Using ground-based ionisation to enhance rainfall in the Hajar Mountains, Oman

Chambers, Ray; Beare, Stephen; Peak, Scott; Al-Kalbani, Mohammed Saif

doi:10.1007/s12517-016-2515-6

Cited by 14 publications

(8 citation statements)

References 8 publications

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“…In recent years, under the crisis of global water scarcity [13] and the potential negative impacts of chemical cloudseeding materials on the environment and human health [14], more and more countries, such as the UAE, Russia, Mexico [15], Australia [16], and Oman [17], have carried out the field trial of charged particles catalyzing rainfall enhancement based on the ionization of air by corona discharge because of its economy and efficiency [18]. Although the statistical results of these field trials are positive in rain enhancement, experimental implementation of this technology still has encountered many difficulties in providing direct and convincing evidence of experimental feedbacks, such as spectrum evolution and charging states of water droplets, especially under the non-stationary temporal and spatial variation [16].…”

Section: Introductionmentioning

confidence: 99%

“…However, results show that, in a short time scale, strong electric field and high ions density between electrodes are necessary conditions for inducing water vapor condensation and droplet growth. Moreover, it is worth noting that the gap between wire corona discharge electrode and the ground surface is too narrow (less than tens of centimeters) to meet the field application conditions where the discharge gaps is several meters high [16,17]. Therefore, under the conditions of the field environment, there is still a lot of work to be done on the influence of unipolar corona discharge, which is also the first direct evidence chain.…”

Section: Introductionmentioning

confidence: 99%

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Density enhancement of nano-sized and submicron-sized water droplets induced by charges released from corona discharge

Wang¹,

Li²,

Zhang³

et al. 2020

J. Phys. D: Appl. Phys.

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Corona discharge is widely used as an ionization source in field experiments of weather modification induced by charged particles due to its high efficiency and economy. However, deficient research efforts have been devoted to the effects of corona discharge on the size distribution and evolution of droplets in the humid air. In this paper, the characteristic of water droplets spectrum evolution in humid air with unipolar corona discharge is studied by an electrical low pressure impactor (ELPI) experiment in a 96 m 3 cloud chamber. Results show that nano-sized water droplets with diameters from 9 nm to 25 nm grow rapidly because of the inducement of charges released from corona discharge. Additionally, an increase in the concentration of submicron droplets appears at 20 min. To reveal the potential mechanism of the phenomena, the average charge values of charged droplets measured by ELPI are further analyzed. Meanwhile, the relationship between saturated vapor pressure over charged droplet's surface and its radius is discussed by the modified Kelvin-Thomson equation. Results show that, for the density enhancement of nano-sized droplets, condensational growth induced by charges released from corona discharge dominates significantly. The subsequent increase in the density of submicron-sized droplets is regarded as the break-up of the micron-sized droplets, with the process of evaporation when droplets are approaching the Rayleigh limit in the sub-saturated environment. This research may bring some new perspectives to further study of weather modification and cloud-seeding induced by charged particles, such as by increasing condensed nuclei density, broadening cloud droplets spectrum, and suppressing the evaporation of cloud droplets, etc.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Density enhancement of nano-sized and submicron-sized water droplets induced by charges released from corona discharge

Wang¹,

Li²,

Zhang³

et al. 2020

J. Phys. D: Appl. Phys.

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“…The operation of the ions emitters resulted in a positive and significant rainfall enhancement. [ 17 ] However, these large‐scale, ground‐based corona discharge systems are like "waiting for a rabbit behind the tree" and have the disadvantages of poor flexibility and high cost…”

Section: Introductionmentioning

confidence: 99%

Deposition of charged aerosols by E × B enhanced low‐temperature plasma jet array

Chen

Huang

Liu

2021

Plasma Processes & Polymers

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In this paper, an efficient plasma jet array based on the E × B enhancement was developed. The direction of the magnetic field was the same as the propagation direction of the plasma jet, and the direction of the electric field was perpendicular to the plasma jet. The E × B enhancement increased the length of the plasma jet from 0.5 to 1.8 cm, the discharge current peak by 37.8%, and the plasma power by 11.1%, compared with the control case. Three‐dimensional simulation of electrons movement indicates that the confinement of electrons in the high argon concentration region was the main reason for the E × B enhancement. The stronger discharge based on the E × B enhancement increased the ion density in the open air significantly. The charged aerosols were generated through the diffusion charging mechanism. The image charge electric force between charged and neutral aerosols increased the collision rate between aerosols, therefore, the larger aerosols were generated, and 108% more deposition of aerosols than the natural settlement case were achieved.

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“…Because of this, it is also adopted to ionize the air in the field experiments of weather modification [7], [8]. As one of the emerging applications of the corona discharge technique, rain enhancement induced by atmospheric ionization has made a remarkable breakthrough [9], [10]. In the application, ions released from the ground-based corona discharge device can be captured by aerosols and tiny water droplets in the air and be transported into the cloud with the ascending airflow.…”

Section: Introductionmentioning

confidence: 99%

“…Although the positive effect on the rain enhancement of atmospheric ionization caused by artificial radioactivity [13] and corona discharge generating ions [10] had been proved, it still encountered many difficulties in the field implementations. The reason is that the positive enhanced rainfall data are derived from rainfall statistics of rain gauges, which is controversial under the nonstationary temporal and spatial variations of the field experiments [14].…”

Section: Introductionmentioning

confidence: 99%

Electrostatic Effects of Corona Discharge on the Spectrum and Density Evolution of Water Droplets in Air

Wang

et al. 2020

IEEE Access

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As one of the emerging application areas of the corona discharge technique, rain enhancement induced by atmospheric air ionization has made a great breakthrough. Although natural rainfall modified by artificial ionization was successfully observed via the statistical data of field experiments, deficient efforts have been devoted to the research on the near-field effect of corona discharge on the evolution of water droplets around the discharge device. In this paper, we studied the electrostatic effects of corona discharge on the spectrum and density evolution of water droplets in a 96-m 3 cloud chamber. An interesting phenomenon was found that two different electrostatic effects appeared when various high voltages were applied on the corona electrode. In detail, the growth of droplets larger than 10 μm was detected once the applied high voltage exceeds the critical value (e.g.-80 kV in our discharge device), and this is attributed to the electrostatic induction effect. By contrast, a narrow droplet size spectrum and reduced density caused by the strong electrostatic precipitation effect were shown below this critical voltage. To figure out the mechanisms underlying these phenomena, the charging status of water droplets with various sizes, forces of charged droplets under various electric field strength, and collision kernels between droplets, are analyzed through theoretical calculations. Results show that the electric field plays a dominant role in the charging process of droplets and the acceleration of collision-coalescence between charged and neutral droplets, which results in the different electrostatic effects on the evolution of droplets. This paper may provide some enlightenment to fog elimination in industrial application and cloudseeding in atmospheric water resources comprehensive utilization.

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Using ground-based ionisation to enhance rainfall in the Hajar Mountains, Oman

Cited by 14 publications

References 8 publications

Density enhancement of nano-sized and submicron-sized water droplets induced by charges released from corona discharge

Density enhancement of nano-sized and submicron-sized water droplets induced by charges released from corona discharge

Deposition of charged aerosols by E × B enhanced low‐temperature plasma jet array

Electrostatic Effects of Corona Discharge on the Spectrum and Density Evolution of Water Droplets in Air

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