Climate of Triton
The atmosphere of Triton is rather thin, with a surface pressure of only 1.4 Pa (1.38×10−5 atm) at the time of Voyager 2's flyby,[1]: 873 but heavily variable.
Triton's climate is dominated by extreme seasonal fluctuations that induce global volatile transport between its polar caps, leading to variable atmospheric circulation.
Triton appears to host a distinct troposphere, which may be thermally-defined by the atmosphere's vertical temperature profile.
However, the apparent reversal of wind direction ~8 km above Triton's south polar cap, as indicated by the plumes observed by Voyager 2, remains largely unexplained.
[10] Images of Triton's limb and terminator by Voyager 2 discovered multiple thin, bright clouds.
[5] The haze is likely formed by the action of ultraviolet light on atmospheric methane and nitrogen,[14][1]: 873 and may be influenced by the presence of carbon monoxide[14] the condensation of hydrocarbon ice.
[5] The resulting material aggregates into particles about 100–200 nm in size, largely composed of a variety of hydrocarbons and nitriles termed tholins.
[17] However, despite large regions of Triton being comparatively darker, ground-based spectral observations indicate that Triton's surface is mostly covered in a layer of transparent or translucent nitrogen ice; furthermore, modelling fails to replicate the observed distribution of bright and dark surfaces.
[19] It has been suggested that small, freshly-deposited grains of nitrogen ice eventually metamorphize into a clear, transparent layer within a Triton season.
[19] At the time of Voyager 2's arrival, Triton was experiencing an unusually intense southern hemisphere summer.
[3][4] Climate models predicted a steady decrease in atmospheric pressure through 2005–2060 as sublimated nitrogen from the southern polar cap migrates to and deposits in the expanding northern polar cap, so the causes of the rapid fluctuations in pressure remain unclear.
