Electric Structure of Oceanic Tropical Clouds and Charge Separation Processes

Takahashi, Tsutomu

doi:10.2151/jmsj1965.61.4_656

Cited by 6 publications

(9 citation statements)

References 44 publications

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“…The K dp is insensitive to particles that appear spherical in bulk. Takahasi (1983) measured electric fields in tropical convection using balloon borne instruments and found a maximum of about 90 kV m 21 at an altitude around 8 km (MacGorman and Rust 1998). The vertically aligned ice results in the negative K dp and the larger ice particles yield the near-0 dB intrinsic Z dr .…”

Section: Discussionmentioning

confidence: 99%

Modeling and Interpretation of S-Band Ice Crystal Depolarization Signatures from Data Obtained by Simultaneously Transmitting Horizontally and Vertically Polarized Fields

Hubbert

Ellis

Chang

et al. 2014

Journal of Applied Meteorology and Climatology

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Data collected by the National Center for Atmospheric Research S-band polarimetric radar (S-Pol) during the Terrain-Influenced Monsoon Rainfall Experiment (TiMREX) in Taiwan are analyzed and used to infer storm microphysics in the ice phase of convective storms. Both simultaneous horizontal (H) and vertical (V) (SHV) transmit polarization data and fast-alternating H and V (FHV) transmit polarization data are used in the analysis. The SHV Z dr (differential reflectivity) data show radial stripes of biased data in the ice phase that are likely caused by aligned and canted ice crystals. Similar radial streaks in the linear depolarization ratio (LDR) are presented that are also biased by the same mechanism. Dual-Doppler synthesis and sounding data characterize the storm environment and support the inferences concerning the ice particle types. Small convective cells were observed to have both large positive and large negative K dp (specific differential phase) values. Negative K dp regions suggest that ice crystals are vertically aligned by electric fields. Since high jK dp j values of 0.88 km 21 in both negative and positive K dp regions in the ice phase are accompanied by Z dr values close to 0 dB, it is inferred that there are two types of ice crystals present: 1) smaller aligned ice crystals that cause the K dp signatures and 2) larger aggregates or graupel that cause the Z dr signatures. The inferences are supported with simulated ice particle scattering calculations. A radar scattering model is used to explain the anomalous radial streaks in SHV Z dr and LDR.

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Section: Discussionmentioning

confidence: 99%

Modeling and Interpretation of S-Band Ice Crystal Depolarization Signatures from Data Obtained by Simultaneously Transmitting Horizontally and Vertically Polarized Fields

Hubbert

Ellis

Chang

et al. 2014

Journal of Applied Meteorology and Climatology

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“…During a period of more than 40 years Takahashi has made a substantial number of measurements of charge on individual precipitation particles from balloons, as well as their size and composition (e.g. Takahashi 1965;1983). Takahashi (1978) describes a radiosonde package to measure the charge and phase of precipitation particles which consisted of an induction ring, with a roll of filter paper mounted beneath the ring.…”

Section: Measurements Of Droplet Chargementioning

confidence: 99%

“…Summary of commonly encountered problems when making airborne measurements of atmospheric electrical parameters, and their possible solutions Gerdien (1903Gerdien ( ,1904Gerdien ( ,1905aGerdien ( ,1905b Manned Byrne et al (1983Byrne et al ( , 1987Byrne et al ( , 1989 Free balloon E Corona probe Oklahoma, USA Takahashi (1983) Free balloon E and q Radioactive collector and induction cylinder Ponape, Micronesia Dye et al (1986Dye et al ( , 1989) Aircraft E and q Electric field mills and induction cylinder Montana and New Mexico, USA Marshall et al (1989Marshall et al ( , 1995a Stolzenberg et al (1994Stolzenberg et al ( , 1998aStolzenberg et al ( , 1998bStolzenberg et al ( , 1998cStolzenberg et al ( , 2007 Free balloon E Electric Field Meter (EFM) Oklahoma and New Mexico, USA Takahashi et al (1995 Free balloon q Induction cylinder with video sonde Ponape, Micronesia and Japan Bateman et al (1995Bateman et al ( , 1999a Free Table 5 …”

Section: Tablementioning

confidence: 99%

Measurements of Atmospheric Electricity Aloft

Nicoll

2012

Surv Geophys

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Measurements of the electrical characteristics of the atmosphere above the surface have been made for over 200 years, from a variety of different platforms, including kites, balloons, rockets and aircraft. From these measurements, a great deal of information about the electrical characteristics of the atmosphere has been gained, assisting our understanding of the global atmospheric electric circuit, thunderstorm electrification and lightning generation mechanisms, discovery of transient luminous events above thunderstorms, and many other electrical phenomena. This paper surveys the history of atmospheric electrical measurements aloft, from the earliest manned balloon ascents to current day observations with free balloons and aircraft. Measurements of atmospheric electrical parameters in a range of meteorological conditions are described, including clear air conditions, polluted conditions, non-thunderstorm clouds, and thunderstorm clouds, spanning a range of atmospheric conditions, from fair weather, to the most electrically active.2

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“…Controversy still exists as to whether tropical convection can become significantly electrified to produce lightning while warm rain processes dominate storm microphysics or whether mixed-phase microphysics (involving ice in the presence of supercooled water) is required (e.g., Vonnegut 1994). Several laboratory studies (e.g., Takahashi 1978a;Jayaratne at al. 1983;Saunders et al 1991; among others) of the noninductive charging (NIC) of graupel particles during rebounding collisions with ice crystals in the presence of supercooled cloud liquid water strongly support the latter argument.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, we explore the role of drop freezing in the production of significant graupel mass. As mentioned earlier, graupel is one of three key ingredients for the separation of charge via the NIC mechanism (e.g., Takahashi 1978a). The presence or absence of the other two key ingredients (supercooled cloud liquid water and cloud ice) are inferred indirectly from the vertical structure and temporal evolution of the precipitation field.…”

Section: Introductionmentioning

confidence: 99%

The Relationship between Precipitation and Lightning in Tropical Island Convection: A C-Band Polarimetric Radar Study

2000

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One of the primary scientific objectives of the Maritime Continent Thunderstorm Experiment was to study cloud electrification processes in tropical island convection, in particular, the coupling between ice phase precipitation and lightning production. To accomplish this goal, a C-band polarimetric radar was deployed in the Tropics (11.6ЊS, 130.8ЊE) for the first time, accompanied by a suite of lightning measurements. Using observations of the propagation-corrected horizontal reflectivity and differential reflectivity, along with specific differential phase, rain and ice masses were estimated during the entire life cycle of an electrically active tropical convective complex (known locally as Hector) over the Tiwi Islands on 28 November 1995. Hector's precipitation structure as inferred from these raw and derived radar fields was then compared in time and space to the measured surface electric field, cloud-to-ground (CG) and total lightning flash rates, and ground strike locations. During Hector's developing stage, precipitating convective cells along island sea breezes were dominated by warm rain processes. No significant electric fields or lightning were associated with this stage of Hector, despite substantial rainfall rates. Aided by gust front forcing, a cumulus merger process resulted in larger, taller, and more intense convective complexes that were dominated by mixed-phase precipitation processes. During the mature phase of Hector, lightning and the surface electric field were strongly correlated to the mixed phase ice mass and rainfall. Merged convective complexes produced 97% of the rainfall and mixed-phase ice mass and 100% of the CG lightning. As Hector dissipated, lightning activity rapidly ceased. As evidenced from the multiparameter radar observations, the multicell nature of Hector resulted in the continuous lofting of supercooled drops to temperatures between Ϫ10Њ and Ϫ20ЊC in discrete updraft cores during both the early and mature phases. The freezing of these drops provided instantaneous precipitation-sized ice particles that may have subsequently rimed and participated in thunderstorm electrification via the noninductive charging mechanism.

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Electric Structure of Oceanic Tropical Clouds and Charge Separation Processes

Abstract: The electric charge of precipitation particles was measured both at the ground and in the clouds at Ponape, Micronesia.

Cited by 6 publications

References 44 publications

Modeling and Interpretation of S-Band Ice Crystal Depolarization Signatures from Data Obtained by Simultaneously Transmitting Horizontally and Vertically Polarized Fields

Modeling and Interpretation of S-Band Ice Crystal Depolarization Signatures from Data Obtained by Simultaneously Transmitting Horizontally and Vertically Polarized Fields

Measurements of Atmospheric Electricity Aloft

The Relationship between Precipitation and Lightning in Tropical Island Convection: A C-Band Polarimetric Radar Study

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