by neufer » Thu Jun 15, 2017 3:32 pm
https://en.wikipedia.org/wiki/Johann_Georg_Estor wrote:
<<Johann Georg Estor (6 June 1699 – 25 October 1773), was a German theorist of public law, historian and book collector. In the second volume of his "neue kleine Schriften" there is a little note, in which Estor says that he had explored the landscapes of Hessen-Darmstadt on horseback or walking to accomplish a book about the national geography of this county. This was in the years around 1730. His teachers Verdrieß and Johann Jakob Scheuchzer had given him a hint, to make observations "coelo tristi" (in a sad sky). So, following this hint, he one day went uphill one of the highest mountains in the Vogelsberg near Burgharts, called "the saddle", through a thundercloud. In the middle of the cloud he felt little water droplets on his skin like dew.
And as he had reached the top of the mountain, he saw the blue sky above him and the cloud beneath like a white sea, from which flashes mounted as well directly up into the sky and shot down to the earth.>>
https://en.wikipedia.org/wiki/Sprite_(lightning) wrote:
<<Sprites are large-scale electrical discharges that occur high above thunderstorm clouds, or cumulonimbus, giving rise to a quite varied range of visual shapes flickering in the night sky. They are triggered by the discharges of positive lightning between an underlying thundercloud and the ground.
Sprites appear as luminous reddish-orange flashes. They often occur in clusters within atmosphere above the troposphere at an altitude range of 50–90 km. Sporadic visual reports of sprites go back at least to 1886, but they were first photographed on July 6, 1989 by scientists from the University of Minnesota and have subsequently been captured in video recordings many thousands of times.
Sprites are sometimes inaccurately called upper-atmospheric lightning.
However, sprites are cold plasma phenomena that lack the hot channel temperatures of tropospheric lightning, so they are more akin to fluorescent tube discharges than to lightning discharges.>>
https://en.wikipedia.org/wiki/Lightning#Positive_lightning wrote:
<<Most cloud-to-ground (CG) lightning is negative, meaning the ground is more positive. Large bolts of lightning can carry up to 120 kA and 350 coulombs (2.2 ×10
21 protons).
Unlike the far more common "negative" lightning, positive lightning originates from the positively charged top of the clouds (generally anvil clouds) rather than the lower portion of the storm. Leaders form in the anvil of the cumulonimbus and may travel horizontally for several kilometers before veering towards the ground. A positive lightning bolt can strike anywhere within several kilometers of the anvil of the thunderstorm, often in areas experiencing clear or only slightly cloudy skies; they are also known as "bolts from the blue" for this reason. Positive lightning typically makes up less than 5% of all lightning strikes.
Because of the much greater distance to ground, the positively charged region can develop considerably larger levels of charge and voltages than the negative charge regions in the lower part of the cloud. Positive lightning bolts are considerably hotter and longer than negative lightning. They can develop six to ten times the amount of charge and voltage of a negative bolt and the discharge current may last ten times longer. The potential at the top of the cloud may exceed a billion volts — about 10 times that of negative lightning. During a positive lightning strike, huge quantities of extremely low frequency (ELF) and very low frequency (VLF) radio waves are generated. As a result of their greater power, as well as lack of warning, positive lightning strikes are considerably more dangerous. At the present time, aircraft are not designed to withstand such strikes, since their existence was unknown at the time standards were set, and the dangers unappreciated until the destruction of a glider in 1999.
Positive lightning has also been shown to trigger the occurrence of Upper-atmospheric lightning between the tops of clouds and the ionosphere. Positive lightning tends to occur more frequently in winter storms, as with thundersnow, during intense tornadoes and in the dissipation stage of a thunderstorm.>>
[quote=" https://en.wikipedia.org/wiki/Johann_Georg_Estor"]
<<Johann Georg Estor (6 June 1699 – 25 October 1773), was a German theorist of public law, historian and book collector. In the second volume of his "neue kleine Schriften" there is a little note, in which Estor says that he had explored the landscapes of Hessen-Darmstadt on horseback or walking to accomplish a book about the national geography of this county. This was in the years around 1730. His teachers Verdrieß and Johann Jakob Scheuchzer had given him a hint, to make observations "coelo tristi" (in a sad sky). So, following this hint, he one day went uphill one of the highest mountains in the Vogelsberg near Burgharts, called "the saddle", through a thundercloud. In the middle of the cloud he felt little water droplets on his skin like dew. [b][color=#FF0000]And as he had reached the top of the mountain, he saw the blue sky above him and the cloud beneath like a white sea, from which flashes mounted as well directly up into the sky and shot down to the earth.[/color][/b]>>[/quote][quote=" https://en.wikipedia.org/wiki/Sprite_(lightning)"]
[float=left][img3=""]https://upload.wikimedia.org/wikipedia/commons/thumb/5/5b/BigRed-Sprite.jpg/800px-BigRed-Sprite.jpg[/img3][/float]<<Sprites are large-scale electrical discharges that occur high above thunderstorm clouds, or cumulonimbus, giving rise to a quite varied range of visual shapes flickering in the night sky. They are triggered by the discharges of positive lightning between an underlying thundercloud and the ground.
Sprites appear as luminous reddish-orange flashes. They often occur in clusters within atmosphere above the troposphere at an altitude range of 50–90 km. Sporadic visual reports of sprites go back at least to 1886, but they were first photographed on July 6, 1989 by scientists from the University of Minnesota and have subsequently been captured in video recordings many thousands of times.
Sprites are sometimes inaccurately called upper-atmospheric lightning. [b][color=#FF0000]However, sprites are cold plasma phenomena that lack the hot channel temperatures of tropospheric lightning, so they are more akin to fluorescent tube discharges than to lightning discharges.[/color][/b]>>[/quote][quote=" https://en.wikipedia.org/wiki/Lightning#Positive_lightning"]
<<Most cloud-to-ground (CG) lightning is negative, meaning the ground is more positive. Large bolts of lightning can carry up to 120 kA and 350 coulombs (2.2 ×10[sup]21[/sup] protons).
Unlike the far more common "negative" lightning, positive lightning originates from the positively charged top of the clouds (generally anvil clouds) rather than the lower portion of the storm. Leaders form in the anvil of the cumulonimbus and may travel horizontally for several kilometers before veering towards the ground. A positive lightning bolt can strike anywhere within several kilometers of the anvil of the thunderstorm, often in areas experiencing clear or only slightly cloudy skies; they are also known as "bolts from the blue" for this reason. Positive lightning typically makes up less than 5% of all lightning strikes.
Because of the much greater distance to ground, the positively charged region can develop considerably larger levels of charge and voltages than the negative charge regions in the lower part of the cloud. Positive lightning bolts are considerably hotter and longer than negative lightning. They can develop six to ten times the amount of charge and voltage of a negative bolt and the discharge current may last ten times longer. The potential at the top of the cloud may exceed a billion volts — about 10 times that of negative lightning. During a positive lightning strike, huge quantities of extremely low frequency (ELF) and very low frequency (VLF) radio waves are generated. As a result of their greater power, as well as lack of warning, positive lightning strikes are considerably more dangerous. At the present time, aircraft are not designed to withstand such strikes, since their existence was unknown at the time standards were set, and the dangers unappreciated until the destruction of a glider in 1999.
Positive lightning has also been shown to trigger the occurrence of Upper-atmospheric lightning between the tops of clouds and the ionosphere. Positive lightning tends to occur more frequently in winter storms, as with thundersnow, during intense tornadoes and in the dissipation stage of a thunderstorm.>>[/quote]