Noun
a wispy white cloud (usually of fine ice crystals) at a high altitude (4 to 8 miles)
Source: WordNetCirrus fibratus clouds Based upon data taken from the United States using these methods, cirrus cloud cover was found to vary diurnally and seasonally. Source: Internet
Balloon-carried hygrometers give information on the humidity of the cirrus cloud but are not accurate enough to measure the depth of the cloud. Source: Internet
In winter, the cirrus cloud cover did not vary appreciably from day to night. Source: Internet
The ice crystals in contrails are much smaller than those in naturally-occurring cirrus cloud, as they are around 0.001 millimeters to 0.1 millimeters in length. Source: Internet
These may contribute to cirrus cloud formation. Source: Internet
These percentages include clear days and nights, as well as days and nights with other cloud types, as lack of cirrus cloud cover. Source: Internet