Astronomy Picture of the Day
Astronomy Picture of the Day
Discover the cosmos! [1] Each day a different image or photograph of our
fascinating universe is featured, along with a brief explanation written by a
professional astronomer.
2018 August 19
[2]
Asperitas Clouds Over New Zealand
Image Credit & Copyright: Witta Priester [3]
Explanation: What kind of clouds are these? Although their cause is presently
unknown, such unusual atmospheric structures, as menacing as they might seem,
do not appear to be harbingers of meteorological doom [4] . Formally
recognized as a distinct cloud type [5] only last year, Asperitas [6] clouds
can be stunning in appearance, unusual in occurrence, and are relatively
unstudied. Whereas most low cloud decks are flat bottomed [7] , asperitas
clouds [8] appear to have significant vertical structure underneath.
Speculation therefore holds that asperitas clouds [9] might be related to
lenticular clouds [10] that form near mountains, or mammatus clouds [11]
associated with thunderstorms, or perhaps a foehn wind [12] -- a type of dry
downward wind that flows off mountains. Such a wind [13] called the Canterbury
arch [14] streams toward the east coast of New Zealand's South Island [15] .
The featured image<a/>, taken above Hanmer Springs [17] in Canterbury [18] ,
New Zealand [19] , in 2005, shows great detail partly because sunlight
illuminates the undulating clouds [20] from the side.
Tomorrow's picture: our almost quiet sun
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Authors & editors: Robert Nemiroff [32] (MTU [33] ) & Jerry Bonnell [34]
(UMCP [35] )
NASA Official: Phillip Newman Specific rights apply [36] .
NASA Web Privacy Policy and Important Notices [37]
A service of: ASD [38] at NASA [39] / GSFC [40]
& Michigan Tech. U. [41]
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Site notes:
[1] archivepix.html
[2] image/1808/asperatus_priester_1024.jpg
[3] http://www.flickr.com/people/wittap/
[4] ap101130.html
[5] https://scied.ucar.edu/webweather/clouds/clou...
[6] https://en.wikipedia.org/wiki/Asperitas_(clou...
[7] http://www.wrh.noaa.gov/fgz/science/flatcloud...
[8] http://cloudappreciationsociety.org/asperatus...
[9]
http://www.usatoday.com/story/weather/2015/06...
28994525/
[10] ap090121.html
[11] ap121023.html
[12] http://en.wikipedia.org/wiki/Foehn_wind
[13] http://en.wikipedia.org/wiki/Nor%27west_arch
[14] http://en.wikipedia.org/wiki/Canterbury_arch
[15] http://en.wikipedia.org/wiki/South_Island,_Ne...
[16] http://www.flickr.com/photos/wittap/440613786...
[17] https://www.youtube.com/watch?v=gn7ck-N53k0
[18] http://en.wikipedia.org/wiki/Canterbury_Regio...
[19] http://en.wikipedia.org/wiki/New_Zealand
[20]
https://www.nasa.gov/audience/forstudents/5-8...
what-are-clouds-58.html
[21] ap180818.html
[22] archivepix.html
[23] lib/apsubmit2015.html
[24] lib/aptree.html
[25] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
[26] calendar/allyears.html
[27] /apod.rss
[28] lib/edlinks.html
[29] lib/about_apod.html
[30] http://asterisk.apod.com/discuss_apod.php?dat...
[31] ap180820.html
[32] http://www.phy.mtu.edu/faculty/Nemiroff.html
[33] http://www.phy.mtu.edu/
[34] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
[35] http://www.astro.umd.edu/
[36] lib/about_apod.html#srapply
[37] https://www.nasa.gov/about/highlights/HP_Priv...
[38] https://astrophysics.gsfc.nasa.gov/
[39] https://www.nasa.gov/
[40] https://www.nasa.gov/centers/goddard/
[41] http://www.mtu.edu/
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