Electric Field Variation in Clear and Convective Conditions at a Tropical Urban Location
About: This article is published in Journal of Geophysical Research.The article was published on 2019-02-27. It has received 9 citations till now. The article focuses on the topics: Liquid water content.
Citations
More filters
TL;DR: In this article, preliminary results from the measurement of potential gradient (PG) for the period of March 2018-February 2019 at the University of Kashmir, Srinagar, (34° 03′ N, 74° 51’ E, 1585m amsl) India is reported.
10 citations
TL;DR: Data indicates that the electrical conductivity of the air is more sensitive to the presence of airborne radioactivity than the atmospheric electric potential gradient (PG), which is particularly important in studying microphysical effects of enhanced radioactivity in the air where no other distance monitoring method exists.
8 citations
TL;DR: A comparative analysis between the percentage of stratiform and convective rain durations shows significant dominance of strat Uniformitarian rain over convectiveRain at the present location showssignificant dominance of Stratiform rain over Convective rain.
Abstract: This article aims to classify precipitation into two categories, namely stratiform and convective. Multiple techniques, such as utilizing the micro rain radar (MRR), electric field monitor (EFM), radiometer, and disdrometer measurements, have been deployed for this purpose, at a tropical location Kolkata, India. A new rain classification technique, using logistic regression modeling of the sixth to third moment ratio ${(M6/M3)}$ , has been proposed. Classification of rain types based on the new technique shows high consistency with that based on radar reflectivity ( ${Z}$ ) values obtained from disdrometer measurements. This article also distinguishes mixed rain from stratiform and convective rain. The observations on the bright band structure by MRR and on differential brightness temperature at 31.4 and 22.23 GHz by a radiometer are utilized to classify mixed rain types. Although the EFM measurements do not classify rain types directly, they give a distinct signature of the impending stratiform/convective rain events. A comparative analysis between the percentage of stratiform and convective rain durations shows significant dominance of stratiform rain over convective rain. At the present location, the convective phenomenon shows higher occurrences during the pre-monsoon period compared to the monsoon period.
6 citations
Cites background from "Electric Field Variation in Clear a..."
...precipitation, there is no aggregation of ice particles due to strong updrafts and downdrafts [17], and hence there will be...
[...]
TL;DR: In this article, the authors investigated the impact of both local and global factors and meteorological parameters in the diurnal variation of atmospheric potential gradient on the annual and seasonal time scale.
6 citations
TL;DR: In this article, a highly sensitive and robust electric field sounding sensor based on an existent micro-electro-mechanical system chip and a new protective package that augments sensor sensitivity was introduced.
Abstract: High-altitude electric fields are a critical parameter of electricity in the atmosphere. Due to such drawbacks as their bulk and high cost, traditional electric field mills are not available for daily atmospheric sounding purposes. This paper introduces a highly sensitive and robust electric field sounding sensor based on an existent micro-electro-mechanical systems chip and a new protective package that augments sensor sensitivity. To gain high sensitivity, an innovative external metal electrode connects to the electric field microchip’s package cap, hangs down out of the guardian foam, and effectively enhances the local electric field near the microchip due to the distortion effect. This distortion regularity was studied during a series of finite element simulations, calibrations, and comparison experiments. With a 1.5-meter-long external electrode, the sensitivity of the sensor reached 465 mV/kV/m with a resolution that was better than 10 V/m in an actual long-term ground comparison test. Furthermore, the microsensor chip and its circuit are protected inside a foam while the metal electrode is exposed outside, therefore gaining a robust stability during harsh environments such as low temperature, rainfall, etc. To examine the performances, we built an electric field sounding system, including the electric field sensor, a radiosonde, and a receiving antenna, and measured high-altitude electric fields in various weather conditions. Intended for atmospheric electricity research, our innovative electric field sounding sensor would be especially propitious if integrated with a radiosonde and applicable to daily sounding services.
5 citations
Cites background from "Electric Field Variation in Clear a..."
...Therefore, measuring changes in the strength of atmospheric E-fields can help analyze the relationship between industrialization and air pollution [8], [9]....
[...]
References
More filters
Book•
31 Jul 1988
TL;DR: In this article, the boundary layer is defined as the boundary of a boundary layer, and the spectral gap is used to measure the spectral properties of the boundary layers of a turbulent flow.
Abstract: 1 Mean Boundary Layer Characteristics.- 1.1 A boundary-layer definition.- 1.2 Wind and flow.- 1.3 Turbulent transport.- 1.4 Taylor's hypothesis.- 1.5 Virtual potential temperature.- 1.6 Boundaiy layer depth and structure.- 1.7 Micrometeorology.- 1.8 Significance of the boundary layer.- 1.9 General references.- 1.10 References for this chapter.- 1.11 Exercises.- 2 Some Mathematical and Conceptual Tools: Part 1. Statistics.- 2.1 The significance of turbulence and its spectrum.- 2.2 The spectral gap.- 2.3 Mean and turbulent parts.- 2.4 Some basic statistical methods.- 2.5 Turbulence kinetic energy.- 2.6 Kinematic flux.- 2.7 Eddy flux.- 2.8 Summation notation.- 2.9 Stress.- 2.10 Friction velocity.- 2.11 References.- 2.12 Exercises.- 3 Application of the Governing Equations to Turbulent Flow.- 3.1 Methodology.- 3.2 Basic governing equations.- 3.3 Simplifications, approximations, and scaling arguments.- 3.4 Equations for mean variables in a turbulent flow.- 3.5 Summary of equations, with simplifications.- 3.6 Case studies.- 3.7 References.- 3.8 Exercises.- 4 Prognostic Equations for Turbulent Fluxes and Variances.- 4.1 Prognostic equations for the turbulent departures.- 4.2 Free convection scaling variables.- 4.3 Prognostic equations for variances.- 4.4 Prognostic equations for turbulent fluxes.- 4.5 References.- 4.6 Exercises.- 5 Turbulence Kinetic Energy, Stability, and Scaling.- 5.1 The TKE budget derivation.- 5.2 Contributions to the TKE budget.- 5.3 TKE budget contributions as a function of eddy size.- 5.4 Mean kinetic energy and its interaction with turbulence.- 5.5 Stability concepts.- 5.6 The Richardson number.- 5.7 The Obukhov length.- 5.8 Dimensionless gradients.- 5.9 Miscellaneous scaling parameters.- 5.10 Combined stability tables.- 5.11 References.- 5.12 Exercises.- 6 Turbulence Closure Techniques.- 6.1 The closure problem.- 6.2 Parameterization rules.- 6.3 Local closure - zero and half order.- 6.4 Local closure - first order.- 6.5 Local closure - one-and-a-half order.- 6.6 Local closure - second order.- 6.7 Local closure - third order.- 6.8 Nonlocal closure - transilient turbulence theory.- 6.9 Nonlocal closure - spectral diffusivity theory.- 6.10 References.- 6.11 Exercises.- 7 Boundary Conditions and External Forcings.- 7.1 Effective surface turbulent flux.- 7.2 Heat budget at the surface.- 7.3 Radiation budget.- 7.4 Fluxes at interfaces.- 7.5 Partitioning of flux into sensible and latent portions.- 7.6 Flux to and from the ground.- 7.7 References.- 7.8 Exercises.- 8 Some Mathematical and Conceptual Tools: Part 2. Time Series.- 8.1 Time and space series.- 8.2 Autocorrelation.- 8.3 Structure function.- 8.4 Discrete Fourier transform.- 8.5 Fast Fourier Transform.- 8.6 Energy spectrum.- 8.7 Spectral characteristics.- 8.8 Spectra of two variables.- 8.9 Periodogram.- 8.10 Nonlocal spectra.- 8.11 Spectral decomposition of the TKE equation.- 8.12 References.- 8.13 Exercises.- 9 Similarity Theory.- 9.1 An overview.- 9.2 Buckingham Pi dimensional analysis methods.- 9.3 Scaling variables.- 9.4 Stable boundary layer similarity relationship lists.- 9.5 Neutral boundary layer similarity relationship lists.- 9.6 Convective boundary layer similarity relationship lists.- 9.7 The log wind profile.- 9.8 Rossby-number similarity and profile matching.- 9.9 Spectral similarity.- 9.10 Similarity scaling domains.- 9.11 References.- 9.12 Exercises.- 10 Measurement and Simulation Techniques.- 10.1 Sensor and measurement categories.- 10.2 Sensor lists.- 10.3 Active remote sensor observations of morphology.- 10.4 Instrument platforms.- 10.5 Field experiments.- 10.6 Simulation methods.- 10.7 Analysis methods.- 10.8 References.- 10.9 Exercises.- 11 Convective Mixed Layer.- 11.1 The unstable surface layer.- 11.2 The mixed layer.- 11.3 Entrainment zone.- 11.4 Entrainment velocity and its parameterization.- 11.5 Subsidence and advection.- 11.6 References.- 11.7 Exercises.- 12 Stable Boundary Layer.- 12.1 Mean Characteristics.- 12.2 Processes.- 12.3 Evolution.- 12.4 Other Depth Models.- 12.5 Low-level (nocturnal) jet.- 12.6 Buoyancy (gravity) waves.- 12.7 Terrain slope and drainage winds.- 12.8 References.- 12.9 Exercises.- 13 Boundary Layer Clouds.- 13.1 Thermodynamics.- 13.2 Radiation.- 13.3 Cloud entrainment mechanisms.- 13.4 Fair-weather cumulus.- 13.5 Stratocumulus.- 13.6 Fog.- 13.7 References.- 13.8 Exercises.- 14 Geographic Effects.- 14.1 Geographically generated local winds.- 14.2 Geographically modified flow.- 14.3 Urban heat island.- 14.4 References.- 14.5 Exercises.- Appendices.- A. Scaling variables and dimensionless groups.- B. Notation.- C. Useful constants parameters and conversion factors.- D. Derivation of virtual potential temperature.- Errata section.
9,111 citations
Book•
28 Jun 2010TL;DR: In this paper, the authors present a model of lightning and its effects in the atmosphere and the distant lightning electromagnetic environment: atmospherics, Schumann resonances and whistlers.
Abstract: Preface 1. Introduction 2. Incidence of lightning 3. Electrical structure of lightning-producing clouds 4. Downward negative lightning discharges to ground 5. Positive and bipolar lightning discharges to ground 6. Upward lightning initiated by ground-based objects 7. Artificial initiation (triggering) of lightning by ground-based activity 8. Winter lightning in Japan 9. Cloud discharges 10. Lightning and airborne vehicles 11. Thunder 12. Modelling of lightning processes 13. The distant lightning electromagnetic environment: atmospherics, Schumann resonances and whistlers 14. Lightning effects in the middle and upper atmosphere 15. Lightning effects on the chemistry of the atmosphere 16. Extraterrestrial lightning 17. Lightning locating systems 18. Deleterious effects of lightning and protective techniques 19. Lightning hazards to humans and animals 20. Ball lightning, bead lightning, and other unusual discharges Appendix. books on lightning and related subjects Subjects Index.
1,715 citations
"Electric Field Variation in Clear a..." refers background in this paper
...A linear fit has been done between ground level and rooftop values of PG for clear weather conditions (MacGorman & Rust, 1998; Rakov & Uman, 2003), which yields a slope or correction factor of 0.51....
[...]
TL;DR: In this paper, the effect of the electrical field on charge separation during riming and the freezing potential of drops of rime was examined in cold room experiments simulating thunderstorm conditions.
Abstract: Riming electrification was studied in cold room experiments simulating thunderstorm conditions. When both ice crystals and supercooled droplets coexist in the experimental chamber, high electric charge occurs on the riming probes. Both the sign and magnitude of riming electrification are highly dependent on the temperature and cloud water content. Electric charge of the order of 10−4 esu (33 fC) is separated on riming with each ice crystal collision under conditions typical of the in-cloud environment of continental thunderstorms. This amount of charge is sufficient to produce the high electrification required for lightning discharge within reasonably short periods of time. The effect of the electrical field on charge separation during the riming and effect of the freezing potential of drops of rime also were examined. It appears that these effects play only a secondary role for charge separation in thunderstorms. Three different physical mechanisms of charge separation during riming are proposed...
826 citations
"Electric Field Variation in Clear a..." refers background in this paper
...Shower clouds and thunderstorms affect atmospheric PG values (MacGorman & Rust, 1998; Phillips & Kinzer, 1958; Reynolds et al., 1957; Saunders, 1993; Saunders & Peck, 1998; Takahashi, 1978)....
[...]
Book•
01 Jan 1998
TL;DR: In this article, the authors present an overview of the electrical properties of the Earth's atmosphere and discuss the effect of electricity on cloud microphysics, including electricity and magnetism.
Abstract: Tutorial: Basic Electricity and Magnetism 1. Overview of the Electrical Nature of the Earth's Atmosphere 2. Electrified Non-Thunderstorm Clouds 3. Introduction to the Electrical Nature of Thunderstorms 4. Corona and Point Discharge 5. Lightning 6. Instruments 7. Observations of the Electrical Characteristics of Thunderstorms, Part 1 8. Observations of the Electrical Characteristics of Thunderstorms, Part 2 9. Numerical Models of Thunderstorm Electrification 10. Electrical Effects on Cloud Microphysics
650 citations
"Electric Field Variation in Clear a..." refers background in this paper
...A linear fit has been done between ground level and rooftop values of PG for clear weather conditions (MacGorman & Rust, 1998; Rakov & Uman, 2003), which yields a slope or correction factor of 0.51....
[...]
...The thunderstorms and convective events act as charge separators and modify the local atmospheric electric field near the ground (MacGorman & Rust, 1998)....
[...]
...Shower clouds and thunderstorms affect atmospheric PG values (MacGorman & Rust, 1998; Phillips & Kinzer, 1958; Reynolds et al., 1957; Saunders, 1993; Saunders & Peck, 1998; Takahashi, 1978)....
[...]
TL;DR: In this article, the tripole structure of electrified clouds is summarized and the observed structure is quantitatively consistent with the results of laboratory simulations and suggests that collision between ice crystals and rimed graupel particles is the dominant mechanism for charge separation.
Abstract: Evidence for the tripole structure of electrified clouds is summarized. The observed structure is quantitatively consistent with the results of laboratory simulations and suggests that collision between ice crystals and rimed graupel particles is the dominant mechanism for charge separation in thunderstorms. The physical basis for this mechanism is poorly understood.
414 citations
"Electric Field Variation in Clear a..." refers background in this paper
...A thunderstorm has typically three charged regions, namely, upper positive, middle negative, and lower small positive (MacGorman et al., 2005; Williams, 1989), forming a tripolar structure in cloud that changes the normal PG values near ground (Maitra et al., 2014)....
[...]