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Topic: Thunderclouds

In the News (Thu 16 Feb 12)

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	Langmuir Laboratory: History & Facilities
		The use of balloons by C. Moore to carry instruments into thunderclouds led to the erection of a balloon hangar on the open meadow 1 km northwest of the Laboratory in 1968.
		The increased balloon and rocket probing of thunderclouds prompted the establishment in 1970 of a small restricted airspace, R5113, by the Federal Aviation Administration and the Office of Naval Research.
		While much of the work at the Laboratory is directed toward the study of thunderclouds, lightning, and atmospheric electricity by Institute scientists, other investigators have undertaken a wide variety of research including investigations of cosmic rays, of ozone, and of the oxides of nitrogen.
	www.ee.nmt.edu /~langmuir/brochure.html (2608 words)

	Bernard Vonnegut (Site not responding. Last check: 2007-11-02)
		He proposed an inductive mechanism for the electrification of convective clouds in which ions in the air around the clouds become attached to cloud particles and thereafter are carried by the motions of the cloud.
		He argued that the Wilson current of negative ions that flows to the positively-charged tops of thunderclouds and the point-discharge positive ions that are carried from the Earth toward an electrified cloud base were not necessarily dissipative of cloud electrification.
		The thundercloud thus acts as an electrostatic influence machine with positive feedback driven by convection in which the Wilson and point discharge currents increase the electrification.
	www.atmos.albany.edu /deas/bvonn/bvonnegut.html (2026 words)

	Thunderstorms are affected by pollution
		Previous studies have proven that ice particles are smaller in the upper reaches of thunderclouds when there is more pollution, and when the rising air in the clouds (convection) is stronger.
		Aerosol particles are necessary for clouds to form, and it has been suspected that clouds might be altered by large concentrations of them, from a fire for example.
		The mission of NASA's ESE is to develop a scientific understanding of the Earth System and its response to natural or human-induced changes to enable improved prediction capability for climate, weather and natural hazards.
	www.eurekalert.org /pub_releases/2002-05/nsfc-taa050102.php (632 words)

	Thunderclouds Good Judgment On The Subject Of Thunderclouds We Have This Complete (Site not responding. Last check: 2007-11-02)
		Simulations of the charge separation in thunderclouds and the evolution of the electric field were...
		Weekes, having diverted into his laboratory a free supply of atmospheric electricity from passing thunderclouds, was able to carry out experiments in comfort-but most certainly not in safety-with...
		Thunderclouds were already massing when his men hastily loaded the ships with treasure pilfered from the vaults of Zento; Gozu regretted ignoring the Captainís advice to hug the coast and find a safe...
	cloudstratus.samestratus.com /thunderclouds (855 words)

	Thunderclouds Good Judgment On The Subject Of Thunderclouds We Have This Complete (Site not responding. Last check: 2007-11-02)
		Thunderclouds and rain, tornado and many other dangers are waiting for you on the way to glory.
		Thunderclouds: Have a listen to what the The Analogues did with their Mustapick Deep Baritone.
		The thunderclouds rolled And wind began to blow This was the day to tell To let everybody know Her voice began to quiver And tears reached her sad eyes To tell her mother all the truth And the words...
	cloudpicturestratus.samestratus.com /thundercloudseqb (934 words)

	ESD Journal - The ESD & Electrostatics Magazine
		In order for a lightning strike to be triggered, the motion of thunderclouds had to be monitored to choose the precise time for a laser shot to take place.
		Plasma channels were produced when thunderclouds were ready to discharge because of the microsecond response of the laser trigger.
		Precursor ultra-high-frequency pulses that are generated in thunderclouds when the electrical field becomes critical allowed the precise timing to be achieved by detection of preliminary breakdown pulses.
	www.esdjournal.com /articles/lightn.htm (707 words)

	thunderclouds - OneLook Dictionary Search (Site not responding. Last check: 2007-11-02)
		We found 2 dictionaries with English definitions that include the word thunderclouds:
		Tip: Click on the first link on a line below to go directly to a page where "thunderclouds" is defined.
		thunderclouds : Cambridge International Dictionary of English [home, info]
	www.onelook.com /?w=thunderclouds (69 words)

	Stormy notion \| News \| Down To Earth magazine
		In these updrafts, winds that often move parallel to each other in a shearing motion transform into a spinning column of air called a vortex; when this vortex becomes starkly visible as a funnel of clouds and reaches the ground, it is termed as a tornado.
		Their investigation shows that the difference between tornadic and non-tornadic thunderclouds is determined by the transport properties or rather by the very presence of an internal ‘skeleton’, which is composed of nanodust particles (carbon nanotubes or similar structures of other chemical elements).
		This electric charge initiates a sort of electric ‘crash’ between the thunderclouds and the ground, and during this process, heat from the charge is transformed into gases and plasma moving chaotically inside the cloud.
	www.downtoearth.org.in /full.asp?foldername=20040515&filename=news&sid=44 (450 words)

	Savage Planet: Deadly Skies - How Lightning Forms
		Thunderclouds are large, anvil-shaped masses that can stretch miles across at the base, and reach 40,000 feet or more into the atmosphere.
		The genesis of lightning is a subject of great theoretical debate, says Dr. Vladimir Rakov of the Lightning Research Center at the University of Florida.
		We know that electrical charges build up within thunderclouds, but there is no single theory that fully describes why.
	www.thirteen.org /savageplanet/03deadlyskies/01lforms/indexmid.html (376 words)

	Thunderclouds (Site not responding. Last check: 2007-11-02)
		The scientists report that the jets emerged from the core of the thunderclouds and lasted about half a second...
		Science and Technology at Scientific American.com: Gigantic Jets Connect Thunderclouds to the Ionosphere -- daily science news and technology news with in-depth astronomy, spaces, nanotechnology, chemistry, and physics coverage...
		Simulation of the electrification of winter thunderclouds using the three-dimensional Regional Atmospheric Modeling...
	stratuscloud.mittstratus.com /thunderclouds (855 words)

	Aktuelle Pressemitteilungen
		They will study tropical thunderclouds in order to find out more about the exchange of trace and greenhouse gases between the strata of the atmosphere.
		At this time of year, gigantic thunderclouds that can reach up to an altitude of 20 kilometres appear almost daily on Darwin's doorstep.
		Without these gigantic thunderclouds, the exchange of air in the equatorial region would be much slower.
	www.fz-juelich.de /portal/index.php?index=281&cmd=show&mid=316&portal=0 (569 words)

	SCOUT :: News
		SCOUT-O3 On 4 November, the Russian high-altitude aircraft "Geophysica" and the research aircraft "Falcon" took off towards Darwin, Australia, for a spectacular measurement campaign in gigantic thunderclouds.
		In tropical thunderclouds on the north coast of Australia, climate-relevant trace and greenhouse gases could be transported from the lower into the upper strata of the atmosphere in just a few hours.
		From the results, important findings on the radiative budget and the regeneration of the ozone layer are expected.
	www.fz-juelich.de /projects/index.php?index=355 (77 words)

	Flight Campaign in Darwin Brought to a Successful Close
		The measurement campaign in Australia focused on thunderclouds, which form almost daily at this time of year at altitudes of up to 20 kilometres at the "top end" of Australia.
		The tropics are of particular importance because this is where the exchange of air masses occurs between the lower (troposphere) and upper atmosphere (stratosphere).
		The gigantic thunderclouds on Darwin’s doorstep transport these air masses directly into the stratosphere within a short period of time.
	innovations-report.com /html/reports/earth_sciences/report-52757.html (723 words)

	Frequently Asked Questions (FAQ) about lightning (Site not responding. Last check: 2007-11-02)
		Cumulonimbus clouds with lightning activity are generally referred to as thunderclouds.
		The classical thundercloud model can be described as a positive electric dipole with a positively charged region above a negatively charged region.
		There are two general theories to explain the charge buildup required to electrify a thundercloud.
	nofc.cfs.nrcan.gc.ca /science/research/lightning_e.html (2506 words)

	ES&T Online News: Aerosols enhance ozone depletion
		Steven Sherwood of Yale University reports that large concentrations of aerosols change the composition of thunderclouds by depressing the size and increasing the number of ice crystals.
		These modified thunderclouds may alter atmospheric humidity “in a way that traps more heat near the ground, but cools the stratosphere.”
		By studying 12 years of aerosol data from satellites and statistically analyzing thunderclouds in the tropics, Sherwood found that clouds over land contained ice crystals with average diameters 10–20% smaller than ice crystals in clouds over the sea.
	pubs.acs.org /subscribe/journals/esthag-w/2002/may/science/mb_aerosols.html (314 words)

	EO Newsroom: New Images - Thunderstorms over the Amazon (Site not responding. Last check: 2007-11-02)
		Studies have also proven that ice particles are smaller in the upper reaches of thunderclouds when there is more pollution and when the rising air in the clouds (convection) is stronger.
		Aerosol particles are necessary for clouds to form, and it has been suspected that clouds might be altered by large concentrations of them.
		By looking at ten years of aerosol data and statistically analyzing many thunderclouds, Sherwood was able to confirm that they were affected.
	earth.jsc.nasa.gov /EarthObservatory/Thunderstorms_over_the_Amazon.htm (651 words)

	HAL :: BROWSE
		A randomly stepped leader propagation model is developed to study gigantic jets, a new type of lightning, connecting thunderclouds to the ionosphere.
		The thundercloud is considered as an electrode igniting gigantic jets and the ionosphere is assumed as the other.
		The electric field is considered due to the thundercloud charges and the self-consistently propagating leader.
	hal.ccsd.cnrs.fr /ccsd-00001934/en (248 words)

	EO Study: Seeing into the Heart of a Hurricane Page 2
		They are replenished by evaporated water that condenses in the air above the hurricane to form cloud droplets, which are then subsumed by the thunderclouds.
		The cylinders are the thunderclouds inside the eye wall.
		But if the hurricane wanders over an area of the ocean where the sea's surface has been heated and the air is humid and stagnant, the thunderclouds can grow extremely violent in a matter of hours.
	earthobservatory.nasa.gov /Study/HurricaneHeart/heart_2.html (845 words)

	Benjamin Franklin and Lightning Rods - Physics Today January 2006
		Franklin's seminal contributions were his suggestions that tall, insulated rods could be used to determine if thunderclouds are, in fact, electrified and that tall, grounded rods would protect against lightning damage.
		He acknowledged that insulated rods or "electroscopes" did verify that thunderclouds are electrified, but for the rest of his life he steadfastly opposed the use of grounded rods as "preservatives." In 1753, he published a series of letters attacking Franklin's Experiments and Observations and suggested other methods of lightning protection.
		The discovery that thunderclouds contain electricity and that lightning is an electrical discharge revolutionized human perceptions of the natural world, and the invention of protective rods was a clear example of how basic, curiosity-driven research can lead to significant practical benefits.
	www.physicstoday.org /vol-59/iss-1/p42.html (3595 words)

	Sprites (Site not responding. Last check: 2007-11-02)
		Although rather common and visible to the naked eye under the right viewing conditions, TLE’s were not observed or accounted for, except, perhaps, in reports of high flying pilots.
		In the last couple of years, the importance of TLE’s to the global electrical circuit and to the chemistry of the upper atmosphere (including, possibly, the ozone layer) have been recognized, and the field is very active.
		Studies focus on the relation between the lower thundercloud and its activity to sprite formation and on the morphology of sprites.
	geophysics.tau.ac.il /meidex/Sprites/sprites.htm (352 words)

	Research on Convective Snows - References
		Fukao, S., Y. Maekawa, Y. Sonoi, and F. Yoshino, 1991: Dual polarization radar observation of thunderclouds on the coast of the Sea of Japan in the winter season.
		Kocin, R. Uccellini, J. Zach, and M. Kaplan, 1985: A mesoscale numerical forecast of an intense convective snowburst anlong the east coast.
		Michimoto, K., 1991: A study of radar echoes and their relation to lightning discharge of thunderclouds in the Hokuriku district.
	weather.missouri.edu /ROCS/refs.html (1555 words)

	[No title] (Site not responding. Last check: 2007-11-02)
		Out of the twenty-five Hans Hofmann paintings currently on display at the McNay (through September 15th), the pne that held my interest was And Thunderclouds Pass, painted in 1961.
		Though a beautiful representation, it is my opinion that there is no canvas large enough to properly contain a storm.
		And Thunderclouds Pass is full of dark, foreboding colors which are, naturally, reminiscent of a storm.
	users3.ev1.net /~rooftopyawp/other/hofmann.doc (390 words)

	Thunderclouds Gifts
		Any of these cartoons (subject to the above) can be bought as prints/originals or printed on the merchandise at the bottom of this page.
		Copyright in this image is owned by the original artist, rights to reproduce or use the image may be obtained from www.CartoonStock.com.
		Related topics: gender, gender differences, rain, raincloud, rainclouds, thundercloud, thunderclouds, cloud, clouds, rain cloud, rain clouds, thunder cloud, thunder clouds, stormcloud, stormclouds, storm cloud, storm clouds, umbrella, umbrellas, organised, prepared, preparation,
	www.cartoonstock.com /directory/t/thunderclouds_gifts.asp (548 words)

	Abstract - Analysis of lightning storms in the coastal region of israel as a case study for understanding the ... (Site not responding. Last check: 2007-11-02)
		The main objective was to study the changes in the microphysical and electrical properties of thunderclouds as the storms cross the coastline from the sea into the northern and central parts of Israel.
		The second part of the work was the numerical simulations and its goal was to study the influence of mesoscale factors (like topography and sea-land temperature contrast) on thunderclouds electrical evolution.
		For this purpose the RAMS, 3D mesoscale model was modified to include charge separation and calculations of the charge distributions in a cloud field.
	geophysics.tau.ac.il /news/abstract.asp?sem_id=41 (252 words)

	Scientific American: Gigantic Jets Connect Thunderclouds to the Ionosphere (Site not responding. Last check: 2007-11-02)
		Depending on the shape their upper halves took on, the lightning streaks were classified as tree jets or carrot jets.
		All five jets, the authors write, "establish a direct link between a thundercloud and the ionosphere," and measurements showed that there was a significant flow of current moving charge upward from the clouds.
		The researchers also detected extremely-low-frequency radio waves that were detected thousands of kilometers away during four of the five events.
	www.sciam.com /print_version.cfm?articleID=00052B00-FA6A-1EF9-BA6A80A84189EEDF (288 words)

	HAL :: BROWSE
		The initiation of giant electrical discharges called as "gigantic jets" connecting thunderclouds to the ionosphere is investigated by numerical simulation method in this paper.
		Using similarity relations, the triggering conditions of streamer formation in laboratory situations are extended to form a criterion of initiation of gigantic jets.
		The energy source causing a gigantic jet is considered due to the quasi-electrostatic field generated by thunderclouds.
	hal.ccsd.cnrs.fr /ccsd-00001935/en (242 words)

	Thunderclouds Wildflowers John Muir Wilderness Sierra Nevada California Fine Art Prints Stock Photography (Site not responding. Last check: 2007-11-02)
		I find this to be a rather subtle photograph, but feel that the combination of its’ parts make for a more engaging moment than at first glance.
		I recognized right away that I would need a neutral-density graduated filter to get detail in both the building thundercloud and the shadowed foreground.
		By the time I was ready for the exposure the thunderhead had grown almost out of the frame, and the quality of light had improved, as can be seen by the warmer tones of color on the tree.
	homepage.mac.com /wildincognito/Thunderclouds.htm (114 words)

	SPIE Bookstore
		The maximum electric fields typically measured in thunderclouds are reviewed with a view toward lightning initiation mechanism.
		Narrow bipolar pulses attributed to the so-called compact intracloud discharges are characterized.
		Proposed mechanisms of lightning initiation in thunderclouds are presented and discussed.
	bookstore.spie.org /index.cfm?fuseaction=DetailPaper&ProductId=675583&coden= (113 words)

	EO News: Thunderstorms Are Affected By Pollution - May 2, 2002
		"I've found that aerosols depress the size of ice crystals in thunderclouds over land and oceans -- and as a result may reduce precipitation," said Steven Sherwood of Yale University.
		Clouds require water vapor and water-soluble aerosols like salt from Earth's surface to form.
		Unfortunately pollution-produced aerosols increase the number of and depress the size of ice crystals in thunderclouds.
	earthobservatory.nasa.gov /Newsroom/NasaNews/2002/200205029305.html (776 words)

	Severe Storms - March - Scribbly Gum - ABC Science Online
		Severe storms are characterised by dark thunderclouds, lightning strikes, strong winds, rain and hail.
		Looking like marshmallow castles, thunderclouds, or cumulonimbus, are towering masses of circulating air that can extend 15 kilometres from the base of the cloud to the tropopause, the part of the upper atmosphere between the troposphere and the stratosphere.
		But despite their height, severe storms are generally localised and the width of the cloud may be only a few kilometres.
	www.abc.net.au /science/scribblygum/march2005 (1578 words)

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