark)

    Stolle, Claudia; Olsen, Nils; Richmond, Arthur D.

    2017-01-01

    (seconds to days) magnetic field variations that are caused by currents in the ionosphere and magnetosphere when solar activity, and correspondingly the electric currents in Earth’s environment, are enhanced. However, for studying the internal sources of the geomagnetic field, originating in the core...

  17. Simulation of geomagnetic field variations during an intensive magnetic storm

    International Nuclear Information System (INIS)

    Fel'dshtejn, Ya.I.; Dremukhin, L.A.; Veshcherova, U.B.

    1993-01-01

    The intensity of asymmetric part of magnetic field of ring current is closely linked with energy flow entering the magnetosphere from solar wind. Quantitative description assumes usage of data on parameters of solar wind before few hours

  18. SECULAR GRAVITATIONAL INSTABILITY OF A DUST LAYER IN SHEAR TURBULENCE

    International Nuclear Information System (INIS)

    Michikoshi, Shugo; Kokubo, Eiichiro; Inutsuka, Shu-ichiro

    2012-01-01

    We perform a linear stability analysis of a dust layer in a turbulent gas disk. Youdin investigated the secular gravitational instability (GI) of a dust layer using hydrodynamic equations with a turbulent diffusion term. We obtain essentially the same result independently of Youdin. In the present analysis, we restrict the area of interest to small dust particles, while investigating the secular GI in a more rigorous manner. We discuss the time evolution of the dust surface density distribution using a stochastic model and derive the advection-diffusion equation. The validity of the analysis by Youdin is confirmed in the strong drag limit. We demonstrate quantitatively that the finite thickness of a dust layer weakens the secular GI and that the density-dependent diffusion coefficient changes the growth rate. We apply the results obtained to the turbulence driven by the shear instability and find that the secular GI is faster than the radial drift when the gas density is three times as large as that in the minimum-mass disk model. If the dust particles are larger than chondrules, the secular GI grows within the lifetime of a protoplanetary disk.

  19. Modelling the secular evolution of migrating planet pairs

    Science.gov (United States)

    Michtchenko, T. A.; Rodríguez, A.

    2011-08-01

    The subject of this paper is the secular behaviour of a pair of planets evolving under dissipative forces. In particular, we investigate the case when dissipative forces affect the planetary semimajor axes and the planets move inwards/outwards the central star, in a process known as planet migration. To perform this investigation, we introduce fundamental concepts of conservative and dissipative dynamics of the three-body problem. Based on these concepts, we develop a qualitative model of the secular evolution of the migrating planetary pair. Our approach is based on the analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces is invoked. We show that, under the assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the Mode I and Mode II stationary solutions of the conservative secular problem. The ultimate convergence and the evolution of the system along one of these secular modes of motion are determined uniquely by the condition that the dissipation rate is sufficiently smaller than the proper secular frequency of the system. We show that it is possible to reassemble the starting configurations and the migration history of the systems on the basis of their final states and consequently to constrain the parameters of the physical processes involved.

  20. Secularization- the promoter of “new type of man”

    Directory of Open Access Journals (Sweden)

    Traian-Alexandru MIU

    2017-06-01

    Full Text Available Secularization is a phenomenon supposing major mutations on the social level. Thus, based on the principle of rationality, secularization has led to the removal of religion from the social sphere, the desacralization, aiming, ultimately, that the sacred disappear altogether from man's life. Within the globalizing-secularizing society, economics seeks to take possession of the entire social and spiritual life, helped by a policy-aggressive mercantile mentality. Secularization has led to manipulation of man so that he believes he has to build his future by abstaining from religion. The secularized man has come to the conclusion that only by his own forces helped by reason, economy and technology he can be the one who creates progress, namely perfection for himself and for the world he lives in. The hypermodern man is a man of ephemerality, a human being looking for his accomplishment in trifles, who no longer has deification as his final goal. The problems that man is facing today can be solved by taking the eternity as reference system for them.

  1. The influence of meteorological and geomagnetic factors on acute myocardial infarction and brain stroke in Moscow, Russia.

    Science.gov (United States)

    Shaposhnikov, Dmitry; Revich, Boris; Gurfinkel, Yuri; Naumova, Elena

    2014-07-01

    Evidence of the impact of air temperature and pressure on cardiovascular morbidity is still quite limited and controversial, and even less is known about the potential influence of geomagnetic activity. The objective of this study was to assess impacts of air temperature, barometric pressure and geomagnetic activity on hospitalizations with myocardial infarctions and brain strokes. We studied 2,833 myocardial infarctions and 1,096 brain strokes registered in two Moscow hospitals between 1992 and 2005. Daily event rates were linked with meteorological and geomagnetic conditions, using generalized linear model with controls for day of the week, seasonal and long-term trends. The number of myocardial infarctions decreased with temperature, displayed a U-shaped relationship with pressure and variations in pressure, and increased with geomagnetic activity. The number of strokes increased with temperature, daily temperature range and geomagnetic activity. Detrimental effects on strokes of low pressure and falling pressure were observed. Relative risks of infarctions and strokes during geomagnetic storms were 1.29 (95% CI 1.19-1.40) and 1.25 (1.10-1.42), respectively. The number of strokes doubled during cold spells. The influence of barometric pressure on hospitalizations was relatively greater than the influence of geomagnetic activity, and the influence of temperature was greater than the influence of pressure. Brain strokes were more sensitive to inclement weather than myocardial infarctions. This paper provides quantitative estimates of the expected increases in hospital admissions on the worst days and can help to develop preventive health plans for cardiovascular diseases.

  2. The practice of mindfulness: from Buddhism to secular mainstream in a post-secular society

    Directory of Open Access Journals (Sweden)

    Liselotte Frisk

    2014-01-01

    Full Text Available The article focuses on the practice of mindfulness, which has migrated from being part of a religion, Buddhism, to being an integral part of Western psychology. Mindfulness is especially used in cognitive behavioural therapy, but also in, e.g., dialectical behavioural therapy (DBT and acceptance and commitment therapy (ACT. In Sweden several doctors, psychologists and psychiatrists use and recommend mindfulness for therapeutic purposes. Mindfulness is used today in many segments of mainstream medical and therapeutic care. Mindfulness is also used outside the mainstream medical and therapeutic sector, in the area of personal development or spirituality, as well as in more traditional Buddhist groups and innovative Buddhist groups such as vipassana groups. This paper investigates the migration of mindfulness from a religious to a secular sphere, and discusses whether mindfulness is a religious practice or not.

  3. Mathematical Properties Relevant to Geomagnetic Field Modeling

    DEFF Research Database (Denmark)

    Sabaka, Terence J.; Hulot, Gauthier; Olsen, Nils

    2010-01-01

    be directly measured. In this chapter, the mathematical foundation of global (as opposed to regional) geomagnetic field modeling is reviewed, and the spatial modeling of the field in spherical coordinates is focussed. Time can be dealt with as an independent variable and is not explicitly considered......Geomagnetic field modeling consists in converting large numbers of magnetic observations into a linear combination of elementary mathematical functions that best describes those observations.The set of numerical coefficients defining this linear combination is then what one refers.......The relevant elementary mathematical functions are introduced, their properties are reviewed, and how they can be used to describe the magnetic field in a source-free (such as the Earth’s neutral atmosphere) or source-dense (such as the ionosphere) environment is explained. Completeness and uniqueness...

  4. Mathematical Properties Relevant to Geomagnetic Field Modeling

    DEFF Research Database (Denmark)

    Sabaka, Terence J.; Hulot, Gauthier; Olsen, Nils

    2014-01-01

    be directly measured. In this chapter, the mathematical foundation of global (as opposed to regional) geomagnetic field modeling is reviewed, and the spatial modeling of the field in spherical coordinates is focused. Time can be dealt with as an independent variable and is not explicitly considered......Geomagnetic field modeling consists in converting large numbers of magnetic observations into a linear combination of elementary mathematical functions that best describes those observations. The set of numerical coefficients defining this linear combination is then what one refers....... The relevant elementary mathematical functions are introduced, their properties are reviewed, and how they can be used to describe the magnetic field in a source-free (such as the Earth’s neutral atmosphere) or source-dense (such as the ionosphere) environment is explained. Completeness and uniqueness...

  5. Evaluation of geomagnetic storm effects on the GPS derived Total Electron Content (TEC)

    International Nuclear Information System (INIS)

    Purohit, P K; Atulkar, Roshni; Mansoori, Azad A; Khan, Parvaiz A; Bhawre, Purushottam; Tripathi, Sharad C; Khatarkar, Prakash; Bhardwaj, Shivangi; Aslam, A M; Waheed, Malik A; Gwal, A K

    2015-01-01

    The geomagnetic storm represents the most outstanding example of solar wind- magnetospheric interaction, which causes global disturbances in the geomagnetic field as well as triggers ionospheric disturbances. We study the behaviour of ionospheric Total Electron Content (TEC) during the geomagnetic storms. For this investigation we have selected 47 intense geomagnetic storms (Dst ≤ -100nT) that were observed during the solar cycle 23 i.e. during 1998- 2006. We then categorized these storms into four categories depending upon their solar sources like Magnetic Cloud (MC), Co-rotating Interaction Region (CIR), SH+ICME and SH+MC. We then studied the behaviour of ionospheric TEC at a mid latitude station Usuda (36.13N, 138.36E), Japan during these storm events produced by four different solar sources. During our study we found that the smooth variations in TEC are replaced by rapid fluctuations and the value of TEC is strongly enhanced during the time of these storms belonging to all the four categories. However, the greatest enhancements in TEC are produced during those geomagnetic storms which are either caused by Sheath driven Magnetic cloud (SH+MC) or Sheath driven ICME (SH+ICME). We also derived the correlation between the TEC enhancements produced during storms of each category with the minimum Dst. We found the strongest correlation exists for the SH+ICME category followed by SH+MC, MC and finally CIR. Since the most intense storms were either caused by SH+ICME or SH+MC while the least intense storms were caused by CIR, consequently the correlation was strongest with SH+ICME and SH+MC and least with CIR. (paper)

  6. Geomagnetic oriented electromagnetic radiation in the ionosphere

    International Nuclear Information System (INIS)

    Benton, C.U.; Fowles, H.M.; Goen, P.K.

    1976-08-01

    Strong bursts of electromagnetic radiation were observed in the ionosphere during the Waso rocket Electromagnetic Pulse (EMP) experiment. The pulses have a frequency content from below 20 MHz to above 70 MHz. They vary in duration between 5 μs and 2 ms and in peak-amplitudes of 2 mV/m to greater than 200 mV/m. These pulses show a high degree of geomagnetic correlation and are of unknown origin

  7. Uncertainty Quantification in Geomagnetic Field Modeling

    Science.gov (United States)

    Chulliat, A.; Nair, M. C.; Alken, P.; Meyer, B.; Saltus, R.; Woods, A.

    2017-12-01

    Geomagnetic field models are mathematical descriptions of the various sources of the Earth's magnetic field, and are generally obtained by solving an inverse problem. They are widely used in research to separate and characterize field sources, but also in many practical applications such as aircraft and ship navigation, smartphone orientation, satellite attitude control, and directional drilling. In recent years, more sophisticated models have been developed, thanks to the continuous availability of high quality satellite data and to progress in modeling techniques. Uncertainty quantification has become an integral part of model development, both to assess the progress made and to address specific users' needs. Here we report on recent advances made by our group in quantifying the uncertainty of geomagnetic field models. We first focus on NOAA's World Magnetic Model (WMM) and the International Geomagnetic Reference Field (IGRF), two reference models of the main (core) magnetic field produced every five years. We describe the methods used in quantifying the model commission error as well as the omission error attributed to various un-modeled sources such as magnetized rocks in the crust and electric current systems in the atmosphere and near-Earth environment. A simple error model was derived from this analysis, to facilitate usage in practical applications. We next report on improvements brought by combining a main field model with a high resolution crustal field model and a time-varying, real-time external field model, like in NOAA's High Definition Geomagnetic Model (HDGM). The obtained uncertainties are used by the directional drilling industry to mitigate health, safety and environment risks.

  8. Elliptical magnetic clouds and geomagnetic storms

    Czech Academy of Sciences Publication Activity Database

    Antoniadou, I.; Geranios, A.; Vandas, Marek; Panagopoulou, M.; Zacharopoulou, O.; Malandraki, O.

    2008-01-01

    Roč. 56, 3-4 (2008), s. 492-500 ISSN 0032-0633 R&D Projects: GA AV ČR 1QS300120506; GA ČR GA205/06/0875 Institutional research plan: CEZ:AV0Z10030501 Keywords : magnetic clouds * geomagnetic storms * solar wind Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.506, year: 2008

  9. The study of the midlatitude ionospheric response to geomagnetic activity at Nagycenk Geophysical Observatory

    Science.gov (United States)

    Berényi, Kitti; Kis, Árpád; Barta, Veronika; Novák, Attila

    2016-04-01

    Geomagnetic storms affect the ionospheric regions of the terrestrial upper atmosphere, causing several physical and chemical atmospheric processes. The changes and phenomena, which can be seen as a result of these processes, generally called ionospheric storm. These processes depend on altitude, term of the day, and the strength of solar activity, the geomagnetic latitude and longitude. The differences between ionospheric regions mostly come from the variations of altitude dependent neutral and ionized atmospheric components, and from the physical parameters of solar radiation. We examined the data of the ground-based radio wave ionosphere sounding instruments of the European ionospheric stations (mainly the data of Nagycenk Geophysical Observatory), called ionosonde, to determine how and what extent a given strength of a geomagnetic disturbance affect the middle latitude ionospheric regions in winter. We chose the storm for the research from November 2012 and March 2015. As the main result of our research, we can show significant differences between the each ionospheric (F1 and F2) layer parameters on quiet and strong stormy days. When we saw, that the critical frequencies (foF2) increase from their quiet day value, then the effect of the ionospheric storm was positive, otherwise, if they drop, they were negative. With our analysis, the magnitude of these changes could be determined. Furthermore we demonstrated, how a full strong geomagnetic storm affects the ionospheric foF2 parameter during different storm phases. It has been showed, how a positive or negative ionospheric storm develop during a geomagnetic storm. For a more completed analysis, we compared also the evolution of the F2 layer parameters of the European ionosonde stations on a North-South geographic longitude during a full storm duration. Therefore we determined, that the data of the ionosonde at Nagycenk Geophysical Observatory are appropriate, it detects the same state of ionosphere like the

  10. Thermal interaction of the core and the mantle and long-term behavior of the geomagnetic field

    Science.gov (United States)

    Jones, G. M.

    1977-01-01

    The effects of temperature changes at the earth's core-mantle boundary on the velocity field of the core are analyzed. It is assumed that the geomagnetic field is maintained by thermal convection in the outer core. A model for the thermal interaction of the core and the mantle is presented which is consistent with current views on the presence of heat sources in the core and the properties of the lower mantle. Significant long-term variations in the frequency of geomagnetic reversals may be the result of fluctuating temperatures at the core-mantle boundary, caused by intermittent convection in the lower mantle. The thermal structure of the lower mantle region D double prime, extending from 2700 to 2900 km in depth, constitutes an important test of this hypothesis and offers a means of deciding whether the geomagnetic dynamo is thermally driven.

  11. Characteristics of the variability of a geomagnetic field for studying the impact of the magnetic storms and substorms on electrical energy systems

    Science.gov (United States)

    Belakhovsky, V. B.; Pilipenko, V. A.; Sakharov, Ya. A.; Selivanov, V. N.

    2018-01-01

    There are numerous models of geomagnetically induced currents in which the role of the main sources is allotted to the variations in the intensity of the auroral electrojet inducing the currents flowing along the latitude. Based on this it is believed that magnetic disturbances mainly threaten technological systems that are elongated in the longitudinal (W-E) direction. In this work, we make an attempt to employ new characteristics to describe the variability of the geomagnetic field during the geomagnetic storm of March 17, 2013. These characteristics, calculated from the data of the IMAGE magnetometer network stations, are compared to the records of the induced currents in the power lines on the Kola Peninsula and in Karelia. The vector technique revealed a considerably lower variability of the horizontal component of the geomagnetic field compared to its derivative. Quantitative estimates of the variability supported the fact that the variations of the field occur on a commensurate scale both in magnitude and direction. These results cannot be accounted for by the simple model of the extended ionospheric current and demonstrate the importance of allowing for small-scale current structures (with the spatial scales of a few hundred km) in the calculations of the geomagnetically induced currents. Our analysis shows that the geomagnetically induced currents are not only hazardous for the technological objects oriented in the longitudinal (W-E) direction but also for those elongated meridionally.

  12. AI techniques in geomagnetic storm forecasting

    Science.gov (United States)

    Lundstedt, Henrik

    This review deals with how geomagnetic storms can be predicted with the use of Artificial Intelligence (AI) techniques. Today many different Al techniques have been developed, such as symbolic systems (expert and fuzzy systems) and connectionism systems (neural networks). Even integrations of AI techniques exist, so called Intelligent Hybrid Systems (IHS). These systems are capable of learning the mathematical functions underlying the operation of non-linear dynamic systems and also to explain the knowledge they have learned. Very few such powerful systems exist at present. Two such examples are the Magnetospheric Specification Forecast Model of Rice University and the Lund Space Weather Model of Lund University. Various attempts to predict geomagnetic storms on long to short-term are reviewed in this article. Predictions of a month to days ahead most often use solar data as input. The first SOHO data are now available. Due to the high temporal and spatial resolution new solar physics have been revealed. These SOHO data might lead to a breakthrough in these predictions. Predictions hours ahead and shorter rely on real-time solar wind data. WIND gives us real-time data for only part of the day. However, with the launch of the ACE spacecraft in 1997, real-time data during 24 hours will be available. That might lead to the second breakthrough for predictions of geomagnetic storms.

  13. Geomagnetic storm under laboratory conditions: randomized experiment

    Science.gov (United States)

    Gurfinkel, Yu I.; Vasin, A. L.; Pishchalnikov, R. Yu; Sarimov, R. M.; Sasonko, M. L.; Matveeva, T. A.

    2017-10-01

    The influence of the previously recorded geomagnetic storm (GS) on human cardiovascular system and microcirculation has been studied under laboratory conditions. Healthy volunteers in lying position were exposed under two artificially created conditions: quiet (Q) and storm (S). The Q regime playbacks a noise-free magnetic field (MF) which is closed to the natural geomagnetic conditions on Moscow's latitude. The S regime playbacks the initially recorded 6-h geomagnetic storm which is repeated four times sequentially. The cardiovascular response to the GS impact was assessed by measuring capillary blood velocity (CBV) and blood pressure (BP) and by the analysis of the 24-h ECG recording. A storm-to-quiet ratio for the cardio intervals (CI) and the heart rate variability (HRV) was introduced in order to reveal the average over group significant differences of HRV. An individual sensitivity to the GS was estimated using the autocorrelation function analysis of the high-frequency (HF) part of the CI spectrum. The autocorrelation analysis allowed for detection a group of subjects of study which autocorrelation functions (ACF) react differently in the Q and S regimes of exposure.

  14. Geomagnetic storm under laboratory conditions: randomized experiment.

    Science.gov (United States)

    Gurfinkel, Yu I; Vasin, A L; Pishchalnikov, R Yu; Sarimov, R M; Sasonko, M L; Matveeva, T A

    2018-04-01

    The influence of the previously recorded geomagnetic storm (GS) on human cardiovascular system and microcirculation has been studied under laboratory conditions. Healthy volunteers in lying position were exposed under two artificially created conditions: quiet (Q) and storm (S). The Q regime playbacks a noise-free magnetic field (MF) which is closed to the natural geomagnetic conditions on Moscow's latitude. The S regime playbacks the initially recorded 6-h geomagnetic storm which is repeated four times sequentially. The cardiovascular response to the GS impact was assessed by measuring capillary blood velocity (CBV) and blood pressure (BP) and by the analysis of the 24-h ECG recording. A storm-to-quiet ratio for the cardio intervals (CI) and the heart rate variability (HRV) was introduced in order to reveal the average over group significant differences of HRV. An individual sensitivity to the GS was estimated using the autocorrelation function analysis of the high-frequency (HF) part of the CI spectrum. The autocorrelation analysis allowed for detection a group of subjects of study which autocorrelation functions (ACF) react differently in the Q and S regimes of exposure.

  15. Large short-term deviations from dipolar field during the Levantine Iron Age Geomagnetic Anomaly ca. 1050-700 BCE

    Science.gov (United States)

    Shaar, R.; Tauxe, L.; Ebert, Y.

    2017-12-01

    Continuous decadal-resolution paleomagnetic data from archaeological and sedimentary sources in the Levant revealed the existence a local high-field anomaly, which spanned the first 350 years of the first millennium BCE. This so-called "the Levantine Iron Age geomagnetic Anomaly" (LIAA) was characterized by a high averaged geomagnetic field (virtual axial dipole moments, VADM > 140 Z Am2, nearly twice of today's field), short decadal-scale geomagnetic spikes (VADM of 160-185 Z Am2), fast directional and intensity variations, and substantial deviation (20°-25°) from dipole field direction. Similar high field values in the time frame of LIAA have been observed north, and northeast to the Levant: Eastern Anatolia, Turkmenistan, and Georgia. West of the Levant, in the Balkans, field values in the same time are moderate to low. The overall data suggest that the LIAA is a manifestation of a local positive geomagnetic field anomaly similar in magnitude and scale to the presently active negative South Atlantic Anomaly. In this presentation we review the overall archaeomagnetic and sedimentary evidences supporting the local anomaly hypothesis, and compare these observations with today's IGRF field. We analyze the global data during the first two millennia BCE, which suggest some unexpected large deviations from a simple dipolar geomagnetic structure.

  16. Five millions years of paleosecular variations from the Golan Heights volcanic field, Israel

    Science.gov (United States)

    Behar, N.; Shaar, R.; Asefaw, H.; Ebert, Y.; Koppers, A.; Tauxe, L.

    2017-12-01

    One of the most fundamental assumption in paleomagnetism is that the averaged geomagnetic field on geological timescales is a geocentric axial dipole (GAD). Given the first order importance of the GAD hypothesis, it is essential to rigorously test its validity and to understand the limits of its use. Additionally, it is equally vital to characterize statistically paleomagnetic secular variations (PSV) over timescales of 106 years. The Plio-Pleistocene volcanic field in the Golan Heights, Israel (32.7°N-33.3°N) is a nearly ideal location to investigate these issues, owing to excellent exposure of basaltic flows, dated using more than 100 radiometric (K/Ar and Ar/Ar) ages covering the past 5 Myr. Here we present new data from 89 basalt flows from the Golan Heights with ages spanning from 5.4 Ma to 0.1 Ma, and 18 new Ar/Ar ages. This relatively large dataset allows us to calculate three different Virtual Geomagnetic Poles (VGP): Pleistocene, Pliocene, and a combined Plio-Pleistocene. From each pole we calculate the inclination anomaly (ΔI) and the VGP scatter parameter (SB). The Pleistocene pole yields a VGP scatter parameter around SB =13, lower than predictions of PSV models. Also, it demonstrates negligible inclination anomaly of less than 2°, suggesting validation of the GAD model. The Pliocene pole shows a larger scatter (SB 18) and a negative inclination anomaly around ΔI = -7°. We discuss these results in view of the worldwide paleomagnetic database and the available PSV models.

  17. Familial resemblance in religiousness in a secular society

    DEFF Research Database (Denmark)

    Hvidtjørn, Dorte; Petersen, Inge; Hjelmborg, Jacob

    2013-01-01

    generally considered more religious than the very secular northern European countries. Comparisons of the results are complicated by diverse definitions of religiousness, but several studies indicate that the influence of the family environment is most predominant in early life, whereas genetic influences...... increase with age. We performed a population-based twin study of religiousness in a secular society using data from a Web-based survey sent to 6,707 Danish twins born 1970-1989, who were identified in the Danish Twin Registry. We applied Fishman's three conceptual dimensions of religiousness: cognition...

  18. The conditions of believe and unbelieve in a secular Age

    Directory of Open Access Journals (Sweden)

    Juan Manuel Cincunegui

    2014-05-01

    Full Text Available In A Secular Age the Canadian philosopher Charles Taylor offered an analytical description and a genealogy of the current conditions of belief and unbelief in the North Atlantic contemporary societies. He encouraged as well a set of similar investigations in other cultural settings that are affected by the processes of modernization. He argues about the existence of ‘alternative modernities’ each one of them facing critically the univocal sociological theories of modernity and secularization that interpreted as universal the process of disenchantment occurred in the West and the setbacks with regard to the presence of religion in the public sphere and religious practice in some contemporary Western societies

  19. Last three millennia Earth's Magnetic field strength in Mesoamerica and southern United States: Implications in geomagnetism and archaeology

    Science.gov (United States)

    Goguitchaichvili, Avto; Ruiz, Rafael García; Pavón-Carrasco, F. Javier; Contreras, Juan Julio Morales; Arechalde, Ana María Soler; Urrutia-Fucugauchi, Jaime

    2018-06-01

    Earth's Magnetic Field variation strength may provide crucial information to understand the geodynamo mechanism and elucidate the conditions on the physics of the Earth's deep interiors. Aimed to reveal the fine characteristics of the geomagnetic field during the last three millennia in Mesoamerica, we analyzed the available absolute geomagnetic intensities associated to absolute radiometric dating as well some ages provided by historical documents. This analysis is achieved using thermoremanent magnetization carried by volcanic lava flows and burned archaeological artefacts. A total of 106 selected intensities from Mesoamerica and other 100 from the southern part of the United States represent the main core of the dataset to construct the variation curve using both combined bootstrap method and temporal penalized B-spline methods. The obtained intensity paleosecular variation curve for Mesoamerica generally disagrees with the values predicted by the global geomagnetic field models. There is rather firm evidence of eastward drift when compared to similar reference curves in Western Europe, Asia and Pacific Ocean. The recent hypothesis about the relationship between the geomagnetic field strength and paleoclimate is also critically analyzed in the light of this new data compilation.

  20. An impending geomagnetic transition? Hints from the past

    OpenAIRE

    Laj, Carlo; Kissel, Catherine

    2015-01-01

    The rapid decrease of the geomagnetic field intensity in the last centuries has led to speculations that an attempt to a reversal or an excursion might be under way. Here we investigate this hypothesis by examining past records of geomagnetic field intensity obtained from sedimentary cores and from the study of cosmogenic nuclides. The selected records describe geomagnetic changes with an unprecedented temporal resolution between 20 and 75 kyr B.P. We find that some aspects of the present-day...

  1. Secular trends in hip fractures worldwide: opposing trends East versus West.

    Science.gov (United States)

    Ballane, Ghada; Cauley, Jane A; Luckey, Marjorie M; Fuleihan, Ghada El-Hajj

    2014-08-01

    Despite wide variations in hip rates fractures worldwide, reasons for such differences are not clear. Furthermore, secular trends in the age-specific hip fracture rates are changing the world map of this devastating disease, with the highest rise projected to occur in developing countries. The aim of our investigation is to systematically characterize secular trends in hip fractures worldwide, examine new data for various ethnic groups in the United States, evidence for divergent temporal patterns, and investigate potential contributing factors for the observed change in their epidemiology. All studies retrieved through a complex Medline Ovid search between 1966 and 2013 were examined. For each selected study, we calculated the percent annual change in age-standardized hip fracture rates de-novo. Although occurring at different time points, trend breaks in hip fracture incidence occurred in most Western countries and Oceania. After a steep rise in age-adjusted rates in these regions, a decrease became evident sometimes between the mid-seventies and nineties, depending on the country. Conversely, the data is scarce in Asia and South America, with evidence for a continuous rise in hip fracture rates, with the exception of Hong-Kong and Taiwan that seem to follow Western trends. The etiologies of these secular patterns in both the developed and the developing countries have not been fully elucidated, but the impact of urbanization is at least one plausible explanation. Data presented here show close parallels between rising rates of urbanization and hip fractures across disparate geographic locations and cultures. Once the proportion of the urban population stabilized, hip fracture rates also stabilize or begin to decrease perhaps due to the influence of other factors such as birth cohort effects, changes in bone mineral density and BMI, osteoporosis medication use and/or lifestyle interventions such as smoking cessation, improvement in nutritional status and fall

  2. A high-resolution paleosecular variation record from Black Sea sediments indicating fast directional changes associated with low field intensities during marine isotope stage (MIS) 4

    Science.gov (United States)

    Nowaczyk, Norbert R.; Jiabo, Liu; Frank, Ute; Arz, Helge W.

    2018-02-01

    A total of nine sediment cores recovered from the Archangelsky Ridge in the SE Black Sea were systematically subjected to intense paleo- and mineral magnetic analyses. Besides 16 accelerator mass spectrometry (AMS) 14C ages available for another core from this area, dating was accomplished by correlation of short-term warming events during the last glacial monitored by high-resolution X-ray fluorescence (XRF) scanning as maxima in both Ca/Ti and K/Ti ratios in Black Sea sediments to the so-called 'Dansgaard-Oeschger events' recognized from Greenland ice cores. Thus, several hiatuses could be identified in the various cores during the last glacial/interglacial cycle. Finally, core sections documenting marine isotope stage (MIS) 4 at high resolution back to 69 ka were selected for detailed analyses. At 64.5 ka, according to obtained results from Black Sea sediments, the second deepest minimum in relative paleointensity during the past 69 ka occurred, with the Laschamp geomagnetic excursion at 41 ka being associated with the lowest field intensities. The field minimum during MIS 4 is associated with large declination swings beginning about 3 ka before the minimum. While a swing to 50°E is associated with steep inclinations (50-60°) according to the coring site at 42°N, the subsequent declination swing to 30°W is associated with shallow inclinations of down to 40°. Nevertheless, these large deviations from the direction of a geocentric axial dipole field (I = 61 °, D = 0 °) still can not yet be termed as 'excursional', since latitudes of corresponding virtual geomagnetic poles (VGP) only reach down to 51.5°N (120°E) and 61.5°N (75°W), respectively. However, these VGP positions at opposite sides of the globe are linked with VGP drift rates of up to 0.2° per year in between. These extreme secular variations might be the mid-latitude expression of a geomagnetic excursion with partly reversed inclinations found at several sites much further North in Arctic

  3. Secular decline in male testosterone and sex hormone binding globulin serum levels in Danish population surveys

    DEFF Research Database (Denmark)

    Andersson, Anna-Maria; Jensen, Tina Kold; Juul, Anders

    2007-01-01

    Adverse secular trends in male reproductive health have been reported to be reflected in increased testicular cancer risk and decreased semen quality in more recently born men. These secular trends may also be reflected by changes in Leydig cell function....

  4. Morphology of geomagnetic storms, recorded at Hurbanovo, and its relation to solar activity

    International Nuclear Information System (INIS)

    Ochabova, P.; Psenakova, M.

    1977-01-01

    The morphological structure of geomagnetic storms was investigated using the data on 414 storms, recorded in the years 1949 to 1968 at the Geomagnetic Observatory of Hurbanovo (phi=47.9 deg N, lambda=18.2 deg E). These data also formed a suitable basis for investigating the effect of the solar activity on the characteristic features of storms. The storm-time variation of the geomagnetic field was considered after the Sq-variation had been eliminated. The sets of storms, i.e. 263 storms recorded at a time of high sunspot activity and 151 storms recorded at a time of low activity, were divided into 7 groups, depending on the duration of their initial phase. In 92% of the investigated storms the increase in the horizontal component lasted from 0 to 15 hrs. The effect of the solar activity was markedly reflected in the occurrence of very severe storms, as well as in the maximum decrease in the H-component in the main phase. This can also be seen in the rate at which the storms recover. (author)

  5. Secular decline in male testosterone and sex hormone binding globulin serum levels in Danish population surveys

    DEFF Research Database (Denmark)

    Andersson, Anna-Maria; Jensen, Tina K; Juul, Anders

    2007-01-01

    Adverse secular trends in male reproductive health have been reported to be reflected in increased testicular cancer risk and decreased semen quality in more recently born men. These secular trends may also be reflected by changes in Leydig cell function.......Adverse secular trends in male reproductive health have been reported to be reflected in increased testicular cancer risk and decreased semen quality in more recently born men. These secular trends may also be reflected by changes in Leydig cell function....

  6. Environmental and geomagnetic factors in relation to self-destructive ideation and behaviour

    Science.gov (United States)

    Bergiannaki, J. D.; Psarros, C.; Nastos, P. Th.; Paparigopoulos, T.; Paliatsos, A. G.; Tritakis, V. P.; Stefanis, C. N.

    2001-09-01

    Besides the individual factors such as the reaction to conflicts, several exogenous factors environmental and social may exert a pathogenic influence on suicidal behavior, suicide attempts and complete suicide on predisposed individuals. In the turn of the century many reports accord for the seasonality of suicides, which seems to have a bimodal distribution with a major peak around the spring-summer (April-May) and a second minor in autumn. On the other hand, the seasonal variation of environmental factors (daylight, sunlight duration, weather, temperature, air pressure, humidity, geomagnetism, solar activity, etc), of biological factors (melatonin, serotonin, serotonin precursors, etc) as also of sociological factors (ethnic events, major holidays, weekends etc) possibly influences the seasonal pattern of self-destructive behavior. Bimodal seasonal variation is also reported for biochemical parameters (L-tryptophan, serotonin, endorphin I fraction) that matches seasonal pattern in the prevalence of violent suicide in the total population and also in the incidence of the affective disorders. The aim of this study is to investigate the relation of environmental factors expressed by the Discomfort Index (DI) and geomagnetic factors expressed by the geomagnetic field Index DST in relation to suicidal behavior. The total number (4803) of patients recorded in the Ambulance of a Phychiatric Hospital (Eginition) throughout 1994 was used along with the records of 2750 patients of the year 1989. The Index DI is a function of dry and wet-bulb temperature. DST is probably one of the geomagnetic indices that expresses and monitors with the greatest accuracy the equatorial ring current variations. Our results show that there is a seasonal variation of suicidal behavior (Fourier analysis) with a major peak during summer (July) and a minor one during spring. A difference in the occurrence of the peaks was observed among genders. A relation of self-destructive behavior and the

  7. Teaching about Religion in History Classes: Sacred and Secular History.

    Science.gov (United States)

    Abrahamson, Brant; Smith, Fred

    In teaching about religion there is the fundamental distinction between secular history, which is restricted to natural cause and effect relationships, and sacred histories, which assume that a spirit world exists and that human/divine interaction has taken place. In the United States, the academically approved way of dealing with these…

  8. Post-Secularism, Religious Knowledge and Religious Education

    Science.gov (United States)

    Carr, David

    2012-01-01

    Post-secularism seems to follow in the wake of other (what are here called) "postal" perspectives--post-structuralism, postmodernism, post-empiricism, post-positivism, post-analytical philosophy, post-foundationalism and so on--in questioning or repudiating what it takes to be the epistemic assumptions of "modernism." To be sure, post-secularism…

  9. Questioning Engelhardt's assumptions in Bioethics and Secular Humanism.

    Science.gov (United States)

    Ahmadi Nasab Emran, Shahram

    2016-06-01

    In Bioethics and Secular Humanism: The Search for a Common Morality, Tristram Engelhardt examines various possibilities of finding common ground for moral discourse among people from different traditions and concludes their futility. In this paper I will argue that many of the assumptions on which Engelhardt bases his conclusion about the impossibility of a content-full secular bioethics are problematic. By starting with the notion of moral strangers, there is no possibility, by definition, for a content-full moral discourse among moral strangers. It means that there is circularity in starting the inquiry with a definition of moral strangers, which implies that they do not share enough moral background or commitment to an authority to allow for reaching a moral agreement, and concluding that content-full morality is impossible among moral strangers. I argue that assuming traditions as solid and immutable structures that insulate people across their boundaries is problematic. Another questionable assumption in Engelhardt's work is the idea that religious and philosophical traditions provide content-full moralities. As the cardinal assumption in Engelhardt's review of the various alternatives for a content-full moral discourse among moral strangers, I analyze his foundationalist account of moral reasoning and knowledge and indicate the possibility of other ways of moral knowledge, besides the foundationalist one. Then, I examine Engelhardt's view concerning the futility of attempts at justifying a content-full secular bioethics, and indicate how the assumptions have shaped Engelhardt's critique of the alternatives for the possibility of content-full secular bioethics.

  10. Secularism in Nigeria: An Assessment | Ogoloma | AFRREV IJAH ...

    African Journals Online (AJOL)

    Secularism is not the absence of religions in the state. Rather, it is the absence of a state sponsored religion where everyone will be made to choose a religion of their choice. People are free to follow which religious tenets they like without any fear, intimidation, victimization or favour. The central and state administrations ...

  11. SPIRITUALITY IN A SECULAR AGE: FROM CHARLES TAYLOR TO ...

    African Journals Online (AJOL)

    the secular is ignored or where exclusive humanism is seen as the inevitable conclusion of a .... responsible for ordinary events in the world. Various .... immanent frame is dependent on and open to a transcendent source while for others, the ...

  12. Institutional Confidence in the United States: Attitudes of Secular Americans

    Directory of Open Access Journals (Sweden)

    Isabella Kasselstrand

    2017-04-01

    Full Text Available The First Amendment to the United States’ Constitution addresses freedom of religion and the separation of church and state. However, the historical influence of religion in laws, policies, and political representation have left secular individuals feeling excluded. At the same time, levels of confidence in social and political institutions in the United States are at an all-time low. This begs the question: Is there a relationship between secularity and confidence in various social and political institutions (e.g. the armed forces, churches, major companies, government, police, and political parties? This question is examined using data on the United States from the World Values Survey from 1995–2011. While controlling for a range of key demographics, the findings show a negative relationship between secularity and institutional confidence. More specifically, atheists and nonreligious individuals are less likely than those who are religious to have confidence in all six institutions. Based on previous literature and the empirical evidence presented in this study, we argue that overall lower levels of institutional confidence among secular Americans is an outcome of the exclusion of such individuals from American social life. Thus, it highlights the importance of addressing the stereotypes and prejudice that this minority group faces.

  13. Secularity and religiosity: keystones of Turkish national identity

    Directory of Open Access Journals (Sweden)

    Sergey V. Olyunin

    2011-01-01

    Full Text Available According to many experts Turkish National Federation experiences crisis of its national identity. The article concerns the problem of secular and religious balance in Turkish nationalism. Special attention is attached to Turkey as a project and Turkey as a process, war factor in a birth of the nation, national idea reproduction, Islam nationalization and nationalism Islamisation.

  14. Religion, Education and the Post-Secular Child

    Science.gov (United States)

    Davis, Robert A.

    2014-01-01

    This essay endeavours to reframe current discussion of the relationship of religion to education by highlighting an often seriously neglected element of contemporary educational thought: the changing, post-secular understanding of childhood in the globalised age. Drawing upon recent ethnographies of childhood, and an older anthropological…

  15. The Possibility of Religion in a Scientific and Secular Culture ...

    African Journals Online (AJOL)

    ... anthropological arguments in the modern period, to a contemporary argument from interpersonal relationships, a deepening insight into human nature produces an evermore comprehensive conception of a god, one that is not incompatible with a scientific worldview, or the secular rejection of the supernatural in the name ...

  16. Secular Life Philosophy as a Subject in Schools in Norway.

    Science.gov (United States)

    Horn, Kristian

    1981-01-01

    In Norway changes in legislation in recent years have loosened the firm hold of Christian philosophy in the schools and given room for alternative secular philosophy. This article presents background information and an outline of the basic plan for life philosophy as a school subject. (Author/SJL)

  17. On the scaling features of high-latitude geomagnetic field fluctuations during a large geomagnetic storm

    Science.gov (United States)

    De Michelis, Paola; Federica Marcucci, Maria; Consolini, Giuseppe

    2015-04-01

    Recently we have investigated the spatial distribution of the scaling features of short-time scale magnetic field fluctuations using measurements from several ground-based geomagnetic observatories distributed in the northern hemisphere. We have found that the scaling features of fluctuations of the horizontal magnetic field component at time scales below 100 minutes are correlated with the geomagnetic activity level and with changes in the currents flowing in the ionosphere. Here, we present a detailed analysis of the dynamical changes of the magnetic field scaling features as a function of the geomagnetic activity level during the well-known large geomagnetic storm occurred on July, 15, 2000 (the Bastille event). The observed dynamical changes are discussed in relationship with the changes of the overall ionospheric polar convection and potential structure as reconstructed using SuperDARN data. This work is supported by the Italian National Program for Antarctic Research (PNRA) - Research Project 2013/AC3.08 and by the European Community's Seventh Framework Programme ([FP7/2007-2013]) under Grant no. 313038/STORM and

  18. Equatorial E Region Electric Fields and Sporadic E Layer Responses to the Recovery Phase of the November 2004 Geomagnetic Storm

    Science.gov (United States)

    Moro, J.; Resende, L. C. A.; Denardini, C. M.; Xu, J.; Batista, I. S.; Andrioli, V. F.; Carrasco, A. J.; Batista, P. P.; Schuch, N. J.

    2017-12-01

    Equatorial E region electric fields (EEFs) inferred from coherent radar data, sporadic-E (Es) layers observed from a digital ionosonde data, and modeling results are used to study the responses of the equatorial E region over São Luís (SLZ, 2.3°S, 44.2°W, -7° dip angle), Brazil, during the super storm of November 2004. The EEF is presented in terms of the zonal (Ey) and vertical (Ez) components in order to analyze the corresponding characteristics of different types of Es seen in ionograms and simulated with the E region ionospheric model. We bring out the variabilities of Ey and Ez components with storm time changes in the equatorial E region. In addition, some aspects of the electric fields and Es behavior in three cases of weak, very weak, and strong Type II occurrences during the recovery phase of the geomagnetic storm are discussed. The connection between the enhanced occurrence and suppressions of the Type II irregularities and the q-type Es (Esq) controlled by electric fields, with the development or disruption of the blanketing sporadic E (Esb) layers produced by wind shear mechanism, is also presented. The mutual presence of Esq along with the Esb occurrences is a clear indicator of the secular drift of the magnetic equator and hence that of the equatorial electrojet (EEJ) over SLZ. The results show evidence about the EEJ and Es layer electrodynamics and coupling during geomagnetic disturbance time electric fields.

  19. Spatial patterns and secular trends in human leishmaniasis incidence in Morocco between 2003 and 2013.

    Science.gov (United States)

    Sadeq, Mina

    2016-05-11

    Few studies on spatial patterns or secular trends in human leishmanias have been conducted in Morocco. This study aimed to examine spatial patterns and trends associated with the human leishmaniasis incidence rate (HLIR) at the province/prefecture level between 2003 and 2013 in Morocco. Only the available published country data on the HLIR between 2003 and 2013, from the open access files of the Ministry of Health, were used. Secular trends were examined using Kendall's rank correlation. An exploratory spatial data analysis was also conducted to examine the spatial autocorrelation (Global Moran's I and local indicator of spatial association [LISA]), and spatial diffusion at the province/prefecture level. The influence of various covariates (poverty rate, vulnerability rate, population density, and urbanization) on the HLIR was tested via spatial regression (ordinary least squares regression). At the country level, no secular variation was observed. Poisson annual incidence rate estimates were 13 per 100 000 population (95 % CI = 12.9-13.1) for cutaneous leishmaniasis (CL) and 0.4 per 100 000 population (95 % CI = 0.4-0.5) for visceral leishmaniasis (VL). The available data on HLIR were based on combined CL and VL cases, however, as the CL cases totally outnumbered the VL ones, HLIR may be considered as CL incidence rate. At the provincial level, a secular increase in the incidence rate was observed in Al Hoceima (P = 0.008), Taounate (P = 0.04), Larache (P = 0.002), Tétouan (P = 0.0003), Khenifra (P = 0.008), Meknes (P = 0.03), and El Kelaa (P = 0.0007), whereas a secular decrease was observed only in the Chichaoua province (P = 0.006). Even though increased or decreased rate was evident in these provinces, none of them showed clustering of leishmaniasis incidence. Significant spatial clusters of high leishmaniasis incidence were located in the northeastern part of Morocco, while spatial clusters of low leishmaniasis

  20. Ten cycles of solar and geomagnetic activity

    International Nuclear Information System (INIS)

    Legrand, J.P.

    1981-01-01

    Series of 110 years of sunspot numbers and indices of geomagnetic activity are used with 17 years of solar wind data in order to study through solar cycles both stream and shock event solar activity. According to their patterns on Bartels diagrams of geomagnetic indices, stable wind streams and transient solar activities are separated from each other. Two classes of stable streams are identified: equatorial streams occurring sporadically, for several months, during the main phase of sunspot cycles and both polar streams established, for several years, at each cycle, before sunspot minimum. Polar streams are the first activity of solar cycles. For study of the relationship between transient geomagnetic phenomena and sunspot activity, we raise the importance of the contribution, at high spot number, of severe storms and, at low spot number, of short lived and unstable streams. Solar wind data are used to check and complete the above results. As a conclusion, we suggest a unified scheme of solar activity evolution with a starting point every eleventh year, a total duration of 17 years and an overlapping of 6 years between the first and the last phase of both successive series of phenomena: first, from polar field reversal to sunspot minimum, a phase of polar wind activity of the beginning cycle is superimposed on the weak contribution of shock events of the ending cycle; secondly, an equatorial phase mostly of shock events is superimposed on a variable contribution of short lived and sporadic stable equatorial stream activities; and thirdly a phase of low latitude shock events is superimposed on the polar stream interval of the following cycle. (orig.)

  1. Observations of secular changes in the kinematic model of SS433

    International Nuclear Information System (INIS)

    Collins, G.W. II; Newsom, G.H.

    1982-01-01

    In this paper the authors present evidence that several of the defining parameters of the Kinematic Model for SS433 are not constant but rather exhibit long term systematic changes. Recent data confirm the existence of the previously reported decrease in the precessional period. The value for this period change, when combined with the observed change in the period of the synodic spectral variations, implies that the orbital period is not significantly changing on a time scale less than 1000 years. In addition they find mounting evidence for a statistically significant (4sigma) secular change in the cone angle theta at a rate of about -1.5 x 10 -3 deg/day. However, the surprisingly short time scales implied by the observed values of dP/dt and dtheta/dt when combined with estimates of the system age suggest the possible existence of detectable higher time derivatives. This view is supported by the most recent data which suggest a value for d 2 P/dt 2 approximately 10 -5 (days) -1 . It is possible to understand these secular changes in terms of the motions to be expected from an object exhibiting classical precession in response to an external torque. (Auth.)

  2. Diurnal global variability of the Earth's magnetic field during geomagnetically quiet conditions

    Science.gov (United States)

    Klausner, V.

    2012-12-01

    This work proposes a methodology (or treatment) to establish a representative signal of the global magnetic diurnal variation. It is based on a spatial distribution in both longitude and latitude of a set of magnetic stations as well as their magnetic behavior on a time basis. We apply the Principal Component Analysis (PCA) technique using gapped wavelet transform and wavelet correlation. This new approach was used to describe the characteristics of the magnetic variations at Vassouras (Brazil) and 12 other magnetic stations spread around the terrestrial globe. Using magnetograms from 2007, we have investigated the global dominant pattern of the Sq variation as a function of low solar activity. This year was divided into two seasons for seasonal variation analysis: solstices (June and December) and equinoxes (March and September). We aim to reconstruct the original geomagnetic data series of the H component taking into account only the diurnal variations with periods of 24 hours on geomagnetically quiet days. We advance a proposal to reconstruct the Sq baseline using only the PCA first mode. The first interpretation of the results suggests that PCA/wavelet method could be used to the reconstruction of the Sq baseline.

  3. Properties of Pliocene sedimentary geomagnetic reversal records from the Mediterranean

    NARCIS (Netherlands)

    Linssen, J.H.

    1991-01-01

    In the history of the Earth the dipolar geomagnetic field has frequently reversed polarity. Though this property was already known early this century (Brunhes, 1906), nowadays the characteristics and the origin of polarity transitions are still largely unknown. The geomagnetic field and its

  4. International Geomagnetic Reference Field: the 12th generation

    DEFF Research Database (Denmark)

    Thébault, Erwan; Finlay, Chris; Beggan, Ciarán D.

    2015-01-01

    The 12th generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2014 by the Working Group V-MOD appointed by the International Association of Geomagnetism and Aeronomy (IAGA). It updates the previous IGRF generation with a definitive main field model for epoch ...

  5. Geomagnetic observations on Tristan da Cunha, South Atlantic Ocean

    DEFF Research Database (Denmark)

    Matzka, J.; Olsen, Nils; Maule, C. F.

    2009-01-01

    Few geomagnetic ground observations exist of the Earth's strongest core field anomaly, the South Atlantic Anomaly (SAA). The geomagnetic repeat station on the island Tristan da Cunha, located half-way between South Africa and South America at 37 degrees 05' S, 12 degrees 18' W, is therefore of cr...

  6. Computation of geomagnetic elements for Nigeria for the year 2000 ...

    African Journals Online (AJOL)

    The Earth's magnetic field may be considered to be the sum of two parts, the main geomagnetic field which originates from the earth's fluid core, and the anomaly field that has its sources in the earth crust. The analysis of the geomagnetic field residual or anomaly, obtained from the difference between these two sources are ...

  7. Effect of local perturbations of the geomagnetic field on cosmic ray cutoff rigidities at Jungfraujoch and Kiel

    International Nuclear Information System (INIS)

    Flueckiger, E.O.; Smart, D.F.; Shea, M.A.

    1983-01-01

    We have investigated the effect of local perturbations of the geomagnetic field on the vertical cosmic ray cutoff rigidities at Jungfraujoch and Kiel as representative mid-latitude neutron monitor stations. The main, effective, and Stoermer vertical cutoff rigidities and their changes were determined by utilizing the trajectory-tracing technique in a magnetic field which is modeled as a simple dipole field to which the disturbance field is superposed. It was found that the cosmic ray cutoff rigidities are most sensitive to variations of the z component of the geomagnetic field at geomagnetic latitudes -20 0 0 and at longitudes within 90 0 to the east of these northern hemisphere stations. Furthermore, cutoff rigidity variations at Kiel are predominantly due to changes of the geomagnetic field within geocentric distances 2.5R/sub E/< r<6R/sub E/, whereas at Jungfraujoch changes in cutoff rigidities are caused almost exclusively by magnetic disturbances within 1R/sub E/< r<4.5R/sub E/. For both locations the dependence of the main, effective, and Stoermer vertical cutoff rigidities on the radial, latitudinal and longitudinal structure of the magnetic perturbations is given explicitly. The results are discussed with respect to the theory by Treiman (1953) describing the effect of a ring current on cosmic ray cutoff rigidities. It is also shown that for the analysis of the characteristic properties of the correlation between cutoff rigidity variations and specific geomagnetic perturbations the rigidity corresponding to the first ''discontinuity band'' of the rigidity spectrum is an extremely useful parameter

  8. Optimal Transmission Line Switching under Geomagnetic Disturbances

    International Nuclear Information System (INIS)

    Lu, Mowen; Nagarajan, Harsha; Yamangil, Emre; Bent, Russell; Backhaus, Scott

    2017-01-01

    Recently, there have been increasing concerns about how geomagnetic disturbances (GMDs) impact electrical power systems. Geomagnetically-induced currents (GICs) can saturate transformers, induce hot spot heating and increase reactive power losses. These effects can potentially cause catastrophic damage to transformers and severely impact the ability of a power system to deliver power. To address this problem, we develop a model of GIC impacts to power systems that includes 1) GIC thermal capacity of transformers as a function of normal Alternating Current (AC) and 2) reactive power losses as a function of GIC. We also use this model to derive an optimization problem that protects power systems from GIC impacts through line switching, generator dispatch, and load shedding. We then employ state-of-the-art convex relaxations of AC power flow equations to lower bound the objective. We demonstrate the approach on a modified RTS96 system and UIUC 150-bus system and show that line switching is an effective means to mitigate GIC impacts. We also provide a sensitivity analysis of decisions with respect to GMD direction.

  9. Resolving issues concerning Eskdalemuir geomagnetic hourly values

    Directory of Open Access Journals (Sweden)

    S. Macmillan

    2011-02-01

    Full Text Available The hourly values of the geomagnetic field from 1911 to 1931 derived from measurements made at Eskdalemuir observatory in the UK, and available online from the World Data Centre for Geomagnetism at http://www.wdc.bgs.ac.uk/, have now been corrected. Previously they were 2-point averaged and transformed from the original north, east and vertical down values in the tables in the observatory yearbooks. This paper documents the course of events from discovering the post-processing done to the data to the final resolution of the problem. As it was through the development of a new index, the Inter-Hour Variability index, that this post-processing came to light, we provide a revised series of this index for Eskdalemuir and compare it with that from another European observatory. Conclusions of studies concerning long-term magnetic field variability and inferred solar variability, whilst not necessarily consistent with one another, are not obviously invalidated by the incorrect hourly values from Eskdalemuir. This series of events illustrates the challenges that lie ahead in removing any remaining errors and inconsistencies in the data holdings of different World Data Centres.

  10. Geomagnetic storm effects on GPS based navigation

    Directory of Open Access Journals (Sweden)

    P. V. S. Rama Rao

    2009-05-01

    Full Text Available The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena.

    Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(>10 dB L-band scintillation events, adversely affecting the GPS based navigation.

  11. Solar Wind Charge Exchange During Geomagnetic Storms

    Science.gov (United States)

    Robertson, Ina P.; Cravens, Thomas E.; Sibeck, David G.; Collier, Michael R.; Kuntz, K. D.

    2012-01-01

    On March 31st. 2001, a coronal mass ejection pushed the subsolar magnetopause to the vicinity of geosynchronous orbit at 6.6 RE. The NASA/GSFC Community Coordinated Modeling Center (CCMe) employed a global magnetohydrodynamic (MHD) model to simulate the solar wind-magnetosphere interaction during the peak of this geomagnetic storm. Robertson et aL then modeled the expected 50ft X-ray emission due to solar wind charge exchange with geocoronal neutrals in the dayside cusp and magnetosheath. The locations of the bow shock, magnetopause and cusps were clearly evident in their simulations. Another geomagnetic storm took place on July 14, 2000 (Bastille Day). We again modeled X-ray emission due to solar wind charge exchange, but this time as observed from a moving spacecraft. This paper discusses the impact of spacecraft location on observed X-ray emission and the degree to which the locations of the bow shock and magnetopause can be detected in images.

  12. Geomagnetically trapped carbon, nitrogen, and oxygen nuclei.

    Science.gov (United States)

    Mogro-Campero, A.

    1972-01-01

    Results of measurements carried out with the University of Chicago nuclear composition telescope on the Ogo 5 satellite, establishing the presence of 13- to 33-MeV/nucleon geomagnetically trapped C and O nuclei, with some evidence for N nuclei. These trapped nuclei were found at L less than or equal to 5 and near the geomagnetic equator. The data cover the period from Mar. 3, 1968, to Dec. 31, 1969. The distribution of CNO flux as a function of L is given. No change in the intensity of the average trapped CNO flux was detected by comparing data for 1968 and 1969. The results reported set a new value for the observed high energy limit of trapping as described by the critical adiabaticity parameter. The penetration of solar flare CNO up to L = 4 was observed twice in 1968, in disagreement with Stormer theory predictions. The effects of these results on some models for the origin of the trapped radiation are discussed.

  13. Evidence for geomagnetic imprinting as a homing mechanism in Pacific salmon.

    Science.gov (United States)

    Putman, Nathan F; Lohmann, Kenneth J; Putman, Emily M; Quinn, Thomas P; Klimley, A Peter; Noakes, David L G

    2013-02-18

    In the final phase of their spawning migration, Pacific salmon use chemical cues to identify their home river, but how they navigate from the open ocean to the correct coastal area has remained enigmatic. To test the hypothesis that salmon imprint on the magnetic field that exists where they first enter the sea and later seek the same field upon return, we analyzed a 56-year fisheries data set on Fraser River sockeye salmon, which must detour around Vancouver Island to approach the river through either a northern or southern passageway. We found that the proportion of salmon using each route was predicted by geomagnetic field drift: the more the field at a passage entrance diverged from the field at the river mouth, the fewer fish used the passage. We also found that more fish used the northern passage in years with warmer sea surface temperature (presumably because fish were constrained to more northern latitudes). Field drift accounted for 16% of the variation in migratory route used, temperature 22%, and the interaction between these variables 28%. These results provide the first empirical evidence of geomagnetic imprinting in any species and imply that forecasting salmon movements is possible using geomagnetic models. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Analysis of the ULF electromagnetic emission related to seismic activity, Teoloyucan geomagnetic station, 1998-2001

    Directory of Open Access Journals (Sweden)

    A. Kotsarenko

    2004-01-01

    Full Text Available Results of ULF geomagnetic measurements at station Teoloyucan (Central Mexico, 99.11'35.735''W, 19.44'45.100''N, 2280m height in relation to seismic activity in the period 1998-2001 and their analysis are presented. Variations of spectral densities for horizontal and vertical components, polarization densities and spectrograms of magnetic field, their derivatives are analyzed as a part of traditional analysis in this study. Values of spectral density were calculated for 6 fixed frequencies f=1, 3, 10, 30, 100 and 300mHz. Fractal characteristics of spectra were analyzed in the conception of SOC (Self-Organized Criticality. 2 nighttime intervals, 0-3 and 3-6h by local time have been used to decrease the noise interference in row data. In order to exclude the intervals with a high geomagnetic activity from analysis we referred to Ap indices, calculated for corresponding time intervals. The contribution of seismic events to geomagnetic emission was estimated by seismic index ks=100.75Ms/10D, where Ms is the amplitude of the earthquake and D is the distance from its epicenter to the station.

  15. The signature of the 2011 Tohoku mega earthquake on the geomagnetic field measurements in Japan

    Directory of Open Access Journals (Sweden)

    E.M. Takla

    2013-12-01

    Full Text Available On 11 March 2011 at 05:46:23 UTC, a mega earthquake (EQ with magnitude (Mw 9.0 [The 2011 Tohoku Earthquake] occurred at a depth of about 24 km near the East coast of Honshu Island, Japan as a result of a thrust faulting on or near the subduction plate boundary between the Pacific and North American plates. Geomagnetic data from MAGDAS and Geospatial Information Authority of Japan (GSI networks have been analyzed to examine the signature of the 2011 Tohoku earthquake on the geomagnetic field measurements in Japan. Results of data analysis indicate about 5 nT increase in the total geomagnetic field intensity in the vicinity of the epicenter of 2011Tohoku EQ compared with other reference stations. Moreover, the annual range of the Z-component daily variations tends to decrease near the epicenter before the occurrence of the Tohoku EQ. Concerning the ULF emissions; the Pc 3 amplitude ratio (ZPc3/HPc3 near the epicenter at the Onagawa [ONW] station showed a good correlation with other remote reference stations before the Tohoku EQ but it started to decrease with no correlation to other stations a few weeks before the 2011 Tohoku EQ. On the other hand, the Pc 3 amplitude ratio at ONW station showed a clear anti-correlation compared with reference stations after the 2011 Tohoku EQ.

  16. Enhancement of low energy particle flux around plasmapause under quiet geomagnetic condition

    Science.gov (United States)

    Lee, J.

    2016-12-01

    Plasmapause is the boundary of the plasmaspheric region where cold plasma is dominant. In this boundary, the plasma density shows depletion to 1 10 on direction from the plasmasphere to magnetosphere and changes composition of energy distribution of particle. Some previous study provides that the location of the plasmapause expand beyond geosynchronous orbit under the quiet geomagnetic conditions. In this work, we study the changed characteristic of particle flux around the plasmapause using measurement from Van Allen Probes. On 23 April 2013, the satellites observed simultaneously proton and electron fluxes enhancement with E > 100 eV. During 12 hours prior to this event, the geomagnetic conditions were very quiet, Kp < 1, and geomagnetic storm did not occur. This event maintain for 15 minutes and only proton flux decrease rapidly in the magnetosphere. In this period SYM-H index enhanced abruptly in response to the impact of the dynamic pressure enhancement and AE index increased gradually up to about 200 nT. Electric field started to perturb in coincidence with enhancement of particle flux from the plasmapause. To explain the variation of low energy particle flux we will compare kinetic property of low energy particle by using velocity space distribution function at region of inner and outer boundary of the plasmapause.

  17. Response of the middle atmosphere to the geomagnetic storm of November 2004

    Science.gov (United States)

    Hocke, Klemens

    2017-02-01

    Ozone and temperature profiles of the satellite microwave limb sounder Aura/MLS are used for the derivation of the middle atmospheric response to the geomagnetic superstorm of 9 November 2004. We find a destruction of the tertiary ozone layer at 0.022 hPa (77 km) in the northern winter hemisphere lasting for about one week. This effect is surely due to the solar proton event (SPE) of November 2004. At the same time, the zonal mean temperature is enhanced by 5-10 K in the northern polar mesosphere. On the other hand, the zonal mean temperature is decreased by 5-10 K in the northern polar stratosphere. We do not think that the strong temperature perturbations are directly related to the SPE. It seems that the polar vortex was moved by the geomagnetic storm, and this vortex movement caused the strong temperature variations in the zonal mean. However, internal variability of temperature in the polar middle atmosphere in winter without any significant link to the geomagnetic storm cannot be excluded.

  18. Hausdorff-Based RC and IESIL Combined Positioning Algorithm for Underwater Geomagnetic Navigation

    Directory of Open Access Journals (Sweden)

    Lin Yi

    2010-01-01

    Full Text Available This paper presents a primitive solution with novel scheme and algorithm for Underwater geoMagnetic Navigation (UMN, which now occurs as the hot-point in the research field of navigation. UMN as an independent or supplementary technique can theoretically supply accurate locations for marine vehicles, but in practice there are plenty of restrictions for UMN's application (e.g., geomagnetic daily variation. After analysis of the theoretical model of geomagnetic positioning in the correlation-matching mode from the viewpoint of pattern recognition, this paper proposed an appropriate matching scenario and a combined positioning algorithm for UMN. The subalgorithm of Hausdorff-based Relative Correlation (RC corresponding to the pattern classification module implements the coarse positioning, and the subalgorithm of Isograms Equidistance-Segmenting theIntersection Lines (IESILs associated with the module of feature extraction continues the fine positioning. The experiments based on the simulation platform and the real-surveyed data both validate the new algorithm, and its efficiency and accuracy are also discussed. It can be concluded that the work introduced in this paper gives an initial and real validation of UMN's potentiality.

  19. Sacralizando o secular. Os movimentos etno-fundamentalistas

    Directory of Open Access Journals (Sweden)

    Enzo Pace

    2017-10-01

    Full Text Available Os movimentos religiosos fundamentalistas encaram o Estado secular como um inimigo, porque pretendem sistematizar seu poder como se Deus não atuasse. Esses movimentos consideram sua religião como o repositório de verdade absoluta, a fonte derradeira que legitima as leis humanas. Assim, conquanto sejam pós-seculares, ao mesmo tempo tentam transformar os princípios religiosos em agendas políticas. Com efeito, os militantes agem frequentemente de acordo com princípios políticos, procurando afirmar o primado de sua própria fé sobre a dos outros. Eles se movem dentro das sociedades contemporâneas em nome de uma teologia política radical. Os principais argumentos baseiam-se em dois estudos de caso: o Bodu Bala Sena no Sri Lanka e os movimentos para o Hindutva na Índia.

  20. The equations of motion of a secularly precessing elliptical orbit

    Science.gov (United States)

    Casotto, S.; Bardella, M.

    2013-01-01

    The equations of motion of a secularly precessing ellipse are developed using time as the independent variable. The equations are useful when integrating numerically the perturbations about a reference trajectory which is subject to secular perturbations in the node, the argument of pericentre and the mean motion. Usually this is done in connection with Encke's method to ensure minimal rectification frequency. Similar equations are already available in the literature, but they are either given based on the true anomaly as the independent variable or in mixed mode with respect to time through the use of a supporting equation to track the anomaly. The equations developed here form a complete and independent set of six equations in time. Reformulations both of Escobal's and Kyner and Bennett's equations are also provided which lead to a more concise form.

  1. Identification of the different magnetic field contributions during a geomagnetic storm in magnetospheric and ground observations

    Directory of Open Access Journals (Sweden)

    T. Alberti

    2016-11-01

    Full Text Available We used the empirical mode decomposition (EMD to investigate the time variation of the magnetospheric and ground-based observations of the Earth's magnetic field during both quiet and disturbed periods. We found two timescale variations in magnetospheric data which are associated with different magnetospheric current systems and the characteristic diurnal orbital variation, respectively. On the ground we identified three timescale variations related to the solar-wind–magnetosphere high-frequency interactions, the ionospheric processes, and the internal dynamics of the magnetosphere. This approach is able to identify the different physical processes involved in solar-wind–magnetosphere–ionosphere coupling. In addition, the large-timescale contribution can be used as a local index for the identification of the intensity of a geomagnetic storm on the ground.

  2. Between Christianity and secularity: counselling and psychotherapy provision in Scotland

    OpenAIRE

    Bondi, Liz

    2013-01-01

    Counselling and psychotherapy services have become increasingly prominent within modern urban welfare. Although often perceived to be intrinsically secular, since psychoanalytic thinking and practice arrived in Scotland it has been shaped by the Christian culture it encountered. Early Scottish-born contributors to psychoanalytic theory, including Ian Suttie and W.R.D. Fairbairn, reframed Freud’s ideas in ways that incorporated Scottish Presbyterian understandings of what it is to be human. A ...

  3. [Civic religion, civil religion, secular religion. a historiographical investigation].

    Science.gov (United States)

    Boucheron, Patrick

    2013-01-01

    Because of its conceptual plasiticity, the term civic religion is now widely used by historians, particularly historians of the Middle Ages. Yet, as this article suggests, historians would do well to interrogate the relationships (which can be hidden) that this term bears to similar concepts such as Greek Roman civic religion, Enlightenment civil religion or even the secular religion that emerged in the work of 20(th) century thinkers.

  4. Spirituality and secularization: nursing and the sociology of religion.

    Science.gov (United States)

    Paley, John

    2008-01-01

    The concept of spirituality is much discussed in the UK nursing literature, despite the fact that Britain is one of the most secular countries in the world, and steadily becoming more so. Here, I pose the following question: given this increasing secularization, what accounts for the current interest in spirituality among UK nurses? The literature on spirituality in nursing has blossomed in the last 10 years, and various attempts have been made to define 'spirituality', 'spiritual need' and 'spiritual care'. Most definitions distinguish between 'spirituality' and 'religion', acknowledging that the latter is more institutional, and theologically more restrictive, than the former; and they suggest that spirituality is universal, something which (unlike religion) all human beings share. I draw on the sociology of religion - neglected, for the most part, in the nursing literature - to establish two main points. Firstly, that the UK and the USA are at opposite ends of the religion/secularity spectrum, implying that it is a mistake to assimilate USA and UK sources. Secondly, that the concept of spirituality, as currently understood, is of very recent origin, and is still 'under construction', having become separated from its associations with Christian piety and mysticism only since the 1980s. The extension of spirituality into secular domains is part of a professionalization project in nursing, a claim to jurisdiction over a newly invented sphere of work. For the time being, it remains an academic project (in the UK) as it is not one with which many clinicians identify. Relevance to clinical practice. What counts as 'spiritual need' or 'spiritual care' may not be the same in both countries, and UK clinicians are unlikely to welcome the role of surrogate chaplain, which their USA colleagues are apparently willing to embrace.

  5. The CHAOS-3 Geomagnetic Field Model and Candidates for the 11th Generation IGRF

    DEFF Research Database (Denmark)

    Olsen, Nils; Mandea, Mioara; Sabaka, Terence J.

    2010-01-01

    As a part of the 11th generation IGRF defined by IAGA, we propose a candidate model for the DGRF 2005, a candidate model for IGRF 2010 and a candidate model for the mean secular variation between 2010 and 2015. These candidate models, the derivation of which is described in the following, are bas...... = 20, described by order 6 splines (with 6-month knot spacing) spanning the time interval 1997.0–2010.0. The third time derivative of the squared magnetic field intensity is regularized at the core-mantle boundary. No spatial regularization is applied....

  6. Geomagnetic response to solar and interplanetary disturbances

    Directory of Open Access Journals (Sweden)

    Maris Georgeta

    2013-07-01

    Full Text Available The space weather discipline involves different physical scenarios, which are characterised by very different physical conditions, ranging from the Sun to the terrestrial magnetosphere and ionosphere. Thanks to the great modelling effort made during the last years, a few Sun-to-ionosphere/thermosphere physics-based numerical codes have been developed. However, the success of the prediction is still far from achieving the desirable results and much more progress is needed. Some aspects involved in this progress concern both the technical progress (developing and validating tools to forecast, selecting the optimal parameters as inputs for the tools, improving accuracy in prediction with short lead time, etc. and the scientific development, i.e., deeper understanding of the energy transfer process from the solar wind to the coupled magnetosphere-ionosphere-thermosphere system. The purpose of this paper is to collect the most relevant results related to these topics obtained during the COST Action ES0803. In an end-to-end forecasting scheme that uses an artificial neural network, we show that the forecasting results improve when gathering certain parameters, such as X-ray solar flares, Type II and/or Type IV radio emission and solar energetic particles enhancements as inputs for the algorithm. Regarding the solar wind-magnetosphere-ionosphere interaction topic, the geomagnetic responses at high and low latitudes are considered separately. At low latitudes, we present new insights into temporal evolution of the ring current, as seen by Burton’s equation, in both main and recovery phases of the storm. At high latitudes, the PCC index appears as an achievement in modelling the coupling between the upper atmosphere and the solar wind, with a great potential for forecasting purposes. We also address the important role of small-scale field-aligned currents in Joule heating of the ionosphere even under non-disturbed conditions. Our scientific results in

  7. Secularization and its Impact on the Jews’ Religious Life

    Directory of Open Access Journals (Sweden)

    Vasile Adrian

    2017-12-01

    Full Text Available Secularization brings forward a desacralized world, exclusively oriented to the material and concerned with the “fashion of the day” rather than with the Spirit of God. Secularism made man wander from god and ignore the religious, spiritual and moral principles found in Christianity and Judaism. Secularization caused all social, economic or political aspects be expressed outside these principles and, many times, against them. Man’s religiousness has become something personal and original that has nothing to do with community or the life of the community, thus becoming a strictly private or intimate option, and in many case even a taboo. Therefore we speak about a privatization of the religious feeling that has no connection to Christianity or Judaism. Unfortunately Judaism has been affected in some other way besides what concerns religious life. We are referring to the anti-Semite feeling that reached its peak at the beginning of the last century and tragically ended in the holocaust in which millions of Jews lost their lives.

  8. Secular Extragalactic Parallax and Geometric Distances with Gaia Proper Motions

    Science.gov (United States)

    Paine, Jennie; Darling, Jeremiah K.

    2018-06-01

    The motion of the Solar System with respect to the cosmic microwave background (CMB) rest frame creates a well measured dipole in the CMB, which corresponds to a linear solar velocity of about 78 AU/yr. This motion causes relatively nearby extragalactic objects to appear to move compared to more distant objects, an effect that can be measured in the proper motions of nearby galaxies. An object at 1 Mpc and perpendicular to the CMB apex will exhibit a secular parallax, observed as a proper motion, of 78 µas/yr. The relatively large peculiar motions of galaxies make the detection of secular parallax challenging for individual objects. Instead, a statistical parallax measurement can be made for a sample of objects with proper motions, where the global parallax signal is modeled as an E-mode dipole that diminishes linearly with distance. We present preliminary results of applying this model to a sample of nearby galaxies with Gaia proper motions to detect the statistical secular parallax signal. The statistical measurement can be used to calibrate the canonical cosmological “distance ladder.”

  9. Cognitive dissonance between religious and secular social attitudes

    Directory of Open Access Journals (Sweden)

    Marković Jelena

    2003-01-01

    Full Text Available The initial finding of the study, which served as the basis for the exploration of cognitive dissonance between religious and secular behavioral norms, was revealed in a tendency of the majority of religious students to accept behavioral norms, attitudes and believes (concerning interpersonal relationships and reproduction-related ethical issues which are not supported by Orthodox Christian Church viewpoint and teachings. However, certain cognitive and value system consistency appeared to exist: the intensity of religiousness was related to lower degrees of secular norms approval. It has been found that religious and nonreligious subjects differ significantly in their preference of the strategy used to maintain balance between dissonant religious and secular attitudes- in 3 out of 4 issues considered in the study. Religious subjects most frequently chose relativism strategy, claiming that some specific exceptions from a general rule or standpoint do not necessarily depreciate it, while nonreligious subjects most frequently chose dualistic viewpoint that principally separated and restricted domains of reasoning on spiritual and worldly issues, making them psychologically irrelevant to one another.

  10. Global Ultra-Low-Frequency Geomagnetic Pulsations Associated with the March 24, 1991 Geomagnetic Storm

    Directory of Open Access Journals (Sweden)

    Nan-Wei Chen Jann-Yenq Liu

    2008-01-01

    Full Text Available On 24 March 1991, global ultra-low-frequency (ULF pulsations (1.1 - 3.3 mHz observed in the magnetosphere as well as on the ground were studied via analyzing magnetic field data obtained from a global network, comprising ground-based observatories and geosynchronous satellites. In the magnetosphere, the compressional and transverse components of the magnetic fields recorded at two satellites, GOES 6 and GOES 7, showed dominant fluctuations when they were in the vicinity of the noon sector, whereas the transverse fluctuations became dominant when they were at the dawn side. Similarly, on the ground, the H and D components had major fluctuations along with an increase in amplitude from low to high geomagnetic latitudes. In addition, the amplitude of the ULF pulsation was enhanced at the dawn and dusk sides. The geomagnetic pulsations propagated anti-sunward and were of counterclockwise and clockwise elliptical polarizations at the dawn and dusk sides respectively. The counterclockwise elliptical polarization reversed to a clockwise elliptical polarization at geomagnetic local noon and linear polarization was observed during the reversal. It appears that the analysis of the global network data not only provided us with a study of the characteristics of the waves in the magnetosphere and on the ground but also provided us with correlations between the geosynchronous and ground observations, which should be essential to the determination of possible mechanisms of this storm-related wave event.

  11. Mesospheric Na Variability and Dependence on Geomagnetic and Solar Activity over Arecibo

    Science.gov (United States)

    Jain, K.; Raizada, S.; Brum, C. G. M.

    2017-12-01

    The Sodium (Na) resonance lidars located at the Arecibo Observatory offer an excellent opportunity to study the mesosphere/lower thermosphere(MLT) region. Different metals like Fe, Mg, Na, K, Ca and their ions are deposited in the 80 - 120 km altitude range due to the ablation of meteors caused by frictional heating during their entry into the Earth's atmosphere. We present an investigation of the neutral mesospheric Na atom layers over Arecibo. Data on the Na concentrations was collected using a resonance lidar tuned to the of Na wavelength at 589 nm. This wavelength is achieved with a dye-laser pumped by the second harmonic (532 nm) generated from a state-of-the-art commercial Nd:YAG laser. The backscattered signal is received on a 0.8 m (diameter) Cassegrain telescope. The study is based on this data acquired from 1998-2017 and its relation to variations in geomagnetic and solar conditions. We also investigate seasonal and long term trends in the data. The nightly-averaged altitude profiles were modeled as Gaussian curves. From this modeled data we obtain parameters such as the peak, abundance, centroid and width of the main Na layer. Preliminary results show that the Na abundance is more sensitive to changes in geomagnetic and solar variations as compared to the width and centroid height. The seasonal variation exhibits higher peak densities during the local summer and has a secondary maximum during the winter [as shown in the attached figure]. Our analysis demonstrates a decrease in the peak and the abundance of Na atoms with the increase of solar and geomagnetic activity.

  12. An association between geomagnetic activity and dream bizarreness.

    Science.gov (United States)

    Lipnicki, Darren M

    2009-07-01

    Daily disturbances of the earth's magnetic field produce variations in geomagnetic activity (GMA) that are reportedly associated with widespread effects on human health and behaviour. Some of these effects could be mediated by an established influence of GMA on the secretion of melatonin. There is evidence from unrelated research that melatonin influences dream bizarreness, and it is hypothesised here that there is an association between GMA and dream bizarreness. Also reported is a preliminary test of this hypothesis, a case study in which the dreams recorded over 6.5 years by a young adult male were analysed. Reports of dreams from the second of two consecutive days of either low or high GMA (K index sum or = 28) were self-rated for bizarreness on a 1-5 scale. Dreams from low GMA periods (n=69, median bizarreness=4) were found to be significantly more bizarre than dreams from high GMA periods (n=85, median bizarreness=3; p=0.006), supporting the hypothesised association between GMA and dream bizarreness. Studies with larger samples are needed to verify this association, and to determine the extent to which melatonin may be involved. Establishing that there is an association between GMA and dream bizarreness would have relevance for neurophysiological theories of dreaming, and for models of psychotic symptoms resembling bizarre dream events.

  13. Using statistical correlation to compare geomagnetic data sets

    Science.gov (United States)

    Stanton, T.

    2009-04-01

    The major features of data curves are often matched, to a first order, by bump and wiggle matching to arrive at an offset between data sets. This poster describes a simple statistical correlation program that has proved useful during this stage by determining the optimal correlation between geomagnetic curves using a variety of fixed and floating windows. Its utility is suggested by the fact that it is simple to run, yet generates meaningful data comparisons, often when data noise precludes the obvious matching of curve features. Data sets can be scaled, smoothed, normalised and standardised, before all possible correlations are carried out between selected overlapping portions of each curve. Best-fit offset curves can then be displayed graphically. The program was used to cross-correlate directional and palaeointensity data from Holocene lake sediments (Stanton et al., submitted) and Holocene lava flows. Some example curve matches are shown, including some that illustrate the potential of this technique when examining particularly sparse data sets. Stanton, T., Snowball, I., Zillén, L. and Wastegård, S., submitted. Detecting potential errors in varve chronology and 14C ages using palaeosecular variation curves, lead pollution history and statistical correlation. Quaternary Geochronology.

  14. Statistical Study of False Alarms of Geomagnetic Storms

    DEFF Research Database (Denmark)

    Leer, Kristoffer; Vennerstrøm, Susanne; Veronig, A.

    . A subset of these halo CMEs did not cause a geomagnetic storm the following four days and have therefore been considered as false alarms. The properties of these events are investigated and discussed here. Their statistics are compared to the geo-effective CMEs. The ability to identify potential false......Coronal Mass Ejections (CMEs) are known to cause geomagnetic storms on Earth. However, not all CMEs will trigger geomagnetic storms, even if they are heading towards the Earth. In this study, front side halo CMEs with speed larger than 500 km/s have been identified from the SOHO LASCO catalogue...

  15. There is a Sexular Body: Introducing a Material Approach to the Secular

    Directory of Open Access Journals (Sweden)

    Jelle Wiering

    2017-05-01

    Full Text Available This article calls for more ‘bottom-up inquiry’ into the secular, departing from the assumption that it features normative ideologies and practices that dominate current societies. I plea for collecting and analyzing manifestations of the secular, as the secular as an phenomenon in society is surprisingly unexplored. To stimulate such inquiry, I suggest a material approach to the secular, as it will provide researchers with tools to conduct empirical research on the secular in contemporary societies. Inspired by Joan Scott, Charles Hirschkind, and Talal Asad, this article explores the notion of a Dutch ‘sexular’ body: a body which affective-gestural repertoires, limited here to the context of sexuality, people in society (historically associate with the secular. I conclude by arguing that a material approach to the secular will contribute to (1 obtaining a more comprehensive understanding of the secular, including its cultural conceptualizations and manifestations, and (2 clarifying, and hence facing the normativity the secular imposes on the people living in secular societies.

  16. Regional 3-D Modeling of Ground Geoelectric Field for the Northeast United States due to Realistic Geomagnetic Disturbances

    Science.gov (United States)

    Ivannikova, E.; Kruglyakov, M.; Kuvshinov, A. V.; Rastaetter, L.; Pulkkinen, A. A.; Ngwira, C. M.

    2017-12-01

    During extreme space weather events electric currents in the Earth's magnetosphere and ionosphere experience large variations, which leads to dramatic intensification of the fluctuating magnetic field at the surface of the Earth. According to Faraday's law of induction, the fluctuating geomagnetic field in turn induces electric field that generates harmful currents (so-called "geomagnetically induced currents"; GICs) in grounded technological systems. Understanding (via modeling) of the spatio-temporal evolution of the geoelectric field during enhanced geomagnetic activity is a key consideration in estimating the hazard to technological systems from space weather. We present the results of ground geoelectric field modeling for the Northeast United States, which is performed with the use of our novel numerical tool based on integral equation approach. The tool exploits realistic regional three-dimensional (3-D) models of the Earth's electrical conductivity and realistic global models of the spatio-temporal evolution of the magnetospheric and ionospheric current systems responsible for geomagnetic disturbances. We also explore in detail the manifestation of the coastal effect (anomalous intensification of the geoelectric field near the coasts) in this region.

  17. GEOMAGNETIC CONJUGACY OF MODERN TECTONIC STRUCTURES

    Directory of Open Access Journals (Sweden)

    G. Ya. Khachikyan

    2013-01-01

    Full Text Available An earthquake is an element of the global electric circuit (GEC –  this new idea suggested in the space age is tested in our study. In the frame of the GEC concept, one may expect that tectonic structures of the northern and southern hemispheres may be magnetically conjugated. It is found that the midocean ridges of the southern hemisphere, located along the boundary of the Antarctic lithosphere plate, are magnetically conjugated with the areas of the junction of continental orogens and platforms in the northern hemisphere. The closest geomagnetic conjugacy exists between the southern boundary of Nazca lithospheric plate and the northern boundaries of Cocos and Caribbean lithospheric plates.

  18. Extreme Geomagnetic Storms – 1868–2010

    DEFF Research Database (Denmark)

    Vennerstrøm, Susanne; Lefèvre, L.; Dumbović, M.

    2016-01-01

    presents our investigation of the corresponding solar eventsand their characteristics. The storms were selected based on their intensity in the aa index,which constitutes the longest existing continuous series of geomagnetic activity. They areanalyzed statistically in the context of more well...... occurring in May 1921 and the Quebec storm from March 1989. We identifykey characteristics of the storms by combining several different available data sources, listsof storm sudden commencements (SSCs) signifying occurrence of interplanetary shocks,solar wind in-situ measurements, neutron monitor data...... %), Forbushdecreases (100 %), and energetic solar proton events (70 %). A quantitative comparison ofthese associations relative to less intense storms is also presented. Most notably, we findthat most often the extreme storms are characterized by a complexity that is associated with multiple, often interacting, solar...

  19. Magnetic Field Perturbations from Currents in the Dark Polar Regions During Quiet Geomagnetic Conditions

    DEFF Research Database (Denmark)

    Friis-Christensen, Eigil; Finlay, Chris; Hesse, M.

    2017-01-01

    In the day-side sunlit polar ionosphere the varying and IMF dependent convection creates strong ionospheric currents even during quiet geomagnetic conditions. Observations during such times are often excluded when using satellite data to model the internal geomagneticmain field. Observations from...... the night-side or local winter during quiet conditions are, however, also influenced by variations in the IMF. In this paper we briefly review the large scale features of the ionospheric currents in the polar regions with emphasis on the current distribution during undisturbed conditions. We examine...

  20. Preliminary paleomagnetic and rock magnetic results from 17 to 22 ka sediment of Jeju Island, Korea: Geomagnetic excursional behavior or rock magnetic anomalies?

    Science.gov (United States)

    Ahn, Hyeon-Seon; Sohn, Young Kwan; Lee, Jin-Young; Kim, Jin Cheul

    2018-05-01

    Paleomagnetic and rock magnetic investigations were performed on a 64-cm-thick section of nonmarine unconsolidated muddy sediment from the Gosan Formation on Jeju Island, Korea. This sediment was recently dated to have been deposited between 22 and 17 kyr BP calibrated, with a sedimentation rate of 13-25 cm/kyr, based on many radiocarbon ages. Interestingly, stepwise alternating field (AF) demagnetization revealed characteristic natural remanent magnetizations with anomalous directions, manifested by marked deviations from the direction of today's axial dipole field, for some separate depth levels. On the other hand, stepwise thermal (TH) demagnetization showed more complex behavior, resulting in the identification of multiple remanence components. For all TH-treated specimens, consistently two different components are predominant: a low-temperature component unblocked below 240-320 °C entirely having normal-polarity apparently within the secular variation range of the Brunhes Chron, and a high-temperature component with unblocking temperatures (Tubs) between 240-320 and 520-580 °C that have anomalous directions, concentrated in the 13-34-cm-depth interval ( 17-19 ka in inferred age) and possibly below 53 cm depth (before 20 ka). Rock magnetic results also infer the dominance of low-coercivity magnetic particles having 300 and 580 °C Curie temperature as remanence carriers, suggestive of (titano)maghemite and/or Ti-rich titanomagnetite and magnetite (or Ti-poor titanomagnetite), respectively. A noteworthy finding is that AF demagnetizations in this study often lead to incomplete separation of the two remanence components possibly due to their strongly overlapping AF spectra. The unusual directions do not appear to result from self-reversal remanences. Then, one interpretation is that the low-temperature components are attributable to post-depositional chemical remanences, associated possibly with the later formation of the mineral phase having Tub 300

  1. Basic Geomagnetic Network of the Republic of Croatia 2004 – 2012, with Geomagnetic Field Maps for 2009.5 epoch

    Directory of Open Access Journals (Sweden)

    Mario Brkić

    2013-12-01

    Full Text Available After more than half a century, scientific book Basic Geomagnetic Network of the Republic of Croatia 2004 – 2012, with Geomagnetic Field Maps for 2009.5 epoch describes the recent geomagnetic field on Croatian territory. A review of research in the past decade as well as the original solutions makes the book a document of contribution to geodesy and geomagnetism in Croatia.The book’s introduction gives an overview of two centuries of history and the strategic, security, economic and scientific significance of knowing the geomagnetic field on the Croatian territory. All the activities related to the updating of the geomagnetic information, which took place in the last decade, signified a big step toward the countries where geomagnetic survey is a mature scientific and technical discipline, and a scientific contribution to understanding of the nature of the Earth's magnetism.The declination, inclination and total intensity maps (along with the normal annual changes for the epoch 2009.5 are given in the Appendix. The book Basic Geomagnetic Network of the Republic of Croatia 2004 – 2012, with Geomagnetic Field Maps for 2009.5 epoch (ISBN 978-953-293-521-9 is published by the State Geodetic Administration of the Republic of Croatia. Beside editor in chief, M. Brkić, the authors are: E. Vujić, D. Šugar, E. Jungwirth, D. Markovinović, M. Rezo, M. Pavasović, O. Bjelotomić, M. Šljivarić, M. Varga and V. Poslončec-Petrić. The book contains 48 pages and 3 maps, and is published in 200 copies. CIP record is available in digital catalogue of the National and University Library in Zagreb under number 861937.

  2. Long-term north-south asymmetry in solar wind speed inferred from geomagnetic activity: A new type of century-scale solar oscillation?

    DEFF Research Database (Denmark)

    Mursula, K.; Zieger, B.

    2001-01-01

    A significant and very similar annual variation in solar wind speed and in geomagnetic activity was recently found around all the four solar cycle minima covered by direct SW observations since mid-1960's. We have shown that the phase of this annual variation reverses with the Sun's polarity...... reversal, depicting a new form of 22-year periodicity. The annual variation results from a small north-south asymmetry in SW speed distribution where the minimum speed region is shifted toward the northern magnetic hemisphere. Here we study the very long-term evolution of the annual variation using early...... registrations of geomagnetic activity. We find a significant annual variation during the high-activity solar cycles in mid-19th century and since 1930's. Most interestingly, the SW speed asymmetry in mid-19th century was opposite to the present asymmetry, i.e., the minimum speed region was then shifted toward...

  3. Tendência secular em estatura: uma revisão da literatura Secular height trend: a literature review

    Directory of Open Access Journals (Sweden)

    Gilberto Kac

    1999-09-01

    Full Text Available Esse trabalho constitui-se em uma revisão de literatura sobre tendência secular em estatura (TSE. Os principais tópicos abordados foram a definição do fenômeno, a utilização de dados históricos de estatura como estratégia alternativa no monitoramento de mudanças econômicas, as principais explicações teóricas sugeridas para a ocorrência do fenômeno, o início da antropometria militar, sua utilização no passado e no presente, e a magnitude da tendência em recrutas e na população infantil. Os principais achados revelaram que a TSE tem sido atribuída, sobretudo, a influências ambientais, em particular, a melhorias nas condições sanitárias, econômicas e sociais. As taxas médias de incremento variaram conforme a idade, o estrato sócio-econômico e o país considerado; portanto, deve-se ter cautela nas comparações interpopulacionais. A Segunda Guerra Mundial reduziu a tendência em diversos países, entre eles o Brasil, mas as taxas de incremento no pós-guerra foram ainda maiores do que as observadas no início do século. Constatou-se, por fim, que dados provenientes da antropometria militar são os mais utilizados para estimativas de TSE.This paper presents a literature review of secular height trends. The principal topics included were definition of the phenomenon, use of historical data sets on height as an alternative approach for monitoring economic changes, the main theoretical explanations of the phenomenon, the beginning of military anthropometry, and past and current use in measuring secular height trends in recruits and children. The most important results showed that the positive secular trend can be attributed to environmental influences, especially improvements in health, economic, and social conditions. The mean reported rates in height increases varied with age, socioeconomic status, and country, so one must exercise caution in drawing inferences. World War II slowed the trend in several countries

  4. Effects of geomagnetic storm on low latitude ionospheric total ...

    Indian Academy of Sciences (India)

    1Department of Physics, Tripura University, Suryamaninagar, Tripura 799 022, India. ... the fact that the electro-dynamic effect of geomagnetic storms around EIA region is more effective than ... causes range of error in GPS communication.

  5. A comprehensive analysis of the geomagnetic storms occurred dur

    Directory of Open Access Journals (Sweden)

    Essam Ghamry

    2016-06-01

    Full Text Available The Geomagnetic storms are considered as one of the major natural hazards. Egyptian geomagnetic observatories observed multiple geomagnetic storms during 18 February to 2 March 2014. During this period, four interplanetary shocks successively hit the Earth’s magnetosphere, leading to four geomagnetic storms. The storm onsets occurred on 18, 20, 23 and 27 February. A non-substorm Pi2 pulsation was observed on 26 February. This Pi2 pulsation was detected in Egyptian observatories (Misallat and Abu Simbel, Kakioka station in Japan and Carson City station in US with nearly identical waveforms. Van Allen Probe missions observed non-compressional Pc4 pulsations on the recovery phase of the third storm. This Pc4 event is may be likely attributed to the decay of the ring current in the recovery phase.

  6. A Probabilistic Assessment of the Next Geomagnetic Reversal

    Science.gov (United States)

    Buffett, Bruce; Davis, William

    2018-02-01

    Deterministic forecasts for the next geomagnetic reversal are not feasible due to large uncertainties in the present-day state of the Earth's core. A more practical approach relies on probabilistic assessments using paleomagnetic observations to characterize the amplitude of fluctuations in the geomagnetic dipole. We use paleomagnetic observations for the past 2 Myr to construct a stochastic model for the axial dipole field and apply well-established methods to evaluate the probability of the next geomagnetic reversal as a function of time. For a present-day axial dipole moment of 7.6 × 1022 A m2, the probability of the dipole entering a reversed state is less than 2% after 20 kyr. This probability rises to 11% after 50 kyr. An imminent geomagnetic reversal is not supported by paleomagnetic observations. The current rate of decline in the dipole moment is unusual but within the natural variability predicted by the stochastic model.

  7. An Impending geomagnetic transition? Hints from the past.

    Directory of Open Access Journals (Sweden)

    Carlo eLAJ

    2015-10-01

    Full Text Available The rapid decrease of the geomagnetic field intensity in the last centuries has led to speculations that an attempt to a reversal or an excursion might be under way. Here we investigate this hypothesis by examining past records of geomagnetic field intensity obtained from sedimentary cores and from the study of cosmogenic nuclides. The selected records describe geomagnetic changes with an unprecedented temporal resolution between 20 and 75 kyr B.P. We find that some aspects of the present-day geomagnetic field have some similarities with those documented for the Laschamp excursion 41 kyr ago. Under the assumption that the dynamo processes for an eventual future reversal or excursion would be similar to those of the Laschamp excursion, we tentatively suggest that, whilst irreversible processes that will drive the geodynamo into a polarity change may have already started, a reversal or an excursion should not be expected before 500 to 1000 years.

  8. Geomagnetic field models for satellite angular motion studies

    Science.gov (United States)

    Ovchinnikov, M. Yu.; Penkov, V. I.; Roldugin, D. S.; Pichuzhkina, A. V.

    2018-03-01

    Four geomagnetic field models are discussed: IGRF, inclined, direct and simplified dipoles. Geomagnetic induction vector expressions are provided in different reference frames. Induction vector behavior is compared for different models. Models applicability for the analysis of satellite motion is studied from theoretical and engineering perspectives. Relevant satellite dynamics analysis cases using analytical and numerical techniques are provided. These cases demonstrate the benefit of a certain model for a specific dynamics study. Recommendations for models usage are summarized in the end.

  9. A Probabilistic Assessment of the Next Geomagnetic Reversal

    OpenAIRE

    Buffett, B; Davis, W

    2018-01-01

    ©2018. American Geophysical Union. All Rights Reserved. Deterministic forecasts for the next geomagnetic reversal are not feasible due to large uncertainties in the present-day state of the Earth's core. A more practical approach relies on probabilistic assessments using paleomagnetic observations to characterize the amplitude of fluctuations in the geomagnetic dipole. We use paleomagnetic observations for the past 2 Myr to construct a stochastic model for the axial dipole field and apply wel...

  10. Use of GRACE determined secular gravity rates for glacial isostatic adjustment studies in North-America

    Science.gov (United States)

    van der Wal, Wouter; Wu, Patrick; Sideris, Michael G.; Shum, C. K.

    2008-10-01

    Monthly geopotential spherical harmonic coefficients from the GRACE satellite mission are used to determine their usefulness and limitations for studying glacial isostatic adjustment (GIA) in North-America. Secular gravity rates are estimated by unweighted least-squares estimation using release 4 coefficients from August 2002 to August 2007 provided by the Center for Space Research (CSR), University of Texas. Smoothing is required to suppress short wavelength noise, in addition to filtering to diminish geographically correlated errors, as shown in previous studies. Optimal cut-off degrees and orders are determined for the destriping filter to maximize the signal to noise ratio. The halfwidth of the Gaussian filter is shown to significantly affect the sensitivity of the GRACE data (with respect to upper mantle viscosity and ice loading history). Therefore, the halfwidth should be selected based on the desired sensitivity. It is shown that increase in water storage in an area south west of Hudson Bay, from the summer of 2003 to the summer of 2006, contributes up to half of the maximum estimated gravity rate. Hydrology models differ in the predictions of the secular change in water storage, therefore even 4-year trend estimates are influenced by the uncertainty in water storage changes. Land ice melting in Greenland and Alaska has a non-negligible contribution, up to one-fourth of the maximum gravity rate. The estimated secular gravity rate shows two distinct peaks that can possibly be due to two domes in the former Pleistocene ice cover: west and south east of Hudson Bay. With a limited number of models, a better fit is obtained with models that use the ICE-3G model compared to the ICE-5G model. However, the uncertainty in interannual variations in hydrology models is too large to constrain the ice loading history with the current data span. For future work in which GRACE will be used to constrain ice loading history and the Earth's radial viscosity profile, it is

  11. Contrasting irreligious orientation: atheism and secularity in the USA and Scandinavia

    Directory of Open Access Journals (Sweden)

    Phil Zuckerman

    2012-06-01

    Full Text Available Atheism and secularity are not static, fixed orientations. Rather, atheism and secularity are contoured, malleable, and deeply shaped by cultural and social forces. A clear example of the degree to which atheism and secularity can be lived and expressed quite differently in different socio-cultural locations is revealed by comparing and contrasting the ways in which they are manifested in the United States and Scandinavia.

  12. Influence of geomagnetic activity and atmospheric pressure in hypertensive adults.

    Science.gov (United States)

    Azcárate, T; Mendoza, B

    2017-09-01

    We performed a study of the systolic and diastolic arterial blood pressure behavior under natural variables such as the atmospheric pressure and the horizontal geomagnetic field component. We worked with a group of eight adult hypertensive volunteers, four men and four women, with ages between 18 and 27 years in Mexico City during a geomagnetic storm in 2014. The data was divided by gender, age, and day/night cycle. We studied the time series using three methods: correlations, bivariate analysis, and superposed epoch (within a window of 2 days around the day of occurrence of a geomagnetic storm) analysis, between the systolic and diastolic blood pressure and the natural variables. The correlation analysis indicated a correlation between the systolic and diastolic blood pressure and the atmospheric pressure and the horizontal geomagnetic field component, being the largest during the night. Furthermore, the correlation and bivariate analyses showed that the largest correlations are between the systolic and diastolic blood pressure and the horizontal geomagnetic field component. Finally, the superposed epoch analysis showed that the largest number of significant changes in the blood pressure under the influence of geomagnetic field occurred in the systolic blood pressure for men.

  13. Effects of geomagnetic activity on the mesospheric electric fields

    Directory of Open Access Journals (Sweden)

    A. M. Zadorozhny

    Full Text Available The results of three series of rocket measurements of mesospheric electric fields carried out under different geomagnetic conditions at polar and high middle latitudes are analysed. The measurements show a clear dependence of the vertical electric fields on geomagnetic activity at polar and high middle latitudes. The vertical electric fields in the lower mesosphere increase with the increase of geomagnetic indexes Kp and ∑Kp. The simultaneous increase of the vertical electric field strength and ion conductivity was observed in the mesosphere during geomagnetic disturbances. This striking phenomenon was displayed most clearly during the solar proton events of October, 1989 accompanied by very strong geomagnetic storm (Kp=8+. A possible mechanism of generation of the vertical electric fields in the mesosphere caused by gravitational sedimentation of charged aerosol particles is discussed. Simultaneous existence in the mesosphere of both the negative and positive multiply charged aerosol particles of different sizes is assumed for explanation of the observed V/m vertical electric fields and their behaviour under geomagnetically disturbed conditions.

    Keywords. Atmospheric composition and structure (aerosols and particles · Ionosphere (electric fields and currents · Meteorology and atmospheric dynamics (atmospheric electricity

  14. Effects of geomagnetic activity on the mesospheric electric fields

    Directory of Open Access Journals (Sweden)

    A. M. Zadorozhny

    1998-12-01

    Full Text Available The results of three series of rocket measurements of mesospheric electric fields carried out under different geomagnetic conditions at polar and high middle latitudes are analysed. The measurements show a clear dependence of the vertical electric fields on geomagnetic activity at polar and high middle latitudes. The vertical electric fields in the lower mesosphere increase with the increase of geomagnetic indexes Kp and ∑Kp. The simultaneous increase of the vertical electric field strength and ion conductivity was observed in the mesosphere during geomagnetic disturbances. This striking phenomenon was displayed most clearly during the solar proton events of October, 1989 accompanied by very strong geomagnetic storm (Kp=8+. A possible mechanism of generation of the vertical electric fields in the mesosphere caused by gravitational sedimentation of charged aerosol particles is discussed. Simultaneous existence in the mesosphere of both the negative and positive multiply charged aerosol particles of different sizes is assumed for explanation of the observed V/m vertical electric fields and their behaviour under geomagnetically disturbed conditions.Keywords. Atmospheric composition and structure (aerosols and particles · Ionosphere (electric fields and currents · Meteorology and atmospheric dynamics (atmospheric electricity

  15. Influence of geomagnetic activity and atmospheric pressure in hypertensive adults

    Science.gov (United States)

    Azcárate, T.; Mendoza, B.

    2017-09-01

    We performed a study of the systolic and diastolic arterial blood pressure behavior under natural variables such as the atmospheric pressure and the horizontal geomagnetic field component. We worked with a group of eight adult hypertensive volunteers, four men and four women, with ages between 18 and 27 years in Mexico City during a geomagnetic storm in 2014. The data was divided by gender, age, and day/night cycle. We studied the time series using three methods: correlations, bivariate analysis, and superposed epoch (within a window of 2 days around the day of occurrence of a geomagnetic storm) analysis, between the systolic and diastolic blood pressure and the natural variables. The correlation analysis indicated a correlation between the systolic and diastolic blood pressure and the atmospheric pressure and the horizontal geomagnetic field component, being the largest during the night. Furthermore, the correlation and bivariate analyses showed that the largest correlations are between the systolic and diastolic blood pressure and the horizontal geomagnetic field component. Finally, the superposed epoch analysis showed that the largest number of significant changes in the blood pressure under the influence of geomagnetic field occurred in the systolic blood pressure for men.

  16. Energetic particle counterparts for geomagnetic pulsations of Pc1 and IPDP types

    Directory of Open Access Journals (Sweden)

    T. A. Yahnina

    Full Text Available Using the low-altitude NOAA satellite particle data, we study two kinds of localised variations of energetic proton fluxes at low altitude within the anisotropic zone equatorward of the isotropy boundary. These flux variation types have a common feature, i.e. the presence of precipitating protons measured by the MEPED instrument at energies more than 30 keV, but they are distinguished by the fact of the presence or absence of the lower-energy component as measured by the TED detector on board the NOAA satellite. The localised proton precipitating without a low-energy component occurs mostly in the morning-day sector, during quiet geomagnetic conditions, without substorm injections at geosynchronous orbit, and without any signatures of plasmaspheric plasma expansion to the geosynchronous distance. This precipitation pattern closely correlates with ground-based observations of continuous narrow-band Pc1 pulsations in the frequency range 0.1–2 Hz (hereafter Pc1. The precipitation pattern containing the low energy component occurs mostly in the evening sector, under disturbed geomagnetic conditions, and in association with energetic proton injections and significant increases of cold plasma density at geosynchronous orbit. This precipitation pattern is associated with geomagnetic pulsations called Intervals of Pulsations with Diminishing Periods (IPDP, but some minor part of the events is also related to narrow-band Pc1. Both Pc1 and IPDP pulsations are believed to be the electromagnetic ion-cyclotron waves generated by the ion-cyclotron instability in the equatorial plane. These waves scatter energetic protons in pitch angles, so we conclude that the precipitation patterns studied here are the particle counterparts of the ion-cyclotron waves.

    Key words. Ionosphere (particle precipitation – Magnetospheric physics (energetic particles, precipitating – Space plasma physics (wave-particle interactions

  17. Energetic particle counterparts for geomagnetic pulsations of Pc1 and IPDP types

    Directory of Open Access Journals (Sweden)

    T. A. Yahnina

    2003-12-01

    Full Text Available Using the low-altitude NOAA satellite particle data, we study two kinds of localised variations of energetic proton fluxes at low altitude within the anisotropic zone equatorward of the isotropy boundary. These flux variation types have a common feature, i.e. the presence of precipitating protons measured by the MEPED instrument at energies more than 30 keV, but they are distinguished by the fact of the presence or absence of the lower-energy component as measured by the TED detector on board the NOAA satellite. The localised proton precipitating without a low-energy component occurs mostly in the morning-day sector, during quiet geomagnetic conditions, without substorm injections at geosynchronous orbit, and without any signatures of plasmaspheric plasma expansion to the geosynchronous distance. This precipitation pattern closely correlates with ground-based observations of continuous narrow-band Pc1 pulsations in the frequency range 0.1–2 Hz (hereafter Pc1. The precipitation pattern containing the low energy component occurs mostly in the evening sector, under disturbed geomagnetic conditions, and in association with energetic proton injections and significant increases of cold plasma density at geosynchronous orbit. This precipitation pattern is associated with geomagnetic pulsations called Intervals of Pulsations with Diminishing Periods (IPDP, but some minor part of the events is also related to narrow-band Pc1. Both Pc1 and IPDP pulsations are believed to be the electromagnetic ion-cyclotron waves generated by the ion-cyclotron instability in the equatorial plane. These waves scatter energetic protons in pitch angles, so we conclude that the precipitation patterns studied here are the particle counterparts of the ion-cyclotron waves.Key words. Ionosphere (particle precipitation – Magnetospheric physics (energetic particles, precipitating – Space plasma physics (wave-particle interactions

  18. Study of the solar wind coupling to the time difference horizontal geomagnetic field

    Directory of Open Access Journals (Sweden)

    P. Wintoft

    2005-07-01

    Full Text Available The local ground geomagnetic field fluctuations (Δ B are dominated by high frequencies and 83% of the power is located at periods of 32 min or less. By forming 10-min root-mean-square (RMS of Δ B a major part of this variation is captured. Using measured geomagnetic induced currents (GIC, from a power grid transformer in Southern Sweden, it is shown that the 10-min standard deviation GIC may be computed from a linear model using the RMS Δ X and Δ Y at Brorfelde (BFE: 11.67° E, 55.63° N, Denmark, and Uppsala (UPS: 17.35° E, 59.90° N, Sweden, with a correlation of 0.926±0.015. From recurrent neural network models, that are driven by solar wind data, it is shown that the log RMS Δ X and Δ Y at the two locations may be predicted up to 30 min in advance with a correlation close to 0.8: 0.78±0.02 for both directions at BFE; 0.81±0.02 and 0.80±0.02 in the X- and Y-directions, respectively, at UPS. The most important inputs to the models are the 10-min averages of the solar wind magnetic field component Bz and velocity V, and the 10-min standard deviation of the proton number density σn. The average proton number density n has no influence.

    Keywords. Magnetospheric physics (Solar wind - magnetosphere interactions – Geomagnetism and paleomagnetism (Rapid time variations

  19. A Quaternary Geomagnetic Instability Time Scale

    Science.gov (United States)

    Singer, B. S.

    2013-12-01

    Reversals and excursions of Earth's geomagnetic field create marker horizons that are readily detected in sedimentary and volcanic rocks worldwide. An accurate and precise chronology of these geomagnetic field instabilities is fundamental to understanding several aspects of Quaternary climate, dynamo processes, and surface processes. For example, stratigraphic correlation between marine sediment and polar ice records of climate change across the cryospheres benefits from a highly resolved record of reversals and excursions. The temporal patterns of dynamo behavior may reflect physical interactions between the molten outer core and the solid inner core or lowermost mantle. These interactions may control reversal frequency and shape the weak magnetic fields that arise during successive dynamo instabilities. Moreover, weakening of the axial dipole during reversals and excursions enhances the production of cosmogenic isotopes that are used in sediment and ice core stratigraphy and surface exposure dating. The Geomagnetic Instability Time Scale (GITS) is based on the direct dating of transitional polarity states recorded by lava flows using the 40Ar/39Ar method, in parallel with astrochronologic age models of marine sediments in which O isotope and magnetic records have been obtained. A review of data from Quaternary lava flows and sediments yields a GITS comprising 10 polarity reversals and 27 excursions during the past 2.6 million years. Nine of the ten reversals bounding chrons and subchrons are associated with 40Ar/39Ar ages of transitionally-magnetized lava flows. The tenth, the Guass-Matuyama chron boundary, is tightly bracketed by 40Ar/39Ar dated ash deposits. Of the 27 well-documented excursions, 14 occurred during the Matuyama chron and 13 during the Brunhes chron; 19 have been dated directly using the 40Ar/39Ar method on transitionally-magnetized volcanic rocks and form the backbone of the GITS. Excursions are clearly not the rare phenomena once thought

  20. Secular change of LOD caused by core evolution

    Science.gov (United States)

    Denis, C.; Rybicki, K. R.; Varga, P.

    2003-04-01

    Fossils and tidal deposits suggest that, on the average, the Earth's despinning rate had been five times less in the Proterozoic than in the Phanerozoic. This difference is probably due, for the major part, to the existence of a Proterozoic supercontinent. Nevertheless, core formation and core evolution should have compensated to some extent the effect of tidal friction, by diminishing the Earth's inertia moment. We have investigated quantitatively this contribution of the evolving core to the change of LOD. For the present epoch, we find that the solidification of the inner core causes a relative secular decrease of LOD of approximately 3 μs per century, whereas the macrodiffusion of iron oxides and sulfides from the D" into the outer core across the CMB (inasfar as Majewski's theory holds) leads to a relative secular decrease of LOD by about 15 μs per century. On the other hand, the theory of slow core formation developped by Runcorn in the early 1960s as a by-product of his theory of mantle-wide convection, leads to a relative secular decrease of LOD during most of the Proterozoic of about 0.25 ms per century. Although core formation is now widely assumed to have been a thermal run-away process that occurred shortly after the Earth itself had formed, Runcorn's theory of the growing core would nicely explain the observed palaeo-LOD curve. In any case, formation of the core implies, all in all, a relative decrease of LOD of typically 3 hours.

  1. Parameters of 1-4 mHz (Pc5/Pi3) ULF pulsations during the intervals preceding non-triggered substorms at high geomagnetic latitudes

    Science.gov (United States)

    Nosikova, Nataliya; Yagova, Nadezda; Baddeley, Lisa; Kozyreva, Olga; Lorentzen, Dag; Pilipenko, Vyacheslav

    2017-04-01

    One of the important questions for understanding substorm generation is the possible existence of specific pre-substorm variations of plasma, particles and electromagnetic field parameters. In this case analyzing of isolated non-triggered substorms (i.e. substorms that occur under quiet geomagnetic conditions without any visible triggers in IMF or SW) gives benefits for investigation of processes of substorm preparation. It was shown in previous studies that during a few hours preceding a non-triggered isolated substorm, coherent geomagnetic and aurroral luminosity pulsations are observed. Moreover, PSD, amplitudes of geomagnetic fluctuations in Pc5/Pi3 (1-4 mHz) frequency range and some spectral parameters differ from those registered on days without substorms. In present work this sort of pulsations has been studied in details. Features of longitudinal and latitudinal profiles are presented. Possible correlation with ULF disturbances in IMF and SW as well as in the magnetotail/magnetosheath are discussed.

  2. Variability Analysis of the Horizontal Geomagnetic Component: A Case Study Based on Records from Vassouras Observatory (Brazil)

    Science.gov (United States)

    Klausner, Virginia; Papa, Andres; Mendes, Odim; Oliveira Domingues, Margarete

    It is well known that any of the components of the magnetic field measured on the Earth's surface presents characteristic frequencies with 24, 12, 8 and 6-hour period. Those typical kinds of oscillations of the geomagnetic field are known as solar quiet variation and are primary due to the global thermotidal wind systems which conduct currents flowing in the "dynamo region" of the ionosphere, the E-region. In this study, the horizontal component amplitude observed by ground-based observatories belonged to the INTERMAGNET network have been used to analyze the global pattern variance of the Sq variation. In particular we focused our attention on Vassouras Observatory (VSS), Rio de Janeiro, Brazil, which has been active since 1915. In the next years, a brazilian network of magnetometers will be implemented and VSS can be used as reference. This work aims mainly to highlight and interpret these quiet daily variations over the Brazilian sector compared to the features from other magnetic stations reasonably distributed over the whole Earth's surface. The methodological approach is based on wavelet cross-correlation technique. This technique is useful to isolate the period of the spectral components of geomagnetic field in each station and to correlate them as function of scale (period) between VSS and the other stations. The wavelet cross-correlation coefficient strongly depends on the scale. We study the geomagnetically quiet days at equinox and solstice months during low and high solar activity. As preliminary remarks, the results show that the records in the magnetic stations have primary a latitudinal dependence affected by the time of year and level of solar activity. On the other hand, records of magnetic stations located at the same dip latitude but at different longitude presented some peculiarities. These results indicated that the winds driven the dynamo are very sensitive of the location of the geomagnetic station, i. e., its effects depend upon the direction

  3. Proper Elements and Secular Resonances for Irregular Satellites

    Science.gov (United States)

    Beaugé, C.; Nesvorný, D.

    2007-06-01

    We present results of an analytical study of proper elements and secular resonances for the irregular satellites of the outer planets. In the case of the Jovian system we identify three satellite families, two of them previously known (Carme and Ananke), plus a new agglomeration of four bodies that includes Pasiphae as its largest member. While the distribution of proper elements for Saturn's moons seems to be more random, a small cluster was found for the direct moons formed by Albiorix, Erriapo, and 2004 S1, slightly different from the so-called Gaulish cluster. No significant families are detected in the present study for the Uranian or Neptunian satellite systems. For each satellite system we determine the location of several secular resonances in the proper element space. Apart from the well-known resonance locks of Pasiphae, Sinope, and Siarnaq, a comparison between the resonance locations and proper elements shows that Saturn's satellite Narvi also exhibits temporary librations in the ϖ-ϖsolar resonance. However, unlike the resonant Jovian moons that are located in the same configuration, Narvi's critical argument librates alternately around values near 90° and 270°. Neither the Uranian nor Neptunian systems seem to have resonant moons. The resonant dynamics of the real satellites in the vicinity of ϖ˙-ϖ˙solar=0 is studied with a simple model for secular resonances based on the restricted three-body problem. Depending on the initial conditions, we show the existence of one or two modes of libration that can occur at different values of the critical angle, showing a good correspondence with the observed behavior of all the resonant moons. Finally, we discuss the global distribution of the real satellites with respect to the secular resonances, as compared with synthetic populations of bodies drawn solely from stability conditions. For Saturn, we find that the present satellite population appears compatible with simple random distributions. Although

  4. Religion, secular medicine and utilitarianism: a response to Biggar.

    Science.gov (United States)

    Smith, Kevin R

    2015-11-01

    Nigel Biggar has argued that religion ought to be given a seat at the negotiating table of medical ethics. I respond in broadly utilitarian terms, arguing that the flawed empirical basis, lack of rationality and non-universality inherent in religion disqualify it from ethical discourse. I conclude that while it would be unacceptable to attempt to debar religious individuals from the negotiating table, an exclusively secular approach is required for ethical decision making in medicine. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  5. Geomagnetic field and length-of-day fluctuations at decadal and subdecadal time scales. A plea for looking beyond the atmosphere for partners in Earth's rotation

    Science.gov (United States)

    Demetrescu, C.; Dobrica, V.; Stefan, C.

    2017-12-01

    A rich scientific literature is linking length-of-day (LOD) fluctuations to geomagnetic field and flow oscillations in the fluid outer core. We demostrate that the temporal evolution of the geomagnetic field shows the existence of several oscillations at decadal, inter-decadal, and sub-centennial time scales that superimpose on a so-called inter-centennial constituent. We show that while the subcentennial oscillations of the geomagnetic field, produced by torsional oscillations in the core, could be linked to oscillations of LOD at a similar time scale, the oscillations at decadal and sub-decadal time scales, of external origin, can be found in LOD too. We discuss these issues from the perspective of long time-span main field models (gufm1 - Jackson et al., 2000; COV-OBS - Gillet et al., 2013) that are used to retrieve time series of geomagnetic elements in a 2.5x2.5° network. The decadal and sub-decadal constituents of the time series of annual values in LOD and geomagnetic field were separated in the cyclic component of a Hodrick-Prescott filtering applied to data, and shown to highly correlate to variations of external sources such as the magnetospheric ring current.

  6. Gravity wave generation and propagation during geomagnetic storms over Kiruna (67.8°N, 20.4°E

    Directory of Open Access Journals (Sweden)

    P. R. Fagundes

    1995-04-01

    Full Text Available Atmospheric gravity waves, detected over Kiruna (67.8°N, 20.4°E during geomagnetic storms, are presented and analysed. The data include direct measurements of the OI 630.0 nm emission line intensity, the x-component of the local geomagnetic field and thermospheric (meridional and zonal wind velocities derived from the OI 630.0 nm Doppler shift observed with an imaging Fabry-Perot interferometer (IFPI. A low pass band filter technique was used to determine short-period variations in the thermospheric meridional wind velocities observed during geomagnetic storms. These short-period variations in the meridional wind velocities, which are identified as due to gravity waves, are compared to the corresponding variations observed in the OI 630.0 nm emission line intensity, x-component of the local geomagnetic field and the location of the auroral electrojet. A cross-correlation analysis was used to calculate the propagation velocities of the observed gravity waves.

  7. Stellar aberration correction and thermoelastic compensation of Swarm μASC attitude observations: A comment to the Express Letter “Mysterious misalignments between geomagnetic and stellar reference frames seen in CHAMP and Swarm satellite measurements”, by Stefan Maus

    DEFF Research Database (Denmark)

    Herceg, M.; Jørgensen, P. S.; Jørgensen, J. L.

    2017-01-01

    . However, comparison of the Inter Boresight Angle shows a relative attitude variation between the μASC Camera Head Units. These misalignments between Camera Head Units and a geomagnetic reference frame cannot be explained by incorrect aberration correction (as theorized by Maus). Herceg et al. found them...... and clean from any variation caused by thermoelastic effects....

  8. Geomagnetically Induced Currents Around the World During the 17 March 2015 Storm

    Science.gov (United States)

    Carter, B. A.; Yizengaw, E.; Pradipta, R.; Weygand, J. M.; Piersanti, M.; Pulkkinen, Antti Aleksi; Moldwin, M. B.; Norman, R.; Zhang, K.

    2016-01-01

    Geomagnetically induced currents (GICs) represent a significant space weather issue for power grid and pipeline infrastructure, particularly during severe geomagnetic storms. In this study, magnetometer data collected from around the world are analyzed to investigate the GICs caused by the 2015 St. Patricks Day storm. While significant GIC activity in the high-latitude regions due to storm time substorm activity is shown for this event, enhanced GIC activity was also measured at two equatorial stations in the American and Southeast Asian sectors. This equatorial GIC activity is closely examined, and it is shown that it is present both during the arrival of the interplanetary shock at the storm sudden commencement (SSC) in Southeast Asia and during the main phase of the storm approximately 10 h later in South America. The SSC caused magnetic field variations at the equator in Southeast Asia that were twice the magnitude of those observed only a few degrees to the north, strongly indicating that the equatorial electrojet (EEJ) played a significant role. The large equatorial magnetic field variations measured in South America are also examined, and the coincident solar wind data are used to investigate the causes of the sudden changes in the EEJ approximately 10 h into the storm. From this analysis it is concluded that sudden magnetopause current increases due to increases in the solarwind dynamic pressure, and the sudden changes in the resultant magnetospheric and ionospheric current systems, are the primary drivers of equatorial GICs.

  9. Average configuration of the geomagnetic tail

    International Nuclear Information System (INIS)

    Fairfield, D.H.

    1979-01-01

    Over 3000 hours of Imp 6 magnetic field data obtained between 20 and 33 R/sub E/ in the geomagnetic tail have been used in a statistical study of the tail configuration. A distribution of 2.5-min averages of B/sub z/ as a function of position across the tail reveals that more flux crosses the equatorial plane near the dawn and dusk flanks (B-bar/sub z/=3.γ) than near midnight (B-bar/sub z/=1.8γ). The tail field projected in the solar magnetospheric equatorial plane deviates from the x axis due to flaring and solar wind aberration by an angle α=-0.9 Y/sub SM/-2.7, where Y/sub SM/ is in earth radii and α is in degrees. After removing these effects, the B/sub y/ component of the tail field is found to depend on interplanetary sector structure. During an 'away' sector the B/sub y/ component of the tail field is on average 0.5γ greater than that during a 'toward' sector, a result that is true in both tail lobes and is independent of location across the tail. This effect means the average field reversal between northern and southern lobes of the tail is more often 178 0 rather than the 180 0 that is generally supposed

  10. Geomagnetism during solar cycle 23: Characteristics

    Directory of Open Access Journals (Sweden)

    Jean-Louis Zerbo

    2013-05-01

    Full Text Available On the basis of more than 48 years of morphological analysis of yearly and monthly values of the sunspot number, the aa index, the solar wind speed and interplanetary magnetic field, we point out the particularities of geomagnetic activity during the period 1996–2009. We especially investigate the last cycle 23 and the long minimum which followed it. During this period, the lowest values of the yearly averaged IMF (3 nT and yearly averaged solar wind speed (364 km/s are recorded in 1996, and 2009 respectively. The year 2003 shows itself particular by recording the highest value of the averaged solar wind (568 km/s, associated to the highest value of the yearly averaged aa index (37 nT. We also find that observations during the year 2003 seem to be related to several coronal holes which are known to generate high-speed wind stream. From the long time (more than one century study of solar variability, the present period is similar to the beginning of twentieth century. We especially present the morphological features of solar cycle 23 which is followed by a deep solar minimum.

  11. The Complexity of Solar and Geomagnetic Indices

    Science.gov (United States)

    Pesnell, W. Dean

    2017-08-01

    How far in advance can the sunspot number be predicted with any degree of confidence? Solar cycle predictions are needed to plan long-term space missions. Fleets of satellites circle the Earth collecting science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Statistical and timeseries analyses of the sunspot number are often used to predict solar activity. These methods have not been completely successful as the solar dynamo changes over time and one cycle's sunspots are not a faithful predictor of the next cycle's activity. In some ways, using these techniques is similar to asking whether the stock market can be predicted. It has been shown that the Dow Jones Industrial Average (DJIA) can be more accurately predicted during periods when it obeys certain statistical properties than at other times. The Hurst exponent is one such way to partition the data. Another measure of the complexity of a timeseries is the fractal dimension. We can use these measures of complexity to compare the sunspot number with other solar and geomagnetic indices. Our concentration is on how trends are removed by the various techniques, either internally or externally. Comparisons of the statistical properties of the various solar indices may guide us in understanding how the dynamo manifests in the various indices and the Sun.

  12. The Contribution of a Geophysical Data Service: The International Service of Geomagnetic Indices

    Directory of Open Access Journals (Sweden)

    M Menvielle

    2013-01-01

    Full Text Available Geomagnetic indices are basic data in Solar-Terrestrial physics and in operational Space Weather activities. The International Service of Geomagnetic Indices (ISGI is in charge of the derivation and dissemination of the geomagnetic indices that are acknowledged by the International Association of Geomagnetism and Aeronomy (IAGA, an IUGG association. Institutes that are not part of ISGI started early in the Internet age to circulate on-line preliminary values of geomagnetic indices. In the absence of quality stamping, this resulted in a very confusing situation. The ISGI label was found to be the simplest and the safest way to insure quality stamping of circulated geomagnetic indices.

  13. Why religion deserves a place in secular medicine.

    Science.gov (United States)

    Biggar, Nigel

    2015-03-01

    As a science and practice transcending metaphysical and ethical disagreements, 'secular' medicine should not exist. 'Secularity' should be understood in an Augustinian sense, not a secularist one: not as a space that is universally rational because it is religion-free, but as a forum for the negotiation of rival reasonings. Religion deserves a place here, because it is not simply or uniquely irrational. However, in assuming his rightful place, the religious believer commits himself to eschewing sheer appeals to religious authorities, and to adopting reasonable means of persuasion. This can come quite naturally. For example, Christianity (theo)logically obliges liberal manners in negotiating ethical controversies in medicine. It also offers reasoned views of human being and ethics that bear upon medicine and are not universally held-for example, a humanist view of human dignity, the bounding of individual autonomy by social obligation, and a special concern for the weak. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  14. Ancient Ephesus: Processions as Media of Religious and Secular Propaganda

    Directory of Open Access Journals (Sweden)

    Lilian Portefaix

    1993-01-01

    Full Text Available The significance of religious rituals often reaches beyond their strict religious intentions. Specifically a procession, performed in front of the public, is a most effective instrument of disseminating a message to the crowds. Consequently, this ritual, as is well known, has often been used not only in religious but also in secular contexts; a procession under the cloak of religion can even become a politically useful medium to avoid popular disturbances on peaceful terms. This was the case in ancient Ephesus, where Roman power conflicted with Greek culture from the middle of the first century B.C. onwards. In the beginning of the second century A.D. the public religious life in the city of Ephesus was to a great extent characterized by processions relating to the cult of Artemis Ephesia. The one traditionally performed on the birthday of the goddess called to mind the Greek origin of the city; it was strictly associated with the religious sphere bringing about a close relationship between the goddess and her adherents. The other, artificially created by a Roman, was entirely secular, and spread its message every fortnight in the streets of Ephesus. It referred to the political field of action and intended to strengthen the Roman rule over the city. The Greek origin of Ephesian culture was later included in the message of the procession, reminding the Greeks not to rebel against Roman rule.

  15. Paracelsus, Paracelsianism, and the secularization of the worldview.

    Science.gov (United States)

    Webster, Charles

    2002-03-01

    This paper examines Paracelsus and Paracelsianism in the light of the ideas of Max Weber concerning the social consequences of the Reformation, with special reference to his theories of Entzauberung and secularization. He linked these tendencies both to the rise of capitalism and the growth of experimental science. The detailed case study of Paracelsus' account of diseases linked with saints, in common with his interpretation of many other conditions, demonstrates that he self-consciously extended the boundaries of medicine and eroded the role of magic and witchcraft associated with the church. On the other hand, Paracelsus adopted the Neoplatonic worldview, was immersed in popular magic, and evolved a system of medicine that self-consciously revolved around magic. These factors seem to place a distinct limit on his role in the demystification of knowledge. However, the magic of Paracelsus entailed a decisive break with the entrenched elitist and esoteric tradition of the occultists and hermeticists. It is argued that this reconstructed magic re-establishes the credentials of Paracelsus as a significant contributor to the disenchantment and secularization of the worldview.

  16. Internal and environmental secular evolution of disk galaxies

    Science.gov (United States)

    Kormendy, John

    2015-03-01

    This Special Session is devoted to the secular evolution of disk galaxies. Here `secular' means `slow' i.e., evolution on time scales that are generally much longer than the galaxy crossing or rotation time. Internal and environmentally driven evolution both are covered. I am indebted to Albert Bosma for reminding me at the 2011 Canary Islands Winter School on Secular Evolution that our subject first appeared in print in a comment made by Ivan King (1977) in his introductory talk at the Yale University meeting on The Evolution of Galaxies and Stellar Populations: `John Kormendy would like us to consider the possibility that a galaxy can interact with itself.. . . I'm not at all convinced, but John can show you some interesting pictures.' Two of the earliest papers that followed were Kormendy (1979a, b); the first discusses the interaction of galaxy components with each other, and the second studies these phenomena in the context of a morphological survey of barred galaxies. The earliest modeling paper that we still use regularly is Combes & Sanders (1981), which introduces the now well known idea that box-shaped bulges in edge-on galaxies are side-on, vertically thickened bars. It is gratifying to see how this subject has grown since that time. Hundreds of papers have been written, and the topic features prominently at many meetings (e.g., Block et al. 2004; Falcoń-Barroso & Knapen 2012, and this Special Session). My talk here introduces both internal and environmental secular evolution; a brief abstract follows. My Canary Islands Winter School review covers both subjects in more detail (Kormendy 2012). Kormendy & Kennicutt (2004) is a comprehensive review of internal secular evolution, and Kormendy & Bender (2012) covers environmental evolution. Both of these subject make significant progress at this meeting. Secular evolution happens because self-gravitating systems evolve toward the most tightly bound configuration that is reachable by the evolution processes

  17. Secular stagnation or stagnation policy? Steindl after Summers

    Directory of Open Access Journals (Sweden)

    Eckhard Hein

    2016-03-01

    Full Text Available The debate on secular stagnation suffers from vagueness and several shortcomings, which affect its economic policy implications. In this work we provide an alternative view on the advanced economies’ tendencies to stagnation, based on Josef Steindl’s contributions. Steindl’s pioneering 1952 book in particular is not prone to several problems that affect the current debate on secular stagnation. It does not rely on the dubious notion of an equilibrium real interest rate as the equilibrating force of saving and investment at full employment levels. Rather, it is based on the notion that modern capitalist economies face aggregate demand constraints, and that saving adjusts to investment through income growth and changes in capacity utilisation in the long run. Steindl’s treatment allows for potential growth to become endogenous to actual demand, and it seriously considers the role of institutions and power relationships for long-run growth. In illustrating Steindl’s contributions on this topic, the article presents an original model synthetizing the main points in particular concerning long run growth and stagnation. JEL codes: B22, E11, E12, E65, O11

  18. Secular trends in Cherokee cranial morphology: Eastern vs Western bands.

    Science.gov (United States)

    Sutphin, Rebecca; Ross, Ann H; Jantz, Richard L

    2014-01-01

    The research objective was to examine if secular trends can be identified for cranial data commissioned by Boas in 1892, specifically for cranial breadth and cranial length of the Eastern and Western band Cherokee who experienced environmental hardships. Multiple regression analysis was used to test the degree of relationship between each of the cranial measures: cranial length, cranial breadth and cephalic index, along with predictor variables (year-of-birth, location, sex, admixture); the model revealed a significant difference for all craniometric variables. Additional regression analysis was performed with smoothing Loess plots to observe cranial length and cranial breadth change over time (year-of-birth) separately for Eastern and Western Cherokee band females and males born between 1783-1874. This revealed the Western and Eastern bands show a decrease in cranial length over time. Eastern band individuals maintain a relatively constant head breadth, while Western Band individuals show a sharp decline beginning around 1860. These findings support negative secular trend occurring for both Cherokee bands where the environment made a detrimental impact; this is especially marked with the Western Cherokee band.

  19. Period and phase comparisons of near-decadal oscillations in solar, geomagnetic, and cosmic ray time series

    Science.gov (United States)

    Juckett, David A.

    2001-09-01

    A more complete understanding of the periodic dynamics of the Sun requires continued exploration of non-11-year oscillations in addition to the benchmark 11-year sunspot cycle. In this regard, several solar, geomagnetic, and cosmic ray time series were examined to identify common spectral components and their relative phase relationships. Several non-11-year oscillations were identified within the near-decadal range with periods of ~8, 10, 12, 15, 18, 22, and 29 years. To test whether these frequency components were simply low-level noise or were related to a common source, the phases were extracted for each component in each series. The phases were nearly identical across the solar and geomagnetic series, while the corresponding components in four cosmic ray surrogate series exhibited inverted phases, similar to the known phase relationship with the 11-year sunspot cycle. Cluster analysis revealed that this pattern was unlikely to occur by chance. It was concluded that many non-11-year oscillations truly exist in the solar dynamical environment and that these contribute to the complex variations observed in geomagnetic and cosmic ray time series. Using the different energy sensitivities of the four cosmic ray surrogate series, a preliminary indication of the relative intensities of the various solar-induced oscillations was observed. It provides evidence that many of the non-11-year oscillations result from weak interplanetary magnetic field/solar wind oscillations that originate from corresponding variations in the open-field regions of the Sun.

  20. Global ionospheric effects of geomagnetic storm on May 2-3, 2010 and their influence on HF radio wave propagation

    Science.gov (United States)

    Kotova, Daria; Klimenko, Maxim; Klimenko, Vladimir; Zakharov, Veniamin

    2013-04-01

    In this work we have investigated the global ionospheric response to geomagnetic storm on May 2-3, 2010 using GSM TIP (Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere) simulation results. In the GSM TIP storm time model runs, several input parameters such as cross-polar cap potential difference and R2 FAC (Region 2 Field-Aligned Currents) varied as a function of the geomagnetic activity AE-index. Current simulation also uses the empirical model of high-energy particle precipitation by Zhang and Paxton. In this model, the energy and energy flux of precipitating electrons depend on a 3 hour Kp-index. We also have included the 30 min time delay of R2 FAC variations with respect to the variations of cross-polar cap potential difference. In addition, we use the ground-based ionosonde data for comparison our model results with observations. We present an analysis of the physical mechanisms responsible for the ionospheric effects of geomagnetic storms. The obtained simulation results are used by us as a medium for HF radio wave propagation at different latitudes in quiet conditions, and during main and recovery phase of a geomagnetic storm. To solve the problem of the radio wave propagation we used Zakharov's (I. Kant BFU) model based on geometric optics. In this model the solution of the eikonal equation for each of the two normal modes is reduced using the method of characteristics to the integration of the six ray equation system for the coordinates and momentum. All model equations of this system are solved in spherical geomagnetic coordinate system by the Runge-Kutta method. This model was tested for a plane wave in a parabolic layer. In this study, the complex refractive indices of the ordinary and extraordinary waves at ionospheric heights was calculated for the first time using the global first-principal model of the thermosphere-ionosphere system that describes the parameters of an inhomogeneous anisotropic medium during a

  1. Influence of core flows on the decade variations of the polar motion

    Science.gov (United States)

    Hulot, G.; Le Huy, M.; Le Mouël, J.-L.

    We address the possibility for the core flows that generate the geomagnetic field to contribute significantly to the decade variations of the mean pole position (generally called the Markowitz wobble). This assumption is made plausible by the observation that the flow at the surface of the core-estimated from the geomagnetic secular variation models-experiences important changes on this time scale. We discard the viscous and electromagnetic core-mantle couplings and consider only the pressure torque pf resulting from the fluid flow overpressure acting on the non-spherical core-mantle boundary (CMB) at the bottom of the mantle, and the gravity torque gf due to the density heterogeneity driving the core flow. We show that forces within the core balance each other on the time scale considered and, using global integrals over the core, the mantle and the whole Earth, we write Euler's equation for the mantle in terms of two more useful torques Pgeo and . The "geostrophic torque", γ Pgeo incorporates γpf and part of γgf, while γ is another fraction of γgf. We recall how the geostrophic pressure pgeo, and thus γPgeo for a given topography, can be derived from the flow at the CMB and compute the motion of the mean pole from 1900 to 1990, assuming in a first approach that the unknown γ can be neglected. The amplitude of the computed pole motion is three to ten times less than the observed one and out of the phase with it. In order to estimate the possible contribution of γ we then use a second approach and consider the case in which the reference state for the Earth is assumed to be the classical axisymmetric ellipsoidal figure with an almost constant ellipticity within the core. We show that (γPgeo + γ) is then equal to a pseudo-electromagnetic torque γL3, the torque exerted on the core by the component of the Lorentz force along the axis of rotation (this torque exists even though the mantle is assumed insulating). This proves that, at least in this case and

  2. Secular trends in the geologic record and the supercontinent cycle

    Science.gov (United States)

    Bradley, Dwight C.

    2011-01-01

    Geologic secular trends are used to refine the timetable of supercontinent assembly, tenure, and breakup. The analysis rests on what is meant by the term supercontinent, which here is defined broadly as a grouping of formerly dispersed continents. To avoid the artificial pitfall of an all-or-nothing definition, quantitative measures of “supercontinentality” are presented: the number of continents, and the area of the largest continent, which both can be gleaned from global paleogeographic maps for the Phanerozoic. For the secular trends approach to be viable in the deep past when the very existence of supercontinents is debatable and reconstructions are fraught with problems, it must first be calibrated in the Phanerozoic against the well-constrained Pangea supercontinent cycle. The most informative geologic variables covering both the Phanerozoic and Precambrian are the abundances of passive margins and of detrital zircons. Both fluctuated with size of the largest continent during the Pangea supercontinent cycle and can be quantified back to the Neoarchean. The tenure of Pangea was a time represented in the rock record by few zircons and few passive margins. Thus, previously documented minima in the abundance of detrital zircons (and orogenic granites) during the Precambrian (Condie et al., 2009a, Gondwana Research 15, 228–242) now can be more confidently interpreted as marking the tenures of supercontinents. The occurrences of carbonatites, granulites, eclogites, and greenstone-belt deformation events also appear to bear the imprint of Precambrian supercontinent cyclicity. Together, these secular records are consistent with the following scenario. The Neoarchean continental assemblies of Superia and Sclavia broke up at ca. 2300 and ca. 2090 Ma, respectively. Some of their fragments collided to form Nuna by about 1750 Ma; Nuna then grew by lateral accretion of juvenile arcs during the Mesoproterozoic, and was involved in a series of collisions at ca. 1000 Ma

  3. Transitional geomagnetic impulse hypothesis: Geomagnetic fact or rock-magnetic artifact?

    Science.gov (United States)

    Camps, Pierre; Coe, Robert S.; PréVot, Michel

    1999-08-01

    A striking feature of the Steens Mountain (Oregon) geomagnetic polarity reversal is the two (maybe three) extremely rapid field directional changes (6 degrees per day) proposed to account for unusual behavior in direction of remanent magnetization in a single lava flow. Each of these very fast field changes, or impulses, is associated with a large directional gap (some 90°) in the record. In order to check the spatial reproducibility of the paleomagnetic signal over distances up to several kilometers, we have carried out a paleomagnetic investigation of two new sections (B and F) in the Steens summit region which cover the second and the third directional gap. The main result is the description of two new directions, which are located between the pre second and post second impulse directions. These findings weigh against the hypothesis that the geomagnetic field cause the unusual intraflow fluctuations, which now appears to be more ad hoc as an explanation of the paleomagnetic data. However, the alternative baking hypothesis remains also ad hoc since we have to assume variable rock magnetic properties that we have not yet been able to detect within the flows at the original section Steens A and D 1.5 km to the north. In addition, new results for 22 transitional and normal lava flows in section B are presented that correlate well with earlier results from section A.

  4. Seasonal and diurnal dependence of Pc 3-5 magnetic pulsation power at geomagnetically conjugate stations in the auroral zones

    International Nuclear Information System (INIS)

    Saito, Hiroaki; Sato, Natsuo; Tonegawa, Yutaka; Yoshino, Takeo; Saemundsson, T.

    1989-01-01

    Seasonal and diurnal variations of Pc 3-5 magnetic pulsation powers have been examined using 2 years of magnetic data from geomagnetically conjugate stations, Syowa in Antarctica and Husafell and Tjoernes in Iceland. The magnetic pulsation powers are found to be relatively higher at the winter hemisphere station than at the summer station. The pulsations observed during equinox show a diurnal dependence, i.e., that the power density is higher in the geomagnetic morning at the stations in Iceland than at Syowa, and this relationship is reversed in the afternoon. The power density ratio of Pc 3 pulsations between the conjugate stations, which is associated with the seasons and with local time, is higher than that of Pc 5. These characteristics can be attributed to the effects of sunlight in the ionosphere, i.e., Pc 3-5 pulsations are shielded when the waves propagate from the magnetosphere to the ground through the sunlit ionosphere

  5. Prediction of geomagnetic storm using neural networks: Comparison of the efficiency of the Satellite and ground-based input parameters

    International Nuclear Information System (INIS)

    Stepanova, Marina; Antonova, Elizavieta; Munos-Uribe, F A; Gordo, S L Gomez; Torres-Sanchez, M V

    2008-01-01

    Different kinds of neural networks have established themselves as an effective tool in the prediction of different geomagnetic indices, including the Dst being the most important constituent for determination of the impact of Space Weather on the human life. Feed-forward networks with one hidden layer are used to forecast the Dst variation, using separately the solar wind paramenters, polar cap index, and auroral electrojet index as input parameters. It was found that in all three cases the storm-time intervals were predicted much more precisely as quite time intervals. The majority of cross-correlation coefficients between predicted and observed Dst of strong geomagnetic storms are situated between 0.8 and 0.9. Changes in the neural network architecture, including the number of nodes in the input and hidden layers and the transfer functions between them lead to an improvement of a network performance up to 10%.

  6. Secular and Koranic Literacies in South Asia: From Colonisation to Contemporary Practice

    Science.gov (United States)

    Maddox, Bryan

    2007-01-01

    This paper explores the distinction between "secular" and "Koranic" schooling and literacy in South Asia. It begins by tracing an archaeology of the distinction between secular "literacy" and religious "illiteracy". It locates the emergence of the distinction in the colonial census of the 19th century, in…

  7. Comments on equilibrium, transient equilibrium, and secular equilibrium in serial radioactive decay

    International Nuclear Information System (INIS)

    Prince, J.R.

    1979-01-01

    Equations describing serial radioactive decay are reviewed along with published descriptions or transient and secular equilibrium. It is shown that terms describing equilibrium are not used in the same way by various authors. Specific definitions are proposed; they suggest that secular equilibrium is a subset of transient equilibrium

  8. What Lies between the Religious and the Secular?: Education beyond the Human

    Science.gov (United States)

    Seo, Yong-Seok

    2014-01-01

    The current age is characterised by many as secular, and a source of such a characterisation can be found in the Nietzschean claim that thoughts about there being some ultimate reality have to be jettisoned, and human existence and the world need to be embraced as they are. That claim is renewed by some secular thinkers who insist that education…

  9. One Size Does Not Fit All: Complexity, Religion, Secularism and Education

    Science.gov (United States)

    Davies, Lynn

    2014-01-01

    The continuing incidence of extremist acts committed in the name of religion underscores the need to examine the interplay between religion and learning. This article argues for a secular foundation in society and school to protect against religion contributing to conflict and extremism. However, this is not a hard version of secularism, but a…

  10. "Doing the Secular": Academic Practices in the Study of Religion at Two Danish Universities

    Science.gov (United States)

    Johansen, Birgitte Schepelern

    2011-01-01

    The academic study of religion at the public university often presents itself as a secular, non-religious, scientific endeavor. The identity of the study is thus firmly rooted within one of the central secular-religious divides, namely that between science and religion. Based on the assumption that such distinctions between religion and the…

  11. Habermas and the Meaning of the Post-Secular Society: Complementary Learning Processes

    Science.gov (United States)

    Welton, Michael R.

    2014-01-01

    This essay argues that if social justice is to prevail in our world, we must understand the post-secular nature of our globalized society as a prerequisite for moving beyond "might is right" to national and international relations that heed all voices towards evidence-based interaction. Our post-secular world and postmetaphysical…

  12. Resurrecting Democracies : Secularity Recast in Charles Taylor, Paul Valadier, and Joseph Ratzinger

    NARCIS (Netherlands)

    Ossewaarde-Lowtoo, Roshnee

    In this article, the alternative conception of secularity of Charles Taylor, Paul Valadier and Joseph Ratzinger (former Benedict XVI) is explored. A secularized society, which they take as an established condition, does not necessarily exclude religion, Christianity or Christian transcendence, in

  13. Secular Ethics Education as an Alternative to Religious Education--Finnish Teachers' Views

    Science.gov (United States)

    Zilliacus, Harriet; Kallioniemi, Arto

    2016-01-01

    This study provides a Finnish perspective to international discussions on religious and worldviews education through the subject of secular ethics. This subject has been offered in Finland since 1985 throughout comprehensive schools and is primarily directed at students who are non-affiliated. Secular ethics education has scarcely been researched…

  14. Substitution or Symbiosis? Assessing the Relationship between Religious and Secular Giving

    Science.gov (United States)

    Hill, Jonathan P.; Vaidyanathan, Brandon

    2011-01-01

    Research on philanthropy has not sufficiently examined whether charitable giving to religious causes impinges on giving to secular causes. Examining three waves of national panel data, we find that the relationship between religious and secular giving is generally not of a zero-sum nature; families that increase their religious giving also…

  15. Intermittency and multifractional Brownian character of geomagnetic time series

    Directory of Open Access Journals (Sweden)

    G. Consolini

    2013-07-01

    Full Text Available The Earth's magnetosphere exhibits a complex behavior in response to the solar wind conditions. This behavior, which is described in terms of mutifractional Brownian motions, could be the consequence of the occurrence of dynamical phase transitions. On the other hand, it has been shown that the dynamics of the geomagnetic signals is also characterized by intermittency at the smallest temporal scales. Here, we focus on the existence of a possible relationship in the geomagnetic time series between the multifractional Brownian motion character and the occurrence of intermittency. In detail, we investigate the multifractional nature of two long time series of the horizontal intensity of the Earth's magnetic field as measured at L'Aquila Geomagnetic Observatory during two years (2001 and 2008, which correspond to different conditions of solar activity. We propose a possible double origin of the intermittent character of the small-scale magnetic field fluctuations, which is related to both the multifractional nature of the geomagnetic field and the intermittent character of the disturbance level. Our results suggest a more complex nature of the geomagnetic response to solar wind changes than previously thought.

  16. Green corona, geomagnetic activity and radar meteor rates

    International Nuclear Information System (INIS)

    Prikryl, P.

    1979-01-01

    The short-term dependence of radar meteor rates on geomagnetic activity and/or central meridian passage (CMP) of bright or faint green corona regions is studied. A superimposed-epoch analysis was applied to radar meteor observations from the Ottawa patrol radar (Springhill, Ont.) and Ksub(p)-indices of geomagnetic activity for the period 1963 to 1967. During the minimum of solar activity (1963 to 1965) the CMP of bright coronal regions was followed by the maximum in the daily rates of persistent meteor echoes (>=4s), and the minimum in the daily sums of Ksub(p)-indices whereas the minimum or the maximum, respectively, occurs after the CMP of faint coronal regions. The time delay between the CMP of coronal structures and the corresponding maxima or minima is found to be 3 to 4 days. However, for the period immediately after the minimum of solar activity (1966 to 1967) the above correlation with the green corona is void both for the geomagnetic activity and radar meteor rates. An inverse correlation was found between the radar meteor rates and the geomagnetic activity irrespective of the solar activity. The observed effect can be ascribed to the solar-wind-induced ''geomagnetic'' heating of the upper atmosphere and to the subsequent change in the density gradient in the meteor zone. (author)

  17. ANOMALOUS CHANGES OF THE GEOMAGNETIC FIELD VERTICAL COMPONENT IN KAMCHATKA

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    Smirnov, S.E.

    2016-11-01

    Full Text Available Statistical estimates of the effect in the electric field of the surface layer of the atmosphere parameters, such as time of the beginning, time of a maximum, its intensity and duration, were obtained. It was shown experimentally that the diurnal variation maximum of atmospheric electric field intensity is associated with air temperature height distribution. Power spectra of time variations of electric field intensity in the near ground atmosphere and of the horizontal component of geomagnetic field were under study. It was shown that there are oscillations with the periods of T _ 2, 0–2,5 hours in the power spectra of these parameters during a day. A possible mechanism of generation of these oscillations was proposed. It is associated with vortex motion of convective cells arising during the sunrise in the atmosphere exchange layer.

  18. Secular Orbit Evolution in Systems with a Strong External Perturber—A Simple and Accurate Model

    Energy Technology Data Exchange (ETDEWEB)

    Andrade-Ines, Eduardo [Institute de Mécanique Céleste et des Calcul des Éphémérides—Observatoire de Paris, 77 Avenue Denfert Rochereau, F-75014 Paris (France); Eggl, Siegfried, E-mail: eandrade.ines@gmail.com, E-mail: siegfried.eggl@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, 91109 Pasadena, CA (United States)

    2017-04-01

    We present a semi-analytical correction to the seminal solution for the secular motion of a planet’s orbit under gravitational influence of an external perturber derived by Heppenheimer. A comparison between analytical predictions and numerical simulations allows us to determine corrective factors for the secular frequency and forced eccentricity in the coplanar restricted three-body problem. The correction is given in the form of a polynomial function of the system’s parameters that can be applied to first-order forced eccentricity and secular frequency estimates. The resulting secular equations are simple, straight forward to use, and improve the fidelity of Heppenheimers solution well beyond higher-order models. The quality and convergence of the corrected secular equations are tested for a wide range of parameters and limits of its applicability are given.

  19. Secular chaos and its application to Mercury, hot Jupiters, and the organization of planetary systems.

    Science.gov (United States)

    Lithwick, Yoram; Wu, Yanqin

    2014-09-02

    In the inner solar system, the planets' orbits evolve chaotically, driven primarily by secular chaos. Mercury has a particularly chaotic orbit and is in danger of being lost within a few billion years. Just as secular chaos is reorganizing the solar system today, so it has likely helped organize it in the past. We suggest that extrasolar planetary systems are also organized to a large extent by secular chaos. A hot Jupiter could be the end state of a secularly chaotic planetary system reminiscent of the solar system. However, in the case of the hot Jupiter, the innermost planet was Jupiter (rather than Mercury) sized, and its chaotic evolution was terminated when it was tidally captured by its star. In this contribution, we review our recent work elucidating the physics of secular chaos and applying it to Mercury and to hot Jupiters. We also present results comparing the inclinations of hot Jupiters thus produced with observations.

  20. Post-religional perspective and secular Buddhism: Stephen Batchelor and the post-metaphysical religion

    Directory of Open Access Journals (Sweden)

    Leandro Durazzo

    2015-04-01

    Full Text Available This paper aims to present one of the contemporary trends on Buddhism, specially from the last decades in West, for its encounter with the globalized and dynamic context of present societies. This Buddhist trend, the progressive secularization of its traditions and practices, not to mention its increasing acceptance of historical-textual refutation, finds in Stephen Batchelor - a former monk in two different Buddhist traditions, Tibetan and Korean Zen - a catalyzer and a well-known advocate of secular perspective to the contemporary Buddhism. Here we will present the potential dialogue between the Secular Buddhism - besides the secularizing perspectives over orthodox cultural traditions - and the post-religional subject, as proposed by Marià Corbí and the Ecumenical Association of Third World Theologians. For the purposes of this paper we will focus on the modernizing and secular hermeneutics on Dharma practice, as defended by Stephen Batchelor and others.