Ammonia abundance in Jupiter's atmosphere derived from the attenuation of the Galileo probe's radio signal

The radio signal from the Galileo probe to the orbiter experienced attenuat ion due to ammonia in Jupiter's atmosphere during the probe descent. A prof ile of the ammonia content as a function of depth in the atmosphere has bee n derived from the measurements of the attenuation. The derived ammonia abu ndance rises to a molar fraction of 700 +/- 100 parts per million for press ures greater than 7 bars, about 4 times that expected based on the solar ab undance of nitrogen.