A Global Reference Atmospheric Model for Surface to Orbital Altitudes

Abstract

An empirical atmospheric model has been developed which generates values for pressure, density, temperature and winds from surface levels to orbital altitudes. The output parameters consist of components for: 1) latitude, longitude, and altitude dependent monthly means; 2) quasibiennial oscillations; and 3) random perturbations to partially simulate the variability due to synoptic, diurnal, planetary wave and gravity wave variations. The monthly mean models consist of: (i) NASA's four dimensional worldwide model, developed by Environmental Research and Technology, for height, latitude, and longitude dependent monthly means from the surface to 25 km; and (ii) a newly developed latitude-longitude dependent model which is an extension of the Groves latitude dependent model for the region between 25 and 90 km. The Jacchia 1970 model is used above 90 km and is faired with the modified Groves values between 90 and 115 km. Quasibiennial and random variation perturbations are computed from parameters determined from various empirical studies, and are added to the monthly mean values. This model has been developed as a computer program which can be used to generate altitude profiles of atmospheric variables for any month at any desired location, or to evaluate atmospheric parameters along any simulated trajectory through the atmosphere. Various applications of the model are discussed, and results are presented which show that good simulation of the thermodynamic and circulation characteristics of the atmosphere can be achieved with the model.