用数字测高仪漂移测量研究电离层声重波扰动

STUDY OF IONOSPHERIC GRAVITY WAVE DISTURBANCES FROM DRIFT MEASUREMENTS OF A DIGISONDE

数字测高仪Digisonde中的漂移测量,常用来研究小尺度电离层扰动,如电离层小不均匀体的漂移。文中提出一种新的分析方法,利用漂移测量数据中多普勒频移和到达角参量的最大熵动态功率谱,估算声重波一类大尺度电离层扰动的水平传播速度和传播方向。作为实例,研究了Millstone Hill测高仪站的漂移观测资料,并对处理结果进行了初步分析。分析结果表明,从数字测高仪漂移测量数据中,可有效地提取声重波一类大尺度电离层扰动的传播参量,在电离层动力过程的研究中很有意义。

The present work studies the large scale ionospheric disturbances such as gravity waves from the drift data of a digisonde,which are usually used in the investigation of drift motion of small scale ionospheric irregularities.An analysis method is developed to obtain Doppler frequency shifts and angles of arrival of radio echoes,and to estimate the horizontal velocity and azimuth angle of propagation of the ionospheric gravity wave dismbances.In this method the MEM dynamic spectral technique is adopted to separate each unique gravity wave field from the observed disturbances.The examples of analysis with drift data of Millstone Hill Station reveal some interesting phenomena such as spectral evolution and the diurnal variation of the horizontal propagation of ionospheric disturbances,which indicate that the present method is useful in the experimental investigation of ionospheric dynamics.