Saturn - Saturn's Atmosphere

The intensity of sunlight at Saturn's orbit is about one hundredth that at the Earth's orbit and about one fourth that the orbit of Jupiter. Consequently, and in spite of its internal heat sources, Saturn's surface is cold. When compared at levels with corresponding pressures, Saturn's atmosphere is some 270°F (150°C) cooler than Earth's and about 90°F (50°C) cooler than Jupiter's.

The atmospheres of both Saturn and Jupiter feature distinctive banded structures, horizontal zones of wind flowing in opposite directions at high speeds (e.g., 1,100 miles/hr [1,800 km/hr] at Saturn's equator). Jupiter and Saturn's zonal jets, as these winds are termed, are, according to one theory, the surface manifestations of gigantic, counter-rotating cylindrical shells of fluid in these planets' interiors. Such cylinders form because fluids in a rotating body tend to align their motions with the body's axis of rotation (in this case, the planet's); where the edges of these cylinders contact the approximately spherical outer surface of the planet, matching zonal jets are produced in the northern and southern hemispheres.