Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk movement of
air. In
outer space,
solar wind is the movement of
gases or charged particles from the
sun through space, while
planetary wind is the
outgassing of light
chemical elements from a planet's atmosphere into space. Winds are commonly classified by their
spatial scale, their
speed,
the types of forces that cause them, the regions in which they occur,
and their effect. The strongest observed winds on a planet in our
solar system occur on
Neptune and
Saturn. Winds have various aspects, an important one being its
velocity; another the density of the gas involved; another is the energy content or
wind energy of a wind.
In
meteorology,
winds are often referred to according to their strength, and the
direction from which the wind is blowing. Short bursts of high speed
wind are termed gusts. Strong winds of intermediate duration (around
one minute) are termed
squalls. Long-duration winds have various names associated with their average strength, such as
breeze,
gale,
storm,
hurricane, and
typhoon.
Wind occurs on a range of scales, from thunderstorm flows lasting tens
of minutes, to local breezes generated by heating of land surfaces and
lasting a few hours, to
global winds resulting from the difference in absorption of
solar energy between the
climate zones on Earth. The two main causes of large-scale
atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet (
Coriolis effect). Within the tropics,
thermal low circulations over terrain and high plateaus can drive
monsoon circulations. In coastal areas the
sea breeze/land
breeze cycle can define local winds; in areas that have variable
terrain, mountain and valley breezes can dominate local winds.
In
human civilization, wind has inspired
mythology, influenced the events of
history, expanded the range of
transport and
warfare, and provided a
power source for
mechanical work,
electricity and
recreation. Wind powers the voyages of
sailing ships across Earth's oceans.
Hot air balloons use the wind to take short trips, and powered flight uses it to increase lift and reduce fuel consumption. Areas of
wind shear caused by various
weather phenomena can lead to dangerous situations for
aircraft. When winds become strong, trees and man-made structures are damaged or destroyed.
Winds can shape landforms, via a variety of
aeolian processes such as the formation of fertile soils, such as
loess, and by
erosion.
Dust from large
deserts can be moved great distances from its source region by the
prevailing winds;
winds that are accelerated by rough topography and associated with dust
outbreaks have been assigned regional names in various parts of the
world because of their significant effects on those regions. Wind
affects the spread of
wildfires.
Winds disperse seeds from various plants, enabling the survival and
dispersal of those plant species, as well as flying insect populations.
When combined with cold temperatures, wind has a negative impact on
livestock. Wind affects animals' food stores, as well as their hunting and defensive strategies.
Cause
Wind is caused by differences in the
atmospheric pressure. When a
difference in atmospheric pressure
exists, air moves from the higher to the lower pressure area, resulting
in winds of various speeds. On a rotating planet, air will also be
deflected by the
Coriolis effect, except exactly on the equator. Globally, the two major driving factors of large-scale wind patterns (the
atmospheric circulation) are the differential heating between the equator and the poles (difference in absorption of
solar energy leading to
buoyancy forces) and the
rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, the large-scale winds tend to approach
geostrophic balance. Near the Earth's surface,
friction
causes the wind to be slower than it would be otherwise. Surface
friction also causes winds to blow more inward into low pressure areas.
[1]
A new, controversial theory, suggests atmospheric gradients are caused
by forest induced water condensation resulting in a positive feedback
cycle of forests drawing moist air from the coastline.
[2]
Winds defined by an equilibrium of physical forces are used in the
decomposition and analysis of wind profiles. They are useful for
simplifying the atmospheric
equations of motion and for making qualitative arguments about the horizontal and vertical distribution of winds. The
geostrophic wind component is the result of the balance between Coriolis force and pressure gradient force. It flows parallel to
isobars and approximates the flow above the
atmospheric boundary layer in the midlatitudes.
[3] The
thermal wind is the
difference in the geostrophic wind between two levels in the atmosphere. It exists only in an atmosphere with horizontal
temperature gradients.
[4] The
ageostrophic wind component is the difference between actual and geostrophic wind, which is responsible for air "filling up" cyclones over time.
[5] The
gradient wind is similar to the geostrophic wind but also includes
centrifugal force (or
centripetal acceleration).
[6]
Measurement[edit]
Cup-type anemometer with vertical axis, a sensor on a remote meteorological station
An occluded mesocyclone tornado (Oklahoma, May 1999)
Wind direction is usually expressed in terms of the direction from which it originates. For example, a
northerly wind blows from the north to the south.
[7] Weather vanes pivot to indicate the direction of the wind.
[8] At airports,
windsocks indicate wind direction, and can also be used to estimate wind speed by the angle of hang.
[9] Wind speed is measured by
anemometers,
most commonly using rotating cups or propellers. When a high
measurement frequency is needed (such as in research applications),
wind can be measured by the propagation speed of
ultrasound signals or by the effect of ventilation on the resistance of a heated wire.
[10] Another type of anemometer uses
pitot tubes
that take advantage of the pressure differential between an inner tube
and an outer tube that is exposed to the wind to determine the dynamic
pressure, which is then used to compute the wind speed.
[11]
Sustained wind speeds are reported globally at a 10 meters (33 ft) height and are averaged over a 10 minute time frame. The
United States reports winds over a 1 minute average for tropical cyclones,
[12] and a 2 minute average within weather observations.
[13] India typically reports winds over a 3 minute average.
[14]
Knowing the wind sampling average is important, as the value of a
one-minute sustained wind is typically 14% greater than a ten-minute
sustained wind.
[15]
A short burst of high speed wind is termed a wind gust, one technical
definition of a wind gust is: the maxima that exceed the lowest wind
speed measured during a ten-minute time interval by 10 knots (19 km/h).
A
squall is a doubling of the wind speed above a certain threshold, which lasts for a minute or more.
To determine winds aloft,
rawinsondes determine wind speed by
GPS,
radio navigation, or
radar tracking of the probe.
[16] Alternatively, movement of the parent
weather balloon position can be tracked from the ground visually using
theodolites.
[17] Remote sensing techniques for wind include
SODAR,
Doppler lidars and
radars, which can measure the
Doppler shift of
electromagnetic radiation scattered or reflected off suspended
aerosols or
molecules, and
radiometers
and radars can be used to measure the surface roughness of the ocean
from space or airplanes. Ocean roughness can be used to estimate wind
velocity close to the sea surface over oceans. Geostationary satellite
imagery can be used to estimate the winds throughout the atmosphere
based upon how far clouds move from one image to the next.
Wind Engineering
describes the study of the effects of the wind on the built
environment, including buildings, bridges and other man-made objects.
Wind force scale[edit]
Historically, the
Beaufort wind force scale
provides an empirical description of wind speed based on observed sea
conditions. Originally it was a 13-level scale, but during the 1940s,
the scale was expanded to 17 levels.
[18]
There are general terms that differentiate winds of different average
speeds such as a breeze, a gale, a storm, tornado, or a hurricane.
Within the Beaufort scale, gale-force winds lie between 28 knots
(52 km/h) and 55 knots (102 km/h) with preceding adjectives such as
moderate, fresh, strong, and whole used to differentiate the wind's
strength within the gale category.
[19] A storm has winds of 56 knots (104 km/h) to 63 knots (117 km/h).
[20]
The terminology for tropical cyclones differs from one region to
another globally. Most ocean basins use the average wind speed to
determine the tropical cyclone's category. Below is a summary of the
classifications used by
Regional Specialized Meteorological Centers worldwide:
| [hide]General wind classifications |
Tropical cyclone classifications (all winds are 10-minute averages) |
| Beaufort scale[18] |
10-minute sustained winds (knots) |
General term[21] |
N Indian Ocean
IMD |
SW Indian Ocean
MF |
Australian region
South Pacific
BoM, BMKG, FMS, MSNZ |
NW Pacific
JMA |
NW Pacific
JTWC |
NE Pacific &
N Atlantic
NHC & CPHC |
| 0 |
<1 |
Calm |
Low Pressure Area |
Tropical disturbance |
Tropical low
Tropical Depression |
Tropical depression |
Tropical depression |
Tropical depression |
| 1 |
1–3 |
Light air |
| 2 |
4–6 |
Light breeze |
| 3 |
7–10 |
Gentle breeze |
| 4 |
11–16 |
Moderate breeze |
| 5 |
17–21 |
Fresh breeze |
Depression |
| 6 |
22–27 |
Strong breeze |
| 7 |
28–29 |
Moderate gale |
Deep depression |
Tropical depression |
| 30–33 |
| 8 |
34–40 |
Fresh gale |
Cyclonic storm |
Moderate tropical storm |
Tropical cyclone (1) |
Tropical storm |
Tropical storm |
Tropical storm |
| 9 |
41–47 |
Strong gale |
| 10 |
48–55 |
Whole gale |
Severe cyclonic storm |
Severe tropical storm |
Tropical cyclone (2) |
Severe tropical storm |
| 11 |
56–63 |
Storm |
| 12 |
64–72 |
Hurricane |
Very severe cyclonic storm |
Tropical cyclone |
Severe tropical cyclone (3) |
Typhoon |
Typhoon |
Hurricane (1) |
| 13 |
73–85 |
Hurricane (2) |
| 14 |
86–89 |
Severe tropical cyclone (4) |
Major hurricane (3) |
| 15 |
90–99 |
Intense tropical cyclone |
| 16 |
100–106 |
Major hurricane (4) |
| 17 |
107–114 |
Severe tropical cyclone (5) |
| 115–119 |
Very intense tropical cyclone |
Super typhoon |
| >120 |
Super cyclonic storm |
Major hurricane (5) |
Enhanced Fujita scale[edit]
The
Enhanced Fujita Scale (EF Scale) rates the strength of tornadoes in the United States based on the damage they cause. Below is that scale.
| Scale |
Wind speed |
Relative frequency |
Potential damage |
| mph |
km/h |
| EF0 |
65–85 |
105–137 |
53.5% |
Minor or no damage.
Peels surface off some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over.
Confirmed tornadoes with no reported damage (i.e., those that remain in open fields) are always rated EF0.
|
|
| EF1 |
86–110 |
138–178 |
31.6% |
Moderate damage.
Roofs severely stripped; mobile homes overturned or badly damaged; loss of exterior doors; windows and other glass broken.
|
|
| EF2 |
111–135 |
179–218 |
10.7% |
Considerable damage.
Roofs torn off well-constructed houses; foundations of frame homes
shifted; mobile homes completely destroyed; large trees snapped or
uprooted; light-object missiles generated; cars lifted off ground.
|
|
| EF3 |
136–165 |
219–266 |
3.4% |
Severe damage.
Entire stories of well-constructed houses destroyed; severe damage
to large buildings such as shopping malls; trains overturned; trees
debarked; heavy cars lifted off the ground and thrown; structures with
weak foundations are badly damaged.
|
|
| EF4 |
166–200 |
267–322 |
0.7% |
Extreme damage.
Well-constructed and whole frame houses completely leveled; cars and other large objects thrown and small missiles generated.
|
|
| EF5 |
>200 |
>322 |
<0.1% |
Total Destruction.
Strong-framed, well-built houses leveled off and foundations swept
away; steel-reinforced concrete structures are critically damaged; tall
buildings collapse or have severe structural deformations.
|
|
Station model[edit]
Wind plotting within a station model
The
station model plotted on surface
weather maps uses a wind barb to show both
wind direction and speed. The wind barb shows the speed using "flags" on the end.
- Each half of a flag depicts 5 knots (9.3 km/h) of wind.
- Each full flag depicts 10 knots (19 km/h) of wind.
- Each pennant (filled triangle) depicts 50 knots (93 km/h) of wind.[22]
Winds are depicted as blowing from the direction the barb is facing.
Therefore, a northeast wind will be depicted with a line extending from
the cloud circle to the northeast, with flags indicating wind speed on
the northeast end of this line.
[23] Once plotted on a map, an analysis of
isotachs
(lines of equal wind speeds) can be accomplished. Isotachs are
particularly useful in diagnosing the location of the jet stream on
upper level constant pressure charts, and are usually located at or
above the 300 hPa level.
[24]
Wind power[edit]
Wind energy is the
kinetic energy of the air in motion. The kinetic energy of a packet of air of mass
m with velocity
v is given by
½ m v2. To find the mass of the packet passing through an area
A perpendicular its velocity (which could be the rotor area of a turbine), we multiply its volume after time
t has passed with the
air density ρ, which gives us
m =
A v t ρ. So, we find that the total wind energy is:
Differentiating with respect to time to find the rate of increase of energy, we find that the total wind
power is:
Wind power is thus proportional to the third power of the wind velocity.
Theoretical power captured by a wind turbine[edit]
Total wind power could be captured only if the wind velocity is
reduced to zero. In a realistic wind turbine this is impossible, as the
captured air must also leave the turbine. A relation between the input
and output wind velocity must be considered. Using the concept of
stream tube, the maximal achievable extraction of wind power by a wind turbine is 59% of the total theoretical wind power
[25] (see:
Betz' law).
Practical wind turbine power[edit]
Further insufficiencies, such as rotor blade
friction and
drag,
gearbox losses, generator and converter losses, reduce the power
delivered by a wind turbine. The basic relation that the turbine power
is (approximately) proportional to the third power of velocity remains.
Global climatology[edit]
The westerlies and trade winds
Winds are part of Earth's atmospheric circulation.
Easterly winds, on average, dominate the flow pattern across the poles, westerly winds blow across the
mid-latitudes of the earth, polewards of the
subtropical ridge, while easterlies again dominate the
tropics.
Directly under the
subtropical ridge
are the doldrums, or horse latitudes, where winds are lighter. Many of
the Earth's deserts lie near the average latitude of the subtropical
ridge, where descent reduces the
relative humidity of the air mass.
[26] The strongest winds are in the mid-latitudes where cold polar air meets warm air from the tropics.
Tropics[edit]
The trade winds (also called trades) are the prevailing pattern of
easterly surface winds found in the
tropics towards the Earth's
equator.
[27] The trade winds blow predominantly from the northeast in the
Northern Hemisphere and from the southeast in the
Southern Hemisphere.
[28] The trade winds act as the
steering flow for
tropical cyclones that form over world's oceans.
[29] Trade winds also steer African dust westward across the
Atlantic Ocean into the
Caribbean Sea, as well as portions of southeast
North America.
[30]
A
monsoon is a seasonal prevailing wind that lasts for several months within tropical regions. The term was first used in English in
India,
Bangladesh,
Pakistan, and neighboring countries to refer to the big seasonal winds blowing from the
Indian Ocean and
Arabian Sea in the southwest bringing heavy
rainfall to the area.
[31]
Its poleward progression is accelerated by the development off a heat
low over the Asian, African, and North American continents during May
through July, and over Australia in December.
[32][33][34]
Westerlies and their impact[edit]
The Westerlies or the Prevailing Westerlies are the
prevailing winds in the
middle latitudes between 35 and 65 degrees
latitude. These prevailing winds blow from the
west to the
east,
[35][36] and steer extratropical cyclones in this general manner. The winds are predominantly from the southwest in the
Northern Hemisphere and from the northwest in the
Southern Hemisphere.
[28]
They are strongest in the winter when the pressure is lower over the
poles, and weakest during the summer and when pressures are higher over
the poles.
[37]
Together with the
trade winds,
the westerlies enabled a round-trip trade route for sailing ships
crossing the Atlantic and Pacific Oceans, as the westerlies lead to the
development of strong ocean currents on the western sides of oceans in
both hemispheres through the process of western intensification.
[38] These western ocean currents transport warm, sub tropical water polewards toward the
polar regions.
The westerlies can be particularly strong, especially in the southern
hemisphere, where there is less land in the middle latitudes to cause
the flow pattern to amplify, which slows the winds down. The strongest
westerly winds in the middle latitudes are within a band known as the
Roaring Forties, between
40 and
50 degrees latitude south of the equator.
[39] The Westerlies play an important role in carrying the warm, equatorial waters and winds to the western coasts of continents,
[40][41] especially in the southern hemisphere because of its vast oceanic expanse.
Polar easterlies[edit]
The polar easterlies, also known as Polar Hadley cells, are dry,
cold prevailing winds that blow from the high-pressure areas of the
polar highs at the
north and
south poles
towards the low-pressure areas within the Westerlies at high latitudes.
Unlike the Westerlies, these prevailing winds blow from the
east to the
west, and are often weak and irregular.
[42] Because of the low sun angle,
cold air builds up and
subsides at the pole creating surface high-pressure areas, forcing an equatorward outflow of air;
[43] that outflow is deflected westward by the Coriolis effect.
Local considerations[edit]
Local winds around the world. These winds are formed through the heating of land (from mountains or flat terrain)
Sea and land breezes[edit]
A: Sea breeze (occurs at daytime), B: Land breeze (occurs at night)
In coastal regions, sea breezes and land breezes can be important factors in a location's prevailing winds. The
sea is warmed by the sun more slowly because of water's greater
specific heat compared to land.
[44] As the temperature of the surface of the
land
rises, the land heats the air above it by conduction. The warm air is
less dense than the surrounding environment and so it rises. This
causes a pressure gradient of about 2 millibars from the ocean to the
land. The cooler air above the sea, now with higher
sea level pressure,
flows inland into the lower pressure, creating a cooler breeze near the
coast. When large-scale winds are calm, the strength of the sea breeze
is directly proportional to the temperature difference between the land
mass and the sea. If an offshore wind of 8 knots (15 km/h) exists, the
sea breeze is not likely to develop.
At night, the land cools off more quickly than the ocean because of differences in their
specific heat
values. This temperature change causes the daytime sea breeze to
dissipate. When the temperature onshore cools below the temperature
offshore, the pressure over the water will be lower than that of the
land, establishing a land breeze, as long as an onshore wind is not
strong enough to oppose it.
[45]
Near mountains[edit]
Mountain wave schematic. The wind flows towards a mountain and produces
a first oscillation (A). A second wave occurs further away and higher.
The lenticular clouds form at the peak of the waves (B).
Over elevated surfaces, heating of the ground exceeds the heating of the surrounding air at the same altitude above
sea level, creating an associated thermal low over the terrain and enhancing any thermal lows that would have otherwise existed,
[46][47] and changing the wind circulation of the region. In areas where there is rugged
topography
that significantly interrupts the environmental wind flow, the wind
circulation between mountains and valleys is the most important
contributor to the prevailing winds. Hills and valleys substantially
distort the airflow by increasing friction between the atmosphere and
landmass by acting as a physical block to the flow, deflecting the wind
parallel to the range just upstream of the topography, which is known
as a
barrier jet. This barrier jet can increase the low level wind by 45%.
[48] Wind direction also changes because of the contour of the land.
[49]
If there is a
pass in the mountain range, winds will rush through the pass with considerable speed because of the
Bernoulli principle
that describes an inverse relationship between speed and pressure. The
airflow can remain turbulent and erratic for some distance downwind
into the flatter countryside. These conditions are dangerous to
ascending and descending
airplanes.
[49] Cool winds accelerating through mountain gaps have been given regional names. In
Central America, examples include the
Papagayo wind, the
Panama wind, and the
Tehuano wind. In
Europe, similar winds are known as the
Bora,
Tramontane, and
Mistral.
When these winds blow over open waters, they increase mixing of the
upper layers of the ocean that elevates cool, nutrient rich waters to
the surface, which leads to increased marine life.
[50]
In mountainous areas, local distortion of the airflow becomes
severe. Jagged terrain combines to produce unpredictable flow patterns
and turbulence, such as
rotors, which can be topped by
lenticular clouds. Strong
updrafts, downdrafts and
eddies develop as the air flows over hills and down valleys. Orographic
precipitation occurs on the
windward
side of mountains and is caused by the rising air motion of a
large-scale flow of moist air across the mountain ridge, also known as
upslope flow, resulting in
adiabatic
cooling and condensation. In mountainous parts of the world subjected
to relatively consistent winds (for example, the trade winds), a more
moist climate usually prevails on the windward side of a mountain than
on the
leeward
or downwind side. Moisture is removed by orographic lift, leaving drier
air on the descending and generally warming, leeward side where a
rain shadow is observed.
[51]
Winds that flow over mountains down into lower elevations are known as
downslope winds. These winds are warm and dry. In Europe downwind of
the
Alps, they are known as
foehn. In
Poland, an example is the halny wiatr. In Argentina, the local name for downsloped winds is
zonda. In Java, the local name for such winds is koembang. In
New Zealand, they are known as the
Nor'west arch, and are accompanied by the cloud formation they are named after that has inspired artwork over the years.
[52] In the Great Plains of the United States, the winds are known as a
chinook. In California, downsloped winds are funneled through mountain passes, which intensify their effect, and examples into
Santa Ana and
sundowner winds. Wind speeds during downslope wind effect can exceed 160 kilometers per hour (99 mph).
[53]
Average wind speeds[edit]
As described earlier, prevailing and local winds are not spread
evenly across the earth, which means that wind speeds also differ by
region. In addition, the wind speed also increases with the altitude.
Wind power density[edit]
Nowadays, a yardstick used to determine the best locations for wind
energy development is referred to as wind power density (WPD). It is a
calculation relating to the effective force of the wind at a particular
location, frequently expressed in terms of the elevation above ground
level over a period of time. It takes into account wind velocity and
mass. Color coded maps are prepared for a particular area are described
as, for example, "mean annual power density at 50 meters." The results
of the above calculation are included in an index developed by the
National Renewable Energy Lab and referred to as "NREL CLASS." The
larger the WPD calculation, the higher it is rated by class.
[54] At the end of 2008, worldwide
nameplate capacity of wind-powered generators was 120.8
gigawatts.
[55] Although wind produces only about 1.5% of worldwide electricity use,
[55]
it is growing rapidly, having doubled in the three years between 2005
and 2008. In several countries it has achieved relatively high levels
of penetration, accounting for approximately 19% of electricity
production in
Denmark, 10% in
Spain and
Portugal, and 7% in
Germany and the
Republic of Ireland
in 2008. One study indicates that an entirely renewable energy supply
based on 70% wind is attainable at today's power prices by linking
wind farms with an
HVDC supergrid.
[56]
Wind shear, sometimes referred to as windshear or
wind gradient, is a difference in wind speed and direction over a relatively short distance in the Earth's atmosphere.
[57] Wind shear can be broken down into vertical and horizontal components, with horizontal wind shear seen across
weather fronts and near the coast,
[58] and vertical shear typically near the surface,
[59] though also at higher levels in the atmosphere near upper level jets and frontal zones aloft.
[60]
Wind shear itself is a
microscale meteorological phenomenon occurring over a very small distance, but it can be associated with
mesoscale or
synoptic scale weather features such as
squall lines and
cold fronts. It is commonly observed near
microbursts and
downbursts caused by
thunderstorms,
[61] weather fronts, areas of locally higher low level winds referred to as low level jets, near
mountains,
[62] radiation inversions that occur because of clear skies and calm winds, buildings,
[63] wind turbines,
[64] and
sailboats.
[65]
Wind shear has a significant effect during take-off and landing of
aircraft because of their effects on control of the aircraft,
[66] and was a significant cause of aircraft accidents involving large loss of life within the
United States.
[61]
Sound movement through the atmosphere is affected by wind shear,
which can bend the wave front, causing sounds to be heard where they
normally would not, or vice versa.
[67] Strong vertical wind shear within the troposphere also inhibits
tropical cyclone development,
[68] but helps to organize individual thunderstorms into living longer life cycles that can then produce
severe weather.
[69] The
thermal wind
concept explains how differences in wind speed with height are
dependent on horizontal temperature differences, and explains the
existence of the jet stream.
[70]
Usage of wind[edit]
History[edit]
As a natural force, the wind was often personified as one or more
wind gods or as an expression of the
supernatural in many cultures.
Vayu is the Hindu God of Wind.
[71][72] The Greek wind gods include
Boreas,
Notus,
Eurus, and
Zephyrus.
[72] Aeolus, in varying interpretations the ruler or keeper of the four winds, has also been described as
Astraeus, the god of dusk who fathered the four winds with
Eos, goddess of dawn. The
Ancient Greeks also observed the seasonal change of the winds, as evidenced by the
Tower of the Winds in
Athens.
[72] Venti are the Roman gods of the winds.
[73] Fūjin, is the Japanese wind god and is one of the eldest
Shinto
gods. According to legend, he was present at the creation of the world
and first let the winds out of his bag to clear the world of mist.
[74] In
Norse mythology,
Njord is the god of the wind.
[72] There are also four dvärgar (
Norse dwarves), named
Norðri, Suðri, Austri and Vestri, and probably the
four stags of Yggdrasil, personify the four winds, and parallel the four Greek wind gods.
[75] Stribog is the name of the
Slavic god of winds, sky and air. He is said to be the ancestor (grandfather) of the winds of the eight directions.
[72]
Kamikaze
(神風) is a Japanese word, usually translated as divine wind, believed to
be a gift from the gods. The term is first known to have been used as
the name of a pair or series of typhoons that are said to have saved
Japan from two Mongol fleets under Kublai Khan that attacked Japan in
1274 and again in 1281.
[76] Protestant Wind is a name for the storm that deterred the
Spanish Armada from an invasion of
England in 1588 where the wind played a pivotal role,
[77] or the favorable winds that enabled
William of Orange to invade England in 1688.
[78] During
Napoleon's
Egyptian Campaign, the French soldiers had a hard time with the
khamsin
wind: when the storm appeared "as a blood-stint in the distant sky",
the natives went to take cover, while the French "did not react until
it was too late, then choked and fainted in the blinding, suffocating
walls of dust."
[79] During the
North African Campaign of the
World War II,
"allied and German troops were several times forced to halt in
mid-battle because of sandstorms caused by khamsin ... Grains of sand
whirled by the wind blinded the soldiers and created electrical
disturbances that rendered compasses useless."
[80]
Transportation[edit]
RAF Exeter airfield on 20 May 1944, showing the layout of the
runways that allow aircraft to take off and land into the wind
There are many different forms of sailing ships, but they all have certain basic things in common. Except for
rotor ships using the
Magnus effect, every sailing ship has a
hull,
rigging and at least one
mast to hold up the
sails that use the wind to power the ship.
[81] Ocean journeys by sailing ship can take many months,
[82] and a common hazard is becoming becalmed because of lack of wind,
[83] or being blown off course by severe
storms or winds that do not allow progress in the desired direction.
[84] A severe storm could lead to
shipwreck, and the loss of all hands.
[85] Sailing ships can only carry a certain quantity of supplies in their
hold, so they have to plan long
voyages carefully to include appropriate
provisions, including fresh
water.
[86]
For
aerodynamic aircraft which operate relative to the air, winds affect groundspeed,
[87] and in the case of lighter-than-air vehicles, wind may play a significant or solitary role in their movement and ground track.
[88] The
velocity of surface wind is generally the primary factor governing the direction of flight operations at an airport, and
airfield runways are aligned to account for the common wind direction(s) of the local area. While taking off with a
tailwind may be necessary under certain circumstances, a
headwind is generally desirable. A tailwind increases takeoff distance required and decreases the climb gradient.
[89]
Power source[edit]
Historically, the ancient
Sinhalese of
Anuradhapura and in other cities around
Sri Lanka used the monsoon winds to power furnaces as early as 300
BCE.
[90]
The furnaces were constructed on the path of the monsoon winds to
exploit the wind power, to bring the temperatures inside up to 1,200 °C
(2,190 °F). An early historical reference to a rudimentary
windmill was used to power an
organ in the first century CE.
[91] The first practical
windmills were later built in
Sistan,
Afghanistan, from the 7th century CE. These were vertical-axle windmills, which had long vertical
driveshafts with rectangle shaped blades.
[92] Made of six to twelve
sails covered in
reed matting or cloth material, these windmills were used to grind corn and draw up water, and were used in the
gristmilling and sugarcane industries.
[93]
Horizontal-axle windmills were later used extensively in Northwestern
Europe to grind flour beginning in the 1180s, and many Dutch windmills
still exist.
High altitude wind power is the focus of over 30 companies worldwide using tethered technology rather than ground-hugging compressive-towers.
[94]
Oil is being saved by using wind for powering cargo ships by use of the
mechanical energy converted from the wind's kinetic energy using very
large kites.
[95]
Recreation[edit]
Wind figures prominently in several popular sports, including recreational
hang gliding,
hot air ballooning,
kite flying,
snowkiting,
kite landboarding,
kite surfing,
paragliding,
sailing, and
windsurfing. In gliding, wind gradients just above the surface affect the takeoff and landing phases of flight of a
glider. Wind gradient can have a noticeable effect on
ground launches,
also known as winch launches or wire launches. If the wind gradient is
significant or sudden, or both, and the pilot maintains the same pitch
attitude, the indicated airspeed will increase, possibly exceeding the
maximum ground launch tow speed. The pilot must adjust the airspeed to
deal with the effect of the gradient.
[96]
When landing, wind shear is also a hazard, particularly when the winds
are strong. As the glider descends through the wind gradient on final
approach to landing, airspeed decreases while sink rate increases, and
there is insufficient time to accelerate prior to ground contact. The
pilot must anticipate the wind gradient and use a higher approach speed
to compensate for it.
[97]
Role in the natural world[edit]
In arid climates, the main source of erosion is wind.
[98]
The general wind circulation moves small particulates such as dust
across wide oceans thousands of kilometers downwind of their point of
origin,
[99]
which is known as deflation. Westerly winds in the mid-latitudes of the
planet drive the movement of ocean currents from west to east across
the world's oceans. Wind has a very important role in aiding plants and
other immobile organisms in dispersal of seeds, spores, pollen, etc.
Although wind is not the primary form of seed dispersal in plants, it
provides dispersal for a large percentage of the biomass of land plants.
Erosion[edit]
Erosion can be the result of material movement by the wind. There
are two main effects. First, wind causes small particles to be lifted
and therefore moved to another region. This is called deflation.
Second, these suspended particles may impact on solid objects causing
erosion by abrasion (ecological succession). Wind erosion generally
occurs in areas with little or no vegetation, often in areas where
there is insufficient rainfall to support vegetation. An example is the
formation of sand
dunes, on a beach or in a desert.
[100] Loess is a homogeneous, typically nonstratified, porous,
friable, slightly coherent, often calcareous, fine-grained,
silty, pale yellow or buff, windblown (Aeolian)
sediment.
[101]
It generally occurs as a widespread blanket deposit that covers areas
of hundreds of square kilometers and tens of meters thick. Loess often
stands in either steep or vertical faces.
[102]
Loess tends to develop into highly rich soils. Under appropriate
climatic conditions, areas with loess are among the most agriculturally
productive in the world.
[103]
Loess deposits are geologically unstable by nature, and will erode very
readily. Therefore, windbreaks (such as big trees and bushes) are often
planted by farmers to reduce the wind erosion of loess.
[98]
Desert dust migration[edit]
During mid-summer (July), the westward-moving trade winds south of
the northward-moving subtropical ridge expand northwestward from the
Caribbean Sea into southeastern North America. When dust from the
Sahara
moving around the southern periphery of the ridge within the belt of
trade winds moves over land, rainfall is suppressed and the sky changes
from a blue to a white appearance, which leads to an increase in red
sunsets. Its presence negatively impacts
air quality by adding to the count of airborne particulates.
[104] Over 50% of the African dust that reaches the United States affects Florida.
[105]
Since 1970, dust outbreaks have worsened because of periods of drought
in Africa. There is a large variability in the dust transport to the
Caribbean and Florida from year to year.
[106] Dust events have been linked to a decline in the health of
coral reefs across the Caribbean and Florida, primarily since the 1970s.
[107] Similar dust plumes originate in the
Gobi Desert, which combined with pollutants, spread large distances downwind, or eastward, into North America.
[99]
There are local names for winds associated with sand and dust storms. The Calima carries dust on southeast winds into the
Canary islands.
[108] The
Harmattan carries dust during the winter into the
Gulf of Guinea.
[109] The
Sirocco brings dust from north Africa into southern Europe because of the movement of extratropical cyclones through the
Mediterranean Sea.
[110] Spring storm systems moving across the eastern Mediterranean Sea cause dust to carry across
Egypt and the
Arabian peninsula, which are locally known as
Khamsin.
[111] The
Shamal is caused by cold fronts lifting dust into the atmosphere for days at a time across the
Persian Gulf states.
[112]
Effect on plants[edit]
Tumbleweed blown against a fence
Wind dispersal of seeds, or
anemochory,
is one of the more primitive means of dispersal. Wind dispersal can
take on one of two primary forms: seeds can float on the breeze or
alternatively, they can flutter to the ground.
[113] The classic examples of these dispersal mechanisms include
dandelions (
Taraxacum spp.,
Asteraceae), which have a feathery
pappus attached to their seeds and can be dispersed long distances, and
maples (
Acer (genus) spp.,
Sapindaceae),
which have winged seeds and flutter to the ground. An important
constraint on wind dispersal is the need for abundant seed production
to maximize the likelihood of a seed landing in a site suitable for
germination. There are also strong evolutionary constraints on this dispersal mechanism. For instance, species in the Asteraceae on
islands
tended to have reduced dispersal capabilities (i.e., larger seed mass
and smaller pappus) relative to the same species on the mainland.
[114] Reliance upon wind dispersal is common among many
weedy or
ruderal species. Unusual mechanisms of wind dispersal include
tumbleweeds. A related process to anemochory is
anemophily,
which is the process where pollen is distributed by wind. Large
families of plants are pollinated in this manner, which is favored when
individuals of the dominant plant species are spaced closely together.
[115]
Wind also limits tree growth. On
coasts
and isolated mountains, the tree line is often much lower than in
corresponding altitudes inland and in larger, more complex mountain
systems, because strong winds reduce tree growth. High winds scour away
thin
soils through erosion,
[116] as well as damage limbs and twigs. When high winds knock down or uproot trees, the process is known as
windthrow. This is most likely on
windward slopes of mountains, with severe cases generally occurring to
tree stands that are 75 years or older.
[117] Plant varieties near the coast, such as the
Sitka spruce and
sea grape,
[118] are
pruned back by wind and salt spray near the coastline.
[119]
Wind can also cause plants damage through
sand abrasion. Strong winds will pick up loose sand and
topsoil
and hurl it through the air at speeds ranging from 25–40 miles per
hour. Such windblown sand causes extensive damage to plant seedlings
because it ruptures plant cells, making them vulnerable to evaporation
and drought. Using a mechanical sandblaster in a laboratory setting,
scientists affiliated with the
Agricultural Research Service
studied the effects of windblown sand abrasion on cotton seedlings. The
study showed that the seedlings responded to the damage created by the
windblown sand abrasion by shifting energy from stem and root growth to
the growth and repair of the damaged stems.
[120]
After a period of four weeks the growth of the seedling once again
became uniform throughout the plant, as it was before the windblown
sand abrasion occurred.
[121]
Effect on animals[edit]
Cattle and
sheep are prone to
wind chill
caused by a combination of wind and cold temperatures, when winds
exceed 40 kilometers per hour (25 mph), rendering their hair and wool
coverings ineffective.
[122] Although
penguins use both a layer of
fat and
feathers to help guard against coldness in both water and air, their
flippers and feet are less immune to the cold. In the coldest climates such as
Antarctica,
emperor penguins use
huddling
behavior to survive the wind and cold, continuously alternating the
members on the outside of the assembled group, which reduces heat loss
by 50%.
[123] Flying
insects, a subset of
arthropods, are swept along by the prevailing winds,
[124] while birds follow their own course taking advantage of wind conditions, in order to either fly or glide.
[125] As such, fine line patterns within
weather radar imagery, associated with converging winds, are dominated by insect returns.
[126] Bird migration, which tends to occur overnight within the lowest 7,000 feet (2,100 m) of the
Earth's atmosphere, contaminates wind profiles gathered by weather radar, particularly the
WSR-88D, by increasing the environmental wind returns by 15 knots (28 km/h) to 30 knots (56 km/h).
[127]
Pikas use a wall of pebbles to store dry plants and grasses for the winter in order to protect the food from being blown away.
[128] Cockroaches use slight winds that precede the attacks of potential
predators, such as
toads, to survive their encounters. Their
cerci are very sensitive to the wind, and help them survive half of their attacks.
[129] Elk have a keen sense of smell that can detect potential upwind predators at a distance of 0.5 miles (800 m).
[130] Increases in wind above 15 kilometers per hour (9.3 mph) signals
glaucous gulls to increase their foraging and aerial attacks on thick-billed
murres.
[131]
Sound generation[edit]
Wind causes the generation of sound. The movement of air causes
movements of parts of natural objects, such as leaves or grass. These
objects will produce sound if they touch each other. Even a soft wind
will cause a low level of
environmental noise.
If the wind is blowing harder, it may produce howling sounds of varying
frequencies. This may be caused by the wind blowing over cavities, or
by vortices created in the air downstream of an object.
[132]
Especially on high buildings, many structural parts may be a cause of
annoying noise at certain wind conditions. Examples of these parts are
balconies, ventilation openings, roof openings or cables.
Related damage[edit]
High winds are known to cause damage, depending upon their strength. Infrequent wind gusts can cause poorly designed
suspension bridges
to sway. When wind gusts are at a similar frequency to the swaying of
the bridge, the bridge can be destroyed more easily, such as what
occurred with the
Tacoma Narrows Bridge in 1940.
[133]
Wind speeds as low as 23 knots (43 km/h) can lead to power outages due
to tree branches disrupting the flow of energy through power lines.
[134]
While no species of tree is guaranteed to stand up to hurricane-force
winds, those with shallow roots are more prone to uproot, and brittle
trees such as
eucalyptus, sea
hibiscus, and
avocado are more prone to damage.
[135]
Hurricane-force winds cause substantial damage to mobile homes, and
begin to structurally damage homes with foundations. Winds of this
strength due to downsloped winds off terrain have been known to shatter
windows and sandblast paint from cars.
[53]
Once winds exceed 135 knots (250 km/h), homes completely collapse, and
significant damage is done to larger buildings. Total destruction to
man-made structures occurs when winds reach 175 knots (324 km/h). The
Saffir-Simpson scale and
Enhanced Fujita scale were designed to help estimate wind speed from the damage caused by high winds related to tropical cyclones and
tornadoes, and vice versa.
[136][137]
Australia's
Barrow Island
holds the record for the strongest wind gust, reaching 408 km/h
(253 mph) during tropical cyclone Olivia on 10 April 1996, surpassing
the previous record of 372 km/h (231 mph) set on
Mount Washington (New Hampshire) on the afternoon of 12 April 1934.
[138]
The most powerful gusts of wind on Earth were created by nuclear
detonations. The blast wave is similar to a strong wind gust over the
ground. The largest nuclear explosion (50–58 megatons at an altitude of
about 13,000 ft) generated a 20 bar blast pressure at ground zero,
which is similar to a wind gust of 3,100 miles per hour.
Wildfire intensity increases during daytime hours. For example, burn rates of
smoldering logs are up to five times greater during the day because of lower humidity, increased temperatures, and increased wind speeds.
[139]
Sunlight warms the ground during the day and causes air currents to
travel uphill, and downhill during the night as the land cools.
Wildfires are fanned by these winds and often follow the air currents
over hills and through valleys.
[140] United States wildfire operations revolve around a 24-hour
fire day that begins at 10:00 a.m. because of the predictable increase in intensity resulting from the daytime warmth.
[141]
In outer space[edit]
The solar wind is quite different from a terrestrial wind, in that
its origin is the sun, and it is composed of charged particles that
have escaped the sun's atmosphere. Similar to the solar wind, the
planetary wind
is composed of light gases that escape planetary atmospheres. Over long
periods of time, the planetary wind can radically change the
composition of planetary atmospheres.
Planetary wind[edit]
Possible future for Earth due to the planetary wind: Venus
The hydrodynamic wind within the upper portion of a planet's atmosphere allows light chemical elements such as
hydrogen to move up to the
exobase, the lower limit of the
exosphere, where the gases can then reach
escape velocity, entering
outer space without impacting other particles of gas. This type of gas loss from a planet into space is known as planetary wind.
[142] Such a process over
geologic time causes water-rich planets such as the Earth to evolve into planets like
Venus.
[143] Additionally, planets with hotter lower atmospheres could accelerate the loss rate of hydrogen.
[144]
Solar wind[edit]
Rather than air, the solar wind is a
stream of charged particles—a
plasma—ejected from the
upper atmosphere of the sun at a rate of 400 kilometers per second (890,000 mph). It consists mostly of
electrons and
protons with energies of about 1
keV.
The stream of particles varies in temperature and speed with the
passage of time. These particles are able to escape the sun's
gravity, in part because of the high
temperature of the
corona,
[145] but also because of high
kinetic energy that particles gain through a process that is not well-understood. The solar wind creates the
Heliosphere, a vast bubble in the
interstellar medium surrounding the solar system.
[146] Planets require large magnetic fields in order to reduce the ionization of their upper atmosphere by the solar wind.
[144] Other phenomena caused by the solar wind include
geomagnetic storms that can knock out power grids on Earth,
[147] the
aurorae such as the
Northern Lights,
[148] and the plasma tails of
comets that always point away from the sun.
[149]
On other planets[edit]
Strong 300 kilometers per hour (190 mph) winds at Venus's cloud tops circle the planet every four to five earth days.
[150] When the poles of
Mars are exposed to sunlight after their
winter, the frozen CO
2 sublimates,
creating significant winds that sweep off the poles as fast as 400
kilometers per hour (250 mph), which subsequently transports large
amounts of dust and water vapor over its
landscape.
[151] Other Martian winds have resulted in
cleaning events and
dust devils.
[152][153] On
Jupiter, wind speeds of 100 meters per second (220 mph) are common in zonal jet streams.
[154] Saturn's winds are among the solar system's fastest.
Cassini–Huygens data indicated peak easterly winds of 375 meters per second (840 mph).
[155] On
Uranus, northern hemisphere wind speeds reach as high as 240 meters per second (540 mph) near 50 degrees north latitude.
[156][157][158] At the cloud tops of
Neptune,
prevailing winds range in speed from 400 meters per second (890 mph)
along the equator to 250 meters per second (560 mph) at the poles.
[159] At 70° S latitude on Neptune, a high-speed jet stream travels at a speed of 300 meters per second (670 mph).
[160]
See also[edit]
 |
Wikiquote has quotations related to: Wind |
References[edit]
- Jump up ^ JetStream (2008). "Origin of Wind". National Weather Service Southern Region Headquarters. Retrieved 2009-02-16.
- Jump up ^ Makarieva, Anastassia; V. G. Gorshkov, D. Sheil, A. D. Nobre, B.-L. Li (February 2013). "Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics". Atmospheric Chemistry and Physics 13 (2): 1039–1056. Bibcode:2013ACP....13.1039M. doi:10.5194/acp-13-1039-2013. Retrieved 2013-02-01.
- Jump up ^ Glossary of Meteorology (2009). "Geostrophic wind". American Meteorological Society. Retrieved 2009-03-18.
- Jump up ^ Glossary of Meteorology (2009). "Thermal wind". American Meteorological Society. Retrieved 2009-03-18.
- Jump up ^ Glossary of Meteorology (2009). "Ageostrophic wind". American Meteorological Society. Retrieved 2009-03-18.
- Jump up ^ Glossary of Meteorology (2009). "Gradient wind". American Meteorological Society. Retrieved 2009-03-18.
- Jump up ^ JetStream (2008). "How to read weather maps". National Weather Service. Retrieved 2009-05-16.
- Jump up ^ Glossary of Meteorology (2009). "Wind vane". American Meteorological Society. Retrieved 2009-03-17.
- Jump up ^ Glossary of Meteorology (2009). "Wind sock". American Meteorological Society. Retrieved 2009-03-17.
- Jump up ^ Glossary of Meteorology (2009). "Anemometer". American Meteorological Society. Retrieved 2009-03-17.
- Jump up ^ Glossary of Meteorology (2009). "Pitot tube". American Meteorological Society. Retrieved 2009-03-17.
- Jump up ^ Tropical Cyclone Weather Services Program (2006-06-01). "Tropical cyclone definitions" (PDF). National Weather Service. Retrieved 2006-11-30.
- Jump up ^ Office of the Federal Coordinator for Meteorology. Federal Meteorological Handbook No. 1 – Surface Weather Observations and Reports September 2005 Appendix A: Glossary. Retrieved 2008-04-06.
- Jump up ^ Sharad K. Jain, Pushpendra K. Agarwal, Vijay P. Singh (2007). Hydrology and Water Resources of India. Springer. p. 187. ISBN 978-1-4020-5179-1. Retrieved 2009-04-22.
- Jump up ^ Jan-Hwa Chu (1999). "Section 2. Intensity Observation and Forecast Errors". United States Navy. Retrieved 2008-07-04.
- Jump up ^ Glossary of Meteorology (2009). "Rawinsonde". American Meteorological Society. Retrieved 2009-03-17.
- Jump up ^ Glossary of Meteorology (2009). "Pibal". American Meteorological Society. Retrieved 2009-03-17.
- ^ Jump up to: a b Walter J. Saucier (2003). Principles of Meteorological Analysis. Courier Dover Publications. ISBN 978-0-486-49541-5. Retrieved 2009-01-09.
- Jump up ^ Glossary of Meteorology (2009). "G". American Meteorological Society. Retrieved 2009-03-18.
- Jump up ^ Glossary of Meteorology (2009). "Storm". American Meteorological Society. Retrieved 2009-03-18.
- Jump up ^ Coastguard Southern Region (2009). "The Beaufort Wind Scale". Retrieved 2009-03-18.
- Jump up ^ "Decoding the station model". Hydrometeorological Prediction Center. National Centers for Environmental Prediction. 2009. Retrieved 2007-05-16.
- Jump up ^ "How to read weather maps". JetStream. National Weather Service. 2008. Retrieved 2009-06-27.
- Jump up ^ Terry T. Lankford (2000). Aviation Weather Handbook. McGraw-Hill Professional. ISBN 978-0-07-136103-3. Retrieved 2008-01-22.
- Jump up ^ The Physics of Wind Turbines. Kira Grogg Carleton College (2005) p. 8. (PDF). Retrieved 2011-11-03.
- Jump up ^ Michael A. Mares (1999). Encyclopedia of Deserts. University of Oklahoma Press. p. 121. ISBN 978-0-8061-3146-7. Retrieved 2009-06-20.
- Jump up ^ Glossary of Meteorology (2000). "trade winds". American Meteorological Society. Retrieved 2008-09-08.
- ^ Jump up to: a b Ralph Stockman Tarr and Frank Morton McMurry (1909). Advanced geography. W.W. Shannon, State Printing. p. 246. Retrieved 2009-04-15.
- Jump up ^ Joint Typhoon Warning Center (2006). "3.3 JTWC Forecasting Philosophies". United States Navy. Retrieved 2007-02-11.
- Jump up ^ Science Daily (1999-07-14). "African Dust Called A Major Factor Affecting Southeast U.S. Air Quality". Science Daily. Retrieved 2007-06-10.
- Jump up ^ Glossary of Meteorology (2009). "Monsoon". American Meteorological Society. Retrieved 2008-03-14.
- Jump up ^ "Chapter-II Monsoon-2004: Onset, Advancement and Circulation Features". National Centre for Medium Range Forecasting. 2004-10-23. Retrieved 2008-05-03.
- Jump up ^ "Monsoon". Australian Broadcasting Corporation. 2000. Retrieved 2008-05-03.
- Jump up ^ Dr. Alex DeCaria (2007-10-02). "Lesson 4 – Seasonal-mean Wind Fields". Millersville Meteorology. Retrieved 2008-05-03.
- Jump up ^ Glossary of Meteorology (2009). "Westerlies". American Meteorological Society. Retrieved 2009-04-15.
- Jump up ^ Sue Ferguson (2001-09-07). "Climatology of the Interior Columbia River Basin". Interior Columbia Basin Ecosystem Management Project. Retrieved 2009-09-12.
- Jump up ^ Halldór Björnsson (2005). "Global circulation". Veðurstofu Íslands. Retrieved 2008-06-15.
- Jump up ^ National Environmental Satellite, Data, and Information Service (2009). "Investigating the Gulf Stream". North Carolina State University. Retrieved 2009-05-06.
- Jump up ^ Stuart Walker (1998). The sailor's wind. W. W. Norton & Company. p. 91. ISBN 9780393045550. Retrieved 2009-06-17.
- Jump up ^ Barbie Bischof, Arthur J. Mariano, Edward H. Ryan (2003). "The North Atlantic Drift Current". The National Oceanographic Partnership Program. Retrieved 2008-09-10.
- Jump up ^ Erik A. Rasmussen, John Turner (2003). Polar Lows. Cambridge University Press. p. 68.
- Jump up ^ Glossary of Meteorology (2009). "Polar easterlies". American Meteorological Society. Retrieved 2009-04-15.
- Jump up ^ Michael E. Ritter (2008). "The Physical Environment: Global scale circulation". University of Wisconsin–Stevens Point. Retrieved 2009-04-15.
- Jump up ^ Dr. Steve Ackerman (1995). "Sea and Land Breezes". University of Wisconsin. Retrieved 2006-10-24.
- Jump up ^ JetStream: An Online School For Weather (2008). "The Sea Breeze". National Weather Service. Retrieved 2006-10-24.
- Jump up ^ National Weather Service Forecast Office in Tucson, Arizona (2008). "What is a monsoon?". National Weather Service Western Region Headquarters. Retrieved 2009-03-08.
- Jump up ^ Douglas G. Hahn and Syukuro Manabe (1975). "The Role of Mountains in the South Asian Monsoon Circulation". Journal of Atmospheric Sciences 32 (8): 1515–1541. Bibcode:...32.1515H 1975JAtS ...32.1515H. doi:10.1175/1520-0469(1975)032<1515:TROMIT>2.0.CO;2. ISSN 1520-0469.
- Jump up ^ J. D. Doyle (1997). "The influence of mesoscale orography on a coastal jet and rainband". Monthly Weather Review 125 (7): 1465–1488. Bibcode:1997MWRv..125.1465D. doi:10.1175/1520-0493(1997)125<1465:TIOMOO>2.0.CO;2. ISSN 1520-0493.
- ^ Jump up to: a b National Center for Atmospheric Research (2006). "T-REX: Catching the Sierra’s waves and rotors". University Corporation for Atmospheric Research. Retrieved 2006-10-21.
- Jump up ^ Anthony Drake (2008-02-08). "The Papaguayo Wind". NASA Goddard Earth Sciences Data and Information Services Center. Retrieved 2009-06-16.
- Jump up ^ Dr. Michael Pidwirny (2008). "CHAPTER 8: Introduction to the Hydrosphere (e). Cloud Formation Processes". Physical Geography. Retrieved 2009-01-01.
- Jump up ^ Michael Dunn (2003). New Zealand Painting. Auckland University Press. p. 93. ISBN 978-1-86940-297-6. Retrieved 2009-06-21.
- ^ Jump up to: a b Rene Munoz (2000-04-10). "Boulder's downslope winds". University Corporation for Atmospheric Research. Retrieved 2009-06-16.
- Jump up ^ Kansas Wind Energy Project, Affiliated Atlantic & Western Group Inc, 5250 W 94th Terrace, Prairie Village, Kansas 66207
- ^ Jump up to: a b World Wind Energy Association (2009-02-06). "120 Gigawatt of wind turbines globally contribute to secure electricity generation". Press release. Retrieved 2009-02-06.
- Jump up ^ David Strahan (2009-03-11). "From AC to DC: Going green with supergrids". New Scientist. Retrieved 2009-03-13.
- Jump up ^ D. C. Beaudette (1988). "FAA Advisory Circular Pilot Wind Shear Guide via the Internet Wayback Machine". Federal Aviation Administration. Archived from the original on 2006-10-14. Retrieved 2009-03-18.
- Jump up ^ David M. Roth (2006). "Unified Surface Analysis Manual". Hydrometeorological Prediction Center. Retrieved 2006-10-22.
- Jump up ^ Glossary of Meteorology (2007). "E". American Meteorological Society. Retrieved 2007-06-03.
- Jump up ^ "Jet Streams in the UK". BBC. 2009. Retrieved 2009-06-20.
- ^ Jump up to: a b Cheryl W. Cleghorn (2004). "Making the Skies Safer From Windshear". NASA Langley Air Force Base. Archived from the original on August 23, 2006. Retrieved 2006-10-22.
- Jump up ^ National Center for Atmospheric Research (Spring 2006). "T-REX: Catching the Sierra’s waves and rotors". University Corporation for Atmospheric Research Quarterly. Retrieved 2009-06-21.
- Jump up ^ Hans M. Soekkha (1997). Aviation Safety. VSP. p. 229. ISBN 978-90-6764-258-3. Retrieved 2009-06-21.
- Jump up ^ Robert Harrison (2001). Large Wind Turbines. Chichester: John Wiley & Sons. p. 30. ISBN 0-471-49456-9.
- Jump up ^ Ross Garrett (1996). The Symmetry of Sailing. Dobbs Ferry: Sheridan House. pp. 97–99. ISBN 1-57409-000-3.
- Jump up ^ Gail S. Langevin (2009). "Wind Shear". National Aeronautic and Space Administration. Archived from the original on October 9, 2007. Retrieved 2007-10-09.
- Jump up ^ Rene N. Foss (June 1978). "Ground Plane Wind Shear Interaction on Acoustic Transmission". WA-RD 033.1. Washington State Department of Transportation. Retrieved 2007-05-30.
- Jump up ^ University of Illinois (1999). "Hurricanes". Retrieved 2006-10-21.
- Jump up ^ University of Illinois (1999). "Vertical Wind Shear". Retrieved 2006-10-21.
- Jump up ^ Integrated Publishing (2007). "Unit 6—Lesson 1: Low-Level Wind Shear". Retrieved 2009-06-21.
- Jump up ^ Laura Gibbs, Ph.D (2007-10-16). "Vayu". Encyclopedia for Epics of Ancient India. Retrieved 2009-04-09.
- ^ Jump up to: a b c d e Michael Jordan (1993). Encyclopedia of Gods: Over 2, 500 Deities of the World. New York: Facts on File. pp. 5, 45, 80, 187–188, 243, 280, 295. ISBN 0-8160-2909-1.
- Jump up ^ Theoi Greek Mythology (2008). "Anemi: Greek Gods of the Winds". Aaron Atsma. Retrieved 2009-04-10.
- Jump up ^ John Boardman (1994). The Diffusion of Classical Art in Antiquity. Princeton University Press. ISBN 0-691-03680-2.
- Jump up ^ Andy Orchard (1997). Dictionary of Norse Myth and Legend. Cassell. ISBN 978-0-304-36385-8.
- Jump up ^ History Detectives (2008). "Feature – Kamikaze Attacks". PBS. Retrieved 2009-03-21.
- Jump up ^ Colin Martin, Geoffrey Parker (1999). The Spanish Armada. Manchester University Press. pp. 144–181. ISBN 978-1-901341-14-0. Retrieved 2009-06-20.
- Jump up ^ S.
Lindgrén and J. Neumann (1985). "Great Historical Events That Were
Significantly Affected by the Weather: 7, "Protestant Wind"—"Popish
Wind": The Revolusion of 1688 in England". Bulletin of the American Meteorological Society 66 (6): 634–644. Bibcode:1985BAMS...66..634L. doi:10.1175/1520-0477(1985)066<0634:GHETWS>2.0.CO;2.
- Jump up ^ Nina Burleigh (2007). Mirage. Harper. p. 135. ISBN 978-0-06-059767-2.
- Jump up ^ Jan DeBlieu (1998). Wind. Houghton Mifflin Harcourt. p. 57. ISBN 978-0-395-78033-6.
- Jump up ^ Ernest Edwin Speight and Robert Morton Nance (1906). Britain's Sea Story, B.C. 55-A.D. 1805. Hodder and Stoughton. p. 30. Retrieved 2009-03-19.
- Jump up ^ Brandon Griggs and Jeff King (2009-03-09). "Boat made of plastic bottles to make ocean voyage". CNN. Retrieved 2009-03-19.
- Jump up ^ Jerry Cardwell (1997). Sailing Big on a Small Sailboat. Sheridan House, Inc. p. 118. ISBN 978-1-57409-007-9. Retrieved 2009-03-19.
- Jump up ^ Brian Lavery and Patrick O'Brian (1989). Nelson's navy. Naval Institute Press. p. 191. ISBN 978-1-59114-611-7. Retrieved 2009-06-20.
- Jump up ^ Underwater Archaeology Kids' Corner (2009). "Shipwrecks, Shipwrecks Everywhere". Wisconsin Historical Society. Retrieved 2009-03-19.
- Jump up ^ Carla Rahn Phillips (1993). The Worlds of Christopher Columbus. Cambridge University Press. p. 67. ISBN 978-0-521-44652-5. Retrieved 2009-03-19.
- Jump up ^ Tom Benson (2008). "Relative Velocities: Aircraft Reference". NASA Glenn Research Center. Retrieved 2009-03-19.
- Jump up ^ Library of Congress (2006-01-06). "The Dream of Flight". Retrieved 2009-06-20.
- Jump up ^ "Flight Paths". Bristol International Airport. 2004. Archived from the original on 2007-05-08. Retrieved 2009-03-19.
- Jump up ^ G. Juleff (1996). "An ancient wind powered iron smelting technology in Sri Lanka". Nature 379 (3): 60–63. Bibcode:1996Natur.379...60J. doi:10.1038/379060a0.
- Jump up ^ A.G. Drachmann (1961). "Heron's Windmill". Centaurus 7: 145–151.
- Jump up ^ Ahmad Y Hassan and Donald Routledge Hill (1986). Islamic Technology: An illustrated history. Cambridge University Press. p. 54. ISBN 0-521-42239-6.
- Jump up ^ Donald Routledge Hill (May 1991). Mechanical Engineering in the Medieval Near East. Scientific American. pp. 64–69.
- Jump up ^ Dietrich Lohrmann (1995). "Von der östlichen zur westlichen Windmühle". Archiv für Kulturgeschichte 77 (1): 1–30. doi:10.7788/akg.1995.77.1.1.
- Jump up ^ SkySails. SkySails. Retrieved 2011-11-03.
- Jump up ^ Glider Flying Handbook. U.S. Government Printing Office, Washington D.C.: U.S. Federal Aviation Administration. 2003. pp. 7–16. FAA-8083-13_GFH. Retrieved 2009-06-17.
- Jump up ^ Derek Piggott (1997). Gliding: a Handbook on Soaring Flight. Knauff & Grove. pp. 85–86, 130–132. ISBN 978-0-9605676-4-5.
- ^ Jump up to: a b Vern Hofman and Dave Franzen (1997). "Emergency Tillage to Control Wind Erosion". North Dakota State University Extension Service. Retrieved 2009-03-21.
- ^ Jump up to: a b James K. B. Bishop, Russ E. Davis, and Jeffrey T. Sherman (2002). "Robotic Observations of Dust Storm Enhancement of Carbon Biomass in the North Pacific". Science 298 (5594): 817–821. Bibcode:2002Sci...298..817B. doi:10.1126/science.1074961. PMID 12399588. Retrieved 2009-06-20.
- Jump up ^ United States Geological Survey (2004). "Dunes – Getting Started". Retrieved 2009-03-21.
- Jump up ^ F. von Richthofen (1882). "On the mode of origin of the loess". Geological Magazine (Decade II) 9 (7): 293–305. doi:10.1017/S001675680017164X.
- Jump up ^ K.E.K. Neuendorf, J.P. Mehl, Jr., and J.A. Jackson (2005). Glossary of Geology. Springer-Verlag, New York. p. 779. ISBN 3-540-27951-2.
- Jump up ^ Arthur Getis; Judith Getis and Jerome D. Fellmann (2000). Introduction to Geography, Seventh Edition. McGraw-Hill. p. 99. ISBN 0-697-38506-X.
- Jump up ^ Science Daily (1999-07-14). "African Dust Called A Major Factor Affecting Southeast U.S. Air Quality". Retrieved 2007-06-10.
- Jump up ^ Science Daily (2001-06-15). "Microbes And The Dust They Ride In On Pose Potential Health Risks". Retrieved 2007-06-10.
- Jump up ^ Usinfo.state.gov (2003). "Study Says African Dust Affects Climate in U.S., Caribbean". Retrieved 2007-06-10.
- Jump up ^ U. S. Geological Survey (2006). "Coral Mortality and African Dust". Retrieved 2007-06-10.
- Jump up ^ Weather Online (2009). "Calima". Retrieved 2009-06-17.
- Jump up ^ Henrik Breuning-Madsen and Theodore W. Awadzi (2005). "Harmattan dust deposition and particle size in Ghana". Catena 63 (1): 23–38. doi:10.1016/j.catena.2005.04.001.
- Jump up ^ Weather Online (2009). "Sirocco (Scirocco)". Retrieved 2009-06-17.
- Jump up ^ Bill Giles (O.B.E) (2009). "The Khamsin". BBC. Retrieved 2009-06-17.
- Jump up ^ Thomas J. Perrone (August 1979). "Table of Contents: Wind Climatology of the Winter Shamal". United States Navy. Retrieved 2009-06-17.
- Jump up ^ J. Gurevitch, S. M. Scheiner, and G. A. Fox (2006). Plant Ecology, 2nd ed. Sinauer Associates, Inc., Massachusetts.
- Jump up ^ M. L. Cody and J. M. Overton (1996). "Short-term evolution of reduced dispersal in island plant populations". Journal of Ecology 84: 53–61. doi:10.2307/2261699. JSTOR 2261699.
- Jump up ^ A. J. Richards (1997). Plant Breeding Systems. Taylor & Francis. p. 88. ISBN 978-0-412-57450-4. Retrieved 2009-06-19.
- Jump up ^ Leif Kullman (2005). "Wind-Conditioned 20th Century Decline of Birch Treeline Vegetation in the Swedish Scandes". Arctic 58 (3): 286–294. Retrieved 2009-06-20.
