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CLIMATE & CLIMATE CHANGE WHAT IS CLIMATE?   Weather: the day‐to‐day events in a par1cular area at a par1cular 1me (cloudy, sunny, rain, etc.)   Climate: the average year‐a;er‐year condi1ons of temperature, precipita1on, winds & clouds in an area WHAT CAUSES CLIMATE?   2 Main Factors determine the climate of a region  Temperature  Precipita1on FACTORS AFFECTING TEMPERATURE  La1tude  Ocean Currents  Al1tude  Distance from large bodies of water Learning about climates is a L.O.A.D. of fun! LATITUDE   La1tude: the distance north or south, measured in degrees, from the equator   Loca1ons further from the equator are cooler; those closer to the equator are warmer LATITUDE   Earth is broken up into 3 zones:   Polar – from 66.5° to 90° north and south; the sun is at a lower angle, crea1ng a cold climate   Temperate – from 23.5° to 66.5° north and south la1tude; summers get more direct rays, while winter receives less sun, crea1ng seasons   Tropical – from the ; receives direct sunlight year round, crea1ng a warm climate ALTITUDE   Al/tude: the distance or height of an object above sea level   As eleva1on (al1tude) increase, the ability of the air to transfer energy from the ground to the atmosphere decreases   High land areas everywhere have cool climates, no maVer the la1tude DISTANCE FROM WATER   Water absorbs and releases heat slower than land does, so water helps moderate the temperatures of the land around it.   Marine Climates: the climate of coastal regions, with rela1vely warm winters & cool summers   Con/nental Climates: the climate of centers of con1nents, with cold winters & warm/hot summers; too far inland to be affected by the ocean OCEAN CURRENTS   Ocean Currents – streams of water within the oceans that move in regular paVerns   Warm currents bring heated water from the equator to polar regions, and cold water from polar regions to the equator   Gulf Stream: starts in the Gulf of Mexico, then goes North along the eastern US, where it crosses the Atlan1c Ocean to become the Mid‐
Atlan1c Dri; FACTORS AFFECTING PRECIPITATION  Prevailing Winds  Presence of Mountains PREVAILING WINDS   Winds that blow in a par1cular direc1on (from West to East, in the Northern Hemisphere)   Warm air masses that pass through carry greater moisture (humid)   Cooler air masses that pass through carry less moisture (dry)   Amount of water vapor in prevailing winds depends on where the wind blows from   Winds blowing inland (from water) carry more water vapor   Winds blowing over the land carry less water vapor PRESENCE OF MOUNTAINS   Mountains get in the way of prevailing winds   Winds are forced up, causing warm air to cool and drop water vapor it’s carrying in the form of clouds or precipita1on   Windward – the side of the mountain facing oncoming winds; where rain and snow falls   Leeward – the protected (opposite) side of the mountain that is in the rain show; weather is cool and dry (o;en a desert) MICROCLIMATES   Microclimate – a small area with specific climate condi1ons   Local features can influence climate, crea1ng a local climate   Inland mountains   Lakes   Forests   Example: NYC has a lot of concrete so it has a warmer temperature than just outside of the city where it is more open CLASSIFYING CLIMATES   Climates are classified according to their temperature & precipita1on   5 Main Climate Regions: 1.  Tropical Rainy 2.  Dry (hot or cold) 3.  Temperature Marine 4.  Temperate Con1nental 5.  Polar ** Highland climate has cooler temperatures due to eleva=on, and can occur in any other climate zone.** 1. TROPICAL RAINY   Two types of rainy climates:   Tropical Wet   Rain Forests – has year round heat and rainfall, crea1ng areas of dense vegeta1on   This zone is right along the equator   Receives over 10 meters of rain per year   Only US area is windward side of Hawaii   Tropical Wet‐and‐Dry   Savanna – tropical coarse grassland with scaVered clumps of trees that can survive the dry season   Receive slightly less rain than rain forests, with definite dry and wet seasons   Southern 1p of Florida is only US loca1on 2. DRY (ARID)   Dry – the amount of precipita1on that falls is less than the amount of water that can poten1ally evaporate   O;en inland, far from oceans   O;en in the rain shadow on the leeward side of mountains   Two types of dry climates:   Arid   Deserts– get less than 25 cm of rain every year; extreme hot and cold temperatures; only specialized plants can survive (cactus)   Only US area is windward side of California, the Great Basin & southwest   Semiarid   Steppe– prairie or grassland of short grasses & low growing bushes   Usually located along the edges of deserts   In the US, the Great Plains is a steppe 3. TEMPERATE MARINE   Occurs along coastlines of con1nents in temperate zones; humid, with mild winters   Three types of temperate marine climates:   Marine West Coast   Humid ocean air brings rainy summers & mild, rainy winters; thick forests of conifers due to heavy rain   In the US it’s located in northern California, to southern Alaska   Mediterranean   Drier, warmer climate with two seasons; winter is cool/rainy, summer is warmer with liVle rain; results in dense shrubs & small trees called chaparral   In the US, located in southern California   Humid Subtropical   Located along the edge of the tropics, that is wet and warm, but not as constantly hot as the tropics   In the US, the southeast has this climate 4. TEMPERATE CONTINENTAL   Found on con1nents in the northern
hemisphere with extremes in temperatures because it’s not influenced at all by the ocean   Two types of dry climates:   Humid Con/nental   Shi;ing tropical or polar air masses constantly change weather crea1ng seasons with extreme highs and lows   In the US, this is located in the Northeast (us!) and midwest   Subar/c   Lies north of the humid con1nental climate, with short/cool summers, and long/very cold winter   Usually located along the edges of deserts   Found in loca1ons like Alaska, Canada & Russia 5. POLAR   Coldest climate region composed of tundra & ice caps; found only at the poles (north & south)   Two types of polar climates:   Ice Cap   Climate where average temperatures are always at or below freezing; land covered in ice and snow; cold makes very dry air   Only lichen and a few low plants grow here   Found mainly in Greenland and Antarc1c   Tundra   Region with short, cool summers, followed by biVerly cold winters   Permafrost – tundra soil that is permanently frozen   No trees, only mosses, lichens, grasses and small shrubs   Stretches across northern Alaska, Canada & Russia STUDYING CLIMATE CHANGE   Scien1sts believe that plants/animals today need the same condi1ons to live as those from the past   We use several tools to show past climates:   Fossil evidence   Tree rings   Pollen records CAUSES OF CLIMATE CHANGE   Earth’s Posi/on   One theory is that the 1me of year when Earth is closest to the sun changes every 26,000 years   Or the axis 1lt may change slightly over log periods of 1me   Solar Energy   Sunspots (dark/cool areas) may cause short‐term climate changes   Changes occur every 11 years, which matches sun’s energy cycles   Movements of Con/nents   Changing wind/ocean paVerns from moving con1nents causes climate change   Human Impact   Chlorofluorocarbons (CFC’s) ‐ Chlorine compounds formerly used in appliances & spray cans   Greenhouse effect/Global warming   Alternate Hypothesis: Natural Cycles