The streaks may look like fine lines, comma-shaped, or a mix of irregular lines, but generally move across the sky from west to east.Ĭirrus clouds are high altitude clouds. One common feature is the fall streaks it has, that result from falling ice crystals, or blown away ice crystals by high winds. They appear as silky, delicate, or tuft of hair (such as a horsetail). They occur in fair weather, and they usually point in the direction of the acting winds. Lynch, et al., eds., Cirrus (Oxford University Press, 2001).Cirrus clouds (cirrus means tuft of hair in Latin) are found above 20,000ft. de Villiers, Windswept: The Story of Wind and Weather (Walker and Company, 2007) D.K. Peterson, eds., Peterson First Guide to Clouds and Weather (Houghton Mifflin, 1998) M. SEE ALSO: Aerosols Albedo Clouds, Cumulus Clouds, Stratus Precipitation Troposphere Weather.īIBLIOGRApHY: J.A. In 2007, investigations at the University of Alabama at Huntsville found that global warming might paradoxically be leading to a thinning of these greenhouse-inducing cirrus clouds. This latter phenomenon adds to the greenhouse effect. The nature of the clouds allows them to reflect sunlight away from the earth, known as the albedo effect, but also to trap infrared light beneath them on the earth's surface. Each CCN is approximately one one-hundredth the size of the cloud droplet, which is itself approximately one one-hundredth the size of a rain droplet (usually about. These droplets condense around cloud condensation nuclei (CCN), which are often particles of aerosol providing a scaffold around which the cloud can form. A cloud forms when water vapor reaches its dewpoint and condenses to form a water droplet. The next atmospheric layer is the stratosphere, extending to 31 mi. The troposphere is the lowest atmospheric region and is where all weather takes place. The modeling of these clouds and their effects is difficult, due to the irregular nature of the sizes and shapes of their ice crystals.Ĭlouds can be found in the atmospheric layer called the troposphere. Studies are currently being conducted at the United States National Aeronautics and Space Administration (NASA) to determine the role of cirrus clouds in global warming and the Earth's climate. In contrast, the high cirrus clouds can both conserve heat and reflect it, but are often better at conserving it. This imbalance is due to the fact that lower clouds are weaker at conserving solar heat, but are very good at reflecting it back into the atmosphere. Some meteorologists use cirrus clouds to predict rain.īecause of the high altitude of these clouds, their albedo effect is often overridden by their greenhouse effect.
Cirrus clouds usually form in the summer and winter, when opposing weather fronts meet, such as warm, dry air and cool, dry air. In the case of Cirrus Kelvin-Helmholtz, the clouds lie in the turbulent atmospheric region. Other formations include cirrus aviaticus (also called contrails, the artificial cirrus clouds generated by aircraft), cirrus castellanus (castle-like, with towers rising from a base), cirrus duplicatus (multiple sheets), cirrus fibratus (fibrous, and resembling a horse's tail), cirrus floccus (rounded above), cirrus intortus (tangled), cirrus Kelvin-Helmholtz (slender and signaling atmospheric turbulence), cirrus radiatus (with horizontal banding), cirrus spissatus (thick and gray in color when in front of the sun), cirrus uncinus (hooked, and reminiscent of cirrus fibratus but with more curling at the ends), cirrus vertebratus (rib-like horizontal strips of clouds), and cirrus with mamma-tus (rounded underneath).Ĭirrus clouds are generally seen in fair weather, sometimes following a thunderstorm, and their wisps typically point in the direction of the high-altitude wind flow. Type of cloud formation occurs when the thin strands of clouds are so dense that they cannot be deciphered. Some cirrus clouds are called cirrostratus this Cirrus are the high, wispy clouds composed predominantly of tiny ice crystals formed in the cold region of the troposphere. If cirrus clouds drop their ice crystals, these crystals evaporate before they arrive at the ground.Ĭirrus clouds can take on a variety of formations, including a more tuft-like characteristic called cirro-cumulus, which also include supercooled water droplets.
They are composed predominantly of tiny ice crystals, because they form in the cold region of the troposphere. The name cirrus comes from the Latin word for curl. Cirrus clouds ARE the thin and wisp-like clouds seen at high altitudes (higher than 20,000 to 26,000 ft., or 6,000 to 8,000 m.).
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