A parameterization of Long-Continuing-Current (LCC) lightning in the lightning submodel LNOX (version 3.0) of the Modular Earth Submodel System (MESSy, version 2.54)

Abstract. Lightning flashes can produce a discharge in which a continuing electrical current flows for more than 40 ms. This type of flashes are proposed to be the main precursors of lightning-ignited wildfires and also to trigger sprite discharges in the mesosphere. However, lightning parameterizations implemented in global atmospheric models do not include information about the continuing electrical current of flashes. The continuing current of lightning flashes cannot be detected by conventional lightning location systems. Instead, these so-called Long-Continuing-Current (LCC) flashes are commonly observed by Extreme Low Frequency (ELF) sensors and by optical instruments located in space. Previous reports of LCC lightning flashes tend to occur in winter and oceanic thunderstorms, which suggests a connection between weak convection and the occurrence of this type of discharge. In this study, we develop a parameterization of LCC lightning flashes based on a climatology derived from optical lightning measurements reported by the Lightning Imaging Sensor (LIS) on-board the International Space Station (ISS) between March 2017 and March 2020. We use meteorological data from reanalyses to find a global parameterization that uses the vertical velocity at 450 hPa pressure level as a proxy for the ratio of LCC to typical lightning in thunderstorms. We implement this parameterization into the LNOX submodel of the Modular Earth Submodel System (MESSy) for usage within the EMAC model, and compare the observed and the simulated climatologies of LCC lightning flashes using six different lightning parameterizations. We find that the best agreement between the simulated and the observed spatial distribution is obtained when using a novel combined lightning parameterization based on the cloud top height over land and on the convective precipitation over ocean.

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Concurrent satellite and ground-based lightning observations from the Optical Lightning Imaging Sensor (ISS-LIS), the low-frequency network Meteorage and the SAETTA Lightning Mapping Array (LMA) in the northwestern Mediterranean region

Atmospheric Measurement Techniques ◽

10.5194/amt-13-853-2020 ◽

2020 ◽

Vol 13 (2) ◽

pp. 853-875 ◽

Cited By ~ 4

Author(s):

Felix Erdmann ◽

Eric Defer ◽

Olivier Caumont ◽

Richard J. Blakeslee ◽

Stéphane Pédeboy ◽

...

Keyword(s):

Mediterranean Sea ◽

Detection Efficiency ◽

Space Station ◽

Low Frequency ◽

Integration Time ◽

Very High Frequency ◽

Pixel Resolution ◽

Mapping Array ◽

Imaging Sensor ◽

Northwestern Mediterranean

Abstract. The new space-based Lightning Imager (LI) onboard the Meteosat Third Generation (MTG) geostationary satellite will improve the observation of lightning over Europe, the Mediterranean Sea, Africa and the Atlantic Ocean from 2021 onwards. In preparation for the use of the upcoming MTG-LI data, we compare observations by the Lightning Imaging Sensor (LIS) on the International Space Station (ISS), which applies an optical technique similar to MTG-LI, to concurrent records of the low-frequency (LF) ground-based network Meteorage. Data were analyzed over the northwestern Mediterranean Sea from 1 March 2017 to 20 March 2018. Flashes are detected by ISS-LIS using illuminated pixels, also called events, within a given (2.0 ms) frame and during successive frames. Meteorage describes flashes as a suite of intra-cloud and cloud-to-cloud (IC) pulses and/or cloud-to-ground (CG) strokes. Both events as well as pulses and strokes are grouped to flashes using a novel in-house algorithm. In our study, ISS-LIS detects about 57 % of the flashes detected by Meteorage. The flash detection efficiency (DE) of Meteorage relative to ISS-LIS exceeds 80 %. Coincident matched flashes detected by the two instruments show a good spatial and temporal agreement. Both peak and mean distances between matches are smaller than the ISS-LIS pixel resolution (about 5.0 km). The timing offset for matched ISS-LIS and Meteorage flashes is usually shorter than the ISS-LIS integration time frame (2.0 ms). The closest events and the pulses and strokes of matched flashes achieve sub-millisecond offsets. Further analysis of flash characteristics reveals that longer-lasting and more spatially extended flashes are more likely detected by both ISS-LIS and Meteorage than shorter-duration and smaller-extent flashes. The ISS-LIS relative DE is lower for daytime versus nighttime as well as for CG versus IC flashes. A second ground-based network, the very high-frequency (VHF) SAETTA Lightning Mapping Array (LMA), further enhances and validates the lightning pairing between ISS-LIS and Meteorage. It also provides altitude information on the lightning discharges and adds a detailed lightning mapping to the comparison for verification and better understanding of the processes. Both ISS-LIS and Meteorage flash detections feature a high degree of correlation with the SAETTA observations (without altitude information). In addition, Meteorage flashes with ISS-LIS match tend to be associated with discharges that occur at significantly higher altitudes than unmatched flashes. Hence, ISS-LIS flash detection suffers from degradation, with low-level flashes resulting in lower DE.

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Concurrent Satellite and ground-based Lightning Observations from the Optical Lightning Imaging Sensor (ISS-LIS), the LF network Meteorage and the SAETTA LMA in the northwestern Mediterranean region

10.5194/amt-2019-149 ◽

2019 ◽

Author(s):

Felix Erdmann ◽

Eric Defer ◽

Olivier Caumont ◽

Richard J. Blakeslee ◽

Stéphane Pédeboy ◽

...

Keyword(s):

Mediterranean Sea ◽

Detection Efficiency ◽

Space Station ◽

Low Frequency ◽

Time Frame ◽

Integration Time ◽

Very High Frequency ◽

Pixel Resolution ◽

Imaging Sensor ◽

Northwestern Mediterranean

Abstract. The new space-based Lightning Imager (LI) on board the Meteosat Third Generation (MTG) geostationary satellite will improve the observation of lightning over Europe, the Mediterranean Sea, Africa and the Atlantic Ocean from 2021 onwards. In preparation of the use of the upcoming MTG-LI data, we compare observations by the Lightning Imaging Sensor (LIS) on the International Space Station (ISS), which applies an optical technique similar to MTG-LI, to concurrent records of the Low Frequency (LF) ground-based network Meteorage. Data were analyzed over the northwestern Mediterranean Sea from March 01, 2017 to March 20, 2018. Flashes are detected by ISS-LIS using illuminated pixels, also called events, within a given (2.0 ms) frame and during successive frames. Meteorage describes flashes as a suite of Intra-Cloud/cloud-to-cloud (IC) pulses and/or Cloud-to-Ground (CG) strokes. Both events and pulses/strokes are grouped to flashes using a novel in-house algorithm. In our study, ISS-LIS detects about 57 % of the flashes detected by Meteorage. The flash detection efficiency (DE) of Meteorage relative to ISS-LIS exceeds 80 %. Coincident matched flashes detected by the two instruments show a good spatial and temporal agreement. Both peak and mean distance between matches are smaller than the ISS-LIS pixel resolution (about 5.0 km). The timing offset for matched ISS-LIS and Meteorage flashes is usually shorter than the ISS-LIS integration time frame (2.0 ms). The closest events and pulses/strokes of matched flashes achieve sub-millisecond offsets. Further analysis of flash characteristics reveals that longer lasting and more spatially extended flashes are more likely detected by both ISS-LIS and Meteorage than shorter duration and smaller extent flashes. ISS-LIS' relative DE is lower for daytime versus nighttime as well as for CG versus IC flashes. A second ground-based network, the Very High Frequency (VHF) SAETTA Lightning Mapping Array (LMA), further enhances and validates the lightning pairing between ISS-LIS and Meteorage. It also provides altitude information of the lightning discharges and adds a detailed lightning mapping to the comparison for verification and better understanding of the processes. Both ISS-LIS and Meteorage flash detections feature a high degree of correlation with the SAETTA observations (without altitude information). In addition, Meteorage flashes with ISS-LIS match tend to be associated with discharges that occur at significantly higher altitudes than unmatched flashes. Hence, ISS-LIS flash detection suffers degradation with low-level flashes resulting in lower DE.

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Integration of Multi-geophysical Approaches to Identify Potential Pathways of Heavy Metals Contamination - A Case Study in Zeida, Morocco

Journal of Environmental and Engineering Geophysics ◽

10.32389/jeeg9-067 ◽

2020 ◽

Vol 25 (3) ◽

pp. 415-423

Author(s):

Ahmed Lachhab ◽

El Mehdi Benyassine ◽

Mohamed Rouai ◽

Abdelilah Dekayir ◽

Jean C. Parisot ◽

...

Keyword(s):

Heavy Metals ◽

Seismic Velocity ◽

Seismic Refraction ◽

Geophysical Methods ◽

Low Frequency ◽

Electrical Current ◽

P Wave ◽

Low Resistivity ◽

Refraction Tomography ◽

Geophysical Surveys

The tailings of Zeida's abandoned mine are found near the city of Midelt, in the middle of the high Moulouya watershed between the Middle and the High Atlas of Morocco. The tailings occupy an area of about 100 ha and are stored either in large mining pit lakes with clay-marl substratum or directly on a heavily fractured granite bedrock. The high contents of lead and arsenic in these tailings have transformed them into sources of pollution that disperse by wind, runoff, and seepage to the aquifer through faults and fractures. In this work, the main goal is to identify the pathways of contaminated water with heavy metals and arsenic to the local aquifers, water ponds, and Moulouya River. For this reason, geophysical surveys including electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and very low-frequency electromagnetic (VLF-EM) methods were carried out over the tailings, and directly on the substratum outside the tailings. The result obtained from combining these methods has shown that pollutants were funneled through fractures, faults, and subsurface paleochannels and contaminated the hydrological system connecting groundwater, ponds, and the river. The ERT profiles have successfully shown the location of fractures, some of which extend throughout the upper formation to depths reaching the granite. The ERT was not successful in identifying fractures directly beneath the tailings due to their low resistivity which inhibits electrical current from propagating deeper. The seismic refraction surveys have provided valuable details on the local geology, and clearly identified the thickness of the tailings and explicitly marked the boundary between the Triassic formation and the granite. It also aided in the identification of paleochannels. The tailings materials were easily identified by both their low resistivity and low P-wave velocity values. Also, both resistivity and seismic velocity values rapidly increased beneath the tailings due to the compaction of the material and lack of moisture and have proven to be effective in identifying the upper limit of the granite. Faults were found to lie along the bottom of paleochannels, which suggest that the locations of these channels were caused by these same faults. The VLF-EM surveys have shown tilt angle anomalies over fractured areas which were also evinced by low resistivity area in ERT profiles. Finally, this study showed that the three geophysical methods were complementary and in good agreement in revealing the pathways of contamination from the tailings to the local aquifer, nearby ponds and Moulouya River.

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Nonlinear impedance of mineral‐electrolyte interfaces: Part II. Galena, Chalcopyrite, and Graphite

Geophysics ◽

10.1190/1.1440890 ◽

1978 ◽

Vol 43 (6) ◽

pp. 1235-1249 ◽

Cited By ~ 8

Author(s):

J. D. Klein ◽

R. T. Shuey

Keyword(s):

Low Frequency ◽

Reference Electrode ◽

Drill Hole ◽

Hydrogen Gas ◽

Mineral Dissolution ◽

Nonlinear Phenomena ◽

Reaction Products ◽

Single Interface ◽

Current Flows ◽

Anodic Reactions

The impedance of the interface between an acidic electrolyte and monomineralic, polished electrodes of galena, graphite, and chalcopyrite has been investigated at current densities in the nonlinear range (up to [Formula: see text]). The potential across a single interface relative to a reference electrode was measured in response to a current sinusoid of low frequency, 0.002 Hz. Polarization curves, or linear plots of current density versus electrode potential, consisted of distorted Lissajous patterns. Onset of a new electrochemical reaction resulted in a decrease in impedance of the interface, and hence increase in slope of the polarization curve. For some reactions, the electrical characteristics were diagnostic of bulk mineral composition. Diagnostic reactions include (1) mineral dissolution and gas evolution reactions at extreme anodic and cathodic potentials, (2) reactions at intermediate potentials which involve reaction products from previous reactions. Response is thus dependent on previous reactions and therefore on sample history. Anodic reactions were generally independent of pH, and consisted primarily of mineral dissolution reactions. Potentials of cathodic reactions increased with increasing pH indicating the involvement of [Formula: see text] as demonstrated by the evolution of hydrogen gas and/or [Formula: see text] gas. The potentials of the main graphite reactions were larger in magnitude than any of the sulfide reaction potentials. Measurements with polymineralic electrodes indicate that current flows mainly through minerals with reactions at less extreme potentials and consequently reactions involving other minerals at higher potential do not occur. Due to its more extreme reaction potentials, graphite does not respond in the presence of sulfide minerals. It appears that nonlinear phenomena could be used for mineral discrimination in drill hole logging.

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Three years of the Lightning Imaging Sensor onboard the International Space Station: Expanded Global Coverage and Enhanced Applications

10.1002/essoar.10502896.3 ◽

2020 ◽

Author(s):

Timothy J Lang ◽

Richard Blakeslee ◽

William J. Koshak ◽

Dennis E. Buechler ◽

Patrick Gatlin ◽

...

Keyword(s):

International Space Station ◽

Space Station ◽

International Space ◽

Global Coverage ◽

Imaging Sensor

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Cellular pathways of the conducted electrical response in arterioles of hamster cheek pouch in vitro

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1995.269.6.h2031 ◽

1995 ◽

Vol 269 (6) ◽

pp. H2031-H2038 ◽

Cited By ~ 44

Author(s):

J. Xia ◽

T. L. Little ◽

B. R. Duling

Keyword(s):

Electrical Response ◽

Electrical Current ◽

Cell Types ◽

Cheek Pouch ◽

Resting Membrane Potential ◽

Hamster Cheek Pouch ◽

Cellular Pathways ◽

Current Flows ◽

Electrical Responses

We have previously shown that conducted vasomotor responses follow patterns that are consistent with a passive spread of electrical current along the length of the arterioles [(Xia and Duling, Am. J. Physiol. 269 (Heart Circ. Physiol. 38): H2022-H2030, 1995]. In this study, we define the cells through which the current flows. Isolated arterioles of hamster cheek pouch were used. The mean resting membrane potential (RMP) for randomly sampled arteriolar cells was -67 mV. When cell types were identified by dye injection, the RMPs were -68 and -67 mV for smooth muscle (SM) and endothelium (EC), respectively. Pulses of KCl induced transient, monophasic depolarizations at the site of stimulation (local), which were conducted decrementally along the length of the arteriole over several millimeters. During electrical conduction, three patterns of responses could be observed, but identical patterns of the conducted electrical responses were always observed in SM and EC. Phenylephrine stimulation also caused transient local and conducted depolarizations in both SM and EC. As with KCl stimuli, shapes of conducted electrical responses were identical in records made in both cell types. The results suggest that SM and EC are electrically coupled both homocellularly and heterocellularly.

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Output Power Correlation Between Nearby Wind Power Plants

ASME 2003 Wind Energy Symposium ◽

10.1115/wind2003-1342 ◽

2003 ◽

Author(s):

Yih-Huei Wan ◽

Michael Milligan ◽

Brian Parsons

Keyword(s):

Power Plant ◽

Wind Power ◽

Power Output ◽

High Frequency ◽

Power Plants ◽

Meteorological Data ◽

Low Frequency ◽

Spatial Separation ◽

Wind Power Plant ◽

Wind Power Plants

The National Renewable Energy Laboratory (NREL) started a project in 2000 to record long-term, high-frequency (1-Hz) wind power output data from large commercial wind power plants. Outputs from about 330 MW of wind generating capacity from wind power plants in Buffalo Ridge, Minnesota, and Storm Lake, Iowa, are being recorded. Analysis of the collected data shows that although very short-term wind power fluctuations are stochastic, the persistent nature of wind and the large number of turbines in a wind power plant tend to limit the magnitudes and rates of changes in the levels of wind power. Analyses of power data confirm that spatial separation greatly reduces variations in the combined wind power output relative to output from a single wind power plant. Data show that high frequency variations of wind power from two wind power plants 200 km apart are independent of each other, but low frequency power changes can be highly correlated. This fact suggests that time-synchronized power data and meteorological data can aid in the development of statistical models for wind power forecasting.

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Gyro Rock Crusher and Asphalt Plant Sound Power Levels

ASME 2012 Noise Control and Acoustics Division Conference ◽

10.1115/ncad2012-1502 ◽

2012 ◽

Author(s):

Henry A. Scarton ◽

Kyle R. Wilt

Keyword(s):

Sound Pressure Level ◽

Sound Pressure ◽

Low Frequency ◽

Pressure Level ◽

Sound Power ◽

Far Field ◽

Atmospheric Attenuation ◽

Frequency Sound ◽

Sound Pressure Levels ◽

Rock Crusher

Sound power levels including the distribution into octaves from a large 149 kW (200 horsepower) gyro rock crusher and separate asphalt plant are presented. These NIST-traceable data are needed for estimating sound pressure levels at large distances (such as occurs on adjoining property to a quarry) where atmospheric attenuation may be significant for the higher frequencies. Included are examples of the computed A-weighted sound pressure levels at a distance from the source, including atmospheric attenuation. Substantial low-frequency sound power levels are noted which are greatly reduced in the far-field A-weighted sound pressure level calculations.

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