Downslope winds usually refer to winds generated as a deeper layer of air is forced over topography. In contrast to katabatic winds, the diabatic cooling of air in contact with a cold surface plays no essential role in the dynamics of downslope winds.
What are the characteristics of downslope winds?
Downslope winds are very shallow and of a slower speed than upslope winds. The cooled denser air is stable and the downslope flow, therefore, tends to be laminar. Downslope winds may be dammed temporarily where there are obstructions to free flow, such as crooked canyons and dense brush or timber.
What is the difference between Katabatic and downslope winds?
Downslope winds usually refer to winds generated as a deeper layer of air is forced over topography. In contrast to katabatic winds, the diabatic cooling of air in contact with a cold surface plays no essential role in the dynamics of downslope winds.
Why do winds flow upslope and downslope during the day?
They flow upslope during the day as the result of surface heating, and downslope at night because of surface cooling. Slope winds are produced by the local pressure gradient caused by the difference in temperature between air near the slope and air at the same elevation away from the slope.
What is a downslope wind event?
In most downslope wind events (including the typical foehn and chinook) the onset of the downslope wind is accompanied by an increase in the surface temperature and a drop in the dew point.
What is downslope flow?
Downslope flow is air moving over terrain such that it flows from a higher to a lower elevation. This in effect produces a sinking of the air. Air that sinks undergoes adiabatic transformations to temperature and relative humidity.
What are Santa Lucia winds?
Like a semi-truck rolling down the Cuesta Grade, air from the higher elevations of the Santa Lucia Mountains will flow downward along the mountain slopes toward the Pacific Ocean, pulled by the never-ending force of gravity. These downslope winds are called Santa Lucia winds in San Luis Obispo County.
What time of day do downslope winds occur?
In some areas, downslope afternoon winds occur nearly every day during the warm season, while in other areas they occur only occasionally. The time of the wind shift from upslope to downslope on the east side may vary from late forenoon to late afternoon, but most frequently it is around noon or early afternoon.
What are katabatic and 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.
What mountain range is Big Sur in?
the Santa Lucia MountainsWithin Big Sur, the Santa Lucia Mountains rise right up from the ocean, creating ridges that are some 4,000 to 5,000ft (1,200-1500m) above the water. In fact, the range's Cone Peak is one of the steepest coastal mountains in the contiguous United States.
How do you say Santa Lucia?
0:000:27How to pronounce Santa Lucia (Italian/Italy) - PronounceNames.comYouTubeStart of suggested clipEnd of suggested clipGrandes names del arco santalucía santalucía lluvia decoran financiación aviones.MoreGrandes names del arco santalucía santalucía lluvia decoran financiación aviones.
What's a derecho storm?
A derecho, pronounced deh-REY-cho, is a long-lived, fast-moving thunderstorm that causes widespread wind damage. This particular storm system was fed by a heat dome over the eastern United States.
What are the winds in California called?
The Santa Ana winds are strong, extremely dry downslope winds that originate inland and affect coastal Southern California and northern Baja California. They originate from cool, dry high-pressure air masses in the Great Basin.
Why is it so windy in Orange County?
The explorer John C. Fremont is credited with giving the region its name. That lower pressure is found off the Southern California coast. The pressure gradient, or difference, between the high pressure air in the Great Basin and the lower pressure air at the coast creates the Santa Ana winds.
What is katabatic wind Short answer?
katabatic wind, also called downslope wind, or gravity wind, wind that blows down a slope because of gravity. It occurs at night, when the highlands radiate heat and are cooled.
How Anabatic wind is formed?
Anabatic winds are mainly created by ultraviolet solar radiation heating up the lower regions of an orographic area (i.e. valley walls). Due to its limited heat capacity, the surface heats the air immediately above it by conduction. As the air warms, its volume increases, and hence density and pressure decreases.
Are katabatic winds warm?
Though generally cold, katabatic winds can also be warm or hot. This is because as the air moves downhill and is compressed it warms (the katabatic wind would start out cold but become warmer as it moves downhill). A chinook (foehn) wind is a warm dry down slope wind.
How does the general wind affect the valley?
The general wind has its maximum effect on valley winds during the daytime when a strong general wind blows parallel to the valley. If the general wind is blowing in the direction of the upvalley wind and the air is relatively unstable, the influence of the general wind will be felt down to the valley floor.
What is valley wind?
Valley winds are diurnal winds that flow upvalley by day and downvalley at night. They are the result of local pressure gradients caused by differences in temperature between air in the valley and air at the same elevation over the adjacent plain or larger valley.
What is the reverse of the daytime sea breeze circulation?
The land breeze at night is the reverse of the daytime sea-breeze circulation. At night, land surfaces cool more quickly than water surfaces (discussed in chapter 2 ). Air in contact with the land then becomes cooler than air over adjacent water.
What are the factors that affect convective winds?
Any factors affecting heating and cooling will influence convective winds. These winds will also be affected by the general wind flow. The most familiar convective winds are land and sea breezes, valley and slope winds, whirlwinds, and winds associated with convective cumulus and thunderstorm clouds.
How are convective winds augmented?
Convective winds may be augmented, opposed, or eliminated by airflow having its origin in the larger pressure systems. The influence of these general winds on the convective wind systems varies with the strength of the general wind, its direction relative to the convective circulation, and the stability of the lower atmosphere.
What are convective winds?
Convective Winds. Winds of local origin—convective winds caused by local temperature differences—can be as important in fire behavior as the winds produced by the synoptic-scale pressure pattern. In many areas they are the predominant winds in that they overshadow the general winds. If their interactions are understood, and their patterns known, ...
Why does the sea breeze flow inland?
As land surfaces become warmer than adjacent water surfaces during the daytime, and air over the land becomes worm and buoyant, the denser sea breeze begins to flow inland from over the water and forces the less-dense air upward.
What is the name of the wind that carries air from a higher elevation down a slope under the force of
Katabatic wind in Antarctica. A katabatic wind (named from the Greek word κατάβασις katabasis, meaning "descending") is a drainage wind, a wind that carries high-density air from a higher elevation down a slope under the force of gravity. Such winds are sometimes also called fall winds; the spelling catabatic winds is also used.
What is the wind that blows over Greymouth?
Another example is "the Barber", an enhanced katabatic wind that blows over the town of Greymouth in New Zealand when there is a southeast flow over the South Island. "The Barber" has a local reputation for its coldness.
What are some examples of katabatic winds?
Examples of true katabatic winds include the bora in the Adriatic, the Bohemian Wind or Böhmwind in the Ore Mountains, the Santa Ana in southern California, the piteraq winds of Greenland, and the oroshi in Japan. Another example is "the Barber", an enhanced katabatic wind that blows over the town of Greymouth in New Zealand when there is ...
What is the name of the wind that blows through the Greenland region?
In Greenland these winds are called piteraq and are most intense whenever a low pressure area approaches the coast. 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.
How fast can a williwaw wind blow?
Williwaws originate in the snow and ice fields of the coastal mountains, and they can be faster than 120 knots (140 mph; 220 km/h). In California, strong katabatic wind events have been responsible for the explosive growth of many wildfires, including the 2018 Camp Fire and the 2020 North Complex .
How does katabatic wind work?
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.
What are local surface winds?
Local surface winds are often a function of the difference in temperature between the higher and the lower elevations. These winds are sometimes called mountain winds as they mostly occur in mountainous regions. However, meteorologists refer to them as either anabatic or katabatic winds.
Which wind is more of a rain shadow wind?
Some winds such as chinook, fohn, and bergwind are more of rain shadow winds which are formed when the moist air is driven up the slope on the windward side descend on the leeward side as the warm and dry wind.
What is katabatic wind?
Katabatic Winds. Unlike anabatic wind which is an upslope wind, katabatic winds are downslope winds. In a simple definition, these are winds that carry high-density air from higher elevations down the slope. The name “katabatic” is derived from the Greek word “katabasis” which means descending.
Where do Katabatic winds blow out?
Impact Of The Katabatic Winds. Katabatic winds most commonly blow out from large elevated ice sheets in Greenland and Antarctica regions . The high-density cold air that builds up over the ice sheet and the elevation of the ice sheet increases the force of gravity.
What is wind movement?
Wind is the bulk movement of air that either result from temperature difference, largescale synoptic pressure, or local pressure and temperature differences. However, once the wind is generated, its direction and speed if modified by the existing surface structures. Local surface winds are often a function of the difference in temperature between ...
Why does air flow downwards?
Because air density is inversely proportional to the pressure at the top, the air will be forced to flow downwards and warms up in the process of descent. The temperature of the air is determined by the extent of descent and temperature in the source region.
How fast is a hurricane?
Katabatic winds are formed when the mountain surface becomes colder than the surrounding air, forcing the wind to rush down the slope, sometimes in a hurricane speed of up to 80 miles per hour.
