A multi-year study of the anomalous propagation conditions along the coast of the Adriatic sea

Aerological balloon soundings are an abundant and reliable source of modified refractive index profiles. A time series spanning 15 years, collected from 4 Adriatic aerological stations, shows frequent anomalous propagation (anaprop) phenomena over the coast of the Adriatic Sea: radio ducts, superrefractions and subrefractions. Radio ducts are the rarest phenomena, but they have the most dramatic effects on propagation. Radio ducts generally occur in the lower third of the troposphere. Superrefractions are the most frequent anaprop phenomena, occurring mostly in the lower half of the troposphere. Subrefractions occur frequently in cold and dry air higher in the atmosphere; therefore, the vertical distribution shows a significant number of elevated subrefractions. Rare cases of subrefractions in the stratosphere also occur. All anaprop phenomena show distinct annual cycles in both number and vertical distributions.

► 15 years long series of refractive profiles over Adriatic Sea.
► Anomalous phenomena vertical distributions.
► Annual variations of anomalous propagations.