The COSPAR International Reference Atmosphere (CIRA) provides empirical models of atmospheric temperatures and densities as recommended by the Committee on Space Research (COSPAR). A global climatology of atmospheric temperature, zonal velocity and geopotential height derived from a combination of satellite, radiosonde and ground-based measurements. The reference atmosphere extends from pole to pole and 0-120 km. The majority of the data are on a 5 degree latitude grid and approximately 2 km vertical resolution. This dataset is public.

Since the early sixties, several different editions of CIRA have been published. The CIRA Working Group meets biannually during the COSPAR general assemblies. In the thermosphere (above about 100 km) CIRA-86 is identical with the MSIS model, which is available from NSSDC (MI-91E).

The lower part (0-120 km) of CIRA-86 consists of tables of the monthly mean values of temperature and zonal wind with almost global coverage (80°N - 80°S). Two files were compiled by Fleming et al. (1988), one in pressure coordinates including also the geopotential heights, and one in height coordinates including also the pressure values. These tables were generated from several global data compilations including ground-based and satellite (Nimbus 5,6,7) measurements (see Oort (1983) and Labitzke et al. (1985)). The lower part was merged with MSIS-86 at 120 km altitude. In general, hydrostatic and thermal wind balance are maintained at all levels. The model accurately reproduces most of the characteristic features of the atmosphere such as the equatorial wind and the general structure of the tropopause, stratopause, and mesopause.