Weather and Climate

Weather and ClimateWeather and ClimateChapter 3Chapter 3

Factors Affecting ClimateFactors Affecting Climate►WeatherWeather is the is the

condition of the condition of the atmosphere at a atmosphere at a given time and given time and place.place.

►Weather conditions Weather conditions in a geographic in a geographic region over a long region over a long time are called time are called climateclimate..

FactorsFactors►The Sun heats the Earth unevenly.The Sun heats the Earth unevenly.►The tilt of Earth as it revolves around The tilt of Earth as it revolves around

the Sun is very important.the Sun is very important.► It determines which hemisphere It determines which hemisphere

receives the Sun’s most direct rays at receives the Sun’s most direct rays at a given time of year.a given time of year.

►This process causes the changing This process causes the changing seasons.seasons.

What happens to the Sun’s What happens to the Sun’s energy when it reaches energy when it reaches

Earth?Earth?►½ is reflected back into space or ½ is reflected back into space or

absorbed by the atmosphereabsorbed by the atmosphere►Earth’s surface absorbs the other ½Earth’s surface absorbs the other ½►Once absorbed, solar energy is Once absorbed, solar energy is

converted into heat.converted into heat.►The measurement of heat is called The measurement of heat is called

temperature.temperature.

Global Wind BeltsGlobal Wind Belts► Some areas of the world Some areas of the world

have winds that blow have winds that blow from the same direction from the same direction most of the time. These most of the time. These winds are called winds are called prevailing windsprevailing winds..

► DoldrumsDoldrums- area with no - area with no prevailing winds.prevailing winds.

► FrontFront occurs when two occurs when two air masses of different air masses of different temperatures or temperatures or moisture levels meet. moisture levels meet.

Weather FactorsWeather Factors► evaporationevaporation- the process by which - the process by which

water changes from a liquid to a gas.water changes from a liquid to a gas.► humidityhumidity- the amount of water vapor - the amount of water vapor

in the air.in the air.► condensationcondensation- is the process by - is the process by

which water vapor changes from a gas which water vapor changes from a gas into liquid droplets.into liquid droplets.

Mountain EffectsMountain Effects►Orographic effect-Orographic effect-

occurs when moist occurs when moist air pushes against a air pushes against a mountain. The mountain. The barrier forces the barrier forces the air to rise. The air to rise. The rising air cools and rising air cools and condenses, forming condenses, forming clouds and causing clouds and causing precipitation.precipitation.

Rain ShadowRain Shadow► The side of the mountain facing the wind The side of the mountain facing the wind

receives a great deal of moisture. This receives a great deal of moisture. This side is known as the windward side.side is known as the windward side.

► The side of the mountain facing away The side of the mountain facing away from the wind is the leeward side. As the from the wind is the leeward side. As the air moves down the leeward side, it air moves down the leeward side, it warms and dries.warms and dries.

► This drier area is called a This drier area is called a rain shadowrain shadow. . Deserts are often located in rain shadows.Deserts are often located in rain shadows.

StormsStorms► HurricanesHurricanes are the are the

most powerful and most powerful and destructive tropical destructive tropical cyclones. They begin cyclones. They begin over warm tropical over warm tropical areas.areas.

► Hurricanes are called Hurricanes are called typhoonstyphoons in the in the western pacific can western pacific can create dangerous create dangerous high waves.high waves.

ClimateClimate► Tropical Humid-Tropical Humid- is found in areas close to is found in areas close to

the equator.the equator.► Tropical wet and dry-Tropical wet and dry- just to the north and just to the north and

south of the tropical humid climate is the south of the tropical humid climate is the tropical wet and dry climate. It is sometimes tropical wet and dry climate. It is sometimes called the tropical savanna climate. called the tropical savanna climate.

►Arid-Arid- most arid, or desert, climate regions most arid, or desert, climate regions are centered at about 30 degrees north and are centered at about 30 degrees north and south of the equator.south of the equator.

ClimateClimate►Semiarid-Semiarid- is a transition zone between the is a transition zone between the

arid climate and the more humid climates.arid climate and the more humid climates.► Mediterranean-Mediterranean- exists in two areas….one exists in two areas….one

is along coastal areas of southern Europe. is along coastal areas of southern Europe. The other is along west coast of continents The other is along west coast of continents with cool ocean currents.with cool ocean currents.

►Humid Subtropical-Humid Subtropical- is found on the is found on the eastern side of continents where there are eastern side of continents where there are warm ocean currents.warm ocean currents.

ClimateClimate►Marine West Coast-Marine West Coast- heavily heavily

influenced by oceans, is generally influenced by oceans, is generally found on the west coasts of continents found on the west coasts of continents in the upper middle latitudes.in the upper middle latitudes.

►Humid Continental-Humid Continental- found in the found in the interiors and east coasts of upper-interiors and east coasts of upper-middle latitude continents.middle latitude continents.

►Subarctic-Subarctic- located generally about located generally about 50’ nort latitude.50’ nort latitude.

ClimateClimate►Tundra-Tundra- Coastal areas in high latitudes Coastal areas in high latitudes

have a tundra climate. They also have have a tundra climate. They also have long winters.long winters.

►Ice Cap-Ice Cap- found in earth’s polar regions, found in earth’s polar regions, always covered by huge flat masses of always covered by huge flat masses of ice and snow.ice and snow.

►Highland-Highland- can have varying climates can have varying climates b/c temperatures change with elevation.b/c temperatures change with elevation.