中文摘要：

本文通过观测实例探讨并论证了电离层高频多普勒观测在扩展-F研究中的应用．实例和相应分析表明：首先，由于高频多普勒记录的时间连续性，有利于从观测角度了解扩展-F的时间演化过程；其次，高频多普勒偏移对不规则结构造成的回波弥散、对不同尺度行进电离层扰动（TID）以及耀斑引起的突然频率偏移（SFD）效应都很敏感，这些现象在记录上出现的时间关系有利于了解扩展-F的触发因素或扩展-F与其他电离层背景扰动之间的联系或相互作用；最后，高频多普勒记录对于持续时间较长（几小时以上）或很短（小于1小时）的扩展-F都能够完整地反映，不会产生因为观测间歇形成的缺失，也可以有效区分究竟是连续一次还是一段时间内断续的扩展-F现象．高频多普勒观测有其自身的优点同时也具有一定的局限性，本文对其局限性诸如缺乏空间分辨率等也做了分析．指出发挥高频多普勒观测的优势，综合应用多种资料，通过不同手段的数据分析和比较，可以更好地为电离层扰动的物理机制和预报研究提供正确的观测依据．

英文摘要：

In this paper, the applications of the HF Doppler shift observations in the study on ionospheric spread-F are demonstrated with observational cases. These cases show that, the HF Doppler shift observation is continuous so that the evolution process of the ionospheric spread-F can be clearly understood in the view of observation. The HF Doppler frequency shifts are so sensitive to the scattering of the echoes caused by ionospheric irregularities, to the various scale of traveling ionospheric disturbances （TIDs）, and to sudden frequency deviation （SFD） caused by solar flare that it has good advantage to investigate the physics mechanism of spread-F and the correlation between the spread-F and the ionospheric background disturbances according to the time series of the ionospheric disturbances in the observational records. The HF Doppler shift canobserve the different time scale of the spread-F （from less than 1 hour to more than several hours） completely. It will be avoided to lose in the time series in record the spread-F occurrence and can decide the precision start and end time of the spread-F. Beside the obvious advantage, the HF Doppler also has some limitations in the observation, such as the spatial resolution. With comprehensive observation and data analysis, it is helpful for studying the physical mechanisms of the spread-F and for forecasting the ionospheric disturbances.