Robert W. ChristophersonCharlie ThomsenChapter 5Global TemperaturesFrozen tundra, very sensitive to global temperature change. Temperature increase in the polar region is more than double the rate of the rest of the globe.Temperature Concepts and MeasurementPrincipal Temperature ControlsEarth’s Temperature PatternsAir Temperature and the Human BodyGlobal TemperaturesTemperature is a measure of average kinetic energy (motion) of individual molecules in matter.Heat always transfer in the direction from higher temperature to lower temperature.Temperature and Heat are related, but very different. Transfer of heat energy is associated with change in temperature.Sensible heat: heat transfer from warmer objects to cooler ones.TemperatureTemperature ScalesFahrenheitCelsiusKelvinMeasuring TemperatureTemperature Concepts and MeasurementTemperature ScalesFigure 5.1)32(95−= FC15.273+=CKThermometer and Instrument ShelterFigure 5.2 Figure 5.3Min-max thermometerThermal Couple and ThermistorThermistor: is a type of resistor whose resistance varies with temperature. The word is a portmanteau of thermal and resistor. Thermistors are widely used as inrush current limiters, temperature sensors, self-resetting overcurrent protectors, and self-regulating heating elements.Thermal Couple: In 1822, an Estonian physician named Thomas Seebeck discovered (accidentally) that the junction between two metals generates a voltage which is a function of temperature.Unlike a thermometer, the electrical signals from a thermal couple or thermistorcan be logged automatically with much higher accuracy.LatitudeAffects insolationAltitudeHigh altitude has greater daily rangeHigh altitude has lower annual averageCloud Cover: Globally, 50% at any time.High albedoModerate temperatures – cooler days, warmer nightsPrincipal Temperature ControlsLatitude and TemperatureFigure 5.4AltitudeFigure 5.5Normal lapse rate: 6.4oC/1000m3.5oF/1000ftEvaporationTransparencySpecific heatMovementOcean currents and sea-surface temperaturesMarine vs. continental effectsLand–Water Heating DifferencesLand–Water Heating DifferencesFigure 5.7Land Is OpaqueFigure 5.8The Gulf StreamFigure 5.10Red/orange: 25-29oCYellow/green: 17-24oCBlues: 10-16oCPurple: 1-9oCSea-Surface TemperaturesFigure 5.11Mean annual SST increased steadily from 1982 to 2006. Increasing warmth is measured as deep as 1000 m.Ocean’s ability to absorb excess heat energy from the atmosphere may be nearing its capacity.El NinoFigure 5.11Sea surface temperature anomaly in the 1997-1998 El Nino event. This has profound impact of the climate of in many places far away around the globe.El Nino-TeleconnectionsFigure 5.11Marine and Continental Climates:Vancouvervs.WinnipegFigure 5.12Figure 5.13Marine and Continental Climates:San Franciscovs.Wichita, KSMarine and Continental Climates:Trondheimvs.VerkhoyanskFigure 5.16January Temperature MapThermal equator movement southwardMore pronounced over large continentsJuly Temperature MapThermal equator movement northwardMore pronounced over large continentsAnnual Temperature Range MapContinentalityEarth’s Temperature Patterns(b)(c)(a)January TemperaturesFigure 5.14January TemperaturesFigure 5.14(c)(b)(a)July TemperaturesFigure 5.17July TemperaturesFigure 5.17Global Temperature RangesFigure 5.19Arctic Sea Ice ChangesFigure HLC 5.1.1What is at stake with the rapid disappearance of arctic snow cover?What are the physical processes involved?Global TemperaturesGlobal Temperatures Projection ScenariosGlobal TemperaturesGlobal TemperaturesChanges are relative to 1961-1990 averages. Smoothed lines are decadal moving average and the shaded areas are uncertainties.Global TemperaturesThe Hokey StickWind chillCorrelates cold and wind speedHeat indexCorrelates heat and humidityAir Temperature and the Human BodyWind Chill TableFigure FS 5.1.1Heat Index TableFigure FS 5.1.2Robert W. ChristophersonCharlie ThomsenGeosystems 7eAn Introduction to Physical GeographyEnd of Chapter