Abstract:

 The strategic importance of the Arctic region has been increasing because the shortest routes between North America, Europe and Asia go through the Arctic. Atmospheric ducts are important for the application of over-the-horizon radar detection and communication. Spatial and temporal features of atmospheric ducts over the North Pole were analyzed statistically from radiosonde data collected at 16 stations from January 2007 to December 2016. Occurrence probability, thickness and strength of the ducts were calculated, and generation mechanisms were examined. Occurrence probability of ducts over the North Pole was below 50% and probability of surface ducts was higher than that of elevated ducts. Duct thickness and strength were below 30 m and 10 M for surface ducts, and 40–80 m and below 10 M for elevated ducts. High incidence of atmospheric ducts was found over Greenland and the Nordic Seas, but was absent over the northern margin of Eurasia. High incidence of surface ducts was found over Greenland and the Nordic Seas, possibly as a result of the combined effects of the North Atlantic drift, the Greenland cold high and radiation inversion. High incidence of elevated ducts was found in the Nordic Seas and in northeastern Bering Strait, possibly as a result of sea fog formed in northern Europe and the Arctic front in northeastern Bering Strait during the warm season.

Key words: radiosonde data, North Pole, atmospheric duct, spatial and temporal features, weather causes