<P> The South Temperate Region, or South Temperate Belt (STB), is yet another dark, prominent belt, more so than the NTB; until March 2000, its most famous features were the long - lived white ovals BC, DE, and FA, which have since merged to form Oval BA ("Red Jr ."). The ovals were part of South Temperate Zone, but they extended into STB partially blocking it . The STB has occasionally faded, apparently due to complex interactions between the white ovals and the GRS . The appearance of the South Temperate Zone (STZ)--the zone in which the white ovals originated--is highly variable . </P> <P> There are other features on Jupiter that are either temporary or difficult to observe from Earth . The South South Temperate Region is harder to discern even than the NNTR; its detail is subtle and can only be studied well by large telescopes or spacecraft . Many zones and belts are more transient in nature and are not always visible . These include the Equatorial band (EB), North Equatorial belt zone (NEBZ, a white zone within the belt) and South Equatorial belt zone (SEBZ). Belts are also occasionally split by a sudden disturbance . When a disturbance divides a normally singular belt or zone, an N or an S is added to indicate whether the component is the northern or southern one; e.g., NEB (N) and NEB (S). </P> <P> Circulation in Jupiter's atmosphere is markedly different from that in the atmosphere of Earth . The interior of Jupiter is fluid and lacks any solid surface . Therefore, convection may occur throughout the planet's outer molecular envelope . As of 2008, a comprehensive theory of the dynamics of the Jovian atmosphere has not been developed . Any such theory needs to explain the following facts: the existence of narrow stable bands and jets that are symmetric relative to Jupiter's equator, the strong prograde jet observed at the equator, the difference between zones and belts, and the origin and persistence of large vortices such as the Great Red Spot . </P> <P> The theories regarding the dynamics of the Jovian atmosphere can be broadly divided into two classes: shallow and deep . The former hold that the observed circulation is largely confined to a thin outer (weather) layer of the planet, which overlays the stable interior . The latter hypothesis postulates that the observed atmospheric flows are only a surface manifestation of deeply rooted circulation in the outer molecular envelope of Jupiter . As both theories have their own successes and failures, many planetary scientists think that the true theory will include elements of both models . </P>

What physical effect causes circulation in the atmosphere of jupiter