Sun­light heats Earth but is not evenly dis­trib­uted. The re­gions around the Equa­tor re­ceive much more sun­light and so more heat than the po­lar re­gions. The tem­per­a­ture dif­fer­ences and vary­ing pre­cip­i­ta­tion have pro­duced dif­fer­ent cli­mate zones, which are c

Science Illustrated - - CONTENTS -

Be­come knowl­edge­able about how cli­mate works on a plan­e­tary scale!

Earth de­pends on the huge quan­tity of en­ergy that flows to us from the Sun. Ev­ery square me­tre fac­ing the Sun con­stantly re­ceives 1,366 watts, and the to­tal quan­tity is 180,000 times larger than the to­tal power gen­er­a­tion ca­pac­ity of the US. The Sun heats Earth, and to­gether with the nat­u­ral green­house ef­fect, this pro­vides Earth with an av­er­age tem­per­a­ture of 14 de­grees.

How­ever, the heat is not evenly dis­trib­uted. Earth’s axis of ro­ta­tion inclines 21.5-24.5 de­grees as com­pared to Earth’s or­bit around the Sun. The sun­light shines di­rectly on the Equa­tor, whereas it shines more in­di­rectly on po­lar re­gions – i.e. one square me­tre of Earth’s sur­face in the po­lar re­gions re­ceives much less sun­light than one square me­tre in the trop­ics. Due to Earth’s curve, the dis­tance to the Equa­tor de­ter­mines the tem­per­a­ture, and to­gether with pre­cip­i­ta­tion, this forms the ba­sis of cli­mate zones and their var­ied veg­e­ta­tion.

Cli­mate zones are de­fined in dif­fer­ent ways. Most are based on cli­ma­tol­o­gist Wladimir Köp­pen’s work in the 1920s and com­pare av­er­age tem­per­a­tures and pre­cip­i­ta­tion to the dom­i­nant veg­e­ta­tion of the re­gion. The dis­tance to the Equa­tor and to the clos­est ocean and a re­gion’s alti­tude above sea level are im­por­tant fac­tors for the lo­cal cli­mate.

Moun­tains pro­duce their own small cli­mate zones, mak­ing sure that snow can fall on the Equa­tor. In the trop­ics, ice-cov­ered peaks with no veg­e­ta­tion rise above val­leys with trop­i­cal forests in­clud­ing frag­ile veg­e­ta­tion that does not tol­er­ate tem­per­a­tures be­low zero. More­over, moun­tains of­ten func­tion as rain traps, where the air sheds large quan­ti­ties of pre­cip­i­ta­tion.

Coastal re­gions also have com­mon char­ac­ter­is­tics through­out the world. They typ­i­cally re­ceive more pre­cip­i­ta­tion than in­te­rior re­gions, where the dis­tance to the ocean causes a dry cli­mate. More­over, oceans func­tion as huge heat buf­fers, evening out sea­sonal tem­per­a­ture dif­fer­ences, en­sur­ing mild win­ters and cool sum­mers, whereas in­te­rior con­ti­nen­tal re­gions at the same de­grees of lat­i­tude have wild win­ters and hot sum­mers.

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