Method and apparatus for determining return stroke polarity of distant lightning

A method is described for determining the return stroke polarity of distant lightning for distances beyond 600 km by detecting the electric field associated with a return stroke of distant lightning, and processing the electric field signal to determine the polarity of the slow tail of the VLF waveform signal associated with the detected electric field. The polarity of the return stroke of distant lightning is determined based upon the polarity of the slow tail portion of the waveform

Lightning Imaging Sensor (LIS) for the Earth Observing System

Not only are scientific objectives and instrument characteristics given of a calibrated optical LIS for the EOS but also for the Tropical Rainfall Measuring Mission (TRMM) which was designed to acquire and study the distribution and variability of total lightning on a global basis. The LIS can be traced to a lightning mapper sensor planned for flight on the GOES meteorological satellites. The LIS consists of a staring imager optimized to detect and locate lightning. The LIS will detect and locate lightning with storm scale resolution (i.e., 5 to 10 km) over a large region of the Earth's surface along the orbital track of the satellite, mark the time of occurrence of the lightning, and measure the radiant energy. The LIS will have a nearly uniform 90 pct. detection efficiency within the area viewed by the sensor, and will detect intracloud and cloud-to-ground discharges during day and night conditions. Also, the LIS will monitor individual storms and storm systems long enough to obtain a measure of the lightning flashing rate when they are within the field of view of the LIS. The LIS attributes include low cost, low weight and power, low data rate, and important science. The LIS will study the hydrological cycle, general circulation and sea surface temperature variations, along with examinations of the electrical coupling of thunderstorms with the ionosphere and magnetosphere, and observations and modeling of the global electric circuit

Simulating CCD images of elliptical galaxies

We introduce a procedure developed by the ``Teramo Stellar Populations Tools'' group (Teramo-SPoT), specifically optimized to obtain realistic simulations of CCD images of elliptical galaxies. Particular attention is devoted to include the Surface Brightness Fluctuation (SBF) signal observed in ellipticals and to simulate the Globular Cluster (GC) system in the galaxy, and the distribution of background galaxies present in real CCD frames. In addition to the physical properties of the simulated objects - galaxy distance and brightness profile, luminosity function of GC and background galaxies, etc. - the tool presented allows the user to set some of the main instrumental properties - FoV, zero point magnitude, exposure time, etc.Comment: Presented at From Stars to Galaxies: Building the Pieces to Build up the Universe (StarGal 2006), Venice, Italy, 16-20 Oct 200

Maxwell currents beneath thunderstorms

Analyses of single station measurements of the Maxwell current density (Jm) made under Florida thunderstorms during the summer of 1981 have been completed. The results of these analyses indicate that: (1) Jm is usually dominated by the displacement current component when the electric field is close to zero; (2) Jm is steady with time in the intervals between lightning flashes; (3) Jm is not altered significantly by lightning; and (4) the average value of Jm changes slowly and over time scales that are comparable to those required for storm development. Maps have also been derived of the surface Maxwell current density for a number of the Florida TRIP (76-78) storms using field mill data to estimate Jm from the displacement current density. Studies show that these maps provide a good indication of the location and relative intensity of the storm current generators, and area-integrations of the current contours provide estimates of the total storm currents

Lightning Imaging Sensor on International Space Station

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