What is Wind?

Wind is known as the flow of air. It is gases in the atmosphere, that are invisible and is the air that moves horizontally. Wind blows of areas of high pressure, to areas with low pressure. There are different types of winds, all of which are created by differences in temperatures within our atmosphere.

If wind is invisible, How are we able to measure it? Scientists measure wind depending on the direction the wind is coming from. This is known as the compass direction. Prevailing win id is wind that is most often observed in a particular region. There are a few instruments that scientists can use to measure wind as well; they are:

• Wind Vane-used to determine the direction of the wind (image 1)
  
• Anemometer-used to measure wind speed (image 2)
  
• Aerovane-measures both speed, and direction (image 3)
  
• Radiosonde-is a weather balloon (image 4)

Types of Wind

There are many different types and classifications of winds. Terms commonly associated with winds are:

• Local Winds
• Global Winds
• Global Pressure Zones
• Directional Global Winds
• Jet Streams

• Fronts
• Air Mass (and what type of wind they bring along)
  

• El Nino
• La Nina

Learn more about different wind types!

Local Winds

Local Winds only cover small regions. They could be considered Land or Sea Breezes, Monsoons*, Mountain or Valley Breezes, or Chinook wind*.


*Monsoons: Winds that change its direction seasonally (Occur on a regular basis in India)
*Chinook Wind: Warm and dry wind blowing down the Eastern slope of the Rockies

Global Winds, Global Pressure Zones, and Directional Global Winds

Global Winds: cover large areas of the globe at one time. Warm air rises at low pressure areas. Once it reaches an area of high pressure, the air cools. The cooled air will then sink back and travel back toward a low pressure area. This all takes place within a "section" of the globe we refer to as a circulation cell. There are three cells in each of the hemispheres. they are:

• Polar Cells
• Ferrel Cells
• Hadley Cells

Global Presure Zones: Doldrum: low pressure areas around the equator where winds are calm. Horse Latitude (aka subtropical high): hot, dry air, most desserts are located in these latitudes. Polar Fronts: cold air form the poles sinks down and meets with westerlies. Sub Polar Lows: storms often develop here




Directional Global Winds: Trade Wind: Winds meet at the equator. Westerlies: blow poleward side of horse latitudes. Westerlies means the winds are traveling from the west to the east. Polar Easterlies: shallow winds from the NE located in low pressure regions of polar cells.



global winds
more on wind

Jet Streams

A river of fast flowing air in the upper atmosphere is known as a jet stream. In the northern Hemisphere, the jet stream flows along the polar front and are generally 10-12 km high, with winds moving at 200-250mph. In the winter, jet streams bring stronger winds that dip further south.

If the jet stream is north of you, you experience warm temperatures.
If the jet stream is south of you, you will experience colder temperatures.

Fronts

what is a front? A front is the boundary between two air masses that have different temperatures, humidities and densities. There are four different types:

• Stationary Fronts: winds are gentle to non existent
  
• Cold Fronts: Cold air pushes warm air up and creates gusty winds
• Warm Fronts: slow moving warm air slides over cold air and creates gentle winds
• Occluded Fronts: generally small, gentle winds.
  

Learn more about the four different types of fronts

Air Masses

Air Mass is an extremely hot body of air whose temperature and humidity are relatively the same throughout. Source Regions, where the air mass comes from, are generally light, flat winds, found in high pressure areas. Source Regions are what classifies an Air Mass.

• A=Arctic
• E=Equatorial
• P=Poles
• T=Tropic
• c=continental (air is dry because it forms over land)
  
• m=maritime (air is moist because it forms over water)

**Note: Code letters are combined to specify Source Regions**

Air Mass formation: If surface air resides in a region for a few days it acquires thermal and moisture characteristics of the underlying surface. Because it generally takes a few days to form,, ares take shape of high pressures with light winds. Air masses can change as it passes over ares with differing surface characteristics, if this happens, it will change the characteristics of the air mass.


**us code letter above to refer to if necessary:

P=

A or AA
Extremely cold and dry air forming from over the poles.

cP
Contains cold and dry air forming from over sub polar regions. Causes bitterly cold winters, and pleasant summers.

mP
Contains cold and moist air, and may bring along little rain



T=

cT
Warm, dry air; often over southwest US and mexico in the summer, produces temperatures above 100F.

mT Warm moist air originating from the Atlantic ocean, Caribbean Sea, or Gulf of Mexico.



EQUATORIAL
E= almost never reaches Canada, and rarely continental US. Brings extremely hot and humid air, most of equatorial land is covered in humid tropical rain forests.





More on air temperatures and air mass movement
Wikipedia Air Mass

El Nino and La Nina

What is El Nino? El nino is extensive warming of ocean water along the South American cost. It causes strong Easterly winds to blow across the Pacific, and changes precipitation (so often, flooding and droughts occur)

El Nino seems to occur every two to seven years, the worst recorded was in 1982-1983.



What is La Nina? La Nina, usually following an El Nino, is the cause of ocean temperatures cooling. This creates dry weather to the central and Southwest United States.


*just remember: El Nino= Hot, while La Nina=Cold

Dangers of Wind, and Wind Safety

Wind is very powerful and uncontrollable force of life. It can tear trees out of the ground, blow houses apart, create violent weather conditions and damaging situations. Many people think of tornadoes as the most powerful and damaging wind issue. Although tornadoes are very damaging and powerful, studies have shown that it is more common for harsh thunderstorms to produce larger damage, and this happens more frequently, than a tornadoes.

In order to make sure that you are safe from any damage when encountering brutal wind conditions, you should remain inside and away from windows. Board up any doors, cracks, seals, and glass if necessary, and remember to remain calm. If you have the time while it is still safe, secure your light weight items, such as empty garbage cans or small trees, so that they will not blow away and create more of a mess. Park cars in a sheltered area if available, and stay out of the water! Watch your local news station, or listen to the radio, to hear more information about weather conditions in your area, and to hear the tips recommended for your situation in order to remain safe.

Fun With Wind! :-)

Make your own Kite!


Make your very own Anemometer!


Make your own Wind Vane!