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Balloon observations of temporal and spatial fluctuations in stratospheric conductivity

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Abstract

The first campaign of the Polar Patrol Balloon (PPB) experiment (1st-PPB) was carried out at Syowa Station in Antarctica during 1990–1991 and 1992–1993. Based on the results of the 1st-PPB experiment, the next campaign (2nd-PPB) was carried out in the austral summer of 2002–2003. This paper will present stratospheric conductivity results from the 2nd-PPB experiment. In that experiment, three balloons were launched for the purpose of upper atmosphere physics observation (three balloons). Payloads of these three flights were identical with each other, and were launched as close together in time as allowed by weather conditions to constitute a cluster of balloons during their flights. Such a “Balloon Cluster” is suitable to observe temporal evolution and spatial distribution of phenomena in the ionospheric regions and boundaries that the balloons traversed during their circumpolar trajectory. More than 20 days of simultaneous fair weather 3-axis electric field and stratospheric conductivity data were obtained at geomagnetic latitudes ranging from sub-auroral to the polar cap. Balloon separation varied from ∼60 to >1000 km. This paper will present stratospheric conductivity observations with emphasis on the temporal and spatial variations that were observed.

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... Atmospheric electric field. Equation (1) shows that the electric field magnitude inside the Earth-ionosphere capacitor decreases with height z as 1/(R þ z) 2 , departing significantly from the much faster, nearly exponential, decrease of the observed atmospheric electric field with height (e.g., see Holzworth, 1987;Markson et al., 1999;Williams, 2003;Bering et al., 2005;Rycroft et al., 2007;Markson, 2007;among others). ...
... For example, Equation (1) predicts a field reduction of only~0.3% at 10 km and~0.6% at 20 km from the surface field. These values are very much smaller than the corresponding huge reductions of~95% and 99%, respectively, for the measured atmospheric electric field (see, e.g., Markson et al., 1999;Bering et al., 2005;Holzworth et al., 2005) or the modeled electric field in the atmosphere (Williams, 2003;Rycroft et al., 2007). ...
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Simultaneous measurements of the small-ion density and electrical conductivity of the stratosphere over southern Victoria with the usual short balloon-borne Gerdien condens- ers have shown that such measurements are subject to serious errors. The errors arise from the aerodynamic properties of instruments which depend on the vertical ascent of the balloon to aspirate the condensers. Without a flow rate correction which must be calibrated as a function of height for an individual instrument, the recorded ion density may be in error by more than a factor of 2 at the higher altitudes. It is shown also that conductivity measurements are invalid above the altitude where the air velocity profile at the exit of the condenser becomes different from that at the entrance. For the present instrument this altitude is approximately 22 km. Application of an experimental correction factor to the ion density results has led to mobility-height profiles consistent with the inverse density rule up to this limiting altitude. Experiments have been conducted (a) to measure the polar ratios of ion density and con- ductivity with small vertical sounding balloons and (b) to measure the positive ion density and conductivity from a plastic balloon floating at 30.5 kin, where aspiration of the condenser was achieved by means of a pump. Both experiments have yielded results consistent with the previously indicated high stratospheric dust concentration over Melbourne. The ratios of positive to negative ion density and of positive to negative conductivity for the altitude range 4 to 24 km were 1.43 _ .14 and 1.04 _ .09, respectively. The positive-ion density and conductivity at 30.5 km were approximately 1000 ions/eraand 300 esu, respectively. These last two results are again consistent with the inverse density rule for small-ion average mo- bility. The floating balloon experiment indicated a considerable time variation in ion density and conductivity.
Article
Balloonborne measurements of the polar conductivity and the vertical electric field were carried out over a period of 1984–1994 from Hyderabad, Central India. The conductivity values show positive correlation with solar activity between 20 and 35 km. Between 5 and 20 km the conductivity values show an anti-correlation with solar activity. The vertical electric field does not show solar cycle effect. However, the electric field and the conductivity show a semi-diurnal variation at balloon float altitude.
Article
From late December of 1990 to early January of 1991, the National Institute of Polar Research, in collaboration with the Institute of Space and Astronautical Science, launched two large zero-pressure balloons from Syowa Station, which is the Japanese research base in Antarctica. The balloon launched on December 25 returned near Syowa Station after 15 days of flight, keeping a constant altitude of about 30 km. It finally accomplished almost a one and half circumpolar flight. The total flight duration was about 40 days. This article will describe the balloon system and the flight behavior of the balloon.
Article
A newly developed multi-ID (Identification) ARGOS data transfer system for the PPB (Polar Patrol Balloon) experiment (1990-1993) is described. This system on board the PPBs with a main processor continuously transferred data of about 2 kB/h with great reliability during the entire observation periods (longer than one month). This brief report describes the principle and specifications of the system.
Article
Stratospheric electrical conductivity measurements have been made from high altitude research balloons at various locations around the world for more than 30 years. In the stratosphere, conductivity changes may indicate changes in aerosol or water vapor content. In this paper, we will compare data taken in the last five years at mid latitude locations with data taken in the previous three decades at both mid and high latitude. So far, it appears that short term variations owing to Forbush decreases, geomagnetic storms, aerosol injections by volcanos and forest fires, etc. completely obscure any long term climatic trend.
Article
Direct evidence of solar flare modification of stratospheric electric fields is presented through comparison of atmospheric electric field variations with fluxes of solar protons that bombarded the atmosphere during the August 1972 solar flares. Observed order of magnitude variations of the vertical electric field at 30-km altitude in anticorrelation with the intensity of solar protons are quantitatively interpreted in terms of atmospheric conductivity variations produced by solar proton ionization of the air. Other geophysical data are presented which indicate the state of the magnetosphere during this epoch and which further indicate a phenomenological coupling between atmospheric and extraterrestrial events.
Article
A balloon payload instrumented with a double-probe electric field detector and an X ray scintillation counter was launched from Roberval, Quebec, Canada (L=4.1) at 0828 UT (0328 LT) on July 9, 1975. A magnetospheric substorm was observed locally between 0815 and 1100 UT, which produced a maximum ..delta..B of approx.500 nT at approx.0930 UT. A single-cell atmospheric thunderstorm developed northeast of Roberval beginning around 0925 UT which was most intense from approx.1000 to 1035 UT. Detailed study of the electrical properties of the thunderstorm, the X ray precipitation data, and VLF spheric data leads to three conclusions. First, the electrical coupling from the thunderstorm to the magnetosphere increases with frequency from dc to the VLF; for the observed storm the amplitude at the ionosphere of thunderstorm produced electric fields was not significant at frequencies below 0.1 Hz. Second, the atmospheric conductivity above the thunderstorm was observed to be about one-half the fair weather value prior to 1000 UT; decreased to about one-quarter the fair weather value at about 1000 UT; and remained depressed after the end of the thunderstorm. This result was contrary to that expected on the basis of previous work and is one which merits considerably more investigation. Third, the data show a high probability that half-hop whistlers initiated by sferics from the thunderstorm triggered energetic electron precipitation from the magnetosphere.
Article
From 1987 through 1993, three major campaigns, the Wave Induced Particle Precipitation, the Thunderstorm II, and the Extended Life Balloon Borne Observatories, were conducted to investigate atmospheric and global electrodynamics. Design and fabrication for balloon-borne electric field and conductivity detectors are described. The software program for a complex on-board microcontroller based data processing system has been constructed and flown on several long duration balloons, which performed data acquisition, reduction, and transmission. Our balloon-borne measurements made near or over thunderstorms confirm early discovery of thunderstorm-related conductivity variations in the stratosphere. The signature of sferic tail was found to be of two time constants, namely a fast decay followed by a slow decay. These observations suggest that there is a strong upward coupling from thunderstorms and lightning transients to the stratosphere and possibly to the ionosphere. Detailed and accurate knowledge of stratospheric conductivity is crucial to studying electric field and current distributions in the stratosphere, and the coupling process between the Earth and the upper atmosphere. The stratospheric conductivity measurements have been studied using ionization theory. It was found that on average the positive conductivity is about 15% higher than the negative conductivity, suggesting that the negative ion may have more water molecules than the positive ion in the stratosphere. The measured conductivity is significantly different from the values used in various global electric field models. The first global empirical model of stratospheric conductivity was developed based on a data set with long duration and wide spatial coverage. Electric field measurements from long-duration balloon flights have confirmed the earlier discovery of a new source of stratospheric electric fields. This newly found horizontal electric field has a magnitude of 10 to 20 mV/m at night and 100 mV/m to 150 mV/m in the daytime, and has a unique characteristic of counter clockwise rotation of the field vector in the southern hemisphere, with the rotation period near to the atmospheric inertial wave period. In addition, this long-duration data set also provided the most representative measurement of the latitudinal signature of the vertical electric field and air-earth current density in the stratosphere. This latitude effect was due to atmospheric columnar resistance and the Earth's orography.
Article
Balloonborne measurements of polar conductivity made from a low latitude station, Hyderabad (17.3°N, 78.5°E, Geomag. lat. 8°N), India are presented here. The balloon flights were conducted during 1984–1994 covering a period of one solar cycle. The measurements were conducted in the altitude region of 20–35 km. It is known that the production of ionisation in stratosphere is due to cosmic rays. Cosmic ray intensity varies inversely with solar activity. But our measurements show that conductivity is higher during high solar activity period compared to low solar activity period in stratosphere over Hyderabad. We suggest that this is due to breaking up of cluster ions to form lighter ions during the high solar activity periods.
Article
This paper summarizes the results of measurements of the electrical conductivity σ and vertical component of the vector electric field Ez acquired from eight stratospheric balloon flights launched from Amundsen-Scott Station, South Pole, in the austral summer of 1985–1986. The major findings of this research are as follows 1.(1) The data contribute to the set of global atmospheric electricity measurements and extend the work of COBB [(1977), Atmospheric electric measurements at the South Pole. In Electrical Processes in Atmospheres, Dolezalek H. and Reiter R. (eds), pp. 161–167. Steinkopf, Darmstadt, F.R.G.] to determine the electrical environment of the south polar region2.(2) The average vertical profile of the conductivity at the South Pole, when compared with profiles obtained at other Antarctic locations, suggests that the conductivity scale height may increase with increasing geomagnetic latitude across the polar cap.3.(3) The conductivity profiles measured at the South Pole and other Antarctic locations differ significantly from polar cap model profiles. On the basis of these measurements, the model profiles appear to require modification4.(4) The magnitudes of the Ez profiles were observed to vary from day-to-day by a factor of > 25.(5) In all of the flights the air-Earth conduction current Jz, calculated as the product of Ez and σ, decreased with altitude in agreement with previous direct measurements of the air-Earth current by Cobb [( 1977), Atmospheric electric measurements at the South Pole. In Electrical Processes in Atmospheres, Dolezalek H. and Reiter R. (eds), pp. 161–167. Steinkopf, Darmstadt, F.R.G.]6.(6) The magnitude of Jz was 2–3 times larger than the global average, which can be attributed to the lower columnar resistance of the atmosphere above the high-elevation Antarctic plateau. The magnitude of Jz agrees with that observed by Cobb, if the Cobb measurements are multiplied by the Few and Weinheimer [(1986), Factor of 2 error in balloon-borne atmospheric conduction current measurements. J. geophys. Res.91, 10937] correction factor of 27.(7) Ez from all of the flights during times of balloon float demonstrates characteristics of the classical ‘Carnegie’ diurnal variation, which is indicative of global influences on the ionospheric potential8.(8) The influence of geomagnetic activity was observed as a decrease in the amplitude of the diurnal variation of Ez with increasing geomagnetic activity index Kp, which is the predicted effect at the South Pole of the magnetospheric polar-cap potential superimposed on the ‘Carnegie’ potential variation.
Article
Stratospheric electrical conductivity measurements have been made from high altitude research balloons at various locations around the world for more than 40 years. In the stratosphere, conductivity changes may indicate changes in aerosol or water vapor content. In this paper, we will compare the short term variation amplitude in data taken at several latitudes from equatorial to polar cap. Short term variations that occur on time scales of weeks to months (105–107 s) can be attributed to Forbush decreases, geomagnetic storms, aerosol injections by volcanos and forest fires, etc. Variations with time scales of minutes to days (103–105 s) can have amplitudes of a factor of ∼2 or more at high magnetic latitude. The variance at equatorial latitude is much smaller. The sources of these fluctuations and the latitude gradient remain unknown. Variations of all origins completely obscure any long-term climatic trend in the data taken in the previous four decades at both mid and high latitude.
Article
A balloon-borne experiment to measure the atmospheric electric field was flown from the National Scientific Balloon Facility at Palestine, Texas, on July 10, 1973. The electric field and atmospheric conductivity were measured during ascent and for a 4-hour float period at 37-km altitude. Termination of the flight occurred near a thunderstorm line in west Texas. The perturbing influence of the thunderstorms on the electric field was observed at least 100 km from the storm line. The measured electric field is in reasonable agreement with calculations based on simple models of cloud structure and atmospheric conductivity. Large pulses in the measured electric field are interpreted as being the result of intracloud lightning.
Article
Stratospheric electric field and conductivity measurements are presented for sites of latitude greater than 50 deg N GG, during the months of either April or August, in a variety of weather and solar conditions. Vertical electric field data from balloon flights with an average duration of 18 hours at ceiling, in fair weather, are shown to be appropriately modeled by a simple, exponential, altitude-dependent equation. Data collected over electrified clouds and thunderstorms are presented, along with a discussion of the thunderstorm-related electric currents. Current surges in the atmosphere due to DC currents as well as the spheric are calculated, and it is found that in over 1000 hours of balloon data, no direct solar influence is identified except during major flares.
Article
The temporal relationship between subauroral ion drifts (SAIDs) and the phases of an auroral substorm is examined on the basis of multisatellite data. The time of expansive phase onset is identified and the time at which recovery begins is estimated. SAIDs are found to typically occur well after substorm onset (more than 30 min), during the substorm recovery phase. Substantial westward ion drifts and field-aligned currents are observed well equatorward of the auroral oval during the expansion phase of a substorm, but the drifts lack the narrow spike signature associated with SAIDs. A phenomenological model of SAID production that qualitatively agrees with the observed ionospheric signatures and substorm temporal relationship is proposed.
Article
The paper reports the discovery of short-term variability in the planetary-scale-size vertical electric field measured in the stratosphere. Measurements were made on superpressure balloons at 26-km altitude separated by up to 3000 km. Data are presented which show that the large-scale current system is variable, with twice the amplitude of the average diurnal variations, on time scales of tens of minutes to hours.
Article
We report on particles and fields observed during Defense Meteorological Satellite Program (DMSP) F9 and DE 2 crossings of the polar cap/auroral oval boundary in the evening magnetic local time (MLT) sector. Season-dependent, latitudinally narrow regions of rapid, eastward plasma flows were encountered by DMSP near the poleward boundary of auroral electron precipitation. Ten DE 2 orbits exhibiting electric field spikes that drive these plasma flows were chosen for detailed analysis. The boundary region is characterized by pairs of oppositely-directed, field-aligned current sheets. The more poleward of the two current sheets is directed into the ionosphere. Within this downward current sheet, precipitating electrons either had average energies of a few hundred eV or were below polar rain flux levels. Near the transition to upward currents, DE 2 generally detected intense fluxes of accelerated electrons and weak fluxes of ions, both with average energies between 5 and 12 keV. In two instances, precipitating ions with energies greater than 5 keV spanned both current sheets. Comparisons with satellite measurements at higher altitudes suggest that the particles and fields originated in the magnetotail inside the distant reconnection region and propagated to Earth through the plasma sheet boundary layer. Auroral electrons are accelerated by parallel electric fields produced by the different pitch angle distributions of protons and electrons in this layer interacting with the near-Earth magnetic mirror. Electric field spikes driving rapid plasma flows along the poleward boundaries of intense, keV electron precipitation represent ionospheric responses to the field-aligned currents and conductivity gradients. The generation of field-aligned currents in the boundary layer may be understood qualitatively as resulting from the different rates of earthward drift for electrons and protons in the magnetotail's current sheet.
Article
Results are presented for an investigation of rapid subauroral ion drift features using data obtained over a nearly five-year period from the ion RPA/drift meter on Atmosphere Explorer-C. These latitudinally narrow features are found to be confined predominantly to the local time sector between 18:00 and 02:00 hr. They occur either singly or as multiple events, one of which almost always straddles the equatorward edge of the auroral zone. Their occurrence probability suggests a dependence of magnetic substorm activity.
Article
The vertical component of the electric field, conductivity, and the derived current density from eight superpressure balloons are examined. Special emphasis was placed on the fair-weather, simultaneous measurements from widely spaced constant-altitude (26 km) balloons. The conductivity measurements were well organized by a simple ionization rate parameterization depending on the geomagnetic latitude. The variability of all the electrical parameters was found to be independent of the balloon separation. Much of the time the current density measurements were within 20 percent, for simultaneous flights, even though the balloons were up to 6000 km apart. Also, these simultaneous current density data show that the global current source was significantly variable on hourly and daily time scales. Finally, the use of the simultaneous current density data is discussed as a possible 'geoelectric index'. Advantages and limitations of such an index are discussed.
Article
The characteristics of the large-scale electrodynamic parameters, field-aligned currents (FACs), electric fields, and electron precipitation, which are associated with auroral substorm events in the nighttime sector, have been obtained through a unique analysis which places the ionospheric measurements of these parameters into the context of a generic substorm determined from global auroral images. A generic bulge-type auroral emission region has been deduced from auroral images taken by the Dynamics Explorer 1 (DE 1) satellite during a number of isolated substorms, and the form has been divided into six sectors, based on the peculiar emission characteristics in each sector: west of bulge, surge horn, surge, middle surge, eastern bulge, and east of bulge. By comparing the location of passes of the Dynamics Explorer 2 (DE 2) satellite to the simultaneously obtained auroral images, each pass is placed onto the generic aurora. The organization of DE 2 data in this way has systematically clarified peculiar characteristics in the electrodynamic parameters. An upward net current mainly appears in the surge, with little net current in the surge horn and the west of bulge. The downward net current is distributed over wide longitudinal regions from the eastern bulge to the east of bulge. Near the poleward boundary of the expanding auroral bulge, a pair of oppositely directed FAC sheets is observed, with the downward FAC on the poleward side. This downward FAC and most of the upward FAC in the surge and the middle surge are assoc iated with narrow, intense antisunwqard convection, corresponding to an equatorward directed spikelike electric field. This pair of currents decreases in amplitude and latitudinal width toward dusk in the surge and the west of bulge, and the region 1 and 2 FACs become embedded in the sunward convection region. The upward FAC region associated with the spikelike field on the poleward edge of the bulge coincides well with intense electron precipitation and aurora appearing in this western and poleward protion of the bulge. The convection reversal is sharp in the west of bulge and surge horn sectors, and near the high-latitude boundary of the upward region 1, with a near stagnation region often extending over a large interval of latitude. In the eastern bulge and east of bulge sectors, the region 1 and 2 FACs are located in the sunward convection region, while a spikelike electric field occasionally appears poleward of the aurora but usually not associated with a pair of FAC sheets. In the eastern bulge, magnetic field data show complicated FAC distributions which correspond to current segments and filamentary currents.
Article
A Superarcas sounding rocket was launched from Siple Station, Antarctica in January 1978, during a prolonged geomagnetically quiet period with very low VLF activity. The observed electron flux is the first direct measurement in the high latitude mesosphere of the quiet-time precipitating electrons in the South Atlantic anomaly. The integrated flux agrees resonably well with satellite measurements and predictions. The calculated energy spectrum of the precipitating electrons is much softer than typical measured quiet-time trapped spectra reported from satellite measurements after extended periods of low magnetic activity.
Article
This paper reports the first in-situ observation of variations in the electrical conductivity over thunderstorms at 26 km altitude. The vector electric field, positive and negative polar conductivity, and optical lightning power/flash were measured by payloads on superpressure balloons in the Southern Hemisphere in early 1984. It is found that in 72 percent of the thunderstorm periods observed (or in 23 of 32 periods) there were clear cases of conductivity variations while the balloons were over the thunderstorms. Examples from two separate balloons at widely separated dates and locations showing both daytime and nighttime events are presented. The conductivity measurements are made with the relaxation technique, and the vector field measurements are based on the double Langmuir probe high-impedance method. It is found that the positive and negative conductivity measurements vary independently and have a different temporal profile than the dc electric field. The polar conductivity variations can exceed a factor of 2 at this altitude. In seven of the nine most intense thunderstorm events the total conductivity increased, while in only one of these nine events did it decrease (one event had no change). Implications of these observations for global current patterns are discussed.
Article
Regions of enhanced cold plasma, isolated from the main plasmasphere along the Explorer 45 (53-A) orbit in the equatorial plane, have been detected by using the sheath-induced potentials seen by the electric field experiment. The occurrence of these regions has a strong correlation with negative enhancements of Dst, and their locations are primarily in the noon-dusk quadrant. The data support the concept that changes in large-scale convection play a dominant role in the formation of these regions. Plasma tails that are predicted from enhancements of large-scale convection electric fields in general define where these regions may be found. More localized processes are necessary to account for the exact configuration and structure seen in these regions and may eventually result in detachment from the main plasmasphere.
Article
Measurements from nine high-altitude balloon flights at altitudes ranging from 10 to 30 km have been obtained in order to study atmospheric conductivity variations on local and global scales. The conductivity profiles are not correlated with solar or cosmic ray activity, but they exhibit variations which appear to be dominated by local effects. Evidence is provided of stratospheric aerosol layers with number densities of the order of 1000/cu cm. It is suggested that global conductivity models employing latitudinal variations based on cosmic ray ionization alone may be improved by including the effects of latitudinal variations of temperature and aerosols.
Article
Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultrafine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution can affect cloud properties and modify the radiative balance of the atmosphere, through changes communicated globally by the atmospheric electrical circuit. Despite a long history of work in related areas of geophysics, the direct and inverse relationships between the global circuit and global climate remain largely quantitatively unexplored. From reviewing atmospheric electrical measurements made over two centuries and possible paleoclimate proxies, global atmospheric electrical circuit variability should be expected on many timescales
Studies on Variation of the Radiation Belt Particle at South Atlantic Anomaly
  • A Tsuruuchi
Tsuruuchi, A., 1998. Studies on Variation of the Radiation Belt Particle at South Atlantic Anomaly, Master thesis, Tohoku Univ., Sendai, Japan.
  • J Nishimura
  • N Yajima
  • H Akiyama
  • M Ejiri
  • R Fujii
  • S Kokubun
Nishimura, J., Yajima, N., Akiyama, H., Ejiri, M., Fujii, R., Kokubun, S. Polar Patrol Balloon. J. Aircraft 31 (6), 1264-1267, 1994.