Weather and ClimateWeather and Climate

MeteorologyMeteorology

The study of the atmosphereThe study of the atmosphere– Rain, dust, haze, smoke, lightening-- the Rain, dust, haze, smoke, lightening-- the

weatherweather

WeatherWeather

The current state The current state of the atmosphereof the atmosphere

What is going on What is going on right nowright now

ClimateClimate

Long-term Long-term variations of variations of weatherweather

Average over many Average over many yearsyears

Why is there different climates Why is there different climates and seasons?and seasons?

Earth is tilted therefor the sun hits Earth is tilted therefor the sun hits the earth at different anglesthe earth at different angles

The straighter the angle, the warmer The straighter the angle, the warmer the heatthe heat

** Earth distributes the heat ** Earth distributes the heat throughout the globethroughout the globe

Coriolis EffectCoriolis Effect

Because of the rotation of earth Because of the rotation of earth perfect convection currents don’t perfect convection currents don’t occur.occur.

Particles move to the right in the Particles move to the right in the north and the left in the southnorth and the left in the south

The coriolis effect combines with the heat The coriolis effect combines with the heat

imbalance to create a global imbalance to create a global wind systemwind system

Air mass Air mass

A body of air that takes on the A body of air that takes on the characteristic of the area it formscharacteristic of the area it forms

With the movement of the Earth and With the movement of the Earth and convection the air mass moves and convection the air mass moves and exchanges heat with the new area it exchanges heat with the new area it is over.is over.

Global Wind SystemGlobal Wind System

Caused by 3 different convection Caused by 3 different convection cellscells

3 basic wind systems3 basic wind systems– 1. Trade winds1. Trade winds– 2. Prevailing Westerlies2. Prevailing Westerlies– 3. Polar Easterlies3. Polar Easterlies

Trade WindsTrade Winds

Occur at the 30o N and S Occur at the 30o N and S

Air cools and sinks here and moves Air cools and sinks here and moves to the equator where it is warmed to the equator where it is warmed and rises againand rises again

Result of the Trade windsResult of the Trade winds

The rising air from the trade winds The rising air from the trade winds migrate either north or south based migrate either north or south based on the seasonon the season

Causes cloudiness and showers that Causes cloudiness and showers that provide the rain for the rain forestsprovide the rain for the rain forests

Prevailing WesterliesPrevailing Westerlies

Flows between 30o and 60o N and SFlows between 30o and 60o N and S

Circulate opposite the trade winds Circulate opposite the trade winds Responsible for most the weather in Responsible for most the weather in

the United States and Canadathe United States and Canada

Polar EasterliesPolar Easterlies

Lies between 60o Lies between 60o and the polesand the poles

Brings cold air to Brings cold air to the larger the larger continentscontinents

Jet StreamsJet Streams

Earth’s weather is Earth’s weather is influenced by influenced by atmospheric atmospheric conditions and conditions and events that occur events that occur at the boundaries at the boundaries between wind between wind zoneszones

Winds ContWinds Cont

Surface and upper air differ greatly in Surface and upper air differ greatly in temperature and pressuretemperature and pressure

Jet Streams cont.Jet Streams cont.

Narrow bands of fast, high-altitude, Narrow bands of fast, high-altitude, westerly windswesterly winds

Located where the wind systems Located where the wind systems meet (between the polar easterlies meet (between the polar easterlies and prevailing westerlies)and prevailing westerlies)

FrontsFronts

The narrow region separating two air The narrow region separating two air masses of different densities (caused masses of different densities (caused by different pressures or by different pressures or temperatures)temperatures)

4 types of Fronts4 types of Fronts

1. Cold Fronts1. Cold Fronts 2. Warm Fronts2. Warm Fronts 3. Stationary Fronts3. Stationary Fronts 4. Occluded Fronts4. Occluded Fronts

Cold FrontsCold Fronts Forces warm air up and causes clouds, Forces warm air up and causes clouds,

showers, and thunderstormsshowers, and thunderstorms

On a weather map represented as blue On a weather map represented as blue line with blue triangles point in the line with blue triangles point in the direction of movementdirection of movement

Warm FrontWarm Front Extensive Cloudiness and precipitationExtensive Cloudiness and precipitation

– June GloomJune Gloom

Represented by a solid red line with solid Represented by a solid red line with solid red semi-circlesred semi-circles

Stationary FrontStationary Front

Meeting of two mild frontsMeeting of two mild fronts No heavy weather No heavy weather

Represented by a combination of red Represented by a combination of red circles and blue trianglescircles and blue triangles

Occluded FrontOccluded Front

When two cold air masses which force a When two cold air masses which force a warm air mass upwards warm air mass upwards

Strong winds and heavy precipitationStrong winds and heavy precipitation

Pressure zonesPressure zones

High pressure- Associated with fair High pressure- Associated with fair weatherweather

Low pressure-- clouds and Low pressure-- clouds and precipitationprecipitation

When no front is over the When no front is over the area, the weather is like area, the weather is like

the air mass sitting on topthe air mass sitting on top