The Zhubov scale is a way of reporting polar sea ice coverage.
It was developed in the former USSR by Russian naval officer N. N. Zhubov (1895–1960) as a way for Soviet officers to describe ice coverage.
The Zhubov scale is measured by using the unit ball, one ball equals 10% coverage, five balls 50% coverage and so on, with a total of ten unit balls being possible.
References
↑Joseph, Christopher (2022-04-12). How to Measure Anything. London: Ivy Press. p.40. ISBN978-0-7112-6803-6.
12Jerrard, H. G. (2013-03-09). A Dictionary of Scientific Units. Springer Science & Business Media. p.165. ISBN978-94-017-0571-4.