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A barely visible crystalline form of ice that has the shape of needles, columns or plates. Ice crystals are so small that they seem to be suspended in air. Ice crystals occur at very low temperatures in a stable atmosphere.
Ice Crystals (IC) A fall of unbranched (snow crystals are branched) ice crystals in the form of needles, columns, or plates. They are also referred to as Diamond Dust.
Optical effects resulting from the interaction of light with ice crystals. These effects include: sundogs, sun pillars and halos.
Ice Crystals: 1) Hexagonal (6-sided) crystals that form upon the freezing of water, may be in one of several shapes: stars, needles, plates, columns or combinations of these forms. 2) Precipitation in the form of slowly falling, singular or unbranched ice needles, columns, or plates, ...
ice crystals—A type of precipitation composed of unbranched crystals in the form of needles, columns, or plates; usually having a very slight downward motion, may fall from a cloudless sky.
~- A barely visible crystalline form of ice that has the shape of needles, columns or plates. ~ are so small that they seem to be suspended in air. ~ occur at very low temperatures (around zero degrees F and colder) in a stable atmosphere.
Precipitation in the form of slowly falling, singular or unbranched ice needles, columns, or plates. They make up cirriform clouds, frost, and ice fog. Also, they produce optical phenomena such as halos, coronas, and sun pillars. May be called "diamond dust.
~- Frozen water vapor suspended in the air.
Instability- A state of the atmosphere in which convection takes place spontaneously, leading to cloud formation and precipitation.
White ~ deposited on the surface of objects that have a temperature below the freezing point of water.
The increase in global mean temperature, which is believed to be linked to the artificial increase in greenhouse gas concentrations.
FROST: ~ produced from water vapor that has frozen on a surface at or below 32ºF/0ºC.
FROST/FREEZE WARNING: Below-freezing temperatures are expected during the growing season and may cause significant damage to plants and crops.
If these ~ should fall into a warm lower cloud containing much moisture, they melt and then grow as they fall, sweeping up droplets in their path, and falling as rain. This is known as the Bergeron process, after Tor Bergeron, who conceived it in 1928, and published it in 1934.
hexagonal ~ with complex and often fernlike branches.
Frost ~ that are formed by deposition of water vapor on a relatively cold surface.
Frost point The temperature to which air must be cooled at constant pressure to achieve saturation at or below 0·C (32 ·F).
Frost - White ~ that form on a surface, like the ground or leaves of a plant. Frost is created when the air temperature drops below freezing and the water vapor in the air freezes into ~.
During one experiment, Schaefer thought the chamber was too warm and placed dry ice inside to cool it. Water vapor in the chamber formed a cloud around the dry ice. The ~ in the dry ice had provided a nucleus around which droplets of water could form inside the chamber.
White frost ~ that form on surfaces instead of dew when the dew point is below freezing.
Precipitation of ~, most of which are branched (sometimes star shaped).
Southern Oscillation Index (SOI) ...
Deposits of white ~ or frozen dew drops on objects on or near the ground. Formed when the surface temperature falls below freezing (0°).
(or F Scale) A scale of wind damage intensity in which wind speeds are inferred from an analysis of wind damage: ...
Snow - Large flat ~ that hook onto each other and make white flakes.
Gaussian model - a way of calculating concentrations of polluting chemicals from stationary industrial sources. The substance goes downwind and disperses (gets weaker) as it travels, according to Gaussian mathematics.
The altitude which ~ and snowflakes melt as they descend through the atmosphere.
The temperature at which a solid substance undergoes fusion, changing from a solid to a liquid state. Contrast with freezing point.
SNOW Frozen precipitation in the form of white or translucent ~ in complex branched hexagonal form. It most often falls from stratiform clouds, but can fall as snow showers from cumuliform ones. It usually appears clustered into snowflakes.
Produced by reflection of moonlight from ~. Parahelic circle A halo consisting of a faint white circle passing through the sun and running parallel to the horizon for as much as 360° of azimuth. Produced by reflection of sunlight from ~.
They are caused by the refraction of sunlight passing through ~. They are most commonly seen during winter in the middle latitudes and are exclusively associated with cirriform clouds. They are also known as mock suns.
At the higher altitudes, they may also have some ~, but they are composed mainly of water droplets. Altocumulus, altostratus, and nimbostratus are the main types of middle clouds. This altitude applies to the temperate zone.
snowPrecipitation in the form of ~, mainly of intricately branched, hexagonal form and often agglomerated into snowflakes, formed directly from the freezing [deposition] of the water vapor in the air.snowflakeAn aggregate of ~ that falls from a cloud.
GlaciationThe transformation of cloud particles from water drops to ~. Thus, a cumulonimbus cloud is said to have a "glaciated" upper portion.
A cloud based at the earth's surface, consisting of tiny water droplets, or under very cold conditions, ~ or ice fog. It is generally found in calm or low wind conditions. Under foggy conditions, visibility is reduced to less than 1 kilometre.
Fog Bank ...
Stratus does not usually produce precipitation, but when it does occur it is in the form of minute particles, such as drizzle, ~, or snow grains.
Aerosols are important in the atmosphere as nuclei for the condensation of water droplets and ~, as participants in various chemical cycles, and as absorbers and scatterers of solar radiation, thereby influencing the radiation budget of the earth-atmosphere system, ...
Likewise, inside a cold cloud, ~ can also grow to a size where they can break the buoyancy and fall out of the cloud's bottom, and when they pass through a temperature of 0 °C they will melt and become rain drops, also providing the ground with rain.
In many clouds, raindrops actually begin as tiny ~ that form when part or all of a cloud is below freezing. As the ~ fall inside the cloud, they may collide with water droplets that freeze onto them.
The white trails are ribbons of ~. As a by-product of the exhaust of aircraft engines, water vapour is trailed from the engine exhaust which adds to the local humidity of the air the aircraft is flying through, and which tends to super-saturation of the air.
The most important is through the Bergeron Process, theorized by Tor Bergeron, in which supercooled water droplets and ~ in a cloud interact to produce the rapid growth of ~, which precipitate from the cloud and melt as they fall.
Frost: The formation of ~ on the ground or other surfaces in the form of scales, needles, feathers, or fans. Frost develops under conditions similar to dew, except the temperatures of the Earth's surface and earthbound objects fall below 32oF.
It refers to ~ or needle-like spicules which form in supercooled water of river or stream currents which move too fast for surface ice sheets to form. In salt water is is called lolly ice. The term frazil is from the French fraisil which means cinders.
CONTRAIL - A visible trail of vapor and / or ~ caused by a high-flying aircraft. The hot exhaust from an aircraft engine contains various gases, including water vapor.
Leave the bread there overnight so that it freezes and ~ are visible inside the plastic wrapping. Show the bread to your students and ask them how and why the ~ formed. (The moist air, trapped inside the bag, cooled down to its dew point temperature in the freezer.
frost: 1) a cover of ~ produced when atmospheric water vapor is deposited directly on a surface when the temperature is below freezing, 2) the condition that exists when the temperature of the earth's surface and earth-bound objects falls below freezing.
Clouds composed of small particles, mostly ~. Because the particles are fairly widely dispersed, this usually results in relative transparency and whiteness, often producing a halo phenomena not observed in other clouds forms.
Cirrus - High-level clouds (16,000 feet or more), composed of ~ and appearing in the form of white, delicate filaments or white or mostly white patches or narrow bands. Cirrus clouds typically have a fibrous or hairlike appearance, and often are semi-transparent.
ALTOSTRATUS This middle cloud genus is composed of water droplets, and sometimes ~, In the mid-latitudes, cloud bases are generally found between 15,000 and 20,000 feet. White to gray in color, it can create a fibrous veil or sheet, sometimes obscuring the sun or moon.
Cloud: Aggregate of very small droplets of water, ~ or the mixture of both with its base above the surface of the Earth.
Cirrostratus High, thin, sheetlike clouds, composed of ~. They frequently cover the entire sky and often produce a halo.
Cirrus A high cloud composed of ~ in the form of thin, white, featherlike clouds in patches, filaments, or narrow bands.
Frost - The formation of thin ~ on the ground or other surfaces. Frost develops when the temperature of the exposed surface falls below 32 degrees Fahrenheit and water vapor is deposited as a solid.
Gale - Sustained wind speeds from 34 to 47 knots (39 to 54 mph).
A term used to signify cirriform clouds that are composed of ~ and generally have bases above 20,000 feet. The main types of high clouds are cirrus, cirrocumulus, and cirrostratus. This altitude applies to the temperate zone.
Frost- the formation of thin ~ on the ground or other surfaces; frost develops under conditions similar to those of dew, except in temperature of the earth's surface and earthbound objects fall below thirty-two degrees Fahrenheit.
Freezing fog is different from ice fog. Ice fog occurs when the fog particles turn to ~ and the outside temperature has to drop well below freezing for the supercooled droplets to turn to ~ while still in the air.
Cloud - A visible collection of very fine water droplets or ~ suspended in the atmosphere at altitudes from just above the ground to several miles above the sea level.
Condensation - The process by which a gas or vapor changes to a liquid.
CIRRUS (CI) - High clouds, usually above 18,000 feet, composed of ~.
CLASSIC EVENT- Having all the ingredients for a specific type of weather (i.e. classic severe weather event, classic Nor'easter)
CLEAR - Sky condition of less than 1/10 cloud coverage.
Precipitation in the form or small tabular and columnar white ~ formed directly from the water vapor of the air at a temperature of less than 0 degrees Celsius.
Weather Glossary Search Page
Weather Glossary Source List ...
Level at which ~ and snowflakes melt during their descent through the atmosphere.
Person who is professionally employed in the study or practice of meteorology.
Cloud - A visible aggregate of tiny water droplets and/or ~ in the atmosphere above the earth's surface.
Cold Front - A transition zone where a cold air mass advances and replaces a warm air mass.
CIRRUS: High clouds, usually above 18,000 feet, composed of ~.
CLEAR: Sky condition of less than 1/10 cloud coverage.
CLIMATE: The historical record of average daily and seasonal weather events.
Clouds can be categorized into two general groups: cumulus clouds (tall, cotton ball) and stratus clouds (layered); these can be divided even further to 4 sub-groups describing altitude: 20,000 ft and above are the cirrus or cirro clouds (cirrocumulus, cirrostratus), composed of mostly ~; ...
Rings or arcs that seem to encircle the sun or moon. They are caused by the refraction of light through the ~ in cirrus clouds.
stratiform: flat or layered
cumuliform: puffy or globular
cirroform: wispy, made of ~ ...
A narrow white or colored ring or arc around the sun or moon. Haloes are seen as light that is refracted through an ice-crystal cloud or when the sky is filled with falling ~.
See also: What is the meaning of Water, Cloud, Surface, Temperature, Air?