摘要：We present a new set of measurements obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) of Jupiter’s microwave thermal emission near the 1.3 cm ammonia (NH3) absorption band. We use these observations to investigate the ammonia mole fraction in the upper troposphere, near 0.3<P<2 bar, based on radiative transfer modeling. We find that the ammonia mole fraction must be ∼2.4 ´ 10-4 below the NH3 ice cloud, i.e., at 0.8<P<8 bar, in agreement with results by de Pater et al. We find the NH3 cloud forming region between 0.3<P<0.8 bar to be globally sub-saturated by ∼55% on average, in accordance with the result in Gibson et al. Although our data are not very sensitive to the region above the cloud layer, we are able to set an upper limit of 2.4 ´ 10-7 on the mole fraction here, a factor of ∼10 above the saturated vapor curve.
关键词：planetary systems: atmospheres;planets and satellites: individual (Jupiter);radio continuum: planetary systems
