PHYSICAL PROPERTIES OF THE ATMOSPHERE BETWEEN APPROX. 80 KM AND 250 KM,

A relation between the fractional change of concentration with change in height, provided a temperature and its gradient are known at one height, gives the possibility of determining the change in molecular weight with change in temperature and altitude. The molecular weight of the atmosphere between 80 km and 125 km was obtained, assuming molecular oxygen dissociates in this region. The molecular weight of the atmosphere between 130 km and 250 km was obtained, assuming nitrogen dissociates in this region. The calculated values for pressure and density agree quite well with the data obtained from rocket flights, although one may regard this approach as satisfactory only in a qualitative way, because of the rather simple form chosen for the fractional change of concentration with change in height. But in veiw of the uncertainties involved in determining the radiation density, absorption cross section, etc., it is believed that the proposed treatment gives correctly the essential features such as total pressure, mean molecular weight, mean density, and average particle density of the atmosphere at the altitudes considered. Author