wind is a stream of air moving in a certain direction.On other planets, it is a characteristic of the surface mass of gas.On Earth, the wind is moving mostly horizontally.Classification is usually carried out in accordance with the speed, scale, types of forces that cause them, places of distribution.Under the influence of various streams are natural phenomena and weather.Wind contributes to the transfer of dust, plant seeds, contributes to the displacement of flying animals.But how does the air flow direction?Where the wind blows?What determines the duration and strength?And why winds blow?On this and many other - later in the article.
Classification
primarily winds characterize the strength, direction and duration.Gusts are considered strong and short-term travel (up to several seconds) of air flow.If a strong wind blows expectancy (about a minute), it is called a flurry.Longer air flows are named according to their power.So, for example, a light breeze blowing on the coast - is a breeze.There is a typhoon, hurricane, storm, storm.The duration of the winds can also be different.Some last a few minutes, for example.Breeze, depending on the temperature difference on the surface of the relief during the day, can last up to several hours.Local and general circulation of the atmosphere consist of the trade winds and the monsoon.Both of these fall into the category of "global" winds.Monsoons are caused by seasonal changes in temperature and have a duration of up to several months.Trade winds - it's the air masses are constantly moving.They are caused by the temperature difference at different latitudes.
How to explain to a child why the wind blows?
for children at an early age, this phenomenon represents a different interest.The child does not understand where a stream of air, which is why in one place it is, and in the other - no.Simply explain to your child that in the winter, for example, a cold wind blows from the low temperature.How is this process?It is known that the airflow is the mass of the molecules of the atmospheric gases, are moved together in the same direction.A small amount of air flow, blowing high-rise building can whistle, pluck caps with passers-by.But if the mass of the gas molecules has a large volume and a few kilometers wide, it can cover quite a long distance.In enclosed spaces the air hardly moves.And its existence is possible even to forget.But if set, for example, a hand of a moving window of a vehicle, the wheel can feel the air flow and its pressure force.Where the wind blows?The flow is carried out due to the pressure difference in the different parts of the atmosphere.Let us consider this process in more detail.
difference in atmospheric pressure
So why the wind blows?For children a better result in the example of the dam.On the one hand the height of the water column, for example, three, and on the other - six meters.When you open the sluices water flow into the area where it is less.Roughly the same thing happens with the air currents.In different parts of the atmospheric pressure is different.This is due to the difference in temperature.The warm air is faster movement of molecules.The particles tend to fly apart from each other in different directions.In this regard, the warm air is discharged over and weighs less.As a result, pressure is generated therein decreases.If the temperature is lowered, the molecules form a close cluster.Air therefore weighs more.The pressure thus rises.Similarly, water, air has the property of flow from one zone to another.So, the flow proceeds from the portion of higher pressure to an area with reduced.That is why the winds blow.
flow around bodies of water
Why the wind blows in from the sea?Consider an example.On a sunny day and the rays warm up the beach, and a pond.But the water heats up much slower.This is due to the fact that the surface layers of warm immediately begin to mix with the deeper layers, and therefore cold.But the coast is heated much faster.And the air above him more exhausted and the pressure, respectively, below.Atmospheric flows rush to the shore of the reservoir - more free area.There they are heated, rise up again to make room.Instead reappears cool stream.So is the circulation of air.On the beach, guests can occasionally feel the cool breeze.
wind values
find out why the winds blow, it should be said about the impact they have on life on Earth.The wind is of great importance for human civilization.Eddy currents inspired people to create mythological works to expand trade and cultural range, working on historical events.Winds also acts as a supplier of energy for different mechanisms and assemblies.Due to the movement of air flows sailing ships were able to travel long distances for the oceans and seas, and balloons - the sky.For modern aircraft winds are of great practical value - they allow you to save fuel and to increase lift.But it must be said that the air flow and can bring harm to humans.For example, due to vibrations of the gradient wind can be lost control of the aircraft.In small ponds rapid air currents and waves caused by them can destroy buildings.In many cases, the winds help to increase the scale of the fire.In general, phenomena associated with the formation of air streams in different ways effect on wildlife.
Global effects
In many parts of the world is dominated by air masses that have defined the direction of motion.In the area of the poles tend to dominate the eastern and in the temperate latitudes - westerly winds.In the tropics, the air flows take back east.At the boundaries between these zones - subtropical ridge and the polar front - located the so-called area of silence.The prevailing winds in these areas are virtually absent.Here, the movement of air is mostly vertically.This explains the emergence of areas of high humidity (near the polar front) and deserts (about the subtropical ridge).
Tropical
In this part of the world in the trade winds blow westward, closer to the equator.Due to the constant movement of air flow the mixing of atmospheric masses on Earth.This can manifest itself on a large scale.So, for example, the trade winds moving over the Atlantic Ocean, carry dust from the African desert areas in the West Indies and parts of North America.
Local effects of forming air masses
find out why the winds blow, it should be said about the influence of the presence of certain geographic features.One of the local effects of the formation of air masses is considered to be the temperature difference between the not too distant sites.It can be triggered by different coefficients of absorption of light or thermal capacity of different surfaces.Hardest latter effect manifests itself between the water surface and land.The result is a breeze.Another local factor of importance is the presence of mountain ranges.
Influence mountains
These systems can be a barrier to the movement of air currents.Furthermore, in many cases, mountains themselves cause vetroobrazovanie.The air above the hill warmed more than the atmospheric mass above the lowlands at the same height.This contributes to a zone of low pressure over the mountain ridges and vetroobrazovaniyu.This effect often causes the appearance of mountain-valley weather moving masses.Such winds prevail in areas with rough terrain.
Increase friction at the surface of the valley leads to a deviation parallel to the direction of air flow to the height of adjacent mountains.This contributes to a high-altitude jet flow.The rate of flow can exceed the ambient wind force up to 45%.As mentioned above, the mountain can act as obstacles.When bypass circuit flow changes direction and strength.Differences in the mountain ranges have a significant impact on the movement of the wind.For example, if a mountain range, which overcomes the atmospheric mass, there is the pass, the stream passes it to a noticeable increase in speed.In this case, it is running the Bernoulli effect.It should be noted that even a slight elevation changes cause fluctuations in wind speed.Due to the substantial velocity gradient of air flow becomes turbulent, and continues to remain so even a mountain on the plain at a certain distance.These effects are in some cases of particular importance.For example, they are important for the aircraft, carrying off and landing on the mountain airfield.
