In Exercises 3 and 4, find the midpoint of the line segment with the given endpoints. (-4, 7) (8, -11)
CHAPTER9 |1 CLIMATEANDTHEFACTORSTHATAFFECTIT • “Climate”and“weather”arenotsynonymous • Weatheristheday-to-daychangesthatoccurintemperatureandprecipitation. • Climateistheaverageprecipitationandtemperaturecharacteristicsforaregionthatarebasedonlong-termrecords. • Theseaveragesarebasedona30-yeartimeperiod. • TheconceptofclimatecanbeviewedgeographicallybecauseEarthexhibitsdistinctclimatepatterns. • ThestudyofthisgeographicdistributionandthecharacterofEarth’sclimatesisasubfieldofgeographycalled climatology,nottobeconfusedwithmeteorology,whichstudiesshort-termatmosphericphenomenathatconstitute day-to-dayweather. • Climatologists’researchisimportanttomanydisciplinesoutsidethefieldofgeographybecauseclimateisafactor thatinfluenceshumanbehaviorandnaturalprocessesinavarietyofways. • Factorsonlong-termweatherpatternsforaregion: 1. Latitude--intensityofradiationandlengthofday 2. Seasonality--criticalfortworeasonsrelatedtoSunangle: a) Howmanyhoursofsunlightinadaychangesinmanyplacesoverthecourseofayear b) Insolationandtemperaturecanbehighlyvariablebetweenthewinterandsummerseasons. 3. Airmasscirculation--airflowandpositionofhigh-andlow-pressuresystems 4. Marinevs.continentalrelationships--largebodiesofwatermoderatetemperature,influenceairflowandsupplywater vapor. CHAPTER9 |2 5. Topographiceffects--influencesairflow,thewindwardsideofamountainrangeoftenhasheavyprecipitationbecause aircoolsadiabaticallythere,rainshadowsoftenformontheleewardsideofamountainrangeduetodescentofairand adiabaticwarming. KÖPPENCLIMATECLASSIFICATION • Thepurposeofclimateclassificationistoidentifycertaincharacteristics,suchastemperatureandprecipitation,whichhave observableregionalpatterns. • Itisoftendifficulttoclassifymanyclimatezonesbecausetheirgeographydependsonanumberofvariables. CHAPTER9 |3 • Itisalsodifficulttoclassifyclimatezonesbecausetheyformaspatialcontinuum,rarelyformingsharpbreaksfrom oneclimatetoanother. • ThemostwidelyusedclassificationsystemistheKöppenClimeClassificationSystem. • DevelopedbyGermanbotanistandclimatologistWladimirKöppen,whorecognizetherelationshipbetweenmajor vegetationregionsonEarthandregionalclimatecharacteristics. • Thesystemdescribesworldclimatesbasedonaveragemonthlytemperature,averagemonthlyprecipitation,and totalannualprecipitation. • Althoughthesystemisgreatforcharacterizingregionalclimateconditions,itignoremorelocalfactorssuchaswind speedandcloudcover,whichinfluencesconditionsdrasticallyinspecificareas. • TheKöppensystemisbestviewedandunderstoodasahierarchalclassificationwithcategoriesandsubcategories. • Therearesixmajorclimategroups(A,B,C,D,E,H),rangingfromlowlatitudesneartheEquator(A)tohighlatitudes asthepoles(E)andcoverhugegeographicalareas.ClimategroupHisthedesignationforhigh-altituderegions, regardlessoflatitude. • EachcategoryisdistinguishedbasedontemperatureexceptforcategoryB,whichisbasedonmoisture characteristics. • These6majorclimategroupsaresufficienttonotefundamentalclimatecharacteristicsoverbroadareas,butgeographers takeinterestinthemorespecificattributesofsmallerregions. • Toaccomplishthis,themajorKöppengroupsaresubdividedonthebasisoftemperatureandmoisturewiththeuse ofasecondletterandsometimesathird. CHAPTER9 |4
