Weather Vs. Climate Physical Geography: Weather And Climate

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ly rain showers,Lake-Effect SnowcP air masses move south and east Cold air passes over warmer Great Lakes Air masses are warmed and water vapor addedDangerous Weather Cumulonimbus clouds may produce large raindrops, heavyshowers, lightning and thunder, and hail.Lake-Effect Snow Frontal Lifting – Warm FrontSleet – frozen raindrops or partially refrozensnowflakes that bounce when they reach thegroundDangerous Weather Freezing Rain – precipitation that starts as snowat high altitudes, melts and freezes after it hits theground4

6/30/2019HailstonesViolent Weather Thunderstorms - condensation of largeamounts of water vapor creates lots ofenergy, heating the air - Causes updrafts Raindrops create friction - causingdowndrafts Giant cumulonimbus cloudscause dramatic weather Hail is a form of precipitation which consistsof balls or irregular lumps of iceForm in strong thunderstorm clouds, particularlythose with intense updraftsFalls - updraftsOnce it’s too heavy for updraft, it falls to ground Stronger the updrafts – larger the hail stonesHeavy rain, lightning,thunder, hail, heavy windsViolent WeatherHailstones Birth of a Tornado Air at higher altitudes moves faster than surfaceair Creating rotation in the air parallel to the groundFigure 8.21Violent Weather Birth of a Tornado Updrafts create a shift inthe axis of rotation Creating rotation in the airperpendicular to thegroundViolent Weather Birth of a Tornado Mesocyclone forms as a rotating updraft withinthe thunderstorm. If one forms, a tornado will descend from the lowerportion of the mesocyclone.Mesocyclone –a large, rotatingatmosphericcirculation5

6/30/2019Fujita Scale – scale for rating tornado intensitybased on damage to human-made structures,vegetationViolent WeatherCategoryWind SpeedPotential DamageF065-85 mphLight Damage: Minor roof damage, gutters, sidingdamagedBranches broken off treesF186-110 mph36%Moderate Damage: severe roof damage, mobilehomes overturned, broken glassF2111-135 mph19%Considerable Damage: roofs torn off, foundationsshifted, large trees snapped, cars lifted off groundF3136 -165 mph5%Severe Damage: severe damages to largebuildings (malls), trains overturned, structures withweak foundations blown great distancesF4166-200 mph1%Devastating Damage: homes completely leveled,cars thrown, small missiles generatedF5 200 mph 0.1%39%Incredible Damage: houses swept away, carscarried 100 meters, structural damage to highrisesTop Ten Deadliest TornadoesRank States1DateF-Scale6952027Murphysboro, DeSotoLA-MSMay 7, 1840317109Nachez3MO-ILMay 27, 18962551000St. Louis, E. St. Louis4MSApril 5, 1936216700Tupelo5GAApril 6, 19362031600Gainesville181970Glazier, Higgins143770Amite,. Pine, PurvisTX-OK-KS April 9, 1947F5Dead Injured Towns26MO-IL-IN March 18, 1925F5F57LA-MSApril 24, 19088WIJune 12, 1899F5117200New Richmond9MIJune 8, 1953F5115844Flint10TXMay 11, 1953F5114597WacoTornado DamageTornadoesFigure 8.23Figure 8.256

6/30/2019Climate Classification Generalized Climate RegionsKöppen system the A climates are tropical climates Continental – midlatitudes/high latitudes, cold wintersThe E climates are polar Temperate– mid-latitudes, mild wintersthe D climates are associated with continental and high-latitudelocations. DesertArid – tropical/midlatitudesSemi-arid – tropical/midlatitudesthe C climates are generally moderate and are found in themiddle latitudes Tropical – equatorial and tropical latitudesthe B climates are dryHigh latitudes/polar regionsHighland climates – lower temps than similar latitudes (lapserate)Tropical Climates (A) Tropical Rain forest – high temps, highprecipitation all year Dryland Climates (B) Hot deserts – high temperatures, Steppe – transition zones adjacentto deserts Higher rainfall, more seasonaltemperature variation grasslands Dense vegetationTropical Monsoon – high temperatures,season variation in precipitationHumid Midlatitude(C,D) Mediterranean–mildMildwinters,winters, HumidMarineWest Coast –– warmContinentaltempswarmsummers HumidSubtropical– warm tempsin in Cool summersummersummer Most rain in low sun (winter)WestcoastofcontinentsEastsidecontinents Eastsideof ofcontinents Limited rainfallDrought resistant plants/sandPolar Climates (D,E) TundraIce Cap––temperaturetemperature- warmest–continuousextrememonthcold, Subarctic–7-8 monthso & 50o,belowsummersbetween32average- winterfreezingvery coldsnowcoverlow plants& manyforestwild flowersin summer Novegetation Coniferous– calledtaiga 5” precipitation/year7

6/30/2019Highland Climates (H)Highland Climate Highland (H) Climates change rapidly on mountains, becoming colder thehigher the altitude gets.Closely related to the climate of the surrounding climate. The highlands have the same seasons and wet and dry periods asthe climate zoneMountain climates are very important to mid-latitude climates. Snow is kept back until spring and summer when it is released slowly as waterthrough meltingHighland (H) Climates change rapidly on mountains related to the climate of the surrounding climate. The highlands have the same seasons and wet and dry periods as the climate zoneMountain climates are very important to mid-latitude climates.Climatic Change Long-term climatic change Ice agesMedieval warm period and “little ice age”May be due to variations in: shape of Earth’s orbit, tiltof the axis, gyration of the rotation axisShort-term climatic change Natural processes Significant variations over geologic time Climatic Change Certain gases in the atmosphere function as aninsulating barrier, trapping infrared radiationGlobal warming Caused by human activities that have increased theamount of greenhouse gases in the atmosphere Volcanic eruptions, oceanic circulationHuman processes Greenhouse effectEnhanced greenhouse effect Carbon dioxide: burning fossil fuels, deforestationMethane: natural gas and coal mining, agriculture andlivestock, swamps, landfillsNitrous oxides: motor vehicles, industry, fertilizersChlorofluorocarbons: industrial chemicalsClimatic Change Evidence of global warming 20th century was the warmest in 600 years Average surface temp rose over 1 F during the centuryWinter temps in the Arctic have risen about 7 F sincethe 1950sLoss of Arctic ice capGlaciers are thinning and retreatingConsequences of global warming include: Rising sea levelsChanges in temperature and precipitation patterns Impact on soils, vegetation, agriculture8

6/30/2019 1 Physical Geography: Weather and Climate Chapter 4 Weather vs. Climate Weather –short-term, day-to-day expression of atmospheric processes Ex. - Today is clear, cold and sunny Climate –long-term, average conditions Usually at least 30 years of daily weather data (temperatures and precipitation)