"Ribbon lightning" Real or camera movement?

[JohnD]

All,
When photos of stars as seen from Earth are shown as APODs, sometimes people allege they are faked or are made by 'photoshopping', when in fact they are taken by skilled and honourable photographers. So while I am doubtful about a photograph that appears in a UK national paper, I am reluctant to cry "Fake!" What do you think?

Go to http://www.guardian.co.uk/artanddesign/ ... NTCMP=SRCH
Click on the pic to see the whole frame. It purports to be "ribbon lightning" striking a tree in Poland. The 'ribbon' part looks to me as if the camera was moved during the exposure - but look at the tree and the building next to it, illuminated by the strike. No sign of camera movement there.

Is 'ribbon' lightning a real phenomenon?

John

[neufer]

<<High speed videos (examined frame-by frame) show that most lightning strikes are made up of multiple individual strokes. A typical strike is made of 3 to 4 strokes. There may be more. Each re-strike is separated by a relatively large amount of time, typically 40 to 50 milliseconds. Re-strikes can cause a noticeable "strobe light" effect. Each successive stroke is preceded by intermediate dart leader strokes akin to, but weaker than, the initial stepped leader. The stroke usually re-uses the discharge channel taken by the previous stroke. The variations in successive discharges are the result of smaller regions of charge within the cloud being depleted by successive strokes. The sound of thunder from a lightning strike is prolonged by successive strokes.

Ribbon lightning occurs in thunderstorms with high cross winds and multiple return strokes. The wind will blow each successive return stroke slightly to one side of the previous return stroke, causing a ribbon effect.>>

<<Ribbon candy is a type of hard candy which in North America most often appears for sale around the Christmas holiday season. It acquires its shape by first being fashioned as warm sugar into flat strips. A strip is then folded back and forth over itself to form a hardened ribboned stick. The sugar is often colored to appear festive, and the candy often has a glossy sheen. It is commonly made with extracts, often of different mint or citrus flavors. It is usually thin enough to melt quickly in the mouth, but because pieces of it are usually larger than bite size, biting into a stick of it causes shattering and shards. Many types of ribbon candies also tend to become sticky easily, usually either due to body warmth from being held, or simply from room temperature and humidity. Because of what some consider to be its pretty appearance, it is often used like decor, put out on display in candy dishes, plates, or apothecary jars. When it is used in this way it tends to end up sticking together.>>

[JohnD]

Thank you neufer, multidisciplinary as always.

I've been given an explanation that is so logical,I wish I had thought of it. Lightning travels in multiple strokes through a single channle in ionised air. If a wind is blowing, that air will move, during the stroke, so that a fixed camera can separate the individual strokes, thta appear as parallel strokes along seperate channels. So the camera did not move, but the air, and stroke, did!

John

[JohnD]

Came across the Colorado Lightning Resource Page, and its resident expert Steve Hodanish - Hi, Steve, if you are here!
http://www.crh.noaa.gov/pub/?n=ltg.php
Stteve repleid to my queiy about ribbon lightning as follows:

I did a quick review of ribbon lightning in the AMS journal articles. I
need to clarify that this was a quick review. I did find a couple
articles about ribbon lightning, but these articles were written in the
late 1800s (1898), and they discussed photographs of ribbon lightning.

Dr Uman, in his book "Lightning" and "All About Lightning" mention
ribbon lightning, but he hypothesizes it too is caused by the wind.

Overall, I could not find any refereed articles discussing "why" ribbon
lighting occurs. I would agree that the wind is the likely cause.

Note that a camera can observe lightning in ribbons in two ways: The
first would be if it was true ribbon lightning, that is, the electrified
channel is moved by the wind (the camera is stationary). The second way
is if the camera is moving with time AND there are multiple channels
occurring with the cloud to ground flash.

Take care;

Steve Hodanish
NWS Pueblo CO USA

Thanks for your time, Steve. Clearly, this is an under-researched phenomenon.

John