The Relationship Between Cloud-to-Ground Lightning and Precipitations Ice Mass: A Radar study over Houston

2006 ◽  
Author(s):  
Michael L. Gauthier ◽  
Walter A. Petersen ◽  
Lawrence D. Carey ◽  
Jr. Christian ◽  
Hugh J.
1995 ◽  
Vol 22 (19) ◽  
pp. 2613-2616 ◽  
Author(s):  
Vladislav Mazur ◽  
Lothar H. Ruhnke ◽  
Pierre Laroche

Author(s):  
Chin-Leong Wooi ◽  
Zulkurnain Abdul-Malek ◽  
Noor Azlinda Ahmad ◽  
Mehrdad Mokhtari ◽  
Behnam Salimi

<p>This aim of this paper is to study the preliminary breakdown pulses (PBP) of positive cloud-to-ground (+CG) lightning flashes in Malaysia. There is a difference in PBP characteristics when a comparison is made between positive and negative flashes. To the best of the authors’ knowledge, this is the first time the PBP characteristics preceding positive lightning in Malaysia are reported. This study was carried out in Johor Bahru, Malaysia using a broadband antenna system during a monsoon period (Oct-Dec, 2012). It is found that the PBP for +CG lightning is much more complicated compared to the positive cloud-to-ground (–CG) lightning since only negative PBP trains are usually present in the –CG lightning.  Out of 21 analyzed positive flashes, four types of PBP trains were identified according to their initial polarities. These are negative PBP (20%), positive PBP (15%), PBP with polarity reversal (10%), and PBP with irregular polarity (15%). The balance 40% of flashes are without any PBP. The effect of geographical region may also cause the observed differences in the cloud discharge processes including the types of PBP. More studies are needed to determine the relationship between the return stroke and PBP.</p>


Author(s):  
Chin-Leong Wooi ◽  
Zulkurnain Abdul-Malek ◽  
Noor Azlinda Ahmad ◽  
Mehrdad Mokhtari ◽  
Behnam Salimi

<p>This aim of this paper is to study the preliminary breakdown pulses (PBP) of positive cloud-to-ground (+CG) lightning flashes in Malaysia. There is a difference in PBP characteristics when a comparison is made between positive and negative flashes. To the best of the authors’ knowledge, this is the first time the PBP characteristics preceding positive lightning in Malaysia are reported. This study was carried out in Johor Bahru, Malaysia using a broadband antenna system during a monsoon period (Oct-Dec, 2012). It is found that the PBP for +CG lightning is much more complicated compared to the positive cloud-to-ground (–CG) lightning since only negative PBP trains are usually present in the –CG lightning.  Out of 21 analyzed positive flashes, four types of PBP trains were identified according to their initial polarities. These are negative PBP (20%), positive PBP (15%), PBP with polarity reversal (10%), and PBP with irregular polarity (15%). The balance 40% of flashes are without any PBP. The effect of geographical region may also cause the observed differences in the cloud discharge processes including the types of PBP. More studies are needed to determine the relationship between the return stroke and PBP.</p>


1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.


Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.


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