Definition of "okta" in Anglais

noun

1. (meteorology) One eighth of the total area of the celestial dome; used as a measure of cloudiness (one okta means that one eighth of the sky is obscured, two oktas that one quarter is obscured, and so on).

   • ...64% of the low- and 50% of the high-cloud amount differences were within ± 1 okta, although many of these successes (71% in the low-cloud amount) were for cases of totally clear or totally cloudy skies.
   • Mean cloud amount distributions are transformed to normal distributions. The accuracy of the method is indicated by the retrieval of the original distribution with a typical error of 14% in the frequency of each okta of cloud amount.
   • For example, it has been estimated that a Landsat satellite, which revisits a particular location once every 16 days, will obtain a cloud-free scene of a particular location in Britain only once per year, and a scene with 1 okta of cloud (an okta is one eighth of the sky obscured by cloud) only twice per year.