Weather Facts Wind of the World Climate of the World Weather Lore Weather Brains Philip Eden Oil spill Fukushima Volcanic ash Video Katabatic winds Katabatic wind from the Greek: katabaino - to go down is the generic term for downslope winds flowing from high elevations of mountains, plateaus, and hills down their slopes to the valleys or planes below. 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. Warm, dry katabatic winds occur on the lee side of a mountain range situated in the path of a depression. Examples for these descending, adiabatically warmed katabatic winds are the Foehn winds. Cold and usually dry katabatic winds, like the Bora, result from the downslope gravity flow of cold, dense air.
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Theory[ edit ] Sketch of the generation of katabatic winds in Antarctica A katabatic wind originates from radiational cooling of air atop a plateau, a mountain, glacier, or even a hill.
Since the density of air is inversely proportional to temperature , the air will flow downwards, warming approximately adiabatically as it descends. The temperature of the air depends on the temperature in the source region and the amount of descent.
In the case of the Santa Ana, for example, the wind can but does not always become hot by the time it reaches sea level. In Antarctica, by contrast, the wind is still intensely cold. The entire near-surface wind field over Antarctica is largely determined by the katabatic winds, particularly outside the summer season, except in coastal regions when storms may impose their own wind field.
Impacts[ edit ] Coastal polynyas are produced in the Antarctic by katabatic winds Katabatic winds are most commonly found blowing out from the large and elevated ice sheets of Antarctica and Greenland. The buildup of high density cold air over the ice sheets and the elevation of the ice sheets brings into play enormous gravitational energy.
In a few regions of continental Antarctica the snow is scoured away by the force of the katabatic winds, leading to "dry valleys" or " Antarctic oases " such as the McMurdo Dry Valleys. Since the katabatic winds are descending, they tend to have a low relative humidity, which desiccates the region. Other regions may have a similar but lesser effect, leading to "blue ice" areas where the snow is removed and the surface ice sublimates , but is replenished by glacier flow from upstream. In the Fuegian Archipelago Tierra del Fuego in South America as well as in Alaska in North America, a wind known as a williwaw is a particular danger to harboring vessels.
An anabatic wind is warm wind that blows up a mountain slope. Anabatic winds are affected by warm air. Description An anabatic wind is warm wind that blows up a mountain slope due to a warmer temperature on the mountain slope compared to the temperature in the air column. Also known as an upslope wind or upslope flow, the name anabatic wind stems from the Greek word "anabatos," which means "moving upward. The opposite of an anabatic wind is a katabatic wind, which blows down the slope of a mountain.
What Causes Surface Winds, Mountain Winds and Anabatic Winds
Jump to navigation Jump to search 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. These winds typically occur during the daytime in calm sunny weather. A hill or mountain top will be radiatively warmed by the Sun which in turn heats the air just above it. Air at a similar altitude over an adjacent valley or plain does not get warmed so much because of the greater distance to the ground below it. The effect may be enhanced if the lower lying ground is shaded by the mountain and so receives less heat. The air over the hill top is now warmer than the air at a similar altitude around it and will rise through convection. This creates a lower pressure region into which the air at the bottom of the slope flows, causing the wind.
What Are Anabatic Winds?
Jan 28, Wind Measurement Local Surface winds are sometimes more a function of Temperature Differences between mountain tops and lower elevations than overriding Synoptic winds. These winds are sometimes called Mountain Winds as they occur most frequently in mountainous areas, meteorologist call them Katabatic or Anabatic Winds. Anabatic Winds are upslope winds driven by warmer surface temperatures on a mountain slope than the surrounding air column. Katabatic winds are downslope winds created when the mountain surface is colder than the surrounding air and creates a down slope wind. 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. They can produce winds to 80 miles per hour and dominate local weather patterns for extended periods of time weeks. As shown in figure 2.