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This study deals with the conditions of radio wave propagation in the link between the islands Chios and Lemnos and especially with the influence of weather situations upon this propagation. The field fading forms have been classified into three types A, B and C which have an annual course of large amplitude. Types A and B show their maximum frequency during the cold months of the year and their minimum during the warm months, while the type C shows an annual course inverse to the courses of the types A and B. This can be explained if it is taken into consideration that in the eastern Mediterranean the weather situations during the warm season are absolutely different from those of the cold season. Finally for the months January, April, July and October a correlation between the prevailing weather situations and the occurence of the A, B, C fading forms has been attempted, the main results of which were that the type C occurs with weak winds, or with clear and calm weather as well as under the blowing of the Etesian winds, while the type A is almost certainly due to the anticyclonic extensions during the cold season of the year and generally to the strong winds of the north sector. © 1967 Birkhäuser-Verlag.

The partial reflection technique has been used to measure the time variations of D-region electron densities at 74 and 80 km throughout the solar eclipse of 20 May 1966. The average diurnal variation of the electron density has also been derived from measurements over a period of about two weeks prior to the eclipse. The results are presented and compared with Al-absorption measurements. © 1970.

The paper discusses the interpretation of results from ionospheric observations during the annular solar eclipse of 20 May 1966. Observations were made of Lyman-α intensities, positive ion density, and electron density. From the observational results it is possible to estimate how the effective loss rate αeff = q N2 varies through the eclipse. It is concluded that the observed results can be explained in terms of a model of recombination in which two types of positive ions having markedly different recombination rates are present. Near 80 km this model predicts, and the results show, that electron density, N, is proportional to production, q, rather than q1 2 as usually assumed. © 1970.