Yukimarimo
Encyclopedia
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 °C. Electrostatic attraction
between ice crystals explains the formation of yukimarimo at these low temperatures.
in Japanese, and "marimo
" is a ball-like growth of water algae
which the yukimarimo resemble.
. The sizes of the yukimarimo range from a few millimeters to several centimeters in diameter.
Frost
Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...
formed at low temperatures on the Antarctic plateau
Antarctic Plateau
The Antarctic Plateau is a large area of Central Antarctica, which extends over a diameter of about , and which includes the region of the South Pole and the Amundsen-Scott Station...
during weak wind conditions. Yukimarimo were discovered in 1995 at Dome F
Dome F
Dome F, also known as Dome Fuji , Valkyrie Dome, or Valkyrjedomen, is located in east Queen Maud Land at . With an altitude of 3,810 m or 12,500 ft above sea level, it is the second-highest summit or ice dome of the East Antarctic ice sheet and represents an ice divide...
by the 36th Japanese Antarctic Research Expedition (JARE-36) at temperatures of –59 to –72 °C. Electrostatic attraction
Electrostatics
Electrostatics is the branch of physics that deals with the phenomena and properties of stationary or slow-moving electric charges....
between ice crystals explains the formation of yukimarimo at these low temperatures.
Name
Yukimarimo were named by T. Kameda on JARE-36 in 1995. "Yuki" means snowSnow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
in Japanese, and "marimo
Marimo
, also known as Cladophora ball, Lake ball, or Moss Balls in English, is a species of filamentous green algae found in a number of lakes in the northern hemisphere. A marimo is a rare growth form of the species where the algae grow into large green balls with a velvety appearance...
" is a ball-like growth of water algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
which the yukimarimo resemble.
Formation
During a storm on the Antarctic plateau the humidity is higher than normal. After a storm, the temperature rapidly drops and 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, and tumble across the snow in a manner similar to tumbleweedTumbleweed
A tumbleweed is the above-ground part of a plant that, once mature and dry, disengages from the root and tumbles away in the wind. Usually, the tumbleweed is the entire plant apart from the roots, but in a few species it is a flower cluster. The tumbleweed habit is most common in steppe and desert...
. The sizes of the yukimarimo range from a few millimeters to several centimeters in diameter.