Anabatic winds are typically daytime winds during summer. Such winds, particularly when they occur over a wide area, are sometimes called fall winds. Katabatic wind article about katabatic wind by the free. Anabatic wind synonyms, anabatic wind pronunciation, anabatic wind translation, english dictionary definition of anabatic wind. Katabatic is a local wind caused often at night by the flow of air, cooled by radiation, down mountain slopes and valleys. In winter, the polar jet stream winds are stronger and the jet moves farther south and in summer it is weaker be able to explain how seasonal variations and the existence of continental land masses in the real world bring about changes in the regions of high and low pressure that differ from those predicted in the 3cell mode. Katabatic wind, also called downslope wind, or gravity wind, wind that blows down a slope because of gravity. Differentiate between katabatic and anabatic winds. Apr 18, 2017 anabatic, adiabatic and katabatic winds sujeet singh.
On the larger scale, persistent katabatic winds cover vast areas of the earth e. Anabatic winds are upslope winds driven by warmer surface temperatures on a mountain slope than the surrounding air column. These winds typically occur during the daytime in calm sunny weather. Looking at the katabatic winds offers an opportunity to explore air pressure and the properties of hot and cold air. What causes surface winds, mountain winds and anabatic winds. Anabatic wind, also called upslope wind, local air current that blows up a hill or mountain slope facing the sun. What causes surface winds, mountain winds and anabatic. Conversely, katabatic winds are downslope winds, frequently produced at night by the opposite effect, the air near to. With clear skies the slope absorbs solar radiation and heats the air p directly in contact.
Satellite analyses of antarctic katabatic wind behavior article pdf available in bulletin of the american meteorological society 707. Dec 15, 2010 katabatic winds are blowing on the ground and off the high ridges. Katabatic winds are most significant in the two parts of the world with grand continental ice sheets. Anabatic wind meteorology definition,meaning online. Katabatic wind, wind that blows down a slope because of gravity. Anabatic definition of anabatic by the free dictionary. Atoc exam 3 cu boulder 20 prof brown learn with flashcards, games, and more for free. The katabatic winds are most pronounced during winter, when there is no incoming solar radiation, and a large pool of cold air over the interior is formed to feed the katabatic flow. As the air warms, its volume increases, and hence density and pressure decreases. During the day, the sun heats such a slope and the air over it faster than it does the adjacent atmosphere over a valley or a plain at the same altitude. Jan 28, 2009 anabatic winds are upslope winds driven by warmer surface temperatures on a mountain slope than the surrounding air column. A hill or mountain top will be radiatively warmed by the sun which in turn. These winds are remarkably unidirectional, and can be very persistent and strong parish and waight 1987. The katabatic winds on the continent exist due to the airflow from the high pressure, cold, elevated plains down slope to the relatively warmer lower elevations with less pressure.
Speeds in the mountainvalley anabatic flow layer are often 35 m s1. This air then flows up the slope, as it is at a higher temperature than the air q further away at the same level. Githiari answered the question on october 30, 2017 at 08. These winds are known as valley wind or anabatic wind. Katabatic winds exist in many parts of the world and there are many different names for katabatic winds depending where they are located and how they are formed. Conversely, katabatic winds are downslope winds, frequently produced at night by the opposite effect, the air near to the ground losing heat to it faster than air at a similar altitude over adjacent lowlying land. Katabatic winds blow down slope while anabatic winds up slope. Katabatic winds are slope winds that occur over ice sheets and glaciers, and which arise due to the radiative cooling of the surface, which forms a layer of dense, cold air that flows down the ice slope under its own weight davolio and buzzi 2002. Simply put, katabatic wind is cold dense air that pours down the ice slope to the sea, becoming denser and picking up speed as it goes.
Katabatic definition is relating to or being a wind produced by the flow of cold dense air down a slope as of a mountain or glacier in an area subject to radiational cooling. At night, the katabatic winds from the bottom of the slopes drain into the valley, where they start to accumulate. Anabatic wind, local air current that blows up a hill or mountain slope facing the sun. Katabatic definition of katabatic by merriamwebster. Katabatic winds can be deep and powerful, so pilots usually give those southfacing slopes a respectful margin. Results from this study show that for a relatively dry case thermal. Depending on the relative position of the sun and the angle of the orographic surface to the sun, the sunny side of valleys are more prone to anabatic winds than the shady side, where relatively colder air may even flow downwards along the orographic slope, resulting in a katabatic wind. Late wednesday afternoon we had a sudden literally within minutes turn around in the weather, when the winds reversed direction, a white wall of blowing snow descended on camp and the wind speed jumped high enough to make you lean into it. Katabatic and anabatic winds are part of larger circulations in the valley. An anabatic wind, from the greek anabatos, verbal of anabainein meaning moving upward, is a warm wind which blows up a steep slope or mountain side, driven by heating of the slope through insolation. Pdf satellite analyses of antarctic katabatic wind behavior. This pool of cold air is often stratified like a layer cake, with the coldest air at the bottom and lesscold air on top. Often anabatic wind results in cumulus clouds along the ridges on either side of the valley. It occurs at night, when the highlands radiate heat and are cooled.
Anabatic wind a localscale wind which blows upslope, after strong heating of the hillmountainside by the sun. By the book ascending in a balloon is a matter of adding heat and buoyancy to the balloon by firing the propane burner, or by tapping into an anabatic wind. Katabatic wind flowing from the balkan plateau down to the adriatic, resulting in cold and strong winds, reaching 60 knots and gusts to around the 100 knot mark. Dec 04, 2016 anabatic winds can be detrimental to the maximum downhill speed of cyclists. Structure of turbulence in katabatic flows below and above.
Katabatic winds exist in many parts of the world and there are many different names for katabatic winds depending where they are located. Unlike winds in other parts of the world, antarcticas katabatic winds are caused by the shape of the land. Katabatic winds have been experimentally described covering various regions of the. It is caused by ground surface cooling as a result of radiation, which in turn cools the lower air layers. The fohn cumulus clouds anabatic winds this wind is again caused by thermal heat processes. A katabatic wind, from the greek word katabatikos meaning going downhill, is the technical name for a drainage wind, a wind that carries high density air from a higher elevation down a slope under the force of gravity. Oct 30, 2017 katabatic winds blow down slope while anabatic winds up slope. Slopes occur on many scales, and consequently anabatic flows also occur on. The katabatic wind regime at adelie land, antarctica article in international journal of climatology 111. The air in contact with these highlands is thus also cooled, and it becomes denser than the air at the same elevation but away from the slope. Anabatic wind article about anabatic wind by the free.
An early milestone in the conceptual understanding of katabaticanabatic. However, katabatic winds might also reach gale force as an outblowing wind over icecovered surfaces in antarctica and greenland, where the wind may be extremely strong and gusty near the coasts and less severe in mountain regions. Anabatic wind definition of anabatic wind by the free. The katabatic wind regime at adelie land, antarctica. Such winds are observed primarily at night when the ground layer of air cools. This warming decreases the density of the air, causing it to rise. The mechanism of the anabatic wind can be described as follows. The air moving up the slope is subject to expansion. Anabatic winds are mainly created by ultraviolet solar radiation heating up the lower regions of an orographic area i. Katabatic winds are blowing on the ground and off the high ridges. Katabatic winds are nocturnal phenomena in most parts of the world i. Katabatic winds have a long history of investigation and the relevant literature is voluminous. Differentiate between a solfatara and a mofette previous. Such upslope winds can sometimes drag fog stratus in the valley bottom formed after a cold night to upland areas that were previously clear of these phenomena.
Anabatic winds can be detrimental to the maximum downhill speed of cyclists. The occurrence is frequent and widespread in, for example, the fjords of norway, and as an outblowing wind over icecovered surfaces in antarctica and greenland. The data collected on 10 august 1990 from the hawaiian rainband project were analyzed to study the evolution of katabatic flow. As different as anabatic and katabatic helicopters. The warm surface heats a vertical column of the atmosphere starting at the slope surface and reaching up to a few hundred meters deep. A katabatic wind, from the greek word katabatikos meaning going downhill, is a wind that blows down a topographic incline such as a hill, mountain, or glacier.
Katabatic winds are downslope winds created when the mountain surface is colder than the surrounding air and creates a down slope wind. Nearsurface mean streamlines for the period june 2003may 2004 from the antarctic mesoscale prediction system. It is also caused by the flow of cold air down the slopes of ice caps, such as antarctica and greenland. Because heating at the surface promotes deeper mixing than cooling does, the heated layer, often occurring as a convective or mixed layer, is generally deeper than a cooled or katabatic layer. A local wind that flows up the side of the valleys resulting from increased heating. Structure of numerically simulated katabatic and anabatic. Katabatic winds occur where air in contact with sloping ground is colder than air at the same level away from the hillside over the valley see diagram below. A hill or mountain top will be radiatively warmed by the sun which in turn heats the air. A katabatic wind named from the greek word katabasis, meaning descending is the technical name for a drainage wind, a wind that carries highdensity air from a higher elevation down a slope under the force of gravity. The average katabatic wind eventually approach es an equilibrium where drag balances buoyancy. This column is warmer than the column at the same levels over the valley or plain, resulting in hydrostatic low pressure over the slope relative to over the valley or plain.
Anabatic, adiabatic and katabatic winds sujeet singh. Those huge frozen plateaus the last remnants of the enormous ice bodies of the pleistocene glaciations reliably generate katabatic air movements along their margins. Katabatic definition and meaning collins english dictionary. Pdf evolution of katabatic flow on the island of hawaii. A local wind that flows up the side of the valleys resulting from increased heating along the valley walls. Download wind factfile with many more winds metlink.