Sprites and Positive "Superbolts"

[Bill Tabor]

I was just watching a program the other day about Sprites (Sci Channel?). Anyway as I recall it was very interesting as their research seemed to be linking very large blue sprites to positive CG super lightning bolts in thunderstorms. They were also investigating a sprite bolt as part of the reason for the destruction of the space shuttle on reentry but I think they decided the bolt they had on video was an artifact.

Anyone with any interest or knowledge of sprites? As I recall positive cg's are often produced around the storms meso area such as in tornadic thunderstorms. I wonder if all positive bolts are blue sprite related?

 

[Bill Tabor]

Here's a page I found that answers some of the questions I posed. Apparently all sprites are created from positive bolts. What I referred to as blue sprites are actually called blue jets. Blue jets are most associated with severe and tornadic type thunderstorms. Also try Google sprites blue jets positive

http://sky-fire.tv/index.cgi/spritesbluejetselves.html

 

[Oscar van der Velde]

Hi Bill,

indeed, the sprites are usually caused by strong positive cloud-to-ground strokes, as these drain much more charge to the ground than do negative strokes, in general. It is the total charge times the vertical distance it is lowered that is a determining quantity (i.e. : charge moment change) - usually above 200 C*km. Evidence is mounting that large horizontal lightning (spider lightning) in stratiform regions are an important mechanism to supply the charge to (a subset of) these positive CG flashes.

As for blue jets, no parent lightning flash has yet been found crucial, but the sparse observations from 1994 (University of Alaska) have shown that after a blue jet (which emanates from the convective storm top, as opposed to the stratiform/transition region of a MCS for sprites) there can be a lull in intracloud flash activity.

Then there are also the Giant blue jets, but I haven't heard any studies about their parent lightning activity - so far they have only been recorded in the tropics, no NLDN lightning detection network available.

Oscar

www.eurosprite.net

 

[Kevin Bowman]

it was on national geographic channel, great show

 

[Bill Tabor]

Oscar, hey when I made this post I didn't realize we had a Sprite researcher on board....Cool.