ICAE International Commission on Atmospheric Electricity


ICAE 2003 Versailles

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Wednesday 11th June

 


15:00

Session G2 Fair Weather Electricity II (poster)


   
  A. G.Amiranashvili, L. L.Kalaijeva, N. D.Karauli, A. T. Khunjua, and A. G. Nodia
Statistical Characteristics of Air Electric Conductivity in Dusheti
   
K. L. Aplin
A novel technique to determine atmospheric ion mobility spectra
   
  G. Bowker and H.C. Crenshow
The possible role of fair weather electricity on the charging of wind-dispersed pollen
   
  L. Delgado, L. Rivas Soriano, F. de Pablo and E. Garcia Diez
Relationship between the atmospheric electric field (A.E.F.) and air pollution in the lower levels of the atmosphere
   
  A.P. Fews, N.K. Holden, P.A. Keitch and D.L. Henshaw
Corona ion emission from high voltage powerlines-measurement using a novel high resolution ion spectrometer
   
  K. Iinuma and S. Uchida
Analysis of composite mobility peak for multiple atmospheric ions in equilibrium
   
  J. Kirkby and R. G. Harrison
Cosmic rays and atmospheric ions: their importance for clouds and climate
   
  Z. Kobylinski and S. Michnowski
On the atmospheric response to solar cosmic ray events
   
  M. Noppel, M. Kulmala, and H. Vehkamäki
Ion - induced nucleation of sulphuric acid and water: The effect of hydration
   
  K. Nagaraja, B. S. N. Prasad, N. Srinivas, and M. S. Madhava
Electrical conductivity near the Earth's surface: Ion - aerosol model
   
D. Retalis, P. Nastos, and A. Retalis
Variations of large ions concentration in the air above Athens
   
V. V. Smirnov and A. V. Savchenko
The evolution of large ion stream in atmospheric boundary layer
   
V. V. Smirnov and J. M. Mäkelä
Ultrafine nucleus in ionized air
   
  H. Tammet
Method of inclined velocities in the air ion mobility analysis

 


Statistical Characteristics of Air Electric Conductivity in Dusheti
 

A.G.Amiranashvili, L.L.Kalaijeva, N.D.Karauli, A.T.Khunjua, A.G.Nodia,
Institute of Geophysics, Georgian Academy of Sciences
Avto_Amiranashvili@excite.com
Avto_Amiranashvili@hotmail.com

J.I.Vachnadze
Institute of Hydrometeorology, Georgian Academy of Sciences

 

Results of statistical analysis of mean monthly, six month and yearly values of total air electric conductivity Y in Dusheti have been considered (in latitude 42.08 degrees, in longitude 44.7 degrees, 900 m latitude a.s.l.). An observation period makes 25 years, from 1966 to 1990. A measurement unit Y is given in 10^-15 ohm m, omitted further to be more convenient.

Data on intra-yearly variations of mean air electric conductivity values in different time periods have been presented ; analysis of stability of correlation links of air electric conductivity with each other has been conducted by months and seasons of the year; presence of negative trends of Y values for all months of the time period under investigation, has been revealed. In particular, it has been received that:

  1. On the average, through a whole time period (1966-1990), the maximum value Ymax=41.8 in August, the minimum Ymin=26.1 in February. Mean yearly value Ymean=35.4. During a warm six-month period (April-September) on the average Ywarm=38.8, and during a cold six-month period (October-March) Ycold=31.9. Ratio Ywarm/Ycold=1.22. In 1966-1970, on the average,Ymax=46.6(August),Ymin=26.6(February),Ymean=38.1,Ywarm=42.9, Ycold=33.3, Ywarm/Ycold=1.29. In 1986-1990 on the average, Ymax=31.1 (September-October),Ymin=23(February),Ymean=30.9,Ywarm=32.95, Ycold=28.8, Ywarm/Ycold=1.14.
  2. The values Ymean better correlate with Y mean monthly values for July (correlation coefficient is equal to 0.94). The worst is the correlation of Ymean with Y for December (correlation coefficient is equal to 0.37). On thewhole, the correlation by Y between adjacent months is quite a high one. Though, for some winter months (e.g. December-November, etc) a correlation link is low or is not observed, at all.
  3. Estimation of linear trends of Y for a whole time period under investigationhas demonstrated that the biggest rate of decrease of air electric conductivity values was observed in August (Y=-0.7085X+51.01, where X is years: X1=1966,..., X25=1990), the least one was observed in January (Y=-0.093X+30.17). On the whole, Ymean=-0.4221X+40.844; Ywarm=-0.5767X+46.28; Ycold=-0.2676X+35.41. Therefore, in Dusheti, decrease of air electric conductivity has been taking place in time and it was revealed more clearly in a warm six- month period of the year than in a cold one.

 

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The possible role of fair weather electricity on the charging of wind-dispersed pollen
 

G. Bowker
george.bowker@furman.edu

H.C. Crenshow

 

Wind-pollinated plants reproduce by capturing pollen suspended in the air. A charged airborne particle in an electric field experiences an electrostatic force equal to the product of its charge and the electric field at its location. Pollen grains may be charged and electric fields are present around plants due to the ambient fair weather electric field. Consequently, electrostatic forces might affect pollen capture. This study investigates the electrostatic fields around plants, determines the charges on pollen for seven plant species, and predicts some situations where electrostatic forces may influence the capture of pollen.

 

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 Relationship between the atmospheric electric field (A.E.F.) and air pollution in the lower levels of the atmosphere
 
L. Delgado Martín, E. García Diez, F. de Pablo Dávila and L. Rivas Soriano
Departamento de Física de la Atmósfera, Facultad de Ciencias, Universidad de Salamanca, Spain
 

The relationship between atmospheric electric field (AEF) and air pollution is analysed for Salamanca, Spain, between 1996 and 2000. The results show a high correlation between AEF normalized and concentration of neutral pollutants. This correlation values are higher in winter months than in summer ones. We think that AEF influences the pollutants concentration due to their electric properties (like their dipole moments).

 
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Analysis of composite mobility peak for multiple atmospheric ions in equilibrium
 

Koichi Iinuma and Shunsuke Uchida

 

A general solution of coupled diffusion-reaction equations governing the spatiotemporal evolution for the number densities of an arbitrary number of inter-reacting ionic species in the atmosphere has been analytically derived in a framework of particle non-conservation system, using a Fourier transform technique and matrix algebra (1). For IMS/MS analysis, the general solution enables the rigorous analysis of non-homogeneous gas-phase reactions for multiple ionic species intertwined with their drift and diffusion process in a complex way. Based upon this solution, we also developed the steady state solution for all the ionic species approaching dynamic balance between their transport and reaction process. The steady state solution describes a set of similar Gaussian profiles with the same quasi-equilibrium (dynamic equilibrium) mobility and diffusion coefficient on the same peak position (2). This is the analytical profile of the famous composite mobility peak predicted by Mohnen et al. in the mid-1970th. Theoretical formulas for the mobility, the diffusion coefficient, and the equilibrium number densities of all the ionic species in equilibrium have been obtained by introducing the transport-reaction matrices and their determinants.

A new analysis method, founded on this steady state solution, has been developed to determine the mobility of each ionic species independently under equilibrium condition, where all the ionic species appear to have the same mobility with the same core ions (ion family). The composite mobility peak for ammonium- as well as hydronium-based ions-family measured by a few experimental groups using IMS/MS apparatus has been examined in the present analysis.

References:

  1. K. Iinuma, N. Sasaki, and M. Takebe, A general analysis of reactive ion transport in dynamic equilibrium, J. Chem. Phys., Vol. 99, 6907 (1993).
  2. K. Iinuma, Test of a simulation code for the reactive transport analysis of multiple ions in the atmosphere -Evolution of ten ionic species-, J. Atmos. Electr. Vol. 17, 147 (1999).

 

 

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On the Atmospheric Response to Solar Cosmic Ray Events
 

Z. Kobylinski
University of Podlasie, Dept. of Renewable Energies, Siedlce, Poland,
e-mail: kob@ap.siedlce.pl

S. Michnowski
Institute of Geophysics, Pol.Acad.Sci, Warszawa, Poland,
smichn@igf.edu.pl

 

Possible atmosphere responses to different agents of solar variability cannot be directly explained only by changes of energy flux from the Sun. The changes in total solar irradiance (1.36 × 103 W/m2), providing a variable heat input to the ground surface, varies only by about 0.1% in the decadal and shorter-term variations (Frohlich and Lean, 1998). The variation in solar ultraviolet flux that could cause changes in stratospheric dynamics and be coupled with troposphere dynamics, is also very small, not bigger than 0.5 % (Rottman and Woods, 1999). The flux of energy of galactic cosmic ray (GCR) particles, equal to 10-5 W/m2, is of greater variability. The GCR particles, which are essentially the main source of atmospheric ionization in the stratosphere and troposphere down to about 2 km above the ground, are modulated by changes in the solar wind and vary on different time scales, for instance, 11- year modulation of GCR of energy ~ 1 GeV changes their flux by factor 2. The galactic radiation is occasionally supplemented by solar energetic particle events (SEP) coming in part from solar flares. In the latter case, the majority of SEPs is accelerated by shock waves driven by coronal mass ejections. The ground level enhancement (GLE) of energy flux is then also not much higher, for example on 15.08.1959 it was equal 7 × 10-2 W/m2.

Although this energy is smaller at least about 107 times than the energy involved in troposphere dynamic processes, the observational and theoretical suggestions have been made about possible role of cosmic charged particle flux in atmosphere dynamics through modulating the global electric circuit (Tinsley and Dean, 1991). The current flow in this circuit between the ionosphere and the ground surface reponds to the energetic particle flux changes. The changes in this current affect microphysical processes in clouds, which govern the ice production changes and the subsequent changes in cloud albedo, precipitation, and latent heat release, affecting troposphere temperature and dynamics. The release of such heat in warm core cyclones and their intensification by the free energy of horizontal wind shear has been proposed as an explanation of the significant correlation found by Wilcox and others between the strength of cyclones and cosmic ray intensity changes.
In the paper, changes in the strength of winter cyclones in Northern Hemisphere as measured by the vorticity area index (VAI) are analyzed by means of a superposed epoch analysis in order to examine a possible tropospheric response to solar cosmic ray changes. In this approach the data for comparisons were selected for events of SEPs with proton energy >10 MeV and peak intensity >1 proton/cm2 s sr observed at 1 AU in long interval 1955-1993. About 300 cases of SEPs have been examined. SEPs with proton energy > 450 MeV, the ground level enhancements, are also included into analysis. We have observed several percent up to 10% increases of winter VAI after GLEs and stronger SEPs in the periods of enhancement of sulphuric aerosol concentration in the stratosphere due to volcanic eruptions. This does not collide with Tinsley's findings.

References:

Rottman G., Woods T., IUGG Meeting, Birmingham, Program Book, 139, 1999
Tinsley. B. A., Deen G. W. J., Geophys. Res , 96, 22283-22296, 1991.
Frohlich and Lean, J. Geophys. Lett., 25, 4377-4380, 1998.

 

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Ion-induced nucleation of sulphuric acid and water:
The effect of hydration
 

M. Noppel
Institute of Environmental Physics, University of Tartu, Tartu, Estonia

M. Kulmala and H. Vehkamäki
Department of Physical Sciences, University of Helsinki, Finland

 

Cosmic radiation and the decay of radioactive substances generate the ions, which can serve as condensation centres. Sulphuric acid and water are considered as the major species that participate in new particle formation in the atmosphere. One of the difficulties for predicting the nucleation rate of sulphuric acid and water vapours, compared with other binary systems, proceeds from the tendency of sulphuric acid to form hydrates (small clusters of acid and water molecules) in the gas phase. The hydrates stabilise the vapour. Their formation energy is negative, and therefore it is energetically more difficult to form a critical nucleus out of hydrates than out of free acid molecules. In early papers the influence of sulphuric acid hydrates on ion - induced nucleation of sulphuric acid water was not taken into account, or it was not done in a proper way.

In the present paper the effect of hydration of gas phase acid molecules on ion - induced binary nucleation of sulphuric acid and water is considered. The classical nucleation theory is used. The hydration model based on the data of ab initio calculations and experimental data of acid vapour pressure above aqueous solutions of sulphuric acid is applied.

 

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Electrical conductivity near the Earth's surface:
Ion - aerosol model
 

K. Nagaraja, Prasad B. S. N., N. Srinivas and M. S. Madhava
DOS in Physics, University of Mysore, Manasagangotri, Mysore - 570 006, INDIA

 

The electrical conductivity is one of the important parameters for understanding the electrical nature of the earth's atmosphere. This parameter is sensitive to the presence of aerosols. Thus, the aerosol loading has a bearing on the conductivity of the atmosphere. The aerosols reduce the conductivity of the atmosphere by (i) converting the highly mobile small ions into less mobile aerosol ions through ion - aerosol attachment (coefficient b ) and (ii) neutralizing the small ions through the aerosol ion - small ion recombination (coefficient a s). Another process that makes the ion-aerosol attachment rate faster is the charged aerosol - aerosol recombination (coefficient aa). However, a a is small compared to b and a s.

There have been no reports on modeling study of the conductivity in the lower part of the troposphere, in particular near the surface. Modeling for this region requires, ionic aerosols, in addition to the molecular ions. Based on this, a Simple Ion-Aerosol Model (SIAM) is proposed.

Simple Ion-Aerosol Model used in our study is as shown in figure. It involves primary ion pair production rate (q) due to surface radioactivity and cosmic rays, the small ion densities (n± ) and the aerosols. The various recombination coefficients for the loss of oppositely charged small ions (a i), oppositely charged aerosol ions (a a), between small ions and aerosol ions (a s), and the attachment of small ions of similar polarities with aerosols (b ) are used to compute the polar conductivity. The temperature, pressure, relative humidity, ionization rate and aerosol number density along with the different attachment/recombination coefficients are the input parameters for the SIAM.

Diurnal values of conductivity computed on this model are compared with the experimentally determined values. A Gerdien condenser has been fabricated and used for the measurements. Good agreement between the model and the experimental conductivities values are seen.

 

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Variations of large ions concentration in the air above Athens
 

D. Retalis
Institute of Environmental Research and Sustainable Development, National Observatory of Athens, P.O. Box 20048, GR 118 10, Athens, Greece

P. Nastos
Laboratory of Climatology, Department of Geology, University of Athens, Panepistimioupolis, GR 157 84, Athens, Greece

A. Retalis
Institute for Space Applications & Remote Sensing, National Observatory of Athens, Metaxa & V. Pavlou, P. Pendeli, GR 152 36, Athens, Greece

 

Large ions (positive and negative) concentration of air was regularly monitored at the NOA (National Observatory of Athens) atmospheric electricity station (66;=37°58' N, 55;=23°43'E, h=107m) for a long period from 1969-1980.

At the Laboratory of Climatology (66;=37°58' N, 55;=23°47' E, h=243m), University of Athens, Panepistimioupolis, measurements of large ions concentration has been performed regularly since June 2002. The instruments used are of the same type as those used for the NOA recordings. At both stations, measurements of meteorological parameters (temperature, pressure, humidity, etc.) are performed on a daily basis.

In this study the new recordings of the large ions concentration performed at Laboratory of Climatology are presented (which will be extended till time for the extended abstracts comes). The variations of the large ions concentration, the diurnal course, and the range of measurements are presented and compared with the relative recordings performed at NOA station for each month. The effect of meteorological parameters is also examined along with the particulate air pollution.

The preliminary results form the study of the variation of the large ions concentration at both stations showed that:

  • The type of the diurnal course is the same presenting a double oscillation course.
  • The range of measurements differs at Panepistimioupolis station, presenting lower values, which are due to the lower levels of air pollution, and to topographic and meteorological parameters.

Additionally, this paper will present an attempt to find a way for the connection of the long term measurements of large ions concentration performed at NOA station with the new recordings performed at Panepistimioupolis station, trying to find an ideal way for the development of a new database that will be further extended.

References:

Retalis D., Study of large ions concentration in the air above Athens. Arch. Met. Geoph. Biocl., Ser. A, 32, 1983.

Retalis D., Pitta A., and Psallidas P., The conductivity of the air and other electrical parameters in relation to meteorological elements and air pollution in Athens. Meteor. Atmos. Phys., 46, 197-204, 1991.

Retalis D. and A. Retalis, Effects of air pollution and wind on the large-ion concentration in the air above Athens, J. Geophys. Res., 103, 13,927-13,932, 1998.

 

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The evolution of large ion stream in atmospheric boundary layer
 

V.V. Smirnov and A.V. Savchenko
Institute of Experimental Meteorology. Obninsk, 249038, Russia

 

The purpose of experiment is to estimate a character of electric field perturbations in an atmosphere after large ions injection. For ion production the water or diesel fuel droplets were introduced into a hot propulsion jet. Within condensation zone the corona discharge grid was installed. A vapor condenses on negative small ions and droplets are shaped by a diameter about 0.1 µm carrying one elementary charge. The effective current of large ions reached about I = 100 µA.

The measurement data for vertical component of electric field E (X) under a jet by length up to 10 km are submitted in Fig.1. As it may be seen, the field gradient was reduced monotonically from E= -1000 V/cm up to E = -1.5 V/cm on distance 6 km. Experiment results we shall compare to calculation on numerical [1] and analytical [2] models. From calculations it follows that the charge neutralization of jet by background air ions (mean mobility µ+ = 1.4 .10-4 m2/V.s and concentration n+ = 109 m-3 ) should be account for distance X > 1 km. At X> 5 km the contribution of effect should exceed of turbulent diffusion contribution. By the test data on the figure this factor was exhibited more weakly.

As it is visible, the simple analytical relation E (X) » 1\3p e 0X u*, where u* = 0.4 m/s is the dynamical wind speed, describes the experiment more exactly.


Fig.1. Electrical field E(X) under the artificial unipolar stream from large negative ions (diesel oil droplets of 0.1 µm mean dia, mass outlet is 1 kg/s, the initial angle to the horizon is 700, ion current is I = 10-4 A) in atmospheric boundary layer under unstable stratifications.
1 and 2 is maximum and minimum experimental data E(X),
3 - exact model calculation [1],
4 - analytical flat stream model [2],
5 - background value E on distance from the stream on 10 radii.

Measurements of polar electrical conductivities l and the space charge densities r have shown that on distances not less than 100 m from jet axis the l values were equal zero, but the density r have decreased only twice. The last can be the indicator that in a ion jet neighborhood there is a redistribution of space charge spectrum from small ions to large ions with the formation of a zone exhausted with charges.

References:

  • Savchenko A.V., Smirnov V.V., Uvarov A.D. Dynamics on charged aerosol cloud in atmospheric boundary layer. Proc. of Inst. Experimental Meteorology, 1990, No. 51(142), pp.69-77.
  • Smirnov V.V. Ionization in the troposphere. S.-Petersburg, Gidrometeoizdat, 1992, 312p.

 

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Ultrafine nucleus in ionized air
 

Vladimir V. Smirnov
Institute of Experimental Meteorology, Obninsk, 249020 Russia

Jyrki M. Mäkelä
Department of Physics, University of Helsinki, FIN-00014 Finland

 

During of the International experiment HYYTIALA-2000, March-April 2000, Southern Finland (Mäkelä et al., 2000) convincing data were received on existing a interlink between moments of intensive generations of ultrafine particles D » 2 - 5 nm and atmospheric ions of intermediate mobility (0.5 - 0.05 cm2/V s).

These regularities give an essential contribution to the acknowledgement of hypothesis on formation neutral particles after collisions of positive and negative small ions (Mäkelä, 1992; Smirnov, 1992; Turco et al., 1998). Correspond empirical model was accepted in different laboratory (Mäkelä and Kulmala, 1988; Smirnov and Savchenko, 1991; Smirnov, 1993) and natural experiments in the accident area of Chernobyl nuclear power station (Smirnov, 1991; Smirnov and Savchenko, 1996)). Experiment HYYTIALA-2000 has allowed observing an intensive formation of charged and neutral clusters in boundary layer of atmosphere.

Proposed phenomenological model expects existence of Coulomb' associations of negative and positive small ions to form the neutral clusters of nitric or/and sulphate acid molecules M- (H2O)m + H3O+(H2O)m, where SOx or NOx. Characteristic time of neutral cluster formation is t nc = (n . 47;nc)-1/2 = 104 s, where the coagulation constant 47;nc = 5. 10-10 cm3 s-1, calculated on model of McMurry, 1983. In free troposphere the top limit concentration of neutral clusters is near Nnc ~ (n /47;nc )1/2 = 2.105 cm-3, mean diameter is Dnc » 1.3 - 1.5 nm. Association of small ions with neutral clusters transforms the previous into charged cluster or intermediate ions. Characteristic time of process is t cc ~ (b nc Nnc)-1 = 2.104 ± 2.103 s, b nc = p Cli D2nc /4 = 5. 10-10 cm3 s-1, where Cli » 3.104 cm/s is mean heat speed of small ions. Mean diameter of charge cluster is Dcc » 2 - 2.3 nm. Main channel of a sink for intermediate ions is Coulomb' associations between itself and with small ions. Top estimation of concentration for charged clusters possible get by means of formulas Ncc ~ (nli / 45;cc t cc )1/2 = 400 ± 100 cm-3. Here 45;cc = (2-4).10-7 cm3 s-1 is recombination constant.

Below on fig.1 are given a satisfactory comparison of calculation and measurement data for small and intermediate ion concentration.


Fig. 1 - Number concentration of small (D = 0.7 nm) and intermediate air ions (D = 2.1 nm) and neutral cluster (D = 1.4 nm).
Nucleation burst episode, 27 March 2000, Hyytiala, Finland.

 

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Method of Inclined Velocities in the Air Ion Mobility Analysis
 

Hannes Tammet
Institute of Environmental Physics, University of Tartu, 18 Ülikooli St., Tartu, 50090, Estonia.
Phone: +372 7 375 554
E-mail: Hannes.Tammet@ut.ee

 

Measurement of air ion mobility distribution is a key for understanding of the role of ion-induced nucleation in the atmosphere. Traditional measurement methods are drift tube of time-of-flight method and method of transversal velocities using aspiration condensers. An alternative "method of parallel velocities" proposed by Zeleny (1898) is forgotten today. Drift tubes are popular in high-resolution laboratory measurements; they make available Brownian limit of mobility resolution d = do = Ö (2kT/(qV)). The resolution of an aspiration condenser is worse, d = kdo, k > 1, and the resolution of the Zeleny instrument is better, k < 1. Aspiration condenser is still preferred in atmospheric measurements in spite its Brownian limit of resolution is low. Loscertales (1998) introduced the "method of inclined velocities" that composes high resolution (k < 1) with advantages of aspiration condenser. The problem is technical realization. Non-equipotential electrodes proposed by Loscertales encounter technological difficulties. A realistic way to accomplish the inclined field is the method of inclined grids.

In the present report two variants of Inclined Grid Mobility Analyzer (IGMA) are discussed. Plain IGMA is good to keep the homogeneous plug air flow and homogeneous electric field. The mobility resolution can be several times better than of an equal voltage drift tube. Plain IGMA fits well the requirements for analytical laboratory instruments. When considering the atmospheric applications, the configuration of the instrument could be changed with an aim to collect more ions and achieve bigger electrometric signal. Electric field in a modified analyzer is not plain and should be calculated as a numerical solution of the Laplace equation. Design and experiments with an IGMA for atmospheric measurements are described in the report.

 

 

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