Lightning detection with 3‐D discrimination of intracloud and cloud‐to‐ground discharges

Betz, Hans Dieter; Schmidt, Kersten; Oettinger, P.; Wirz, Men

doi:10.1029/2004gl019821

Cited by 140 publications

(116 citation statements)

References 15 publications

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“…VLF/LF systems, such as the operational Lightning Location Network (LINET) use refined antenna techniques, optimised waveform handling and shorter sensor base line of ∼100 km. Hence, they locate also low-current discharges (>1 kA) and discriminate IC and CG events (Betz et al, 2004). Betz et al (2007) find a large number of IC signals especially with low current values.…”

Section: Lightningmentioning

confidence: 99%

“…These systems report mainly strong (>5 kA) CG strokes (Cummins et al, 1998). Advanced VLF/LF measuring and signal processing techniques detect also IC flashes (Betz et al, 2004;Shao et al, 2006). VLF/LF systems, such as the operational Lightning Location Network (LINET) use refined antenna techniques, optimised waveform handling and shorter sensor base line of ∼100 km.…”

Section: Lightningmentioning

confidence: 99%

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The global lightning-induced nitrogen oxides source

2007

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Abstract. The knowledge of the lightning-induced nitrogen oxides (LNO x ) source is important for understanding and predicting the nitrogen oxides and ozone distributions in the troposphere and their trends, the oxidising capacity of the atmosphere, and the lifetime of trace gases destroyed by reactions with OH. This knowledge is further required for the assessment of other important NO x sources, in particular from aviation emissions, the stratosphere, and from surface sources, and for understanding the possible feedback between climate changes and lightning. This paper reviews more than 3 decades of research. The review includes laboratory studies as well as surface, airborne and satellite-based observations of lightning and of NO x and related species in the atmosphere. Relevant data available from measurements in regions with strong LNO x influence are identified, including recent observations at midlatitudes and over tropical continents where most lightning occurs. Various methods to model LNO x at cloud scales or globally are described. Previous estimates are re-evaluated using the global annual mean flash frequency of 44±5 s −1 reported from OTD satellite data. From the review, mainly of airborne measurements near thunderstorms and cloud-resolving models, we conclude that a "typical" thunderstorm flash produces 15 (2-40)×10 25 NO molecules per flash, equivalent to 250 mol NO x or 3.5 kg of N mass per flash with uncertainty factor from 0.13 to 2.7. Mainly as a result of global model studies for various LNO x parameterisations tested with related observations, the best estimate of the annual global LNO x nitrogen mass source and its uncertainty range is (5±3) Tg a −1 in this study. In spite of a smaller global flash rate, the best estimate is essentially the same as in some earlier reviews, implying larger flash-specific NO x emissions. The paper estimates the LNO x accuracy required for various applications and lays out strategies for improving estimates in the future. An accuracy of Correspondence to: U. Schumann (ulrich.schumann@dlr.de) about 1 Tg a −1 or 20%, as necessary in particular for understanding tropical tropospheric chemistry, is still a challenging goal.

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Section: Lightningmentioning

confidence: 99%

Section: Lightningmentioning

confidence: 99%

The global lightning-induced nitrogen oxides source

2007

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“…Two radars owned and operated by the Centre for Australian Weather and Climate Research (CAWCR) were used on this day: the Darwin Berrimah Doppler radar and the C-Band Polarimetric (CPOL) radar based near Gunn Point. A lightning detection network (LINET) (Betz et al, 2004(Betz et al, , 2007) of six stations was also established: Point Stuart, Cape Don, Pirlangimpi, Darwin, Dundee Beach, and Mount Bundy. Figure 1 provides the location of the radar and LINET stations.…”

Section: Observationsmentioning

confidence: 99%

Cloud-resolving chemistry simulation of a Hector thunderstorm

et al. 2013

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Cloud chemistry simulations were performed for a Hector thunderstorm observed on 16 November 2005 during the SCOUT-O3/ACTIVE campaigns based in Darwin, Australia, with the primary objective of estimating the average NO production per lightning flash in this unique storm type which occurred in a tropical island environment. The 3-D WRF-Aqueous Chemistry (WRF-AqChem) model is used for these calculations and contains the WRF nonhydrostatic cloud-resolving model with online gas- and aqueous-phase chemistry and a lightning-NO_x (LNO_x) production algorithm. The model was initialized by inducing convection with an idealized morning sounding and sensible heat source, and initial condition chemical profiles from merged aircraft observations in undisturbed air. Many features of the idealized model storm, such as storm size and peak radar reflectivity, were similar to the observed storm. Tracer species, such as CO, used to evaluate convective transport in the simulated storm found vertical motion from the boundary layer to the anvil region was well represented in the model, with a small overestimate of enhanced CO at anvil altitudes. The lightning detection network (LINET) provided lightning flash data for the model and a lightning placement scheme injected the resulting NO into the simulated cloud. A lightning NO production scenario of 500 moles flash⁻¹ for both CG and IC flashes yielded anvil NO_x mixing ratios that compared well with aircraft observations and were also similar to those deduced for several convective modeling analyses in the midlatitudes and subtropics. However, these NO production values were larger than most estimates for tropical thunderstorms and given several uncertainties, LNO_x production may have been as large as 600 moles flash⁻¹. Approximately 85% of the simulated LNO_x mass was located above 7 km in the later stages of the storm, which was greater than amounts found for subtropical and midlatitude convection. Modeled upper tropospheric NO₂ partial columns were also considerably greater than most satellite observations of tropical marine convective events, as tropical island convection, such as Hector, is more vigorous and more productive of LNO_x. Additional research is needed to investigate whether LNO_x production per flash increases in storms with greater wind shear, such as this Hector storm, which showed significant variation in wind direction with altitude

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“…[8] Cloud-to-ground stroke data are provided by LINET (Lightning Network), a low-frequency time-of-arrival network [Betz et al, 2004] that also detects certain processes inside the clouds and determines their corresponding altitude, polarity, and peak current.…”

Section: Lightning Detection Systemsmentioning

confidence: 99%

Asymmetries in bidirectional leader development of lightning flashes

Velde

Montanyà

2013

JGR Atmospheres

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Lightning flashes develop as a bidirectional tree, with a negative and a positive end propagating simultaneously into cloud charges of the opposite polarity. In recent years, this process has been modeled assuming that the bidirectional channel remains a zero‐net‐charge perfect conductor starting at the electric potential of its initial location. So far, both leader ends were treated identically. We summarize characteristics of bidirectional leader development of various lightning flashes registered by the Ebro 3‐D Lightning Mapping Array at the east coast of Spain, supplemented by high‐speed camera records. In order to follow the horizontal development of positive and negative leaders over time, a time‐distance‐altitude graph was designed, using the flash origin or a cloud‐to‐ground stroke as reference. The examples confirm that negative and positive leaders propagate at characteristic horizontal speeds (105 and 2 · 104 m s−1). The positive leader's low apparent speed corresponds to the phase when recoil processes are active. Very fast negative leaders (up to 8 · 105 m s−1) are detected in association with positive cloud‐to‐ground strokes. Negative leaders respawn repeatedly from the origin or as a retrograde negative leader at the positive branch. Positive leaders remain propagating throughout the flash or until reaching ground. We show that the velocity difference shifts the potential of the leader, increasing the gradient with cloud charge at the positive end while reducing it at the negative end. The positive section lowers its potential through retrograde negative leaders, eventually making it possible to emit a new negative leader into the upper positive potential well.

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Lightning detection with 3‐D discrimination of intracloud and cloud‐to‐ground discharges

Cited by 140 publications

References 15 publications

The global lightning-induced nitrogen oxides source

The global lightning-induced nitrogen oxides source

Cloud-resolving chemistry simulation of a Hector thunderstorm

Asymmetries in bidirectional leader development of lightning flashes

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