Just how does it work? Atmospheric pressure= 14.7 psi Air Pressure Just how does it work? Atmospheric pressure= 14.7 psi

Units of measure for Pressure 2 units for measuring pressure are, millibars, and inches of Mercury 29.73 997 30.18 994

Which pressure gradient would result in greater wind velocity? Isobars- iso is Greek meaning equal, bar is a unit of measuring pressure, so Isobars are lines of equal pressures

Things that effect Air Pressure Altitude (Elevation) Temperature Humidity (moisture in the air)

Altitude The higher the altitude, the lower the air pressure. (less dense) The lower the altitude, the higher the air pressure. (more dense)

Draw the relationship between air pressure and air density.

Temperature As the temperature goes up, the air pressure goes down. (hot molecules are further apart- less dense, less pressure). As the temperature goes down, the air pressure goes up. ( cold air is more dense than warm air).

Humidity Humidity is the amount of moisture in the air. Water vapor weighs less than air molecules. As the air becomes more humid, the air pressure goes down (moist air weighs less than dry air). Drier air has higher pressure because dry air weighs more than moist air, therefore it has greater pressure.

Winds Cause of wind

Wind blows from areas of to areas of high pressure low pressure

How are winds named? The direction from which they come

What instrument is used to measure: wind speed air pressure anemometer barometer [ORIGIN from Greek anemos ‘wind’] [ORIGIN from Greek baros ‘weight’]

How wind develops Caused by differences in air pressure, due to unequal heating of the atmosphere

This is because the air is Therefore, clouds CANNOT form. In a high pressure area, air will (rise, sink) because the air is (less, more) dense. This is because the air is (cold, warm) and (rises, sinks). Therefore, clouds CANNOT form.

This is because the air is In a low pressure area, air will (rise, sink) because the air is (less, more) dense. This is because the air is (cold, warm) and (rises, sinks). Therefore, clouds are LIKELY to form.

Winds are created by… Heating the air, decreases pressure (warm air rises creating a low pressure) Cool air rushes in to replace the warm air (cooler dense air, produces high pressure) Winds form, as air goes from areas of high pressure to areas of low pressure

Coriolis Effect Coriolis Effect Directions Rotation of the Earth causes moving air and water to change direction Northern Hemisphere- winds curve to the right Southern Hemisphere- winds curve to the left

Correctly draw the direction of wind flow around both a high and a low pressure area in the NORTHERN HEMISPHERE. Counter- clockwise Clockwise

counterclockwise wind direction low pressure high pressure warm or cold air air rising or sinking clouds or no clouds clockwise or counterclockwise wind direction winds toward or away from the center warm cold rising sinking clouds no clouds counter clockwise clockwise toward away

2 Types of Wind 1. Global 2. Local

Global Winds Doldrums Trade Winds Prevailing Winds Polar Easterlies Winds that blow over large distances. Do not travel North and South due to the Coriolis Effect 4 Types of Global Winds Doldrums Trade Winds Prevailing Winds Polar Easterlies

Trade Winds Trade Winds

Doldrums At the Equator, surface winds are calm and weak Now known as, Intertropical Convergence Zone (ITCZ) At the Equator, surface winds are calm and weak Why would these winds be calm and weak? When would this cause a problem? ITCZ

Trade Winds 30 degrees North and South of the Equator Calm Winds, few clouds, little rain fall Warm air rising from the equator cools and sinks Also known as the Horse Latitudes

Prevailing Westerlies Strong Winds Located in the belt 30- 60 degrees latitude in both Hemispheres Has an impact on the US weather Is the prevailing wind in the United States

Polar Easterlies Cold, but weak winds Near the North and South Poles US weather is influenced by these Cooling takes place between the 50- 60 degree latitude as it approaches the poles

Jet Stream Discovered in the 1940’s Can be found in the upper Troposphere Strong, high speed and high pressure Moves West to East across the US, moving storms

Local Winds Cover short distances and blow from any direction 2 Types of Local Winds Sea Breezes- from sea to land Land Breezes- from land to sea

Sea Breeze

Land Breeze