Fig. 4

Frequency of twilight events recorded by all GLS in Svalbard throughout the year (grey). Yellow line denotes day length at 76°N (southern edge of Spitsbergen). Hatched areas illustrate times of the year without twilight events (i.e., polar night or midnight sun; yellow) as well as times when latitude estimation is affected by spring (blue) or fall (orange) equinox. Number of days when location estimation is possible (and potentially affected by equinoxes) throughout the year are shown on top