Atmospheric densities from satellites and rocket observation

Atmospheric densities deduced from high altitude rocket nights have a large variability of which a large percentage is undoubtedly due to measurement errors. Prior to the IGY, the available density data gave reasonable support to the ARDC Model Atmosphere. Satellite data which at first appeared to be inconsistent with rocket data are now seen to be continuous with the average of presently available rocket derived densities. The current data suggest the revision of the 1956 ARDC Model to lower densities near 100 km altitude and demand higher densities above 160 km (a twenty fold increase at 500 km). The revised altitude distribution of density implies (1) lower temperatures at 90 km and (2) temperature-altitude gradients between 105 and 160 km (two times the molecular-scale-temperature gradient of the 1956 ARDC Model). Density-altitude and temperature-altitude profiles for a revised model atmosphere are discussed.