Atmosphere of Triton - Weather

Weather

Nitrogen ice particles form clouds in the troposphere a few kilometers above the surface of Triton. Above them a haze is present extending up to 30 km from the surface. It is believed to be composed largely of hydrocarbons and nitriles created by the action of the Sun's and stellar ultraviolet light on methane.

In 1989 Voyager 2 discovered that near the surface there are winds blowing to the east or north-east with a speed of about 5–15 m/s. Their direction was determined by observations of dark streaks located over the southern polar cap, which generally extend from the south-west to north-east. These winds are thought to be related to the sublimation of nitrogen ice from the southern cap as there was summer in the southern hemisphere in 1989. The gaseous nitrogen moves northward and is deflected by the Coriolis force to the east forming an anticyclone near the surface. The tropospheric winds are capable of moving material of over a micrometre in size thus forming the steaks.

Eight kilometers high in the atmosphere near the tropopause, the winds change direction. They now flow to the west and are driven by differences in temperature between the poles and equator. These high winds may distort Triton's atmosphere making it asymmetric. An asymmetry was actually observed during star occultations by Triton in 1990s.