Fig. 3: Spatial structure of Arctic cyclone frequency.
From: Arctic cyclones have become more intense and longer-lived over the past seven decades
Frequency of occurrence of strong cyclones that propagate into or are generated locally within the Arctic region (north of 60°N) for the winters from a 1985/86 to 2020/21 and b 1950/51 to 1984/85. c shows the differences between (a) and (b). d–f are the same as (a–c) but for the summers from 1986 to 2021 and from 1950 to 1985. The dots in (d) and (f) indicate that the differences are statistically significant at the level of p < 0.10 using the two-sided t-test.
