Artificial modification of atmospheric space charge

Vonnegut, B.; Moore, Charles B.; Stout, Glenn E.; Staggs, Donald W.; Bullock, J. W.; Bradley, Wayne E.

doi:10.1029/jz067i003p01073

Cited by 35 publications

(8 citation statements)

References 4 publications

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“…The region of central Illinois near Champaign and Urbana is well suited for a test of this sort, for here in the lower atmosphere up to altitudes of half a kilometer or more the concentration of space charge is naturally quite low during the day--less than I elementary charge cm -•-and the electrical perturbations exhibited by small fair weather cumuli are ordinarily so small as to be undetectable [Moore, ¾onnegut, Semonin, Bullock, and Bradley, 1962]. Experiments have been described [Vonnegut, Moore, Stout, Staggs, Bullock, and Bradley, 1962]…”

Section: Introductionmentioning

confidence: 99%

Effect of atmospheric space charge on initial electrification of cumulus clouds

Vonnegut¹,

Moore²,

Semonin³

et al. 1962

J. Geophys. Res.

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During the summer of 1960, experiments were conducted in Illinois to determine how the electrical potential gradient and space charge above and beneath fair‐weather cumulus clouds depend on the polarity and concentration of the space charge in the air from which they grow. Artificially produced space charge was released into the atmosphere near the ground during convection. Measurements showed that clouds that form in the electrically modified region exhibited significantly larger potential gradient perturbations than otherwise similar clouds forming nearby. When the charge released was negative, the fair‐weather potential gradient over the cloud was enhanced; when it was positive, the potential gradient was decreased or of reversed polarity. Measurements just beneath the cloud base showed that space charge of the polarity released near the ground was being carried up into the center of the cloud and that space charge of the opposite sign was descending around the outer portions of the cloud. The experimental results show that the polarity and intensity of electrification of small nonprecipitating cumulus clouds is determined primarily by the polarity and concentration of the space charge in the air from which they grow. The agreement between the observations and predictions based on the convective electrification process proposed by Grenet and Vonnegut is consistent with the idea that electric charge is being carried by updrafts and by downdrafts as they have suggested.

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Section: Introductionmentioning

confidence: 99%

Effect of atmospheric space charge on initial electrification of cumulus clouds

Vonnegut¹,

Moore²,

Semonin³

et al. 1962

J. Geophys. Res.

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“…Although the results of experiments conducted by Vonnegut's team to prove convective cloud charging were inconclusive, the new concept of charging atmospheric aerosols with open-air DC corona-discharge installations, aiming to remotely modify the electrical state of clouds, was introduced. Vonnegut et al (1962) performed aircraft measurements of the electric potential gradient at different altitudes above the plume of aerosols charged with a 14-km long wire. They observed that the produced space charge mixed rapidly in the lower atmosphere and caused large perturbations in the fairweather electric potential gradient, which were extended downwind 10 km or more.…”

Section: Development Of the Technologymentioning

confidence: 99%

Abstraction of Atmospheric Humidity

Wilderer

Davydova²,

Saveliev³

2011

Treatise on Water Science

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“…The third area involved purposeful modification of clouds and precipitation. Initial studies were of the effects of ion discharge on the electrical charge of cumulus clouds (Vonnegut et al 1962;Semonin et al 1962). This was followed by a 3-year effort to plan and initiate an Illinois-based precipitation modification experiment known as the Precipitation Enhancement Program, or PEP (Changnon 1979a).…”

Section: Introductionmentioning

confidence: 99%

Illinois Precipitation Research: A Focus on Cloud and Precipitation Modification

Changnon

Czys

Scott

et al. 1991

Bull. Amer. Meteor. Soc.

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At the heart of the 40-year atmospheric research endeavors of the Illinois State Water Survey have been studies to understand precipitation processes in order to learn how precipitation is modified purposefully and accidentally, and to measure the physical and socioeconomic consequences of cloud and precipitation modification. Major field and laboratory activities of past years are briefly treated as a basis for describing the key findings of the past ten years. Recent studies of inadvertent and purposeful cloud and rain modification and their effects are emphasized, including a 1989 field project conducted in Illinois and key findings from an ongoing exploratory experiment addressing cloud and rain modification. Results are encouraging for the use of dynamic seeding on summer cumuliform clouds of the Midwest. Typical in-cloud results at-10°C reveal multiple updrafts that tend to be filled with large amounts of supercooled drizzle and raindrops. Natural ice production is vigorous, and initial concentrations are larger than expected from ice nuclei. However, natural ice production is not so vigorous as to preclude opportunities for seeding. Radar-based studies of such clouds reveal that their echo cores usually can be identified prior to desired seeding times, which is significant for the evaluation of their behavior. Cell characteristics show considerable variance under different types of meteorological conditions. Analysis of cell mergers reveals that under conditions of weak vertical shear, mid-level intercell flow at 4 km occurs as the reflectivity bridge between cells rapidly intensifies. The degree of intensification of single-echo cores after they merge is strongly related to the age and vigor of the cores before they join. Hence, cloud growth may be enhanced if seeding can encourage echo cores to merge at critical times. Forecasting research has developed a technique for objectively distinguishing between operational seeding and nonoperational days and for objectively predicting maximum cloud-top height and seeding suitability. An accuracy rate of up to 60% in predicting maximum echo-top height using four categories has been achieved and suggests its use as a covariate in future experimentation. Impact studies illustrate that sizable summer rain increases would be necessary to produce economically beneficial outcomes for Corn Belt agriculture. Increases of >25% in July rainfall across certain high-production crop districts of the Corn Belt would produce economic effects realized nationally.

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Artificial modification of atmospheric space charge

Cited by 35 publications

References 4 publications

Effect of atmospheric space charge on initial electrification of cumulus clouds

Effect of atmospheric space charge on initial electrification of cumulus clouds

Abstraction of Atmospheric Humidity

Illinois Precipitation Research: A Focus on Cloud and Precipitation Modification

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