Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
  • A01G15/00—Devices or methods for influencing weather conditions
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01W—METEOROLOGY
  • G01W1/00—Meteorology

Definitions

• the instant invention relates to methods and devices for modifying atmospheric conditions, known in this context as weather modification, by enhancing electric forces exerted on and between particles of atmospheric air such as water particles, aerosols, molecular clusters, and water molecules possessing their own electric dipole moment.
• weather modification by enhancing electric forces exerted on and between particles of atmospheric air such as water particles, aerosols, molecular clusters, and water molecules possessing their own electric dipole moment.
• Particular applications of weather control require specific methods and devices for their implementation.
• Certain embodiments relate to controlling, increasing or decreasing the amount of precipitation.
• the term "precipitation" means any product of the phase change of atmospheric water vapor that, due to gravitational forces, is deposited onto the surface of the Earth, and such a product may be presented in any form, such as, rain, drizzle, snow, graupel, and so forth.
• target region means a region where it may be desirable to change the local atmospheric conditions which, in the context of this application, means controlling the amount of precipitation. Unless stated otherwise, controlling the amount of precipitation hereinafter means increasing the amount of precipitation. Deploying the described devices for some other weather modification applications is also considered, whereby specific methods are provided and the device parameters are optimized for a particular weather modification.
• the objective of this invention is to provide new and improved methods and devices for weather modification applications whereby the microphysical processes in the atmosphere are affected by electrical influences.
• the concept of weather modification by augmenting the natural charging of non-thunderstorm clouds (remote cloud charging or RCC) and/or locally increasing atmospheric instability by an electrical process which re-distributes atmospheric moisture is introduced.
• RCC remote cloud charging
• a number of improved and new embodiments are proposed. Compared to embodiments of the prior art, the proposed embodiments are superior in performance, scalability, mobility, and ease of deployment and maintenance.
• microphysical processes of precipitation formation from gaseous water can be broadly categorized in two groups.
• the first group includes thermodynamic phase change processes of gas-to-liquid, known as condensation, and gas-to- solid, known as vapor deposition or sublimation.
• Liquid water droplets may grow by condensation from small airborne (aerosol) particles with suitable (wettable) surfaces, called condensation nuclei (CN), when the actual amount of gaseous water in a volume of air exceeds the maximum amount of that water the air can hold at a given temperature, i.e. when the air is supersaturated with vapor.
• the amount of vapor in the air can be expressed in terms of (partial) pressure of vapor.
• the air is supersaturated when the pressure of vapor exceeds its saturation pressure.
• the moist air gets supersaturated when sufficiently cooled.
• ice particles in supersaturated air may grow by vapor deposition from frozen droplets and aerosol particles with suitable surfaces, called ice nuclei (IN). Areas of atmospheric air laden with droplets and ice particles appear as clouds.
• Processes of the second group are cloud particle merging processes.
• the merging of droplets into larger ones by collisions known as the collision-coalescence process or simply coalescence, becomes more efficient than growth by condensation. Due to the forces of gravity and air viscosity, droplets which have grown larger descend faster than small droplets. As they descend, larger droplets, called collectors in this context, collide with smaller droplets. Ice and liquid particles may also be merged in a similar way.
• coalescence is rather a simplified model of the real droplet merging processes in the atmosphere. Droplets can be moved in different directions with different velocities by turbulent air motions.
• droplets of a similar size may also be coalesced.
• the presence of large droplets, even in a small number concentration may significantly enhance coalescence in a turbulent environment, also known as turbulent coagulation (Riemer and Wexler, 2005).
• Methods of cloud modification currently used are generally based on augmenting the targeted mechanism of cloud formation by introducing (seeding) particles of a specific media into the clouds. Such methods are known as cloud seeding methods. Seeding media are typically delivered to clouds by carriers such as airplanes or rockets. Under certain conditions, airborne seeding media can also be delivered by the ascending of air caused by the wind hitting a mountain slope. This technique is known as orographic seeding.
• Particles of substances which evaporate at temperatures much lower than that of atmospheric air are another type of seeding media.
• Pellets of solid carbon dioxide, known as dry ice, and small drops of liquid nitrogen, which take heat from and thus cool the surrounding air while evaporating, are examples of such seeding media.
• higher degrees of supersaturation and super-cooling around those particles may lead to a higher initial growth rate of droplets and ice particles and an increase in the number concentration of IN due to enhanced droplet freezing.
• higher supersaturation and thus the enhanced condensation achieved near the cooling particles may lead to the production of larger droplets.
• those droplets may enhance coalescence by acting as more efficient collectors in this process.
• Another method is based on seeding clouds with fine particles of salts, the vapor saturation pressure over the water-based solute of which is lower compared to that of pure water. Solute droplets which are grown by condensation from such CN or from droplets which have acquired salt particles by attachment may achieve sizes larger than water droplets and thus enhance coalescence as mentioned above. This method is known as hygroscopic seeding.
• the aerosol particle is an ice nucleus
• its scavenging by a liquid droplet will result in the instant freezing of the latter.
• Such a mechanism of ice particle production known as contact freezing, was found to be a particularly efficient mechanism (Sastry, 2005), competing with the Bergeron process.
• an ice particle can be instantly formed from a liquid droplet by contact freezing, bypassing the relatively slow Bergeron growth of the ice-forming nucleus, which involves liquid droplet "re-processing" via evaporation.
• the produced ice particle may continue to grow either by vapor deposition or by further merging with and freezing the next super-cooled droplet, and so on.
• Seeding artificial ice nuclei into a cold cloud enhances both Bergeron and contact freezing processes. Enhancement of the latter is due to the increased probability of ice nuclei scavenging because of their increased number concentration. Introducing too many ice nuclei, however, may result in the formation of too many ice particles becoming small as they compete for the available vapor. This problem is known as over-seeding. In contrast, augmentation of contact freezing by electro-scavenging of natural ice nuclei is advantageous as it may result in a more efficient usage of the latter and, ultimately, the production of fewer but larger ice particles which may precipitate.
• Another effect of attractive electric forces is the increase in collection efficiency of droplet coalescence, which is especially important for rain formation without ice processes in warm clouds. If a charged droplet is to be collected by a larger neutral droplet or a larger droplet charged with either sign in a coalescence event, the latter can be successful even being geometrically impossible without the attractive electric force.
• Another aspect of electrically enhanced coalescence is an increase in coalescence efficiency, i.e. the probability that not only collision but permanent collection of a droplet occurred during coalescence, which means that the droplet did not avoid collision by being deflected by airflow, coalesced temporarily and then separated, possibly breaking into a number of smaller droplets.
• charging cloud particles may augment multiple precipitation formation mechanisms at once, while a particular seeding method, targeting a certain mechanism, is implemented for a specific medium to be seeded in cloudy air within a certain range of number concentrations.
• an increase in precipitation would be achieved in a warm cloud by an electrically enhanced hygroscopic effect on droplets and electrically enhanced coalescence.
• enhanced ice production via droplet electro-freezing in the upper cloud areas would also contribute to the effect.
• descending ice particles may act as efficient coalescence collectors in warm cloud areas, the so-called seeder-feeder effect.
• augmenting a particular process of cloud development requires a certain minimum charge per electrically active cloud particle.
• enhancing coalescence collision efficiency requires at least a few hundred elementary (electronic) charges on droplets with a radius of 10-20 ⁇ m (Khain et al., 2004). Charges per particle of the same order of magnitude are required for effective electro-freezing (Tinsley et al., 2000) and augmenting hygroscopic properties of small droplets (Harrison and Ambaum, 2008). Cloud particles charged sufficiently to significantly modify cloud development processes are referred to hereinafter as supercharged particles.
• the first approach to supercharging cloud particles has been focused on direct charging by generated ions of predominantly the same sign (i.e. unipolar).
• a unipolar ionizer such as a direct current (DC) corona discharge, referred to hereinafter as corona discharge, and other elements enclosed in a body
• corona discharge a direct current corona discharge
• particles to be charged which are taken from a cloud or artificially produced in such a form as water droplets, pass in the vicinity of the emitter electrode of corona discharge (EECD) and thus acquire electric charges by ion attachment.
• ECD corona discharge
• particles acquire an electric charge through contact with a charged electrode.
• the produced charged particles are then introduced (seeded) into a cloud.
• Such methods are described, for example, in the patent application of Khain at al. (2003). In practice, however, implementing methods of direct supercharging cloud particles in a large volume of cloudy air would meet with severe engineering difficulties.
• the average charge on a particle which can be achieved by ion attachment is proportional to the logarithm of the so-called unipolarity factor, which is the ratio of the number concentration of dominant sign ions to the concentration of opposite sign ions (Clement et al., 1991).
• the corresponding unipolarity factor should also be sufficiently high. As ions of the sign opposite to that of corona ions are always present in the air, the required unipolarity can be maintained only within a limited charging zone around the emitter electrode.
• the present invention provides an apparatus for weather modification.
• the apparatus comprises an emitter electrode, means for providing the emitter electrode with an electric charge, electrically coupled to the emitter electrode, an insulating support for supporting the emitter electrode at a predetermined height, and means for earthing the apparatus.
• the emitter electrode comprises a Malter film.
• the Malter film preferably comprises a thin film of one or more electrically non-conducting materials. Particularly preferred materials for the Malter film are one or a combination of the following materials: Al 2 O 3 , Zn2Si ⁇ 3, SiCh, Zr ⁇ 2, CaCCb, Ta2 ⁇ s.
• the emitter electrode is a capacitor with a conductive surface.
• the capacitor is preferably substantially spherical.
• a "substantially spherical" capacitor is to be understood as a capacitor with a somewhat spherical shape. Said shape may, e.g., comprise several planes or planar structures which are arranged in a polygon, which is similar to a spherical shape. For example, several pentagons and hexagons may be arranged as on a soccer ball.
• the emitter electrode comprises one or more emitter electrode assemblies of corona discharge, which are mechanically and/or electrically coupled to each other.
• the support of the apparatus preferably has a height between 6 m and 30 m, particularly preferred between 8 m and 15 m. It is further preferred that the support comprises an insulating layer. Alternatively, the support may be made of an insulating material. The support may further comprise a rigid structure. For example, the emitter electrode can be supported by a frame of a planar polygonal shape having a surface.
• the emitter electrode comprises two or more electrically coupled parallel wire segments traversing the surface of the frame and separated by a distance.
• the means for providing the emitter electrode with an electric charge can be any means which is suitable to provide a large charge density and/or a large voltage.
• One preferred example for the means is a charging engine of a Van der Graaf generator.
• the emitter electrode comprises two or more Malter electrodes, preferably in the shape of a solid or tubular wire, preferably further comprising one or more initiating corona discharge wires.
• the diameter of the Malter electrodes is preferably larger than the diameter of the initiating corona discharge wires.
• the initiation corona discharge wires are preferably positioned in the vicinity of and coupled mechanically and/or electrically to the Malter electrodes.
• the mater electrodes are arranged in parallel segments traversing the surface of the frame and separated by a distance.
• the emitter electrode comprises two or more Malter electrodes in the shape of foil strips.
• the emitter electrode may further comprise a mesh of wire.
• the emitter electrode may comprise a mesh of Malter electrodes.
• the apparatus comprises a generator of high frequency electromagnetic waves, which are suitable for contactless heating of the wire loops of the emitter electrode.
• the apparatus comprises one or more earthed electrodes, wherein the earthed electrodes are located beneath the one or more emitter electrode assemblies and electrically coupled to the means for earthing.
• the apparatus may further comprise one or more collector electrodes.
• the apparatus further comprises a reservoir containing a conductive electrolyte solution.
• an aerosol generator may be provided, which preferably comprises one or more devices for percolating an electrolyte solution.
• the apparatus further comprises one or more means for generating an updraft.
• This means can, e.g., comprise a heat source.
• a heat source is a black substance absorbing solar radiation, which is arranged below or around the apparatus.
• an apparatus for weather modification which comprises a lighter-than-air craft suitable for carrying an emitter electrode, means for providing the emitter electrode with an electric charge, electrically coupled to the emitter electrode, and means for earthing the apparatus.
• the height of operation of the apparatus according to the first aspect of the present invention is limited by the height of the insulating support
• the operating height of the apparatus according to the second aspect of the present invention is basically unlimited, since the emitter electrode may be transported to any operating height by the lighter-than-air craft.
• the apparatus according to the present invention may be elevated to a predetermined height depending on a specific application of the apparatus.
• the height of the apparatus according to the present invention may be regulated in dependence of the height of the clouds present in the target region.
• the lighter-than-air craft is connected to the means for providing the emitter electrode with electric charge via a tether.
• the lighter-than-air craft is a light-than-air capacitor having a surface.
• the lighter- than-air craft forms a capacitor or is essentially made of components which may also be utilized as a capacitor.
• multiple emitter electrode assemblies are arranged around and uniformly fixed to the surface of the lighter-than-air capacitor, e.g., by means of multiple support rods of variable length.
• the support rods may have feet contacting the surface of the capacitor which provide a stress-bearing mechanism.
• the emitter electrode comprises a hollow capacitor which a spherical or quasi-spherical surface, wherein the lighter-than-air craft is arranged inside the capacitor.
• one or more emitter electrode assemblies are arranged around and electrically coupled to the capacitor.
• the emitter electrode assembly is a wire mesh surrounding the surface of the lighter-than-air craft.
• the emitter electrode assembly is supported by spheres placed between the surface of the lighter-than-air craft and the mesh, wherein the spheres are uniformly arranged around the lighter-than-air craft.
• a method of increasing the amount of precipitation in a target region comprises the steps of providing an emitter electrode, analyzing the meteorological situation in and/or close to the target region, and providing the emitter electrode with an electric charge in response to the meteorological analysis, thereby causing the emitter electrode to ionize the vicinity of the emitter electrode.
• the method further comprises the step of elevating the emitter electrode to a predetermined height.
• the predetermined height is between 6 m and 30 m, preferably between 8 m and 15 m.
• the predetermined height is greater than 100 m, preferably greater than 500 m.
• the predetermined height is determined on the basis of the meteorological situation in and/or close to the target region. It is in particular preferred that the predetermined height is determined on the basis of the altitude of the clouds in and/or close to the target region.
• the predetermined height is at least 50 %, preferably at least 65 % of the altitude of the clouds in and/or close to the target region.
• the step of providing an emitter electrode comprises mounting the emitter electrode on an insulating support.
• the step of providing an emitter electrode comprises preferably the step of elevating the emitter electrode by means of a lighter-than-air craft.
• the emitter electrode comprises a Malter film.
• the Malter film comprises a thin film of one or more electrically non-conducting materials, preferably of one or a combination of the following materials: Al 2 O 3 , Zn2Si ⁇ 3, S1O2, Zr ⁇ 2, CaC ⁇ 3, Ta2 ⁇ 5
• the inventive method comprises the step of moisturizing the soil beneath the emitter electrode with water or a water-based conductive electrolyte solution.
• one or more collector electrodes comprising sheets of metal or wire mesh are arranged on the surface of the earth beneath the emitter electrode and are electrically coupled to one or more earthed electrodes.
• the inventive method may comprise the step of providing one or more earthed electrodes.
• a heat source may be placed beneath the emitter electrode. The heat source may be achieved by a substrate absorbing solar radiation, which is distributed beneath the emitter electrode.
• a reservoir containing a conductive electrolyte solution may be provided, wherein the reservoir is placed on the surface of the earth beneath the emitter electrode and electrically coupled to one or more earthed electrodes.
• a layer of conductive carbon granules may be provided on the surface of the earth, wherein the layer is beneath the emitter electrode and electrically coupled to one or more earthed electrodes.
• the inventive method several emitter electrodes are provided and arranged in an emitter electrode assembly.
• several emitter electrode assemblies are provided.
• the several emitter electrode assemblies are preferably supported by a frame of, e.g., planar shape.
• the emitter electrode assemblies are electrically coupled to each other and mechanically coupled with flexible joints to each other and to the sides of the frame.
• the frame is preferably positioned at an angle to the surface of the earth. Said angle is preferably between about 20 and about 70 degrees.
• the emitter electrode comprises two or more electrically coupled parallel wire segments traversing the surface of the frame and separated by a distance.
• the frame is triangular and both wire segment ends are held in place by a number of flexible supports fixed in pairs to each of the two sides of the frame wherein flexible supports provide a stress bearing mechanism on the wire segments.
• the frame is triangular and the wire is wound around the frame in one strand through notches on two sides of the frame wherein the notches are provided in pairs on each of the sides of the frame.
• the emitter electrode assemblies are preferably of isosceles triangular shape and are arranged into one or more pyramids.
• the bases of the pyramids preferably do not contain an emitter electrode and are arranged parallel to the surface of the earth.
• the apices of adjacent pyramids point in different directions.
• the apparatus according to the first and second aspects of the present invention may be utilized in order to perform the method described above.
• two or more apparatuses may be arranged in a row, particularly in the same direction as the prevailing wind.
• the effect to be achieved by the method according to the present invention may be increased or even multiplied.
• two or more parallel rows of apparatuses as described above are arranged in a grid.
• the grid and in particular the distance between adjacent apparatuses is preferably determined on the basis of the meteorological situation in and/or close to the target region.
• the method described above may be utilized in order to achieve a reverse effect. Accordingly, a method for decreasing precipitation in a first target region is provided. The method comprises the steps of selecting a second target region for increasing precipitation, and increasing precipitation in said second target region by the methods described above. Thereby, a decrease of precipitation in said first target region is caused.
• the skilled person will understand that all preferred features described above with respect to the method of increasing precipitation may also be used for the method for decreasing precipitation.
• the present invention is directed to the use of the apparatus and/or the method described above for dissipating fog in a target region.
• the skilled person will understand that the increase of precipitation in a target region using the apparatus and/or the method described above will essentially dissipate all fog present in said target region.
• the present invention is directed to the use of the apparatus and/or method described above for increasing the cloud coverage in a target region. Thereby, the temperature of the surface of the earth in the target region is decreased.
• the present invention is directed to the use of the apparatus and/or method described above for decreasing the probability of the formation and the intensity of cyclones at early stages of their development.
• the present invention is directed to the use of the apparatus and/or method described above for augmenting the inflow of oceanic moisture inland and moisture recycling in terrestrial areas.
• the present invention is directed to the use of the apparatus and/or method described above for re-forestation in a target region.
• Figure 1 shows a sketch of a preferred embodiment of the apparatus according to the present invention.
• Figure 2 shows a sketch of another preferred embodiment of the apparatus according to the present invention.
• Figure 3 shows a further preferred embodiment of the apparatus of the present invention.
• Figure 4 shows a further preferred embodiment of the apparatus according of the present invention.
• Figure 5 shows the arrangement of several emitter electrode assemblies on a pyramidal frame according to a preferred embodiment.
• Figures 6a to 6d show details of the arrangement shown in Figure 5.
• Figures 7a and 7b show triangular embodiments of elementary emitter electrode assemblies according to the present invention.
• Figure 8 shows an alternative embodiment of a triangular elementary emitter electrode assembly.
• Figure 9 shows a further embodiment of a triangular elementary emitter electrode assembly.
• Figure 10 shows a preferred embodiment of the apparatus according to the present invention.
• Figure 11 shows an example of the quasi-spherical capacitor according to the present invention.
• Figure 12 shows an example of a lighter- than-air craft used for the present invention.
• Figure 13 shows a Malter electrode according to the present invention.
• Figures 14 and 15 show a Malter mesh according to the present invention.
• Figure 16 shows a Malter foil strip according to the present invention.
• Figure 17 illustrates the trajectory of a water molecule during its collision with an ion.
• Non-thunderstorm layer clouds in which internal charging is absent or relatively weak, produce a large proportion of the total precipitation on the Earth.
• Such clouds are sensitive to external charging by the fair-weather electric current because the electrical conductivity of cloudy air is typically many times less than that of clear air at the same altitude, mainly due to the attachment of ions, the carriers of fair-weather current, to cloud particles (Zhou and Tinsley, 2007).
• an approximately downward fair-weather current flows through clear-to-cloudy air interfaces with a high gradient of electrical conductivity, electric charges accumulate on particles of cloud boundaries - positive on the top and negative on the bottom.
• Charge separation in external cloud charging occurs in the following way.
• the initial charge separation on a microscopic scale occurs when ion pairs are created by energetic particles.
• ions of opposite polarities are dragged apart in opposite directions, positive downward and negative upward.
• Some of these ions attach to cloud particles thus charging the latter, positively on the top and negatively on the bottom of cloud boundaries.
• Any charge separation requires an energy input.
• the initial energy input to create ion pairs is provided by energetic particles.
• the energy input required to separate opposite sign ions to macroscopic distances is provided by the global electric circuit which in this process acts as an electric power generator.
• weather modification can be achieved by controlling the density of the fair-weather electric current, to which the external charging of non-thunderstorm clouds is sensitive.
• increasing the fair-weather electric field at cloud altitudes is an option.
• This can be achieved locally by the accumulation of an electric charge on an object situated below the clouds which acts as a charge capacitor. Negative charge is preferable as the direction of the electric field of this capacitor is the same (downwards) as that of the fair-weather electric field.
• the capacitor in the above configuration is a sphere with a conductive surface of radius R, which is a common type of charge capacitor, elevated to height h above the ground and maintained at the potential U relative to the ground, the electric field E at cloud altitude H is given by the following expression:
• VDGG Van der Graaf generator
• a practical solution is to have a spherical lighter-than-air craft acting as the VDGG capacitor by making its surface electrically conductive, e.g. covering the surface with a metallic foil or a conductive paint.
• this lighter-than-air capacitor 11 can be anchored to the surface of the Earth 12 with a tethering rope 13, the length of which and thus the capacitor's elevation can be controlled via a reel 14.
• Such a support comprising a lighter-than-air craft and a tethering rope anchored to the surface of the Earth is referred to hereinafter as a tethered support.
• the following expression arises by substituting the expression (3) into (4) and taking into account the expression (2):
• J n is the normal (relative to the boundary surface) component of atmospheric current density
• ⁇ x is the width of the interface between clear and cloudy air
• ⁇ c y is the conductivity of cloudy air
• ⁇ ⁇ / > ⁇ c i d is the conductivity of clear air ( ⁇ > 1).
• J n is the vertical component of atmospheric current density.
• the estimation of time ⁇ required for charge accumulation can be obtained as the ratio of the surface charge on cloud boundary
• ⁇ ⁇ (y - ⁇ )l ⁇ air .
• a unit comprising a two-dimensional grid (a cluster) of elevated capacitors (elements) may be required to achieve a sufficient width of cloud charging area.
• Each capacitor may be at a fixed location or may be mobile, e.g. on a truck or boat.
• the effect may be observed over a period from the beginning of influence ranging from 20-30 minutes to 1-2 hours. Therefore, to achieve the effect in a specified target area under the varying speed and direction of cloud motion and other atmospheric conditions, a network of multiple units, which are selectively operated, is generally required.
• Another approach is based on creating an airborne space charge in an area of atmosphere below the cloud base, which can be achieved from ground-based facilities at elevations lower than those required for the discussed airborne capacitors.
• Space charge in a volume of air is defined as the sum of charges, taking into account their signs, of all particles
• the produced plume of space charge acting as an airborne charged capacitor, is then elevated by natural and/or artificial updrafts.
• the lifetime of space charge accumulated by aerosols is much longer, typically up to about 20-40 min, which allows the space charge plume to be elevated, depending on the updraft, to altitudes of up to a few kilometers.
• the space charge preferably negative, should be continuously produced by charging natural or artificial aerosols in a certain location, at a sufficient rate, and at a sufficient height above the ground, which determines the initial plume elevation.
• clouds may be electrified not necessarily directly above the device, but above the produced space charge plume, which propagates in the atmosphere.
• both the area and degree of cloud electrification, dependant on the space charge plume dynamics, can be predicted based on a set of meteorological data and the characteristics of a particular space charge generator.
• Many models of aerosol plume dynamics based on the Gaussian dispersion model and developed over the last few decades for different atmospheric conditions, can be applied to a plume of charged aerosol particles, the motion of which, due to low electrical mobility, is mostly governed by air motions.
• the basic set of input parameters for a plume model includes the generator's charging rate (i.e.
• the method of forecasting artificial cloud electrification is as follows. If atmospheric conditions are favorable, including the presence of suitable clouds, meteorological data including cloud base, cloud cover, and those relevant to the plume modeling parameters are continuously collected and the parameter values are obtained. The data should be collected over a large area of the possible plume propagation, typically over tens of kilometers.
• the space charge generator's charging rate may depend on atmospheric conditions, which will be discussed later, this rate is also measured and/or modeled based on meteorological data.
• a model that is most suitable for prevailing atmospheric conditions is selected and run.
• a two- dimensional profile for the vertical component of the plume's electric field and thus for the associated atmospheric electric current (AEC) near the cloud base at a known altitude can be obtained from the space charge profile by a numerical integration over the volume of plume.
• other profiles such as those for the induced space charge densities on cloud boundaries, electric field in the cloud, and charge distribution on cloud particles (provided that their spectra are measured, e.g. with a radiometer) can be obtained, for example, based on the approach of Zhou and Tinsley (2007).
• the previously described method for cloud electrification modeling could be further extended to achieve some quantitive estimations of the precipitation to be induced, provided that the following method is implemented.
• the following method is implemented.
• only statistical approaches can provide a certain degree of confidence that there is a good chance that an applied influence, which is parameterized in a certain way, will produce an effect, which should also be properly parameterized.
• Correlations between the influence parameters and the effect parameters under similar atmospheric conditions can be statistically quantified based on historical data of weather modification in a particular area using expert systems of artificial intelligence, such as industry standard Hugin or a custom developed implementation.
• similarity of atmospheric conditions should also be parameterized, and a degree of similarity for each parameter, i.e. the maximum acceptable difference of values between cases, should be defined.
• the set of parameters for the similarity of atmospheric conditions includes but may not be limited to parameters of aerological diagrams and cloud parameters such as cloud type, cloud base altitude, spatial profiles of temperature, ice particle and droplet spectra, supersaturation
• space charge generators As in the case of elevated solid capacitors, deploying space charge generators to produce or enhance precipitation in a reasonably large target area under varying atmospheric conditions may require a network of clusters of such generators.
• space charge generator design should be optimized to achieve the highest possible performance.
• the embodiment should be practical, in particular regarding its deployment and mobility.
• Facilitating the initial vertical transport of space charge may also be advantageous.
• achieving a high space charge production rate, not necessarily supercharging aerosol particles, is important.
• Vonnegut The concept of a cost-effective space charge generator based on charging natural atmospheric aerosols by corona discharge (unipolar) ions in an open air environment was first introduced by Vonnegut (1962).
• Vonnegut and Moore (1958) deployed a simple EECD comprising a straight 7 km long wire of about 0.25 mm in diameter.
• the wire was supported along its length at about 10 m above the ground on 80 metallic antenna masts and connected to the negative electrode of a commercial DC source operating at a voltage of 25 kV.
• the positive electrode of the DC source was earthed, with the ground acting as the collector electrode of corona discharge.
• Using a thin wire as the emitter electrode is more practical than using needle-type electrodes with sharp tips because the latter become blunt due to electrochemical corrosion, while the corrosion of wire occurs more slowly and nearly uniformly along its length.
• Thin wire also minimizes the release of hazardous gases such as ozone and nitrogen oxides under an electric field of excessive strength on the surface of the emitter electrode, which can occur when using sharp tips.
• high ion output can be achieved without the discharge of hazardous gases by using a corona discharge under a moderate electric field on a large surface area of wires.
• a significant improvement to the basic design, as shown in Fig.2, is to compact the wire or electrically coupled wire segments into an emitter electrode assembly (EEA) 21, which is elevated by preferably a single support 22 to a height above the ground and electrically coupled, for example with a suitable wire 23, to the negative electrode 24 of DC source 25, the positive electrode of which is electrically coupled with the earthing point 26.
• EAA emitter electrode assembly
• an EEA comprises one or more electrically coupled emitter electrodes and a structure which supports them, referred to hereinafter as the emitter electrode frame or simply electrode frame.
• the frame of the EEA is in the shape of an isosceles pyramid, and the wire is wound around the pyramid's sides in a single strand.
• a single EEA is mounted on a support by means of holders and a bracket (not shown in Fig.2).
• a high-voltage insulator (not shown in Fig.2) is positioned between the support and the bracket.
• the ratio of the ion production rate, called the ionic current, to the leakage current is an important performance characteristic of a corona discharge embodiment. Attempts should be made to achieve the highest possible value of the ionic current-to-leakage ratio, which, among other factors, depends on the support quality. The latter is determined by both the support's insulating properties and its ability to carry an EEA with the highest possible ionic current output and therefore having a large mechanical load, i.e. weight and momentum which are mostly contributed by the electrode frame.
• the first improvement to the design of Rostopchin at al. is to exclude the insulator and construct a seamless support from a suitable insulating material.
• Such measures may reduce the weight and improve both the mechanical strength and the electrical resistivity of the support.
• the support is a rigid vertical structure with two ends, the first of which is fixed to the ground and the second to an EEA, referred to hereinafter as the ground support
• a non-limiting example of a suitable support is a telescopic mast made of hollow fiberglass segments and stabilized by three or more tethering ropes fixed to the ground.
• Such a mast which is readily transportable in parts and allows easy maintenance of the load, is widely used to support antennas.
• a tethering support for an EEA elevated by a lighter-than-air craft is alternatively used, which is especially advantageous if the elevation height needs to be readily varied, e.g. for maintenance purposes, or the required height is difficult to achieve with a ground support, which, as will be discussed later, is often the case.
• a lighter-than-air craft 31 is mechanically coupled with a rope or a pivot joint 32 to the first end of a support rod 33, carrying an EEA 34 (i.e. fixed to its frame).
• the upper end of the tethering support rope 35 is fixed to the support rod.
• the wire 37 located in the vicinity of the rope by supports 38, e.g. loops attached to the rope, and wound together with the rope on the reel, is electrically coupled with another wire 39 to the first (negative) electrode 310 of a DC source 311, e.g. the charging engine of a VDGG, the second (positive) electrode of which 312 is electrically coupled to the earthing point 313.
• support parts e.g. mast and ropes
• a film of an insulating fat-like water repellent substance to prevent the accumulation of continuous conductive water film on those parts under wet conditions.
• a further improvement to the embodiment is to introduce one or more earthing points 27 in the vicinity of corona discharge, electrically coupled, for example with a suitable wire 28, with the earthing point of a DC source.
• the number of earthing points required depends on the consumption current, type of ground, and the ground area beneath an EEA towards which most of the generated ions move. For negative corona discharge, this area is referred to hereinafter as the anode area. In order to charge aerosols in a larger volume of air, a larger anode area is preferred.
• the radius of anode area should be at least equal to the EEA' s elevation height.
• Type of ground and consumption current define the density of earthing points in the anode area required to maintain a sufficient conductivity of the latter. For example, if the ground is wet soil and the consumption current is about 100-200 ⁇ A, and a single earthing point is introduced beneath an EEA operating under a voltage of 70 kV, the anode area would have a radius up to 5-8 m. If the soil is dry, a grid of earthing points covering the anode area which are electrically coupled to each other and to the earthing point of a DC source is required. In this case, the distance between neighboring earthing points arranged in a grid should be 1-2 m.
• Earthing points which are typically earthed rods made of conductive material, e.g. a metal, should be deep and preferably reach soil layers which are wetter than the surface, if any.
• the minimum recommended depth of an earthed rod is about 0.5 m.
• the minimum depth should be greater.
• the conductivity of the soil in the anode area may be increased by moisturizing (watering) during operations of the space charge generator.
• the soil is moisturized with an environmentally friendly electrolyte such as a water solution with a common mineral that suppresses vegetation growth under the ion generator, i.e. salt water, in order to minimize the positive corona discharge on vegetation tips.
• a highly conductive collector electrode 29, such as one or more sheets of metal or wire mesh, may be positioned on the ground and electrically coupled, for example with a suitable wire, directly to the grounded electrode of the DC source.
• a reservoir 41 filled with a conductive electrolyte solution such as salt water
• a conductive electrolyte solution such as salt water
• a wire 45 may be electrically coupled to the local earthing point 42 and to the earthing point 43 of the DC source 44 with a wire 45, and may be placed under the EEA 46, which is elevated by a ground support 47, acting as the collector electrode of corona discharge.
• percolating the electrolyte solution for example with streams of air, may generate artificial aerosols 48 from residues of evaporating electrolyte drops released by bursting bubbles in addition to improving soil conductivity.
• the separation distance between wire segments determines the density of wiring. This density cannot be increased indefinitely. For a particular segment, the electric field from other segments affects the production of ions. For given values of voltage and wire thickness, there is a certain limit for the separation distance after which adding new wire segments on a frame will not lead to a significant increase in ion productivity. For a voltage of 50-70 kV and a wire with 0.1-0.2 mm diameter, this separation distance is about 1.5-3 cm. Under a given voltage, increasing the maximum efficient density of wiring requires using a thinner wire.
• wire The thinner the wire is, the more sensitive it is to degradation by corrosion and the higher the requirements for its corrosion resistance.
• a non-limiting example of commercially available wire suitable for this purpose is one with a diameter of 0.1-0.2 mm made of monel, a highly corrosion resistant Ni+Co+Cu-based alloy.
• FIG.5 A non-limiting example of such an embodiment 50 is shown in Fig.5 where six EEAs in the shape of a triangular pyramid are deployed.
• the apexes 51a and 52a of adjacent EEAs 51 and 52 point alternatively upward and downward respectively.
• This design enables optimal ventilation by horizontal winds and reduces the number of passes of the same air parcels containing space charge through the EEAs 51 and 52.
• the apexes of upward oriented pyramids are connected by rods 53 which do not carry a strong load and therefore can be lightweight.
• rods or support ropes 54 are connected with rods or support ropes 54 to a plate 55 attached to the top of the mast 56.
• rods 57 which, in turn, are connected with rods or support ropes 58 to the bracket 59 attached to the mast.
• FIG. ⁇ a A non-limiting example of a practical implementation of this design is shown in Fig. ⁇ a where the bases of upward oriented pyramids 61a and the bases of downward oriented pyramids 62a are arranged in different planes 63a and 64a respectively.
• the edges of pyramid bases in different planes are mechanically coupled with supports 61b in Fig. ⁇ b, preferably allowing a certain degree of flexibility .
• the edges of the corresponding pyramids 61c are fixed to the support plate 62c with bolts and nuts 63 c.
• the support plate 62d of each plane to which the edges of the pyramid bases 61 d are fixed with bolts and nuts 63d, is fixed at a certain position along the mast 66d with top and bottom brackets 64d and 65d respectively.
• a pyramidal shape is not the only one optimal for an EEA.
• a large variety of EEAs can be implemented in a modular design where frames of a planar shape, the surfaces of which are traversed by at least two parallel segments and preferably arranged at an angle to the surface of the Earth, are mechanically and electrically coupled to each other.
• Such an EEA module comprising a planar frame and the supported wire segments of an EECD arranged parallel to each other with a separation distance between them is referred to hereinafter as an elementary EEA (EEEA).
• an EEEA frame can be polygonal, but mechanically the most stable shape is triangular. Because of their planar shape, pre-assembled EEEAs can be easily transported in large quantities and EEAs can be assembled from and disassembled into EEEAs at an installation site.
• an EEA of pyramidal shape can be assembled from three or more EEEAs with the same size and shape of isosceles triangles.
• this embodiment is more robust as breaking the wire, e.g. by a bird, will disrupt a smaller fraction of wiring.
• EEEA frame which can be rods or planks, for example, can be made of conductive or non-conductive materials. If a metal frame is used, e.g. made of hollow tubes, care should be taken to prevent the wire from coming into immediate contact in the open air with the frame made of a different metal. Otherwise, wire segments may be quickly destroyed at contact points in the electrochemically corrosive environment and thus fall apart.
• a number of wire segment supports 71a are fixed in pairs to each of two sides 72a and 73a of the frame along their length, each holding the corresponding end of wire segment 74a (inset).
• the wire segments may form a continuous wire or be wound around the supports in more than one strand.
• the ends of these strands are fixed at points 75a and 76a, via which this EEEA is electrically coupled to other EEEAs, which may be electrically coupled to make this EEEA less prone to wire breakage.
• non-metallic supports or those made of the same metal as the wire which are flexible to a certain degree, is preferable, as this may reduce stress on the wire if the sides of the frame are slightly bent under variable external forces.
• the vertical post of supports may also be made in the form of a spring.
• a spring-based support 71b on the inward side of the frame is shown in Fig.7b (inset).
• a solution proposed herein is to separate the weight bearing frame structure from the wire supporting frame structures, but to have them flexibly coupled.
• a number of smaller EEEAs with lightweight frames which are stiff enough to support denser wiring with thinner wire are coupled with flexible joints to each other and to a weight bearing (external) planar frame. If the wiring of an EEEA is broken, this EEEA can be quickly replaced without the need for re- wiring it onsite.
• a flexible joint can be a spring or a zigzag shaped piece of a suitable wire acting as a spring.
• larger EEA structures can be assembled from external frames supporting EEEAs.
• Fig.8 illustrates a non-limiting example of how a triangular EEEA 80 can accommodate a larger total length of thinner wire 81 by making the frame 82 external for a number of smaller EEEAs 83 connected with flexible joints 84.
• Frame 91 made of flat planks of an insulating material, for example painted wood, has notches 92 on each of two sides of the frame along their length, through which the wire 93 is wound around the frame as shown, forming parallel segments between notches on the opposite sides of the frame (wire on the opposite side of the frame is shown as a dashed line).
• the ends of the wire strand are fixed at points 94 and 95, via which this EEEA is electrically coupled to other EEEAs, and can be optionally electrically coupled.
• a wire mesh can be used as an emitter electrode instead of parallel wire segments.
• larger frames can be used as mesh is much less sensitive to frame deformations than wires. Attaching mesh to the frame may be achieved in different ways without the need for multiple supports or notches in the case of wire segments. Compared to the latter, conductive mesh is more robust against breaks both mechanically and electrically. Replacing broken or corroded mesh is also easier.
• Rostopchin at al. noted that operating an EEA at sub-zero temperatures causes the accumulation of frost on the wire, which reduces its performance as the emitter electrode. To combat this problem, they suggested using an electric heater and fan, blowing warm air towards the EEA. Rostopchin at al. recognized that this technique does not work satisfactorily in the presence of a strong wind, which removes the stream of warm air before it reaches the EEA.
• a practical solution to the problem would be to make the wire self-heating by passing a low-voltage current through it.
• Arranging a low-voltage circuit with a conventional source of electricity such as a transformer is problematic as the electrical separation of high- voltage and low-voltage circuits can be technically difficult and a leakage current may be introduced.
• the solution proposed herein is to deploy a source of electromagnetic emission, such as a microwave generator with a suitable antenna, to heat the emitter electrode remotely without direct electrical contact.
• a source of electromagnetic emission such as a microwave generator with a suitable antenna
• the elevation height of an EEA above the ground is an important parameter, which determines aerosol charging efficiency. Ions produced by an EEA tend to flow towards the collector electrode of corona discharge, i.e. downward. Their motion is mostly governed by a strong electric field close to the emitter electrode and, at larger distances from the latter, both by wind and the electric field. As a large proportion of atmospheric aerosols become charged between the EEA and the surface of the Earth, the elevation of the EEA should be preferably high enough to ensure that most of the produced ions are attached to aerosols before they are wasted by recombination when reaching the surface of the Earth.
• this optimal elevation height depends on the spectrum and especially on the number concentration of aerosol particles in atmospheric air, which determine the lifetime of ions in the relatively aerosol-rich terrestrial air where ion recombination can be negligible. Under most conditions, this time usually ranges between 3 and 8 minutes.
• the optimal elevation height in still air can be estimated as the distance to which ions can travel between the EEA and the surface of the Earth during their lifetime.
• this distance for a particular EEA embodiment can be found experimentally by measuring the spatial electric field profile beneath the EEA and the subsequent numerical calculation of the charged particle trajectory (and thus its vertical path) during the ion lifetime, which can also be measured using existing techniques.
• the optimal elevation height can be found experimentally by measuring the concentration of negative ions at increasing elevation heights of the EEA. A substantial reduction in ion concentration after a certain elevation would indicate that the optimal elevation has been reached. [00122] In practice, the optimal elevation height, according to experimental studies by
• the height should be at least 6 m.
• embodiments with a tethered support may be preferred.
• the higher the elevation of an EEA the higher operating voltage required to achieve the same ionic current.
• using a VDGG as an alternative to commercial DC sources can be advantageous.
• a lighter-than-air spherical capacitor of a VDGG can be used as a lighter-than-air craft.
• the frame 101 of an EEA can be positioned around the surface of the lighter-than-air spherical capacitor (craft) 102 with multiple support rods 103 and feet 104, uniformly distributed over the surface.
• the tethering rope 105 fixed to the lighter-than-air spherical capacitor (craft) and the wire 106 electrically coupled to the EEA are connected to other components of this embodiment (not enumerated) in the same fashion as in Fig.3.
• support rods should be of variable length and provide a stress-bearing mechanism on their feet, e.g. by incorporating a spring.
• the frame 111 of an EEA is fixed by non- flexible support rods 112 around the surface of the spherical or quazi-spherical capacitor, which is not a lighter-than-air craft.
• a quazi-spherical capacitor can be assembled from lightweight sheets 113 with conductive external surfaces, e.g. made of plastic and covered with a conductive paint, electrically coupled and joined mechanically.
• such sheets can be cut and arranged like swatches on a soccer ball surface.
• An initially deflated balloon is placed inside the capacitor and then inflated with a lighter-than-air gas, e.g. helium, until it occupies the volume of the capacitor, making the latter buoyant.
• FIG.12 Another proposed lighter-than-air embodiment 120 is shown in Fig.12.
• Sections of wire mesh or EEEAs with either mesh or parallel wire segments 121 are electrically coupled and joined mechanically, forming an EEA of a quazi-spherical shape. If framed EEEAs are used, using flexible joints connecting the sides of the frames is preferred as previously discussed. Inflated spheres 122 are uniformly distributed over and attached, e.g. by small loops, to the inward side of the surface of the mesh. If framed EEEAs are used in this embodiment, the spheres are attached to pairs of joined-frame sides. A balloon 123 is placed inside the EEA and then inflated with a Iighter-than-air gas until the spheres provide a stress- bearing support for the EEA. In this configuration, a sufficiently large EEA with a diameter of several meters may act as both the emitter electrode and the capacitor as in this case the system possesses its own (significant) capacity.
• a significant enhancement of the produced ionic current can be achieved by introducing the Malter effect in the above embodiments.
• Malter (1936) observed that when a thin film of some non-conducting substances such as Al 2 O 3 , Zn2Si ⁇ 3, SiCh, Zr ⁇ 2, CaCCb, Ta2 ⁇ 5 and a few other oxides is applied to a cathode which is subject to bombardment by electrons, secondary electron emission occurs from the surface of film.
• a Malter electrode Such an electrode is referred to hereinafter as a Malter electrode.
• Secondary electron emission leaves a net positive charge on the surface of the film of the Malter electrode, referred to hereinafter as Malter film, causing a strong electric field across the Malter film layer.
• the Malter film As the Malter film is not conductive, the positive charge does not neutralize as fast as it builds up, causing the film layer to act as a dielectric medium of a capacitor, the "plates" of which are oppositely charged film and cathode surfaces. Electrons emitted on the cathode surface in the highly intensive electric field are further tunneled through the Malter film and released into the air, ultimately forming negatively charged molecular clusters, i.e. negative ions.
• an initiating source of particles or ionizing radiation e.g. high energy electrons, ions, X-rays, ultraviolet radiation
• the electron emission rate of the cathode must be greater than the rate of removal of the positive charge from the film surface. If the Malter electrode is bombarded by electrons, the ionic current emitted by this electrode, depending upon conditions, may be up to several thousand times greater than the primary bombarding current (Hawkes, 1992).
• a higher ionic current produced by an EEEA can be achieved, as illustrated in Fig.13, by the introduction of additional Malter electrodes 131 in the form of segments of a thicker wire coated with a Malter film, which are parallel and electrically coupled, for example by soldering points 132 on film-free areas 133 to thin wire segments 134.
• the latter act primarily as initiating sources for the adjacent Malter electrode, which also can be based on a hollow wire (tube) instead of a solid wire to minimize weight.
• tubular wire is referred to hereinafter as wire.
• Such a wire couple 130 substitutes ordinary wires in the discussed embodiments.
• the diameter of Malter wires should be large enough and thin wires should be close enough to Malter wires to assure the effective bombardment of the latter by the emitted electrons and ions.
• the electric field strength on the surface of a wire is inversely proportional to the diameter of the latter, the bombarding electrons and negative ions, decelerated by the electric field of the Malter wire, can reach the surface of this wire and provide the impact required for the secondary emission if the diameter of Malter wire is sufficiently large.
• wires with a larger diameter provide a higher ionization output per unit length as their emitting surface is larger. More than one corona initiating wire per Malter wire can be used.
• the emitter electrode is a mesh as shown in Fig.14 where the segment of a Malter mesh 140 is shown above (left picture) and below (right picture) the surface of the mesh.
• Thin wires 141 are positioned as discussed above and soldered at points 142 to the first set of parallel wires 143 of a thick wire mesh covered with a Malter film.
• thin wires 144 are also positioned below and soldered at points 145 to the second set of parallel mesh wires 146, which are perpendicular to wires 142 of the first set. If the second set of mesh wires is above the first one (e.g.
• FIG.15 Another arrangement of thin wire is given in Fig.15 where the segment of a Malter mesh 150 is shown above (left picture) and below (right picture) the surface of the mesh.
• thin wires 151 are positioned above the wires 152 of the first (bottom) set by soldering at points 153 to the wires 154 of the second (top) set of Malter mesh wires.
• thin wires 155 are positioned below the wires of the second set by soldering at points 156 to the wires of the first set of Malter mesh wires.
• the Malter electrode can be a metal foil, one or both surfaces of which are coated with a Malter film.
• a Malter electrode is referred to hereinafter as Malter foil.
• thin "igniting" corona wires are located in the vicinity and fixed to one or both surfaces of Malter foil as previously discussed in the case of Malter wire.
• FIG.16 A non-limiting example of such a configuration where the Malter foil is a strip is shown in Fig.16.
• One or more thin wires 161 are positioned above and fixed to one or both surfaces 162 of the Malter electrode at points 163.
• such an electrode substitutes wires in the discussed EEEAs.
• a wire mesh can be substituted by a mesh made of strips of Malter foil with corona wires fixed preferably to both active surfaces of the foil.
• another alternative is to substitute the whole surface of wire mesh or wire segments in EEEAs by a Malter foil with corona wires on its outer surface.
• some embodiments may comprise a generator of artificial aerosols, such as, for example, manufactured by TSI Incorporated, of Shoreview, MN, USA, to increase the amount of aerosols in the air surrounding and especially below the EEA.
• the aerosol generator is located below the EEA of the space charge generator.
• a reservoir with a percolated solute, used as an alternative or additional collector electrode as previously discussed, may also be used.
• Air motions such as horizontal wind and vertical updrafts, increase the efficiency of aerosol charging by removing air parcels containing charged aerosols and supplying air parcels with fresh aerosols.
• the optimal elevation height may be decreased due to air motions.
• creating artificial air motions is advantageous, especially updrafts which increase the initial elevation of the space charge plume.
• a fan or a heat source may be placed below the EEA.
• Burners of various types which can also act as aerosol generators, can be deployed as heat sources.
• a wire mesh is used as an additional or alternative collector electrode of corona discharge, it can be made a heat source by elevating it to a short distance from the ground and passing a low-voltage strong electric current, e.g. from a transformer, through it.
• Heating with solar radiation can be achieved by providing a "heat island" around the space charge generator, i.e. a black surface, of a conductive material which can also act as a collector electrode of corona discharge.
• a practical solution is to coat the ground with black and conductive granules of a carbon substance, e.g. natural coal.
• a corona discharge generating a sufficiently high AEC of unipolar ions may produce another effect which is the modification of the relative humidity profile in the atmosphere.
• a vertical motion of moistened air parcels facilitating the elevation of space charge plume may be produced and atmospheric instability may be locally produced or augmented. The latter, under favorable atmospheric conditions, may lead to facilitating cloud formation.
• SMT selective moisture transport
• Fig.17 Trajectories of water vs. non-water molecules are shown in Fig.17, illustrating the effect of the increased collision cross-section for a water molecule with a trajectory 171, moving parallel to axis X at a distance r from it (collision distance) towards an air ion 172 of radius R.
• Non-water molecules moving parallel to the axis X at a distance r from it can collide with the ion only if r ⁇ R.
• those water molecules with a collision distance R ⁇ r ⁇ p can also collide with the ion.
• water molecules behave differently to other air molecules while colliding with atmospheric ions and this difference is described in terms of the collision cross-section, determined in this case by maximum collision distance.
• p > R the collision cross-section of water molecules is larger than that of non-water molecules.
• the collision cross-section ratio of water to non-water molecules has been estimated by Nadykto et al., (2003).
• the enhancement factor was found to be about 7.
• water dimer (H 2 O) 2 and others ((H 2 O) n , n > 2) which appear in higher concentrations when vapor is closer to saturation, the enhancement factor values were found to be even higher.
• an air mass moistened by the SMT may be less stable than that formed by natural convection.
• the effect of the locally increased instability may lead to the condensation of vapor in the moistened air masses, which augments the latter' s buoyancy by the release of latent heat and ultimately forms clouds.
• This process may occur at lower altitudes than in the case of naturally moistened air masses or may occur only in artificially moistened air masses, and its expansion to a larger scale may be possible if the atmosphere is nearly or weakly unstable for natural air masses.
• the elevation height of an EEA that is optimal for SMT is generally lower than that for optimal aerosol charging as the density of the AEC, not just the concentration of ions, is important. Charging the largest possible amount of natural or artificial aerosols is not desirable in this case as the space charge produced in the path of the AEC flow, unless removed at a high rate, e.g. by a strong wind, reduces the density of the AEC. If the primary purpose of operating a corona discharge embodiment is to achieve the maximum possible SMT, no artificial aerosols should be produced and the recombination of the generated ions on the anode area should be favored by selecting a lower EEA elevation height.
• a decrease in precipitation in a target area can be achieved by a planned increase of precipitation in a different area, whereby the area targeted for the decrease of precipitation will be in the precipitation shadow of the area where the precipitation was induced.
• Individual space charge generators may be controlled manually or automatically from a centralized location.
• the embodiments as described above are placed on all relevant types of conveyances (stationary or mobile) on the ground or in the water. In the latter case, a platform on a body of water provided with an anode area electrically coupled with an earthing electrode submerged into the water is required.
• one approach is to position the charged capacitor or an EEA of corona discharge above the fog layer with a tethered support to cause the accumulation of space charge on the boundary of the fog layer.
• multiple lighter- than-air embodiments should be deployed and/or an embodiment or embodiments should be moved to dissipate different fog areas.
• the fog layer should be thick enough for the efficient collection of smaller fog particles by larger ones, which may not take place in all cases.
• the alternative solution is to deploy corona discharge embodiments inside the fog layer operating in an optimal regime for SMT.
• the fog dissipates by droplet evaporation, while in moistened air parcels the droplets and ice crystals, if any, grow large and sediment by the force of gravity, possibly collecting fog particles as they descend.
• the updraft caused by the release of latent heat favors the formation of larger particles suspended and grown for a longer time and causes the convergence of the neighboring foggy air to be modified by the SMT. This convergence may be augmented by the ongoing removal of supersaturated vapor by condensation and, if a fog is cold, by growing ice crystals, leading to the reduction of the vapor partial pressure.
• the initial elevation height of an EEA should preferably be low and then gradually increased to an optimal value.
• corona discharge embodiment or embodiments should start operating before the forecasted occurrence of fog, i.e. in fog prevention mode.
• Another application is the reduction of the temperature of the surface of the
• Non-limiting examples of this application are energy savings in populated areas and the reduction of sea surface temperature for a long period over large areas in order to reduce the occurrence and intensity of cyclones as their genesis is dependent on the water temperature.
• cloud cover at low altitudes which reflects solar radiation back into space can be created or augmented at times of favorable atmospheric conditions by operating corona embodiments in the SMT mode.
• low cloud cover which reduces the emission of infrared radiation into space can be reduced or removed by enhancing precipitation in a target area by deploying charged capacitors or corona discharge embodiments in the aerosol charging mode as discussed.
• the effect can still be achieved even if the size of precipitation hydrometeors is small and they cannot reach the surface of the Earth, however cloud dissipation can be achieved. To some degree, the effect still can be achieved if fewer and larger but not precipitating cloud particles are produced by the influence. In this case, cloud transparency for the outgoing infrared radiation may be increased.
• Tinsley, B.A., 2000 Influence of solar wind on the global electric circuit, and inferred effects on cloud microphysics, temperature, and dynamics in the troposphere. Space Sci. Rev., 94, 231-258
• Tinsley, B.A., and Yu, F., 2002 Atmospheric ionization and clouds as links between solar activity and climate.

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