Defining Climate

Ch. 14. 1

Climatology• Climatology: the study of Earth’s

climate and factors that affect past, present, & future climate changes.• Climate: long-term weather patterns

of an area.–Includes annual (yearly) variations of

temp, precip, wind, & other weather variables.

Climatology• Normals: data averaged monthly or

annually for 30 years & become the standard values for a location.–Data includes: high & low temp, amt.

of rainfall, wind speed & direction, humidity, & air pressure.–Not intended to describe usual

weather conditions.

Causes of Climate• Climatic differences caused by…–Differences in latitude–Topography–Closeness of lakes & oceans–Availability of moisture–Global wind patterns–Ocean currents–Air masses

Differences in Latitude• Different areas of Earth received different

amounts of solar radiation because of the tilt of Earth when facing the Sun.– Creates climate zones found in each hemisphere.

Latitude & Climate Zones• Tropics– Found between 23.5 North and South and the equator.– Warm nearly year-round.

• Temperate Zones– Found between 23.5 and 66.5 degrees North and

South of the equator.– Temperatures are moderate (warm and cold).

• Polar Zones– Found between 66.5 North & South of equator to the

poles.– Temperatures tend to be very cold.

Climate Zones

Topographical Effects• Large bodies of water affect climate.–Water heats up and cools down slower

than land.–Many coastal regions are warmer in

winter & cooler in summer than inland areas at similar latitudes.

• Temp decreases in areas of HIGHER altitude.–Mtns are colder than sea level areas.

Topographical Effects• Climates differ on either side of mtns.–Windward side: side of mtn where air

rises and condenses to form clouds and drops moisture = wet & cool.–Leeward side: opposite side of

windward side, air is drier & warmer as it descends = deserts are common here.

Topographical Effects: Orographic Lifting

Air Masses• Recall #1: Air masses have distinct

regions of origin, caused by differences in amount of solar radiation.• Recall #2: Properties also depend on if

they are formed over water or land.• Air masses will reflect the

characteristics of that areas climate.

Air Masses