نتایج جستجو برای: they produce lightning

تعداد نتایج: 1269572  

Journal: :Chemosphere 2002
V Grewe C Reithmeier D T Shindell

The importance of the interaction between chemistry and dynamics in the upper troposphere and lower stratosphere for chemical species like ozone is investigated using two chemistry-climate models and a Lagrangian trajectory model. Air parcels from the upper troposphere, i.e. regions of lightning and aircraft emissions, are able to be transported into the lowermost stratosphere (LMS). Trajectory...

2003
Odim Mendes Margarete O. Domingues Elbert E. N. Macau Ana Paula dos Santos Novaes José dos Campos

Several objects in the Nature present non-regular random shapes, irregular trajectories, complex dynamics, or are randomly scattered in space. Lightning flashes are considered in this category. In this work some fractal analysis techniques and geometrical statistic methods were chosen and presented to be applied in specific features of lightning. The results were interpreted trying to relate th...

2015
Steven A. Cummer Fanchao Lyu Michael S. Briggs Gerard Fitzpatrick Oliver J. Roberts Joseph R. Dwyer

Radio emissions continue to provide insight into the production of terrestrial gamma ray flashes (TGFs) by thunderstorms, including the critical question of the conditions under which they are generated. We have identified several TGF-associated lightning radio emissions in which the altitudes of in-cloud lightning leader pulses that precede and follow the TGF can be measured. We combine these ...

2003
K. Michimoto T. Shimura T. Suzuki T. Hanada

For about a century, studies concerning summer thunderstorms in the middle latitude zone have elucidated data on both their meteorological and electrical features. By contrast, winter thunderstorms have been studied only for the last few decades. For both reasons of scientific interest and the practical purpose of preventing serious damage by winter thunderbolts to aircrafts and electric power ...

2015

1 Comment: In the paper the terms strokes and lightning are somewhat confused. The authors consider all analysis performed in the paper using the strokes of the LINET network. At the same time they refer and compare their results with works using lightning. Some grouping of the strokes must be performed to compare the results of this paper with findings in other works (see for example Yair et a...

2008
Markus Heber

Photogrammetric survey of lightning discharges is a very challenging task as lightning discharges are very transient, unpredictable, and random structures. In order to acquire images of lightning discharges outdoors, a stereo image acquisition system has been designed and implemented. Two cameras observe a limited area and autonomously detect occurrences of lightning discharges within their fie...

2017
M. Füllekrug C. Price E. R. Williams

The electrodynamic properties of intense oceanic lightning discharges are compared to intense continental lightning discharges. Particularly intense negative lightning discharges with absolute charge moments > 2 kC·km occur more often over the oceans than over the continents during April 1998. Intense continental lightning discharges, with negative and positive polarity, and intense positive oc...

2001
M. Füllekrug E. R. Williams

The electrodynamic properties of intense oceanic lightning discharges are compared to intense continental lightning discharges. Particularly intense negative lightning discharges with absolute charge moments > 2 kC·km occur more often over the oceans than over the continents during April 1998. Intense continental lightning discharges, with negative and positive polarity, and intense positive oc...

2007
Christina P. Kalb Steven Robinson Steven A. Rutledge Richard H. Johnson Ian Baker

The majority of cloud-to-ground (CG) lightning across the United States lowers negative charge to the ground. However, recent studies have documented storms that produce an abundance of positive CG lightning. These positive storms have been shown to occur in different mesoscale regions on the same days, and in different thermodynamic environments. This study uses radar data, and CG lightning da...

1998
John Latham

The maximum measured electric fields in thunderclouds are an order of magnitude less than the fields required for electric breakdown of the air. One explanation for lightning initiation in these low fields is that electric breakdown first occurs at the surfaces of raindrops where the ambient field is enhanced very locally due to the drop geometry . Laboratory experiments [Crabb & Latham, 1974] ...

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