Air Pressure
At the Earth’s surface, wind blows horizontally from high pressure to low pressure areas. The speed is determined by the rate of air pressure change , or gradient, between the two pressure areas. The greater the pressure difference, the faster the winds.
Why is wind so much faster high up in the troposphere than it is near the ground?
Within the troposphere are convection cells (Figure below). Warm air rises, creating a low pressure zone; cool air sinks, creating a high pressure zone. Air that moves horizontally between high and low pressure zones makes wind. The greater the pressure difference between the pressure zones the faster the wind moves .
Why does wind speed increase with altitude?
Going up in altitude, the pressure gradient between the warm air and the cold air increases with height. ... The influence of this friction is less with height above the ground , thus the wind speed increases with height.
Why does wind direction change with altitude?
Higher up, friction is decreased , so winds are stronger. Since the Coriolis effect is proportional to wind speed, it begins deflecting air to the right (or to the left in the Southern Hemisphere). This causes successively more and more deflection with height.
Which has the greatest effect on wind speed?
Air pressure has the greatest effect on wind speed.
What are 3 factors that affect surface winds?
The speed and direction of the wind is governed by three forces; the pressure gradient force (PGF), the Coriolis Force and friction . PGF is the force produced by differences in barometric pressure between two locations and is responsible for the flow of air from an area of high pressure to an area of low pressure.
What are 3 facts about the troposphere?
- The troposphere contains 75% of the atmosphere’s total mass.
- In either space or time the troposphere is not constant.
- Weather occurs in the troposphere.
- The troposphere is 10 miles from the equator.
- The troposphere is 5-7 miles above the poles.
- Does not contain ozone.
Do we live in the troposphere?
We humans live in the troposphere , and nearly all weather occurs in this lowest layer. Most clouds appear here, mainly because 99% of the water vapor in the atmosphere is found in the troposphere. Air pressure drops, and temperatures get colder, as you climb higher in the troposphere.
What height is wind speed?
It is generally accepted that measurements are based on readings at 10 metres (33 feet) above ground and the distance between the anemometer and any obstruction is at least ten times the height of the obstruction!
Is the wind stronger at higher altitudes?
Going up in altitude, the pressure gradient between the warm air and the cold air increases with height. ... A higher slant results in a greater pressure gradient between the warm and cold air and thus stronger wind.
What are the factors affecting wind?
- Pressure Gradient Force:
- Coriolis Force:
- Centripetal Acceleration:
- Frictional Force:
- Primary or Prevailing Winds:
- Secondary or Periodic Winds:
- Tertiary or Local Winds:
Why does wind change direction?
This happens because Earth’s rotation generates what is known as the Coriolis effect . The Coriolis effect makes wind systems twist counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
What has the greatest effect on humidity?
Warm air can possess more water vapor (moisture) than cold air, so with the same amount of absolute/specific humidity, air will have a HIGHER relative humidity if the air is cooler, and a LOWER relative humidity if the air is warmer.
Which factors have the greatest impact on the direction of global winds?
Seasonal temperature changes and the Earth’s rotation also affect wind speed and direction.
How does temperature affect wind?
Temperature is the intensity of heat in a substance while the wind speed is the air in motion from. ... The atmosphere tries to equalize the air pressure at these two spots, forming wind. Generally, the larger the temperature difference, the stronger the resulting winds will be.
What affects the direction of wind on the Earth?
Our planet’s rotation produces a force on all bodies moving relative to theEarth. Due to Earth’s approximately spherical shape, this force is greatest at the poles and least at the Equator. The force, called the “Coriolis effect ,” causes the direction of winds and ocean currents to be deflected.
