Guillot T
Lunar and Planetary Laboratory, University of Arizona, Tucson 85721, USA.
Science. 1995 Sep 22;269(5231):1697-9. doi: 10.1126/science.7569896.
The condensation of chemical species of high molecular mass such as methane, ammonia, and water can inhibit convection in the hydrogen-helium atmospheres of the giant planets. Convection is inhibited in Uranus and Neptune when methane reaches an abundance of about 15 times the solar value and in Jupiter and Saturn if the abundance of water is more than about five times the solar value. The temperature gradient consequently becomes superadiabatic, which is observed in temperature profiles inferred from radio-occultation measurements. The planetary heat flux is then likely to be transported by another mechanism, possibly radiation in Uranus, or diffusive convection.
诸如甲烷、氨和水等高分子质量化学物质的凝结会抑制巨行星氢氦大气中的对流。当甲烷丰度达到太阳值的约15倍时，天王星和海王星的对流受到抑制；而在木星和土星中，如果水的丰度超过太阳值的约5倍，对流也会受到抑制。因此温度梯度会变成超绝热的，这在通过无线电掩星测量推断出的温度剖面中有所观测。然后行星热通量可能通过另一种机制传输，在天王星可能是辐射，或者是扩散对流。
