Longitude-resolved imaging of Jupiter at λ=2 cm

We present a technique for creating a longitude-resolved image of Jupiterʹs thermal radio emission. The technique has been applied to VLA data taken on 25 January 1996 at a wavelength of 2 cm. A comparison with infrared data shows a good correlation between radio hot spots and the 5 μm hot spots seen on IRTF images. The brightest spot on the radio image is most likely the hot spot through which the Galileo probe entered Jupiterʹs atmosphere. We derived the ammonia abundance (= volume mixing ratio) in the hot spot, which is ∼3×10−5, about half that seen in longitude-averaged images of the NEB, or less than 1/3 of the longitude-averaged ammonia abundance in the EZ. This low ammonia abundance probably extends down to at least the 4 bar level.