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. What is the difference between a fall wind and a katabatic. With clear skies the slope absorbs solar radiation and heats the air p directly in contact. The normal airflow over the rocky mountains is west to east. Katabatic wind speeds do not typically not exceed 3 or 4 ms.
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. This warming decreases the density of the air, causing it to rise. 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. Atoc exam 3 cu boulder 20 prof brown learn with flashcards, games, and more for free. Katabatic winds are nocturnal phenomena in most parts of the world i. Climatology of katabatic winds in the mcmurdo dry valleys. Pdf climatology of katabatic winds in the mcmurdo dry.
See cards from the most recent sets and discover what players just like you are saying about them. What causes surface winds, mountain winds and anabatic. This warming decreases the density of the air, causing. 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. In addition, the elevated airsea fluxes of heat, moisture, and momentum associated with these wind events. A new look at southeast greenland barrier winds and. 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. Differentiate between a solfatara and a mofette previous. The surface climatology of an ordinary katabatic wind regime in. Katabatic definition of katabatic by the free dictionary. Abstract the principle features of the katabatic wind in the neighbourhood of commonwealth bay, antarctica, are described with particular emphasis on the.
Katabatic winds can be very strong if the topography is steep and the wind can be channeled. Sounding almost like acrobatic winds, katabatic winds do bear a resemblance to tumbling, since they are essentially winds that flow downhill. These winds are driven by radiative cooling of the ice surface and are not resolved by the typical horizontal and vertical discretization of general circulation models. The preferred spelling for the technical term for katabatic wind seems to be catabatic. Katabatic wind, also called downslope wind, or gravity wind, wind that blows down a slope because of gravity. Katabatic wind may range over fairly large areas as in the case of the santa anna winds experienced throughout southern california during certain times of the year. Katabatics are associated with strong, sudden gusts, but they can be confused with other phenomena. Katabatic winds are downslope winds created when the mountain surface is colder than the surrounding air and creates a down slope wind. Looking at the katabatic winds offers an opportunity to explore air pressure and the properties of hot and cold air. 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.
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. 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. This air then flows up the slope, as it is at a higher temperature than the air q further away at the same level. They are made when cold, dense air flows down from the ice cap to the coast. His theory consists of an ekmantype slab boundary layer of constant. Katabatic winds are most significant in the two parts of the world with grand continental ice sheets. From the greek word katabatikos meaning to flow 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. A monsoon is a seasonal shift in winds and rainfall. Momentum, heat, and moisture budgets of the katabatic wind layer. Now it is recognized that these strong winds are a significant climatic feature of. 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. 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. However, where the ground is covered with snow or ice, katabatic winds can. Such winds, particularly when they occur over a wide area, are sometimes called fall winds.
The term katabatic wind is a more general term for a high density, gravity driven, downslope or drainage wind. These winds typically occur during the daytime in calm sunny weather. As the heating becomes stronger, convective currents begin to rise vertically from the valleys figure 328. Katabatic winds can rush down elevated slopes at hurricane. These winds are remarkably unidirectional, and can be very persistent and strong parish and waight 1987.
The fohn cumulus clouds anabatic winds this wind is again caused by thermal heat processes. 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 winds often originate over high elevation snow covered plateaus where stagnant air. It occurs at night, when the highlands radiate heat and are cooled. In this lesson we look at valley climates and consider. 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. A katabatic wind is a very strong wind which blows downhill. 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. Pdf classification of summer wind fields over complex.
Pdf this paper presents a onedimensional model of katabatic winds in ambient flow and examines types of possible solutions. Anabatic wind, also called upslope wind, local air current that blows up a hill or mountain slope facing the sun. 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, where the wind. Katabatic winds are blowing on the ground and off the high ridges. Katabatic winds on ice sheets and glaciers are buoyancydriven flows, much like turbidity currents in the ocean. They can also be very cold winds like those in antarctica or greenland. 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. Githiari answered the question on october 30, 2017 at 08. Katabatic winds blow down slope while anabatic winds up slope. Differentiate between katabatic and anabatic winds. The expansion of the heated air next to the surface produces a slight local pressure gradient against the ground surface. Meltwater produced by windalbedo interaction stored in an. Anabatic wind a localscale wind which blows upslope, after strong heating of the hillmountainside by the sun. Download wind factfile with many more winds metlink.
Climatology of katabatic winds in the mcmurdo dry valleys, southern victoria land, antarctica article pdf available in journal of geophysical research atmospheres 1093 february 2004 with. Nearsurface mean streamlines for the period june 2003may 2004 from the antarctic mesoscale prediction system. A katabatic wind can affect a much larger area than a simple mountain breeze. The katabatic winds of adelie land and king george v land. On the continental slope, the criteria pick out a coherent subset of the data that aretightly clustered in wind speed and wind direction.
A local wind that flows up the side of the valleys resulting from increased heating. Katabatic wind definition of katabatic wind by the free. Katabatic winds warm and mix the air as it flows downward. Introduction 2 katabatic winds were first documented during the early expeditions to antarctica.
Also known as fall winds, katabatic winds are usually caused by gravity pulling higher density air downslope to lower density air. The warm surface heats a vertical column of the atmosphere starting at the slope surface and reaching up to a few hundred meters deep. Anabatic, adiabatic and katabatic winds sujeet singh. It is caused by thermally direct circulation which reverses between winter dry and summer wet. He described the winds as katabatic and it seemed to tally with the notion we all have. Glacier winds in the eastern alps and also above pasterze glacier have been documented at an early stage tollner 1935. A katabatic wind 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. 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. The mechanism of the anabatic wind can be described as follows. Petermann fjord does not host much multiyear landfast ice since katabatic winds i. Anabatic wind article about anabatic wind by the free. When it descends on the eastern side, the increase in pressure toward lower altitudes causes the temperature to increase.
Dust devils and haboobs are examples of wind phenomena particular to desert regions. I assume you want to know what a katabatic wind is technically, so ill go with the spelling catabatic. A hill or mountain top will be radiatively warmed by the sun which in turn heats the air. Anabatic wind, local air current that blows up a hill or mountain slope facing the sun. 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 definition and meaning collins english dictionary. The air loses much of its moisture content and is chilled as it climbs the western side of the mountains. The air moving up the slope is subject to expansion.
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