An foF2 departure index and its relevance to central European HF signal quality records. II

For pt.I see ICAP, York (1987), vol.274, p.182. The author describes work that has been carried out in connection with the use of an foF2 departure index-a daily measure of how F2 critical frequencies have compared with corresponding 27-day medians-and of a composite HF signal quality index which correlates well with it. He presents an investigation of four years duration which provides new data on solar rotation. The hourly components on which the departure index is based form patterns which may be traced from one ionosonde to another over a wide range of latitudes in Europe; they form an ideal subject for mapping and a detailed example is given of this. All the work is based on professional measurements held in World Data Centres