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 ( NH _ { 3 } ) 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 \sim 2.4 \times 10 ^ { -4 } below the NH _ { 3 } ice cloud , i.e. , at 0.8 < P < 8 bar , in agreement with results by [ ] .
We find the NH _ { 3 } 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 [ ] .
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 \times 10 ^ { -7 } on the mole fraction here , a factor of \sim 10 above the saturated vapor curve .