A5009523378- Lightning and Electromagnetic Phenomena
- Fire effects on ecosystems
- Meteorological Phenomena and Simulations
- Ionosphere and magnetosphere dynamics
- Earthquake Detection and Analysis
- Atmospheric aerosols and clouds
- Solar and Space Plasma Dynamics
- Plant Water Relations and Carbon Dynamics
- Greenhouse Technology and Climate Control
- Advanced Optical Sensing Technologies
- Ocular and Laser Science Research
- Advanced Decision-Making Techniques
- Seismic Waves and Analysis
- Impact of Light on Environment and Health
- High voltage insulation and dielectric phenomena
- Power Line Communications and Noise
- Icing and De-icing Technologies
- Fire Detection and Safety Systems
- Laser-induced spectroscopy and plasma
- Magneto-Optical Properties and Applications
- Geophysics and Sensor Technology
- Complement system in diseases
- Aerosol Filtration and Electrostatic Precipitation
- Power Transformer Diagnostics and Insulation
- Data Quality and Management
University of Alabama in Huntsville
2007-2024
Silicon Austria Labs (Austria)
2021-2024
Geological Survey of Canada
2024
Humboldt-Universität zu Berlin
2010-2023
Charité - Universitätsmedizin Berlin
2017-2023
Freie Universität Berlin
2023
Heidelberg University
2017
Johannes Kepler University of Linz
2016
Technical University of Denmark
2011
University of Alabama
2007-2009
Detectors aboard the Compton Gamma Ray Observatory have observed an unexplained terrestrial phenomenon: brief, intense flashes of gamma rays. These must originate in atmosphere at altitudes above least 30 kilometers order to escape atmospheric absorption and reach orbiting detectors. At a dozen such events been detected over past 2 years. The photon spectra from are very hard (peaking high-energy portion spectrum) consistent with bremsstrahlung emission energetic (million—electron volt)...
Abstract The Atmosphere‐Space Interactions Monitor (ASIM) was launched to the International Space Station on 2 April 2018. ASIM payload consists of two main instruments, Modular X‐ray and Gamma‐ray Sensor (MXGS) for imaging spectral analysis Terrestrial Flashes (TGFs) Multi‐spectral Imaging Array detection, imaging, Transient Luminous Events lightning. is first space mission designed simultaneous observations Events, TGFs, optical During 10 months operation (2 June 2018 1 2019) MXGS has...
Lightning data from the U.S. National Detection Network (NLDN) are used to perform preliminary validation of satellite-based Optical Transient Detector (OTD). Sensor precision, accuracy, detection efficiency, and biases deployed instrument considered. The sensor is estimated have, on average, about 20–40-km spatial better than 100-ms temporal accuracy. efficiency for cloud-to-ground lightning 46%–69%. It most likely slightly higher intracloud lightning. There only marginal day/night in...
Two approaches are used to characterize how accurately the north Alabama Lightning Mapping Array (LMA) is able locate lightning VHF sources in space and time. The first method uses a Monte Carlo computer simulation estimate source retrieval errors. applies algorithm that was recently developed at NASA Marshall Space Flight Center (MSFC) similar, but not identical to, standard New Mexico Tech algorithm. second purely theoretical technique (i.e., chi-squared Curvature Matrix Theory) Both...
Abstract Flights through the central regions of thunderstorms were made over New Mexico on 6 and 15 August 1977 with ONR/NMIMT Schweitzer aeroplane which carried equipment designed to measure all three components electric field, charge, Q , diameter, d individual precipitation elements. On earlier day, information was also obtained with: a rain‐gauge network surrounding Langmuir Laboratory; 3 cm radar; an acoustic system for locating lightning channels; ground‐based field‐change meter. The...
We present the very first simultaneous detection from space of a terrestrial gamma ray flash (TGF) and optical signal lightning. By fortuitous coincidence, two independent satellites passed less than 300 km thunderstorm system that produced TGF lasted 70 μ s. Together with measurements radio emissions, we have an unprecedented coverage event. find was deep in thundercloud at initial stage intracloud (IC) lightning before leader reached cloud top extended horizontally. A strong pulse by...
Abstract Two wholly distinct studies involving TRMM‐satellite global data were conducted. One involved the relationship between lightning frequency f and brightness temperature, other ice‐water‐path. Both demonstrate that globally valid relationships exist thundercloud ice‐precipitation content, from which it follows graupel pellets play a crucial role in charging. Ground‐based field provide further support for this conclusion show is also strongly dependent upon ice crystal content. All...
Abstract This paper reports on a new generation of aircraft-based rotating-vane-style electric field mills designed and built at NASA’s Marshall Space Flight Center. The have individual microprocessors that digitize the signal mill respond to commands from data system computer. are very sensitive (1 V m−1 bit−1), wide dynamic range (115 dB), low noise (±1 LSB). Mounted an aircraft, these can measure fields ±1 ±500 kV m−1. Once-per-second commanding collection computer each allows for precise...
We demonstrate conversion from 64 × 10 Gbit/s optical timedivision multiplexed (OTDM) data to dense wavelength division (DWDM) with 25 GHz spacing.The is achieved by time-domain Fourier transformation (OFT) based on four-wave mixing (FWM) in a 3.6 mm long silicon nanowire.A total of 40 out tributaries OTDM-DPSK signal are simultaneously converted bit-error rate (BER) performance below the 2 -3 FEC limit.Using 50 m highly nonlinear fiber (HNLF) for higher FWM efficiency, 43 OTDM-OOK...
Purpose: The retinal pigment epithelium (RPE) is a main target for complement activation in age-related macular degeneration. anaphylatoxins C3a and C5a, have been thought to mostly play role as chemoattractants macrophages immune cells; here we explore whether they trigger RPE alterations. Specifically, investigated the potential immunoregulatory gate, allowing active changes microenvironment response complement. Design: vitro vivo analysis of signaling pathways. Methods: Individual...
Lightning has been observed from above cloud top by using satellites, balloons, rockets, and high-altitude airplanes, each of which provides a unique perspective holds the potential for gaining new understanding lightning phenomena. During 1980s extensive optical observations have made NASA U-2 airplane with goal toward placing sensor in geostationary orbit. Analysis these measurements suggest that most light generated within escapes, energy measured clouds is not significantly different...
A coordinated aircraft–radar project that investigated the electric fields, cloud microphysics, and radar reflectivity of thunderstorm anvils near Kennedy Space Center is described. Measurements from two cases illustrate extensive nature microphysics field observations. As aircraft flew edges into interior, fields very frequently increased abruptly ∼1 to >10 kV m 1 even though particle concentrations smoothly. The abrupt increase in usually occurred when entered regions with a 10–15 dBZ....
An instrumented free balloon measured electric fields and field changes as it rose through a thundercloud above Langmuir Laboratory, New Mexico. The variation of the with altitude implied that cloud contained negative space charge density −0.6 to −4 nC m −3 between 5.5 8.0 km MSL. environmental temperature at these levels ranged from −5° −20°C. Our measurements imply areal extent this center was significantly greater than cloud's intense precipitation shafts. At altitudes 8 km, instrument...
With its relatively low altitude (520 × 670 km) orbit, SAMPEX is mostly below the stable trapping region where charged particles repeatedly drift around Earth, especially at midlatitudes. Recent analyses of data have revealed a surprisingly common set observations enhanced energetic (>150 keV) electron fluxes L < 3, during times when was located such that any electrons it observed were in loss cone (and thus destined to be precipitated upon reaching longitude South Atlantic Magnetic...
The seismic shear wave velocity is the geophysical parameter which widely used by engineers to predict stability of sediments under dynamic load conditions.In particular, in earthquake engineering studies it estimate ground motion amplification and liquefaction potential unconsolidated response vibrations.In marine environment, assessment situ structure sea floor sediment layers far from straightforward.There are major logistical problems associated with deploying operating sources receivers...
In the fall of 1992 a lightning direction finder network was deployed in western Pacific Ocean area Papua New Guinea. Direction finders were installed on Kapingamarangi Atoll and near towns Rabaul Kavieng, The instruments modified to detect cloud-to-ground out distance 900 km. Data collected from flashes for period 26 November 1992–15 January 1994. analyses are presented 1 1993–31 December 1993. addition, waveform recorder located at Kavieng record both intracloud order provide an estimate...
The first storm‐scale, total lightning observations from space during tornadogenesis are presented. During the overpass of an Oklahoma supercell, just minutes prior to tornado touchdown on 17 April 1995, NASA (National Aeronautics and Space Administration) OTD (Optical Transient Detector) detected a 143 flashes approximately 3 observation time. estimated flash rate ranges 45 (raw counts) 78 (corrected for detection efficiency) min −1 . This was at least times greater than cloud‐to‐ground by...
Abstract Two gamma‐ray glows were observed by a high‐altitude NASA ER‐2 aircraft flying at 20 km altitude over thunderstorm in Colorado, USA. The flux of the first glow rapidly intensified and then abruptly decreased within few tens milliseconds. On timescale seconds, decrease occurred simultaneously with hybrid intra‐cloud/cloud‐to‐ground lightning discharge beneath aircraft. However, more detailed analysis dynamics indicated that activity was unusually calm during actual period decrease....