KnowraCirrus cloudCirrus cloudA high-level cloud composed mainly of ice crystals, typically appearing as thin, wispy strands or filaments.BriefConnectIce nucleation: The process by which ice crystals begin forming in supercooled water or directly from water vapor. Cirrus crystals often form directly from water vapor on atmospheric ice-nucleating particles.Cloud: A visible collection of suspended liquid droplets, ice crystals, or both in an atmosphere. Cirrus is one distinct form of cloud, distinguished by altitude, composition, and appearance.Numerical weather prediction: Forecasting future weather by numerically solving equations that describe the atmosphere. Forecast models must represent cirrus formation and persistence to simulate upper-level moisture and radiation.Cirrus fibratus: A cirrus species composed of separate or merged filaments that appear straight or gently curved. It is the familiar hairlike form often used to recognize cirrus.Cirrus cloud thinning: A proposed climate intervention that aims to reduce cirrus coverage or thickness to increase outgoing infrared radiation. Its feasibility depends on whether changing ice-crystal populations can reliably alter cirrus lifetime.Deposition (meteorology): The phase change in which water vapor becomes ice without first becoming liquid. This process grows ice crystals in the cold, dry air where cirrus clouds form.Troposphere: The lowest atmospheric layer, where most weather and clouds occur. Most cirrus forms in the upper troposphere, above lower cloud families.Satellite cloud detection: The use of satellite measurements to identify and characterize clouds across Earth. Satellite imagery reveals thin cirrus that can be difficult to distinguish from clear sky by eye.Cirrus uncinus: A cirrus species with hooked or comma-shaped heads, often called mares’ tails. Its distinctive hooked ends reveal how falling ice crystals are advected by wind.Ice-nucleating particle: An aerosol particle that enables ice to form at temperatures warmer than would otherwise be possible. Their scarcity and varied properties complicate predictions of cirrus ice crystal numbers.Show all 26Linked from 10 pagesSun dogRelated: Cirrus clouds can supply the crystals that produce sun dogs.Cumulus cloudCompared with: Its icy, wispy structure contrasts with the liquid-water towers of ordinary cumulus.Chemtrail conspiracy theoryRelated: Persistent contrails can spread into cirrus-like cloud cover, changing the sky’s appearance.Cirrostratus cloudCompared with: Unlike cirrus, cirrostratus usually forms a continuous or broad translucent sheet.Noctilucent cloudCompared with: Unlike cirrus, noctilucent clouds lie far higher and can remain sunlit after the lower atmosphere darkens.Cirrocumulus cloudCompared with: Cirrus appears fibrous, unlike cirrocumulus's compact patches and ripples.Fractus cloudCompared with: Cirrus is high and icy, unlike low, droplet-rich fractus.Show all 10