The global cloud cover averages around 0.68 when analyzing clouds with optical depth larger than 0.1. This value is lower (0.56) when considering clouds with an optical depth larger than 2, and higher when counting subvisible cirrus clouds.
How much cloud cover is mostly cloudy?
The terms mostly clear or mostly sunny are used for one-eighth to two-eights cloud cover, partly cloudy or partly sunny three-eighths to four-eights cloud cover, mostly cloudy or considerable cloudiness five-eighths to seven-eighths cloud cover , and cloudy or overcast, when there is eight-eights cloud cover.
How is cloud cover calculated?
The unit of measure for cloud cover is the Okta . Cloud cover is measured on an eight point scale, 0 Oktas being clear sky , one Octa being 1/8 of the sky covered in cloud, and so on up to 8 Oktas – completely overcast.
Can you measure a cloud?
Cloud base is readily measured by instrument to a reasonable level of accuracy. The type of cloud base recorder used widely at synoptic observing stations is shown below.
How is cloud thickness calculated?
Cloud height, also known as cloud thickness or cloud depth is the distance between a cloud’s base, or bottom, and its top. It isn’t measured directly but rather is calculated by subtracting the altitude of its top from that of its base .
What does 70% cloud cover look like?
Mostly cloudy (or broken) is classified as 70 to 80 percent cloud cover or five to seven oktas. This is less than the 90 to 100 percent (eight oktas) used to define overcast skies. On mostly cloudy days, you will be able to see separation in the clouds. On overcast days, the sky looks like one big cloud.
What is good cloud cover?
The global cloud cover averages around 0.68 when analyzing clouds with optical depth larger than 0.1. This value is lower (0.56) when considering clouds with an optical depth larger than 2, and higher when counting subvisible cirrus clouds.
What is Considerable cloudiness?
The NWS definition says the sky is classified as mostly cloudy when 3/4 to 7/8 of the sky is covered by clouds , and it can also be referred to as “considerable cloudiness.” ... When 1/8 to 1/4 of the sky is covered by clouds, it’s classified as mostly sunny, or mostly clear at night, according to the NWS.
What does cloud 9 mean?
: a feeling of well-being or elation —usually used with on still on cloud nine weeks after winning the championship.
How high is the cloud base?
A cloud base (or the base of the cloud) is the lowest altitude of the visible portion of a cloud . It is traditionally expressed either in metres or feet above mean sea level or above a planetary surface, or as the pressure level corresponding to this altitude in hectopascals (hPa, equivalent to the millibar).
How is cloud height calculated?
- Find the difference between the temperature at the surface and the dew point.
- Divide the difference between 2.5.
- Multiply the result by 1,000.
- This will then give you the height above ground level.
- Add the elevation of the airfield and this will give height above sea level.
Can you touch a cloud?
Unfortunately, it does not feel like cotton balls or cotton candy, but most people have technically touched a cloud before . If you wanted to touch an airborne cloud, the best way to do this is either skydiving or in a hot air balloon, though I would not want to be stuck in a cloud while in a hot air balloon.
Is fog a cloud?
Fog is a cloud that touches the ground . ... Fog shows up when water vapor, or water in its gaseous form, condenses. During condensation, molecules of water vapor combine to make tiny liquid water droplets that hang in the air. You can see fog because of these tiny water droplets.
What is the highest cloud ever recorded?
Formation. Noctilucent clouds are composed of tiny crystals of water ice up to 100 nm in diameter and exist at a height of about 76 to 85 km (249,000 to 279,000 ft), higher than any other clouds in Earth’s atmosphere.
Will it rain if it is cloudy?
If it’s raining, then it’s cloudy. If it is raining, then there are clouds . Given: It is raining. ... Given: Conclusion: If it is raining, then there are clouds.
Why is the sky always GREY in winter?
Why is it so persistently more cloudy in the winter than in the warmer months? Dear Doug, It has to do with the thermal structure of the atmosphere . In general, the atmosphere in the summer is warmer in the surface layer (the lower several hundred feet) than it is above that.
