Dangerous Earth: Wind — Introduction (01:48)
Dr. Helen Czerski introduces the topic of wind; tornadoes and solar wind demonstrate the power of nature. New camera and imaging technologies are allowing scientists to examine these phenomena in exciting ways.
Chasing Tornadoes (04:21)
Professor Joshua Wurman of the Center for Severe Weather Research tries to get up close to tornadoes with weather instruments. A better understanding of the causes of tornadoes would help improve warning times and disaster preparation. Czerski watches a tornado from the road.
Tornado Alley (06:27)
See footage of a supercell. David Schultz presents a visual metaphor of the geographic and atmospheric conditions that create tornadoes in this area.
Tornado Formation (03:25)
Tornado formation is a mystery because 75% of supercell storms do not produce tornadoes. Schultz explains how wind shear contributes to the formation of fledgling tornadoes. Czerski shows footage of an extreme downdraft called a microburst.
Lifting Forces (03:55)
See footage of Wurman's team encountering a tornado at night in close proximity. Czerski demonstrates how part of the destructive power of tornadoes is derived from their lift, using footage from Scott McPartland's team of storm chasers. Baker performs experiments that seek to explain the factors that create the lifting force of a tornado.
Path of Devastation (03:37)
Czerski introduces footage of a tornado striking Joplin, Missouri and the aftermath of destruction the tornado left in its wake. Wurman explains the equipment and purpose of the "Doppler on Wheels." Wurman narrates doppler radar images of a tornado forming.
Solar Wind (03:56)
Czerski explains the phenomena of the solar wind and how it creates auroras found at Earth's poles. Over one million tons of charged particles leave the Sun every second, giving rise to the phenomenon.
Aurora Tracking (05:13)
Colin Forsyth uses data from the THEMIS network to study how conditions in space create the specific aurora activity seen across the northern sky. Solar wind bends and distorts the magnetic field of the Earth. As the magnetic field sheds excess energy, it flows back into the upper atmosphere and creates auroras at the poles.
Excited Gas (03:04)
Czerski explains how energy from solar wind excites gas molecules in the atmosphere and contributes the vibrant colors to the visual display. Scientists can measure the emitted light and calculate the expended energy in the aurora.
Solar Flares (03:44)
Czerski introduces footage of the 1989 Quebec electricity grid failure; this outage coincided with a brilliant aurora. Czerski explains how solar flares overwhelm our magnetosphere and affect our modern technology. See footage of the sun from solar monitoring satellites.
Atmospheric Effects (04:12)
Czerski tells the story of SkyLab, a scientific satellite that came crashing back to Earth due to unforeseen atmospheric effects. Increased levels of aurora activity can warm up the atmosphere and increase the depth of the atmosphere and how far it reaches into space.
Imaging the Auroras (05:29)
Forsyth shows footage of aurora beads, taken from the ISS, and explains what the phenomenon is. Hannah Dahlgren uses footage from the ASK camera system to look at the auroral activity high up in the atmosphere to better understand the intricate structures in the aurora.
Credits: Dangerous Earth: Wind (00:34)
Credits: Dangerous Earth: Wind
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