Lightning and Thunder Processes

||IAC Institute for Atmospheric and Climate Science

Cloud Microphysics

Jamin Hörni and Maurice Huguenin-Virchaux

13.12.2014 1

Thunderstorm Electricity

Jamin Hörni and Maurice Huguenin-Virchaux


Two types of charge distribution structure:

Tripole or Dipole

Upper layer (above -20°C) particles carry

positive charges.

Lower/middle layer (-10 till -20°C) particles

carry negative charges.

If tripole: near cloudbase exists a small

positive center.

13.12.2014Jamin Hörni and Maurice Huguenin-Virchaux 2

Electric charge distribution I

Fig. 14.5 from Wang (2013)

A schematic of the charge distribution in a thundercloud. Dashed

contours are isotherms in °C. Thick solid contours are the graupel/hail

mixing ratio, whereas thin solid contours are rain mixing ratio.

||IAC Institute for Atmospheric and Climate Science 13.12.2014Jamin Hörni and Maurice Huguenin-Virchaux 3

Electric charge distribution II

High electric field in charge centers.

Environmental electric field 100-300V/m

Electron avalanche

Füllekrug, M., Mareev, E. A., & Rycroft, M. J. (2006). Sprites, Elves and

Intense Lightning Discharges. Dordrecht, The Netherlands: Dordrecht :

Springer.


balance of charges: fair weather vs. lightning

4 types of discharges

cloud-to-ground flash

intra-cloud flash

inter-cloud flash

cloud-to-space flash


Lightning and Thunder Processes


Cloud-to-Ground Flash

Stepped leader

v ≈ 105 m/s

Streamer

Return stroke

v ≈ 108 m/s

T ≤ 20’000 K

Dart leader and

second return stroke

Fig. 14.6 Wang, 2013.


Intra-/Inter-cloud Flashes

http://ffden2.phys.uaf.edu/211_fall2010.web.dir/Levi_Cowan/lightning.html

Intra-Cloud:

In the same cloud, discharge between upper

(positive) and lower (negative) charge

centers

Sheet lightning

Inter-Cloud:

Electric field > breakdown requirment


TLE = Transient Luminous Event

Blue Jet: blue, trumpet, 18-40 km upward

motion

Red Sprite: Different forms, 70-40 km

downward motion

Red Elves: donut shape, 85-100 km

spreading


Upper Atmospheric Lightning


Thunder


observational study to the right

peak acoustic energy around 200 Hz

Distance to Lightning [km]:

# 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 𝑏𝑒𝑡𝑤𝑒𝑒𝑛 𝑇ℎ𝑢𝑛𝑑𝑒𝑟 𝑎𝑛𝑑 𝐿𝑖𝑔ℎ𝑡𝑛𝑖𝑛𝑔

3 Wang,

2013.


Thunder in popular culture

Chinese: Lei Gong

http://w

ww

.art

-and-a

rcha

eolo

gy.

com

/

Japanese: Raijinhttp://characters.cultural-china.com/



http://wikipedia.org

Greek: Zeus

Phidias at 435 BC

Seven Wonders of the Ancient World



http://r

esourc

es2.n

ew

s.c

om

.au

Norse: Thor


Titlepage: Swiss Lightning: http://clikhear.palmbeachpost.com/wp-content/uploads/2012/08/24swisslightning.jpg

Fig. 14.6 & 14.7 from Wang, 2013.

Chinese Thunder God: http://characters.cultural-china.com/82hz164.html

Japanese Thunder God: http://www.art-and-archaeology.com/japan/s058.jpg

Statue of Zeus at Olympia: https://en.wikipedia.org/wiki/Statue_of_Zeus_at_Olympia#/media/File:Statue_of_Zeus.jpg

Thor the Dark World: http://resources2.news.com.au/images/2013/11/01/1226751/386994-thor-the-dark-world.jpg


References

http://clikhear.palmbeachpost.com/wp-content/uploads/2012/08/24swisslightning.jpg

http://characters.cultural-china.com/82hz164.html

http://www.art-and-archaeology.com/japan/s058.jpg

https://en.wikipedia.org/wiki/Statue_of_Zeus_at_Olympia

http://resources2.news.com.au/images/2013/11/01/1226751/386994-thor-the-dark-world.jpg


Thank you!

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Lightning and Thunder Processes

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