CIRA 1972, RECENT ATMOSPHERIC MODELS, AND IMPROVEMENTS IN PROGRESS

Abstract

Work on the thermospheric section of CIRA 1972 was completed just before the first results from the new era of satellite-borne mass spectrometers could be utilized. The OGO 6 model (1974), although based on data collected within a limited range of height and solar activity (solar maximum), was a first step toward a new generation of models; similar in scope was the ESRO 4 model (1977), based on data recorded at lower heights and lower solar activity. The global Doppler-temperature model of Thuillier et al. (1977) provided a tool for discriminating between temperature and density variations and was utilized in the construction of the Jacchia 1977 model, which was based on a synthesis of temperature, mass-spectrometer, and total-density data from many sources. A similarly eclectic model is the MSIS model (1977), founded on incoherent-scatter temperatures and mass-spectrometer data from various sources. Each of the last two models has its strong and weak points, which are briefly discussed, together with suggestions for improvements. New models of the disturbed thermosphere by the author are compared with recent mass-spectrometer measurements at 170 km.