bluuebunny/crossref_metadata_2025 huggingface dataset:
Electric field effects on ionospheric and thermospheric parameters above the EISCAT station for summer conditions
Authors: Klimenko V. V. , Korenkov Yu. N. , Förster M.
Published: April 2005

Abstract. Numerical calculations of the thermospheric and ionospheric parameters above EISCAT are presented for quiet geomagnetic conditions in summer. The Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) was used. The numerical results were obtained both with a self-consistent calculation of the electric fields of magnetospheric and dynamo-action origin and with the magnetospheric electric fields only. It was found that the dynamo-electric field has some effect on the ionospheric convection pattern during quiet geomagnetic conditions. It has a marked effect mainly on the zonal neutral wind component above EISCAT (±20 m/s at 140 km altitude). We have studied the effects of various field-aligned current (FAC) distributions on thermosphere/ionosphere parameters and we show that a qualitative agreement can be obtained with region-I and -II FAC zones at 75° and 65° geomagnetic latitude, respectively. The maximum FAC intensities have been assumed at 03–21 MLT for both regions with peak values of 2.5×10–7 A m–2 (region I) and 1.25×10–7 A m–2 (region II). These results are in agreement with statistical potential distribution and FAC models constructed by use of EISCAT data. The lack of decreased electron density in the night-time sector as observed by the EISCAT radar was found to be due to the spatial distribution of ionospheric convection resulting from electric fields of magnetospheric origin.Key words. Electric fields and currents · Ionosphere- atmosphere interactions · Modelling and forecasting
Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway
Authors: Blagoveshchenskaya N. F. , Kornienko V. A. , Petlenko A. V. , Brekke A. , Rietveld M. T.
Published: April 2005

Abstract. We present an analysis of phenomena observed by HF distance-diagnostic tools located in St. Petersburg combined with multi-instrument observation at Tromsø in the HF modified ionosphere during a magnetospheric substorm. The observed phenomena that occurred during the Tromsø heating experiment in the nightside auroral Es region of the ionosphere depend on the phase of substorm. The heating excited small-scale field-aligned irregularities in the E region responsible for field-aligned scattering of diagnostic HF waves. The equipment used in the experiment was sensitive to electron density irregularities with wavelengths 12–15 m across the geomagnetic field lines. Analysis of the Doppler measurement data shows the appearance of quasiperiodic variations with a Doppler frequency shift, fd and periods about 100–120 s during the heating cycle coinciding in time with the first substorm activation and initiation of the upward field-aligned currents. A relationship between wave variations in fd and magnetic pulsations in the Y-component of the geomagnetic field at Tromsø was detected. The analysis of the magnetic field variations from the IMAGE magnetometer stations shows that ULF waves occurred, not only at Tromsø, but in the adjacent area bounded by geographical latitudes from 70.5° to 68° and longitudes from 16° to 27°. It is suggested that the ULF observed can result from superposition of the natural and heater-induced ULF waves. During the substorm expansion a strong stimulated electromagnetic emission (SEE) at the third harmonic of the downshifted maximum frequency was found. It is believed that SEE is accompanied by excitation of the VLF waves penetrating into magnetosphere and stimulating the precipitation of the energetic electrons (10–40 keV) of about 1-min duration. This is due to a cyclotron resonant interaction of natural precipitating electrons (1–10 keV) with heater-induced whistler waves in the magnetosphere. It is reasonable to suppose that a new substorm activation, exactly above Tromsø, was closely connected with the heater-induced precipitation of energetic electrons.Key words. Ionosphere (active experiments; ionosphere · magnetosphere interactions). Radio science (nonlinear phenomena).
New techniques for auroral irregularity studies with COSCAT
Authors: Eglitis P. , McCrea I. W. , Robinson T. R. , Nygrén T. , Schlegel K. , Turunen T. , Jones T. B.
Published: April 2005

Abstract. The COSCAT system enables the detection of E-region auroral backscatter with the EISCAT remote receivers at magnetic aspect angles close to 90 °. This is achieved by utilising a low-power transmitter stationed in Oulu, Finland. Many important observations of E-region irregularities have been achieved with this simple experiment. Recent studies have attempted to push the COSCAT system to its experimental limits. Firstly, the CW signal has been phase-modulated with 13-bit Barker codes with baud lengths of 40, 70 and 100 µs. Interpretation of the received power allows the spatial distribution of the auroral scatterers to be determined. The second advance is in the use of a sophisticated correlator program which allows data to be buffered within the correlator at very high time resolution. This enables the coherent backscatter power to be sampled every 12.5 ms and the full auto-correlation function to be measured every 100 ms. These measurements allow the COSCAT system to be employed for the first time in an investigation of the growth and decay of the auroral irregularities.Key words. Ionosphere (ionospheric irregularities) · Radio science (Instruments and techniques)
Seasonal effects in the ionosphere-thermosphere response to the precipitation and field-aligned current variations in the cusp region
Authors: Namgaladze A. A. , Namgaladze A. N. , Volkov M. A.
Published: April 2005

Abstract. The seasonal effects in the thermosphere and ionosphere responses to the precipitating electron flux and field-aligned current variations, of the order of an hour in duration, in the summer and winter cusp regions have been investigated using the global numerical model of the Earth's upper atmosphere. Two variants of the calculations have been performed both for the IMF By < 0. In the first variant, the model input data for the summer and winter precipitating fluxes and field-aligned currents have been taken as geomagnetically symmetric and equal to those used earlier in the calculations for the equinoctial conditions. It has been found that both ionospheric and thermospheric disturbances are more intensive in the winter cusp region due to the lower conductivity of the winter polar cap ionosphere and correspondingly larger electric field variations leading to the larger Joule heating effects in the ion and neutral gas temperature, ion drag effects in the thermospheric winds and ion drift effects in the F2-region electron concentration. In the second variant, the calculations have been performed for the events of 28–29 January, 1992 when precipitations were weaker but the magnetospheric convection was stronger than in the first variant. Geomagnetically asymmetric input data for the summer and winter precipitating fluxes and field-aligned currents have been taken from the patterns derived by combining data obtained from the satellite, radar and ground magnetometer observations for these events. Calculated patterns of the ionospheric convection and thermospheric circulation have been compared with observations and it has been established that calculated patterns of the ionospheric convection for both winter and summer hemispheres are in a good agreement with the observations. Calculated patterns of the thermospheric circulation are in a good agreement with the average circulation for the Southern (summer) Hemisphere obtained from DE-2 data for IMF By < 0 but for the Northern (winter) Hemisphere there is a disagreement at high latitudes in the afternoon sector of the cusp region. At the same time, the model results for this sector agree with other DE-2 data and with the ground-based FPI data. All ionospheric and thermospheric disturbances in the second variant of the calculations are more intensive in the winter cusp region in comparison with the summer one and this seasonal difference is larger than in the first variant of the calculations, especially in the electron density and all temperature variations. The means that the seasonal effects in the cusp region are stronger in the thermospheric and ionospheric responses to the FAC variations than to the precipitation disturbances.Key words. Ionosphere (ionosphere · atmosphere interactions; ionosphere · magnetosphere interactions; ionospheric disturbances).
Proton transport model in the ionosphere. 2. Influence of magnetic mirroring and collisions on the angular redistribution in a proton beam
Authors: Galand M. , Lilensten J. , Kofman W. , Lummerzheim D.
Published: April 2005

Abstract. We investigate the influence of magnetic mirroring and elastic and inelastic scattering on the angular redistribution in a proton/hydrogen beam by using a transport code in comparison with observations. H-emission Doppler profiles viewed in the magnetic zenith exhibit a red-shifted component which is indicative of upward fluxes. In order to determine the origin of this red shift, we evaluate the influence of two angular redistribution sources which are included in our proton/hydrogen transport model. Even though it generates an upward flux, the redistribution due to magnetic mirroring effect is not sufficient to explain the red shift. On the other hand, the collisional angular scattering induces a much more significant red shift in the lower atmosphere. The red shift due to collisions is produced  by <1 -keV protons and is so small as to require an instrumental bandwidth <0.2 nm. This explains the absence of measured upward proton/hydrogen fluxes in the Proton I rocket data because no useable data concerning protons <1 keV are available. At the same time, our model agrees with measured ground-based H-emission Doppler profiles and suggests that previously reported red shift observations were due mostly to instrumental bandwidth broadening of the profile. Our results suggest that Doppler profile measurements with higher spectral resolution may enable us to quantify better the angular scattering in proton aurora.Key words. Auroral ionosphere · Particle precipitation
Mesospheric observations with the EISCAT UHF radar during polar cap absorption events: 3. Comparison with simultaneous EISCAT VHF measurements
Authors: Collis P. N. , Rietveld M. T.
Published: April 2005

Abstract. Mesospheric observations were obtained by the EISCAT UHF and VHF radars during the solar proton event of March 1990. We present the first comparison of incoherent-scatter spectral measurements from the middle mesosphere using simultaneous, co-located observations by the two radars. VHF spectra observed with a vertical antenna were found to be significantly narrower than model predictions, in agreement with earlier UHF results. For antenna pointing directions that were significantly away from the vertical, the wider VHF radar beam gave rise to broadening of the observed spectra due to vertical shears in the horizontal wind. In this configuration, UHF spectral measurements were found to be more suitable for aeronomical applications. Both radar systems provide consistent and reliable estimates of the neutral wind. Spectral results using both the multipulse and pulse-to-pulse schemes were intercompared and their suitability for application to combined mesosphere – lower thermosphere studies investigated.Key words. Mesophere · Lower thermosphere · EISCAT UHF radar · EISCAT VHF radar
Validation of the CUTLASS HF radar gravity wave observing capability using EISCAT CP-1 data
Authors: Arnold N. F. , Jones T. B. , Robinson T. R. , Stocker A. J. , Davies J. A.
Published: April 2005

Abstract. Quasi-periodic fluctuations in the returned ground-scatter power from the SuperDARN HF radars have been linked to the passage of medium-scale gravity waves. We have applied a technique that extracts the first radar range returns from the F-region to study the spatial extent and characteristics of these waves in the CUTLASS field-of-view. Some ray tracing was carried out to test the applicability of this method. The EISCAT radar facility at Tromsø is well within the CUTLASS field-of-view for these waves and provides a unique opportunity to assess independently the ability of the HF radars to derive gravity wave information. Results from 1st March, 1995, where the EISCAT UHF radar was operating in its CP-1 mode, demonstrate that the radars were in good agreement, especially if one selects the electron density variations measured by EISCAT at around 235 km. CUTLASS and EISCAT gravity wave observations complement each other; the former extends the spatial field of view considerably, whilst the latter provides detailed vertical information about a range of ionospheric parameters.Key words. Ionosphere (ionosphere – atmosphere interactions) · Meteorology and atmospheric dynamics (thermospheric dynamics) · Radio science (ionospheric propagations)
Meridional thermospheric neutral wind at high latitude over a full solar cycle
Authors: Witasse O. , Lilensten J. , Lathuillere C. , Pibaret B.
Published: April 2005

Abstract. EISCAT radar experiments over a full solar cycle between January 1984 and March 1995 have been used to construct meridional neutral wind patterns in the ionospheric F region. For locally geomagnetically quiet periods the neutral winds have been binned according to season, solar activity, and universal time. The diurnal and seasonal behaviors and the effect of the solar flux are described. An empirical model of the meridional neutral wind for the high latitudes at eight altitudes in the ionospheric F region over a full solar cycle is presented. Results are compared with other recent empirical models.Key words. Auroral ionosphere · Thermospheric dynamics · EISCAT
Study of the longitudinal expansion velocity of the substorm current wedge
Authors: Belehaki A. , Tsagouri I. , Mavromichalaki H.
Published: April 2005

Abstract. In this work we examine simultaneous observations from the two geosynchronous satellites GOES-5 and GOES-6 located at 282°E and 265°E respectively, and from middle and low latitude ground observatories located within 250°E and 294°E geographic longitude, during isolated substorms of moderate activity. The spatial distribution of our observation points allows us to make a detailed study of the azimuthal expansion of the substorm current wedge. The data analysis shows evidence that the substorm initiation and development mechanism include the cross-tail current diversion/ disruption, the substorm current wedge formation and the azimuthal expansion of the inner plasma sheet. The triggering mechanism is initially confined in a longitudinally narrow sector, estimated to be less than 15° and located very close to local midnight to the east or to the west. The current disruption region expands both eastward and westward in the magnetotail, so that the location of major field-aligned currents flowing into the ionosphere shifts successively eastward, and the location of the currents flowing out of the ionosphere shifts successively westward. Evidence was found that the perturbation travels toward the west with velocities greater than those expanding the wedge eastward. The drastic decrease of the velocity with the azimuthal distance from the location of the disturbance initiation, i.e., the onset sector, indicates that the energy release is a very localized phenomenon. Finally, the transient D perturbation observed by the geosynchronous satellites suggests that the field-aligned currents forming the wedge have a longitudunally limited extent.Key words. Magnetospheric physics (current systems; magnetosphere-ionosphere interactions)
Observations of thermospheric neutral winds within the polar cusp and the auroral oval using a Doppler imaging system (DIS)
Authors: Rees D. , Smith R. W. , Signernes F. , Henriksen K. , Brandstrom U. , Harris M. , Maskall G.
Published: April 2005

Abstract. Two Doppler imaging systems (DIS) or wide-field imaging Fabry-Perot interferometers (FPI), have recently been commissioned, one at the Auroral Station, Adventdalen, Longyearbyen, Svalbard, and the second at the IRF, Kiruna, Sweden. These instruments can provide wide-field (600 * 800 km) images of neutral wind flows in the upper thermosphere, by measuring the Doppler shift of the atomic oxygen forbidden near 630 nm, which is emitted from an altitude of approximately 240 km. From the instrument in Svalbard, at mid-winter, it is possible to observe the dayside polar cusp and the polar cap throughout the entire day, whereas from Kiruna, the night-time auroral oval is observable during the hours of darkness. Measurements of thermospheric dynamics from the DIS can be used in conjunction with observations of ionospheric plasma flows and thermal plasma densities by the EISCAT-Svalbard radar (ESR) and by EISCAT, along with other complementary observations by co-located instruments such as the auroral large-scale imaging system (ALIS). Such combined data sets will allow a wide range of scientific studies to be performed concerning the dynamical response of the thermosphere and ionosphere, and the important energetic and momentum exchange processes resulting from their complex interactions. These processes are particularly important in the immediate vicinity of the polar cusp and within the auroral oval. Early results from Svalbard in late 1995 will be discussed. The DIS in Kiruna observed two interesting geomagnetic disturbances in early 1997, the minor geomagnetic storm of 10, 11 January, and the disturbed period from 7–10 February. During these events, the thermospheric wind response showed some interesting departures from the average behaviour, which we attribute to the result of strong and variable Lorenz forcing (ion drag) and Joule and particle heating during these geomagnetic disturbances.Key words. Ionosphere (Polar ionosphere) · Meteorology and atmospheric dynamics (thermospheric dynamics; instruments and techniques).
A case-study of the low-latitude thermosphere during geomagnetic storms and its new representation by improved MSIS model
Authors: Pant T. K. , Sridharan R.
Published: April 2005

Abstract. The thermospheric temperatures from low and equatorial latitudes during geomagnetically disturbed periods are known to exhibit significant deviations from atmospheric model predictions. Also, the oscillatory features seen in the observations are not accounted for by the models. A simple relation has been established between the difference in the observed and model-predicted temperatures and the rate of change of Dst, the magnetic index representing the ring current variabilities. Using this relation, a correction term has been added to the latest MSIS-90 model algorithm and almost all the observed variations in neutral temperatures spectroscopically determined from Mt.Abu, a low-latitude station in India, are successfully reproduced for two moderate geomagnetic storms.Key words. Low-latitude thermosphere · MSIS model · Stormtime model predictions · FP spectroscopic temperatures
Effects of geomagnetic activity on the mesospheric electric fields
Authors: Zadorozhny A. M. , Tyutin A. A.
Published: April 2005

Abstract. 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)
A quantitative model of the magnetosphere with poloidal vector fields
Authors: Kosik J. C.
Published: April 2005

Abstract. A quantitative model of the magnetospheric magnetic field is developed using poloidal vector fields. This formalism is applied to the ring current region, the distant field and the return currents. The tail model is similar to the unwarped model of Tsyganenko. Several sets of coefficients are obtained for different Kp through a fit of the NSSDC data base. Experimental ΔB contours and theoretical distributed currents contours are correctly described and are Kp-dependent. Field line topology problems and poor ring current description observed in models of similar complexity are avoided. Computer time has been kept reasonable and makes this model particularly adapted to intensive-type calculations.Key words. Magnetospheric physics (magnetospheric · configuration and dynamics).
A case study of electron precipitation in the late substorm growth phase on and nearby a preonset arc
Authors: Olsson A. , Janhunen P.
Published: April 2005

Abstract. We follow the electron precipitation characteristics on and nearby a preonset arc using the high resolution Freja TESP instrument. Our data coverage extends from about 10 min before onset up to 1 min before onset. The arc is the most equatorward one (around MLAT 62°) of a system of growth phase arcs, and it was close to the radiation belt precipitation. Within the preonset arc, inverted-V type precipitation dominates. Poleward of the arc we also find some precipitation regions, and here there is systematically a cold electron population superposed with a warm population. Using single and double Maxwellian fits to the measured electron spectra we find the ionosphere-magnetosphere coupling parameters (field-aligned conductance K and the parallel potential drop V) as well as the effective source plasma properties (density and temperature) during the event. Compared to typical expansion phase features, the preonset parallel potential drop is smaller by a factor of ten, the electron temperature is smaller by a factor of at least five, and the field-aligned conductance is about the same or larger. The fact that there are two isotropic superposed electron populations on the poleward side of the preonset arc suggests that the distance between warm trapped electrons on dipolar field lines and colder electrons on open field lines has become so small near the onset that mixing e.g. due to finite electron Larmor radius effects can take place.Key words. Ionosphere · (ionosophere-magnetosphere interactions) · Magnetospheric physics (auroral phenomena; storms and substorms).
A new southern high-latitude index
Authors: Ballatore P. , Maclennan C. G. , Engebretson M. J. , Candidi M. , Bitterly J. , Meng C.-I. , Burns G.
Published: April 2005

Abstract. We have developed and examined a new regional geomagnetic index AES-80, defined similarly to the classical auroral electrojet AE index, using data from five Antarctic stations located at corrected geomagnetic latitudes about 80 °S. Because only sparse ground-based information can be derived from auroral latitudes in the Southern Hemisphere, and because no index comparable to AE can be constructed from locations in the south, the possibility of using AES-80 as a measure of high latitudes and polar cap activity is investigated. As a global average activity level indicator, it is found that in general AES-80 gives results rather similar to the classical AE index. However AES-80 provides a more robust measure of the occurrence of high-latitude geomagnetic activity.Key words. Magnetospheric physics (auroral phenomena; polar cap phenomena).
Spectral characteristics of spring arctic mesosphere dynamics
Authors: Hall C. M. , Manson A. H. , Meek C. E.
Published: April 2005

Abstract. The spring of 1997 has represented a stable period of operation for the joint University of Tromsø / University of Saskatchewan MF radar, being between refurbishment and upgrades. We examine the horizontal winds from the February to June inclusive and also include estimates of energy dissipation rates derived from signal fading times and presented as upper limits on the turbulent energy dissipation rate, ε. Here we address the periodicity in the dynamics of the upper mesosphere for time scales from hours to one month. Thus, we are able to examine the changes in the spectral signature of the mesospheric dynamics during the transition from winter to summer states.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence; waves and tides).
Meridian-scanning photometer, coherent HF radar, and magnetometer observations of the cusp: a case study
Authors: Milan S. E. , Lester M. , Cowley S. W. H. , Moen J. , Sandholt P. E. , Owen C. J.
Published: April 2005

Abstract. The dynamics of the cusp region and post-noon sector for an interval of predominantly IMF By, Bz < 0 nT are studied with the CUTLASS Finland coherent HF radar, a meridian-scanning photometer located at Ny Ålesund, Svalbard, and a meridional network of magnetometers. The scanning mode of the radar is such that one beam is sampled every 14 s, and a 30° azimuthal sweep is completed every 2 minutes, all at 15 km range resolution. Both the radar backscatter and red line (630 nm) optical observations are closely co-located, especially at their equatorward boundary. The optical and radar aurora reveal three different behaviours which can interchange on the scale of minutes, and which are believed to be related to the dynamic nature of energy and momentum transfer from the solar wind to the magnetosphere through transient dayside reconnection. Two interpretations of the observations are presented, based upon the assumed location of the open/closed field line boundary (OCFLB). In the first, the OCFLB is co-located with equatorward boundary of the optical and radar aurora, placing most of the observations on open field lines. In the second, the observed aurora are interpreted as the ionospheric footprint of the region 1 current system, and the OCFLB is placed near the poleward edge of the radar backscatter and visible aurora; in this interpretation, most of the observations are placed on closed field lines, though transient brightenings of the optical aurora occur on open field lines. The observations reveal several transient features, including poleward and equatorward steps in the observed boundaries, "braiding" of the backscatter power, and 2 minute quasi-periodic enhancements of the plasma drift and optical intensity, predominantly on closed field lines.Key words. Ionosphere (auroral ionosphere; plasma convection) · Magnetospheric physics (magnetopause · cusp · and boundary layers)
Comment on Lockwood and Davis, "On the longitudinal extent of magnetopause reconnection pulses"
Authors: Heikkila W. J.
Published: April 2005

Abstract. Lockwood and Davis (1996) present a concise description of magnetopause reconnection pulses, with the claimed support of three types of observations: (1) flux transfer events (FTE), (2) poleward-moving auroral forms on the dayside, and (3) steps in cusp ion dispersion characteristics. However, there are a number of errors and misconceptions in the paper that make their conclusions untenable. They do not properly take account of the fact that the relevant processes operate in the presence of a plasma. They fail to notice that the source of energy (a dynamo with E · J<0) must be close to the region of dissipation (the electrical load with E · J>0) in transient phenomena, since energy (or information) cannot travel faster than the group velocity of waves in the medium (here the Alfvén velocity VA). In short, Lockwood and Davis use the wrong contour in their attempt to evaluate the electromotive force (emf). This criticism goes beyond their article: a dynamo is not included in the usual definition of reconnection, only the reconnection load. Without an explicit source of energy in the assumed model, the idea of magnetic reconnection is improperly posed. Recent research has carried out a superposed epoch analysis of conditions near the dayside magnetopause and has found the dynamo and the load, both within the magnetopause current sheet. Since the magnetopause current is from dawn to dusk, the sign of E · J reflects the sign of the electric field. The electric field reverses, within the magnetopause; this can be discovered by an application of Lenz's law using the concept of erosion of the magnetopause. The net result is plasma transfer across the magnetopause to feed the low latitude boundary layer, at least partly on closed field lines, and viscous interaction as the mechanism by which solar wind plasma couples to the magnetosphere.
The correct application of Poynting's theorem to the time-dependent magnetosphere: reply to Heikkila
Authors: Lockwood M. , Davis C. J.
Published: April 2005

Abstract. Without Abstract
Global transport and localized layering of metallic ions in the upper atmospherer
Authors: Carter L. N. , Forbes J. M.
Published: April 2005

Abstract. A numerical model has been developed which is capable of simulating all phases of the life cycle of metallic ions, and results are described and interpreted herein for the typical case of Fe+ ions. This cycle begins with the initial deposition of metallics through meteor ablation and sputtering, followed by conversion of neutral Fe atoms to ions through photoionization and charge exchange with ambient ions. Global transport arising from daytime electric fields and poleward/ downward di.usion along geomagnetic field lines, localized transport and layer formation through de- scending convergent nulls in the thermospheric wind field, and finally annihilation by chemical neutralization and compound formation are treated. The model thus sheds new light on the interdependencies of the physical and chemical processes a.ecting atmospheric metallics. Model output analysis confirms the dominant role of both global and local transport to the ion's life cycle, showing that upward forcing from the equatorial electric field is critical to global movement, and that diurnal and semidiurnal tidal winds are responsible for the forma- tion of dense ion layers in the 90±250 km height region. It is demonstrated that the assumed combination of sources, chemical sinks, and transport mechanisms actually produces F-region densities and E-region layer densities similar to those observed. The model also shows that zonal and meridional winds and electric fields each play distinct roles in local transport, whereas the ion distribution is relatively insensitive to reasonable variations in meteoric deposition and chemical reaction rates.Key words. Ionosphere (ion chemistry and composition; ionosphere-atmosphere interactions).
Morphological aspects of a new type of counter electrojet event
Authors: Rastogi R. G.
Published: April 2005

Abstract. The study describes the time and space morphologies of a rather new type of counter electrojet event on the basis of data from the excellent chain of magnetic and ionospheric observatories along the Indo-Russian longitude sector. Abnormally large westward currents are observed during almost the whole of the daytime hours on a series of days. These events do not form any vortices in the current system and do not apparently seem to be associated with tidal effects or any solar magnetosphere events or geomagnetic disturbances. The existence of a westward electric field over the equatorial ionosphere has been confirmed by the absence of an equatorial type of sporadic E in the ionograms at Thumba precisely during the periods when ∆H at Trivandrum minus ∆H at Alibag is negative. The equatorial F region anomaly was also absent on the counter electrojet day. Such counter electrojet events during the northern winter months of low solar activity years are suggested to be the result of the modified wind system in the ionosphere associated with stratospheric warming events.Key words. Geomagnetism and paleomagnetism (time variations · diurnal to secular) · Ionosphere (electric fields and currents; equatorial ionosphere)
The role of dynamics in total ozone deviations from their long-term mean over the Northern Hemisphere
Authors: Petzoldt K.
Published: April 2005

Abstract. Total ozone anomalies (deviation from the long-term mean) are created by anomalous circulation patterns. The dynamically produced ozone anomalies can be estimated from known circulation parameters in the layer between the tropopause and the middle stratosphere by means of statistics. Satellite observations of ozone anomalies can be compared with those expected from dynamics. Residual negative anomalies may be due to chemical ozone destruction. The statistics are derived from a 14 year data set of TOMS (Total Ozone Mapping Spectrometer January 1979-Dec. 1992) and corresponding 300 hPa geopotential (for the tropopause height) together with 30 hPa temperature (for stratospheric waves) at 60°N. The correlation coefficient for the linear multiple regression between total ozone (dependent variable) and the dynamical parameters (independent variables) is 0.88 for the zonal deviations in the winter of the Northern Hemisphere. Zonal means are also significantly dependent on circulation parameters, besides showing the known negative trend function of total ozone observed by TOMS. The significant linear trend for 60°N is \\sim3 DU/year in the winter months taking into account the dependence on the dynamics between the tropopause region and the mid-stratosphere. The highest correlation coefficient for the monthly mean total ozone anomalies is reached in November with 0.94.Key words. Atmospheric composition and structure (middle atmosphere · composition and chemistry) · Meteorology and atmospheric dynamics (middle atmosphere dynamics).
Calculating the azimuth of mountain waves, using the effect of tilted fine-scale stable layers on VHF radar echoes
Authors: Worthington R. M.
Published: April 2005

Abstract. A simple method is described, based on standard VHF wind-profiler data, where imbalances of echo power between four off-vertical radar beams, caused by mountain waves, can be used to calculate the orientation of the wave pattern. It is shown that the mountain wave azimuth (direction of the horizontal component of the wavevector), is given by the vector [ W (PE - P W ) ,W (PN - P S ) ]; PN, PS, PE, PW are radar echo powers, measured in dB, in beams pointed away from vertical by the same angle towards north, south, east and west respectively, and W is the vertical wind velocity. The method is applied to Aberystwyth MST radar data, and the calculated wave vector usually, but not always, points into the low-level wind direction. The mean vertical wind at Aberystwyth, which may also be affected by tilted aspect-sensitive layers, is investigated briefly using the entire radar output 1990-1997. The mean vertical-wind profile is inconsistent with existing theories, but a new mountain-wave interpretation is proposed.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides; instruments and techniques).
Correction to: Further development in theory/data closure of the photoelectron-driven polar wind and day-night transition of the outflow
Authors: Tam S. W. Y. , Yasseen F. , Chang T.
Published: April 2005

Abstract. Without abstract
A simple oblique dip model for geomagnetic micropulsations
Authors: Lawrie J. A. , Smith P. N.
Published: April 2005

Abstract. It is pointed out that simple models adopted so far have tended to neglect the obliquity of the magnetic field lines entering the Earth's surface. A simple alternative model is presented, in which the ambient field lines are straight, but enter wedge shaped boundaries at half a right-angle. The model is illustrated by assuming an axially symmetric, compressional, impulse type disturbance at the outer boundary, all other boundaries being assumed to be perfectly conducting. The numerical method used is checked from the instant the excitation ceases, by an analytical method. The first harmonic along field lines is found to be of noticeable size, but appears to be mainly due to coupling with the fundamental, and with the first harmonic across field lines.Key words. Magnetospheric physics (MHD waves and instabilities).
Who Surfs, Who Manipulates? The Determinants of Opportunistic Election Timing and Electorally Motivated Economic Intervention
Authors: KAYSER MARK ANDREAS
Published: April 2005

In this paper, I develop a career concerns model of government policy choice within a dynamic optimal stopping framework to predict the degree of surfing (opportunistic timing) and manipulation (politically motivated economic intervention) under alternate institutional structures. Among other results, I find that the likelihood of opportunistic elections rises with exogenous economic performance, with longer maximum term lengths, with future electoral uncertainty, and with economic volatility but diminishes in the value of office-holding; manipulation increases with the maximum term length and with the value of office-holding but decreases with exogenous economic performance and with economic volatility. The model suggests that single-party governments should be highly opportunistic in calling elections and that countries that allow opportunistic election timing should experience less economically distortionary political intervention than their fixed-timing counterparts.
Accountability and Abuses of Power in World Politics
Authors: GRANT RUTH W. , KEOHANE ROBERT O.
Published: April 2005

Debates about globalization have centered on calls to improve accountability to limit abuses of power in world politics. How should we think about global accountability in the absence of global democracy? Who should hold whom to account and according to what standards? Thinking clearly about these questions requires recognizing a distinction, evident in theories of accountability at the nation-state level, between “participation” and “delegation” models of accountability. The distinction helps to explain why accountability is so problematic at the global level and to clarify alternative possibilities for pragmatic improvements in accountability mechanisms globally. We identify seven types of accountability mechanisms and consider their applicability to states, NGOs, multilateral organizations, multinational corporations, and transgovernmental networks. By disaggregating the problem in this way, we hope to identify opportunities for improving protections against abuses of power at the global level.
Does Collective Identity Presuppose an Other? On the Alleged Incoherence of Global Solidarity
Authors: ABIZADEH ARASH
Published: April 2005

Two arguments apparently support the thesis that collective identity presupposes an Other: therecognition argument, according to which seeing myself as a self requires recognition by an other whom I also recognize as a self (Hegel); and thedialogic argument, according to which my sense of self can only develop dialogically (Taylor). But applying these arguments tocollectiveidentity involves a compositional fallacy. Two modern ideologies mask the particularist thesis's falsehood. The ideology of indivisible state sovereignty makes sovereignty as such appear particularistic by fusing “internal” with “external” sovereignty; nationalism imagines national identity as particularistic by linking it to sovereignty. But the concatenation of internal sovereignty, external sovereignty, and nation is contingent. Schmitt's thesis that “the political” presupposes an other conflates internal and external sovereignty, while Mouffe's neo-Schmittianism conflates difference (Derrida) with alterity. A shared global identity may face many obstacles, but metaphysical impossibility and conceptual confusion are not among them.
Who Influences U.S. Foreign Policy?
Authors: JACOBS LAWRENCE R. , PAGE BENJAMIN I.
Published: April 2005

Research in international relations has identified a variety of actors who appear to influence U.S. foreign policy, including experts and “epistemic communities,” organized interests (especially business and labor), and ordinary citizens or “public opinion.” This research, however, has often focused on a single factor at a time, rather than systematically testing the relative importance of alternative possible influences. Using extensive survey data gathered over three decades we conduct a comparative test, attempting to account for the expressed foreign policy preferences of policy makers by means of the preferences of the general public and those of several distinct sets of elites. The results of cross-sectional and time-lagged analyses suggest that U.S. foreign policy is most heavily and consistently influenced by internationally oriented business leaders, followed by experts (who, however, may themselves be influenced by business). Labor appears to have significant but smaller impacts. The general public seems to have considerably less effect, except under particular conditions. These results generally hold over several different analytical models (including two-observation time series) and different clusters of issues (economic, military, and diplomatic), with some variations across different institutional settings (the U.S. House, Senate, and executive branch).
The Rise of Third Parties in the 1993 Canadian Federal Election: Pinard Revisited
Authors: Bélanger Éric
Published: April 2005

Abstract.This study proposes a new test of Maurice Pinard's theory on the rise of third parties applied to the case of the 1993 Canadian federal election. We assess the effect at the individual level of Pinard's factors (one-party dominance and grievances) on support for the Reform party and the Bloc Québécois using data from the Canadian Election Study. Logistic regression analyses of vote choice indicate that the extent to which the second major party was perceived to be electorally weak at the constituency level was a significant factor in leading some Western voters to support Reform. In Quebec, however, perceptions of predominance did not matter to a vote for the Bloc because the latter is a “radical” third party attracting support mostly on the basis of communal values and interests. The results further show that political grievances, but not economic ones, were a significant predictor of support for both third parties in that election.

Résumé.Cette étude propose un nouveau test empirique de la théorie de Maurice Pinard concernant la percée électorale des tiers partis. L'impact des facteurs de Pinard (prédominance d'un parti et présence de griefs) sur l'appui au Parti réformiste et au Bloc québécois à l'élection fédérale canadienne de 1993 est vérifié au niveau micro-sociologique à l'aide des données de l'Étude sur l'élection canadienne. Les analyses de régression logistique du vote indiquent que la perception que certains électeurs de l'Ouest avaient de la faible compétitivité du second parti traditionnel dans leur circonscription les a encouragés à appuyer le Parti réformiste. Au Québec, les perceptions de prédominance n'ont cependant pas eu d'effet significatif sur le vote en faveur du Bloc en raison du fait que ce dernier est un tiers parti “ radical ” dont l'appui repose principalement sur des valeurs et des intérêts de groupe. Les résultats indiquent enfin que, contrairement aux griefs de nature économique, les griefs politiques régionaux ont significativement contribué au succès électoral des deux partis.
Social Capital and Civic Community in Alberta
Authors: Pickup Mark , Sayers Anthony , Knopff Rainer , Archer Keith
Published: April 2005

Abstract.We investigate the nature of civic community and social capital in Alberta. We find a civic community with high levels of interpersonal trust and civic participation, that values formal political equality and direct participation, yet expresses high levels of alienation from and low levels of confidence in its governments. While exogenous variables contribute to a strong civic community, only endogenous variables can account for the comparatively higher levels of participation and trust. Using a model developed by John Brehm and Wendy Rahn, we discover a virtuous circle between trust and participation, with its roots in the agrarian, populist past of the province. Economic and social changes have helped sustain this pattern, as have politicians bent on using it to defend Alberta's exceptionalism.

Résumé.Nous examinons la nature de la communauté civique et du capital social en Alberta. Nous y trouvons une communauté civique riche en confiance interpersonnelle et en participation civique et trés attachée à la fois à l'égalité politique formelle et à la participation directe. Cette communauté exprime cependant un profond sentiment d'aliénation et de méfiance à l'égard de ses gouvernements. Alors que des variables exogènes contribuent au développement d'une communauté civique vigoureuse, seules les variables endogènes peuvent expliquer les niveaux relativement élevés de participation et de confiance. En nous servant du modèle développé par John Brehm et Wendy Rahn, nous avons découvert une relation circulaire “ vertueuse ” entre la confiance et la participation, ayant des racines dans le passé agraire et populiste de la province. Les changements économiques et sociaux ont aidé à promouvoir ce modèle comme le font aussi les politiciens enclins à défendre l'exceptionalisme albertain.
Secession as Defence of a Political Liberty: A Liberal Answer to a Nationalist Demand
Authors: Pavković Aleksandar
Published: April 2005

Abstract.Unilateral secession breaches the principle of majority rule and the principle of equal rights to which liberal democratic states adhere. How can one justify such a breach in a case in which the seceding state also aspires to be a liberal democratic state? If the government of the parent state, following a pro-secession referendum, refuses to negotiate with the secessionists over their secession, it thereby denies them the liberty of pursuing a politically satisfying life. A unilateral secession in pursuit of such a liberty could be justified within a Rawlsian framework, which ranks liberties higher than economic interests. But within the same framework a unilateral secession is unjustified if, as its consequence, the parent state can no longer protect those citizen rights which it protected before. While useful in assessing some cases of secession, the Rawlsian ranking does not provide universal criteria for assessment of all secessions.

Résumé.La sécession unilatérale rompt avec le principe de la règle majoritaire ainsi qu'avec celui de l'égalité des droits auxquels adhèrent les États libéraux démocratiques. Comment peut-on justifier une telle rupture dans un cas où l'État sécessionniste aspire aussi à être un État libéral démocratique? Si le gouvernement de l'État originaire, à la suite d'un référendum pro-sécessionniste, refuse de négocier avec les sécessionnistes sur leur sécession, il leur refuse ainsi la liberté de poursuivre une vie politiquement satisfaisante. Une sécession unilatérale visant à gagner cette liberté pourrait se justifier dans une optiquerawlsiennequi accorde plus d'importance aux libertés qu'aux intérêts économiques. Mais dans cette même optique une sécession unilatérale est injustifiée si, du fait de la sécession, l'État originaire ne peut plus protéger les droits de ses citoyens, qu'il protégeait auparavant. Utile pour l'évaluation de certains cas de sécession, l'ordre de valeursrawlsienne fournit pas des critères universels pour les évaluer toutes.