AGU journal highlights -- Sept. 3, 2008(ference gives rise to the global electri...)

Date:9/3/2008

ference gives rise to the global electric circuit (GEC) through the presence of electrical generators in the atmospherethunderstorms, shower clouds, dust storms, and snowstorms. Important contributors to the GEC are cloud-to-ground (CG) and intracloud lightning flashes. CG flash charges are quickly distributed over the surface and thereby contribute to the Earth's total charge and to charging or discharging of the GEC. After this fast process, a slow transient stage occurs, caused by redistribution of charge in the atmosphere. Noting that contributions of transient currents to the GEC are poorly understood, Mareev et al. use a numerical model of the transient electric field due to CG and intracloud flashes. They find that because the slow transients counteract the flashes, only a portion of the charge neutralized by a flash contributes to the GEC, with efficiency depending on the altitudes of the lightning charges.

Title: On the role of transient currents in the global electric circuit

Authors: E. A. Mareev, S. A. Yashunin, and S. S. Davydenko: Institute of Applied Physics, Russian Academy of Science, Nizhny Novgorod, Russia;

T. C. Marshall, M. Stolzenburg, and C. R. Maggio: Department of Physics and Astronomy, University of Mississippi, University, Mississippi, U.S.A.;

Source: Geophysical Research Letters (GRL) paper 10.1029/2008GL034554, 2008; http://dx.doi.org/10.1029/2008GL034554

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6. Meteor-produced ionization influences radio propagation

Radio communication relies on a region within the ionosphere (the F region, between 250 and 350 kilometers (160-220 miles) in altitude) that reflects and refracts radio waves so that long-distance communication can be achieved. However, at lower altitudes (in the ionosphere's E region, between 90 and 160 km (56-99 mi), small pockets of unusually ionized gas can also reflect radio waves, intermitten
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Contact: Peter Weiss pweiss@agu.org 202-777-7507 American Geophysical Union Source:Eurekalert

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