OKTA

Article summary

In meteorology, an okta is a scale of measurement used to describe the amount of cloud cover at any given location such as a weather station. Sky conditions are estimated in terms of how many eighths of the sky are covered in cloud, ranging from 0 oktas (completely clear sky) through to 8 oktas (completely overcast). In addition, in the SYNOP code there is an extra cloud cover indicator '9' indicating that the sky is totally obscured (i.e. hidden from view), usually due to dense fog or heavy snow. When used in weather charts, okta measurements are shown by means of graphic symbols (rather than numerals) contained within weather circles, to which are attached further symbols indicating other measured data such as wind speed and wind direction. Although relatively straightforward to measure (visually, for instance, by using a mirror ), oktas only estimate cloud cover in terms of the area of the sky covered by clouds. They do not account for cloud type or thickness, and this limits their use for estimating cloud albedo or surface solar radiation receipt. Cloud oktas can also be measured using satellite imagery from geostationary satellites equipped with high-resolution image sensors such as Himawari-8. Similar to traditional approaches, satellite images do not account for cloud composition.…

Key claims

1. date of foundation: 1978 — source: Wikipedia · confidence 0.95

Discussion questions

1. Summarise the article in your own words. Which single claim would you verify first, and why?
2. The record states that the date of foundation is "1978". What evidence would count against this claim?
3. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
4. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

Bibliography

1. Wikipedia https://en.wikipedia.org/w/index.php?oldid=1359628784