Comparisons of recent data of density scale height at 544-877 km with CIRA model

Abstract. In order to obtain the observed scale height at high altitude a calculation method has been derived for determining density scale height from the difference between two satellite's heights. Two balloon satellites, Chinese DQ-1A and DQ-1B, were launched together into a nearly circular orbit at a height near 900 km and they were together in orbit for 190 days. According to the difference of the orbital heights of these two balloon satellites from 19 September 1990 to 9 March 1991, 67 values of density scale height at heights of about 544–877 km were determined. In comparison with CIRA model the results show that: (1) the trend of the variation of the scale height with height is in agreement with CIRA; (2) the determined scale height values present an oscillatory variation with time and height; and (3) the mean of the observed scale height is 3.7% lower than the mean of corresponding values from CIRA-72 and 0.8% lower than CIRA-86.