Weather Topic 7 Created by P. Bordas MS, CCC-SLP Remember to wait for the vocabulary word to pop up at the end! Can you guess it before it comes up?

Weather Variables Include temperature, air pressure, wind, moisture conditions, cloud cover, precipitation, and storms teachers.saschina.org/aolivas/

Troposphere The part of the atmosphere immediately above the Earths surface. Where most of the weather changes occur

Atmospheric Pressure and Density

Atmospheric Pressure (or barometric pressure or air pressure) The pressure due to the weight of the overlying atmosphere pushing down on any given area

Barometers Instrument used to measure air pressure

Isobars Used to show air pressure on weather maps

Wind

Air Pressure Gradient The difference in air pressure for a specific distance

Anemometer Instrument used to measure wind speed

General Circulation of the Air in the Troposphere

Jet Streams Bands of easterly moving air at the top of the troposphere

Planetary Wind Belts Results because of the Coriolis effect (winds moving away from high air pressure and deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere). Within these, the winds move generally in a specific direction much of the time so they are prevailing winds. d.curran/images/A07_14.gif&imgrefurl= curran/outline2.htm&usg=__4EzI0dKYxO5- 4b5Agt0poS3Hl3c=&h=258&w=411&sz=26&hl=en&start=12&um=1&itb s=1&tbnid=MmWjuknAdEitVM:&tbnh=78&tbnw=125&prev=/images%3 Fq%3Dplanetary%2Bwind%2Bbelts%26um%3D1%26hl%3Den%26saf e%3Dactive%26rlz%3D1T4GZAZ_enUS316US317%26tbs%3Disch:1

Monsoons Extreme weather changes caused by the shifting wind and pressure belts

Atmospheric Moisture

Water Vapor Gaseous water in the atmosphere

Humidity General term that refers to the water vapor content of the atmosphere

Relative Humidity The ratio of the amount of water vapor in the air (absolute humidity) to the maximum amount it can hould (its moisture capacity)

Dew Point The temperature at which air is filled with water vapor

Psychrometer Instrument used to measure relative humidity G

Precipitation The falling of liquid or solid water from clouds toward the surface of Earth

Cloud Cover The fraction or percent of the total sky at a location that is covered by clouds

Atmospheric Transparency How transparent the atmosphere is to insolation

Visibility How far you can see along Earths surface expressed in miles

Air Masses and Fronts

Air Mass A large body of air in the troposphere with similar characteristics of pressure, moisture and temperature

Cyclones Have low pressure

Cold Front The boundary of an advancing cold air mass and a warmer air mass, where the underlying cold air pushes forward like a wedge

Warm Front The boundary of an advancing warm air mass and retreating wedge of cooler air mass. The cooler air is heavier, the warm air mass is forced to rise as it advances ?imgurl= graphy.net/fundamentals/images /warmfront.GIF&imgrefurl= damentals/7r.html&usg=__csBK Cc0ogNKYd8c7lPrpD1VDD00= &h=325&w=594&sz=27&hl=en& start=1&um=1&itbs=1&tbnid=IC EirI7Rq4Em3M:&tbnh=74&tbnw =135&prev=/images%3Fq%3Dw arm%2Bfront%26um%3D1%26h l%3Den%26safe%3Dactive%26r lz%3D1T4GZAZ_enUS316US31 7%26tbs%3Disch:1

Occluded Front Boundary of opposing wedges of cold air masses formed when a cold front overtakes a warm front, lifting the warm air mass off the ground ww.physicalgeography.net/fundamentals/images/ warmfront.GIF&imgrefurl= graphy.net/fundamentals/7r.html&usg=__csBKCc 0ogNKYd8c7lPrpD1VDD00=&h=325&w=594&sz =27&hl=en&start=7&um=1&itbs=1&tbnid=ICEirI7 Rq4Em3M:&tbnh=74&tbnw=135&prev=/images% 3Fq%3Doccluded%2Bfront%26um%3D1%26hl% 3Den%26safe%3Dactive%26rlz%3D1T4GZAZ_e nUS316US317%26tbs%3Disch:1