Preliminary results from the Pioneer Venus Orbiter infrared radiometer: Temperature and dynamics in the upper atmosphere

Data from the infrared radiometer aboard the Pioneer Venus Orbiter are examined and interpreted within the context of zonally averaged temperatures and circulation in the upper atmosphere of Venus. Surprisinglythe northern hemisphere pole is warmer than the equator throughout most of the region sampled. This implies both a rapid decrease with height of the 100 m/s cloud top winds previously observedand the probable existence of large (50 to 100 m/s) meridional winds.