Low latitude density variations in the earth's neutral atmosphere between 200 and 400km,from August 1969 to May 1970

The daily averages of the dawn and dusk observed exospheric temperatures (deduced from solar EUV attenuation measurements between 250 and 400 km) are presented for 280 days from day 227, 1969. They are compared with the empirical model of the US Standard Atmosphere Supplements 1966 and the Jacchia 35 H model. Although consistently lower temperatures than either model were found, a better fit to the latter rather than the former was observed. The exospheric response to solar and geomagnetic activity is investigated, and refinements to the models are suggested.