{{Short description| Balls of fine frost formed in Antarctica}} thumb|Yukimarimo snow balls '''Yukimarimo''' are balls of fine frost formed at low temperatures on the Antarctic plateau during weak wind conditions. Yukimarimo were discovered in 1995 at Dome F by the 36th Japanese Antarctic Research Expedition (JARE-36) at temperatures of –59 to –72&nbsp;°C.<ref name="Kameda1999" group="Ref"/><ref name="Kameda2007" group="Ref"/> Electrostatic attraction between ice crystals explains the formation of yukimarimo at these low temperatures.<ref name = "Nelson2003" group = "Ref"/>

== Name ==

Yukimarimo were named by T. Kameda on JARE-36 in 1995. "Yuki" means snow in Japanese, and "marimo" is a ball-like growth of water algae which the yukimarimo resemble.

== Formation == During a storm on the Antarctic plateau, humidity rises above normal levels. After a storm, the temperature drops rapidly and, due to the excess humidity, hoarfrost forms on the surface of the snow. At these low temperatures, electrostatic attraction between the rapidly formed ice crystals is high, due to growth charging during formation. When a light wind blows after the formation of this hoarfrost, the hoarfrost breaks apart and the frost crystals clump together and stick due to the high electrostatic attraction and subsequent fusing of the ice crystals. They then tumble across the snow in a manner similar to tumbleweed.<ref name = "Nelson2003" group = "Ref"/> The sizes of the yukimarimo range from a few millimeters to several centimeters in diameter.<ref name="Kameda1999" group="Ref"/><ref name="Petenko2016" group="Ref"/>

<gallery mode="packed" heights="150px"> File:Yukimarimo south pole dawn 2009.jpg|Yukimarimo at South Pole Station, Antarctica, in 2008 File:Yukimarimo at Concordia Station (closeup).jpg|Yukimarimo at Concordia Station, Antarctica, in 2014 </gallery>

== See also == *{{annotated link | Snow roller}}

== References == <!--- See http://en.wikipedia.org/wiki/Wikipedia:Footnotes on how to create references using <ref></ref> tags which will then appear here automatically -->

{{reflist|group="Ref"|refs= <ref name="Kameda1999"> {{Cite journal|last1=Kameda|first1=T.|last2=Yoshimi|first2=H.|last3=Azuma|first3=N.|last4=Motoyama|first4=H.|date=1999|title=Observation of "yukimarimo" on the snow surface of the inland plateau, Antarctic ice sheet|journal=Journal of Glaciology|language=en|volume=45|issue=150|pages=394–396|doi=10.1017/S0022143000001891|bibcode=1999JGlac..45..394K|issn=0022-1430|doi-access=free}}</ref>

<ref name="Kameda2007">{{Cite journal |author = T. Kameda |title = Discovery and reunion with yukimarimo |journal = Seppyo (Journal of Japanese Society of Snow and Ice) |year = 2007 |volume = 69 |number = 3 |pages = 403–407 |url = http://homepage3.nifty.com/takaokameda/en/Kameda2007-AboutYukimarimo-inSeppyo.pdf |archive-date = 2016-09-13 |access-date = 2010-07-22 |archive-url = https://web.archive.org/web/20160913213206/http://homepage3.nifty.com/takaokameda/en/Kameda2007-AboutYukimarimo-inSeppyo.pdf |url-status = dead }}</ref>

<ref name="Nelson2003"> {{Cite journal|last1=Nelson|first1=J.|last2=Baker|first2=M.|date=2003-01-06|title=Charging of ice-vapor interfaces|journal=Atmospheric Chemistry and Physics Discussions|volume=3|issue=1|pages=41–73|doi=10.5194/acpd-3-41-2003|issn=1680-7375|url=https://hal.archives-ouvertes.fr/hal-00300838/file/acpd-3-41-2003.pdf|doi-access=free}}</ref>

<ref name="Petenko2016"> {{Cite journal |author = Petenko, I. |title = Yukimarimo at Dome C, Antarctica |journal = Journal of Glaciology |year = 2016 |volume = 62 |number = 233 |pages = 593–598 |url = https://doi.org/10.1017/jog.2016.30 |doi = 10.1017/jog.2016.30 |doi-access = free }} </ref>

}}

== External links == * [https://web.archive.org/web/20160303201345/http://homepage3.nifty.com/takaokameda/en/yukimrimo_en2.html Archive of Yukimarimo homepage which is now offline]

Category:Frost and rime