GEOG 111 1st Edition Lecture 12 Outline of Last Lecture I Combating global warming II Temperature a Heat vs temperature Outline of Current Lecture I Temperature a Relationships i Heat vs Temperature ii Urban vs Rural landscapes b Measuring temperature Current Lecture I Temperature a Relationships i Heat vs temperature 1 Heat is a form of energy a Atmosphere s strong transmissivity absorbs radiation 2 Temperature is a measure of molecular activity a The average speed of molecules or vibrations in a solid b After applying heat to a material temperature will rise 3 Three factors that control the relationship a Specific heat the amount of energy required to raise one gram of a material one degrees Celsius i Takes more energy to warm water than land continental areas have a higher seasonal range and diurnal range than temperatures than marine areas ii Heating and cooling rates are inversely related to specific heat iii Does Hatteras Island NC or Monterey CA have a more marine climate Monterey even though Hatteras has more water around it because of ocean currents and prevailing wind directions W E from the Pacific Ocean b Density the amount of mass of a material per volume mass unit volume These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute i Low density structures because there s less material to warm up will warm up more quickly than a high density structure but they also cool more quickly at night when Q 0 1 Ex Brick houses take longer to warm than wood shed 2 Ex Rural landscapes are dominated by vegetation and soil somewhat lower density than urban areas so they warm more quickly during the day drop more quickly overnight a However rural landscapes aren t necessarily warmer during the day other factors come into play c Water content evaporation a major cooling factor i The more vegetation the more evapotranspiration which more than negates the warming ii Vegetation shields the area from shortwave radiation more shaded areas ii Urban vs Rural landscapes 1 The urban heat island an island where temperatures are warmer than the surrounding areas retains heat better b Where should air temperatures be measured i Shielded from radiative effects 1 Shaded from incoming K not in direct sunlight 2 Away from L sources that have been warmed radiatively warmed buildings cold ground hot asphalt etc ii Air must be ventilated allow air to flow freely 1 Ex problems with measuring daily max temperatures at RDU painting asphalt white as a way of modifying the environment for a more accurate read herbicide was used to kill off weeds that were creating a cooling effect Briar Creek has added to the urban heat island effect of the airport c Apparent temperature what it feels like i Contributing factors 1 Heat index 2 Wind speed wind chill a How does wind create a chill Heat moves from your body to the air a boundary layer of thin air with low conductivity forms around your skin surface and gets very warm when you move or when wind blows the boundary layers goes away and there s a cooling effect b What happens when air temperature exceeds body temperature Sensible heat flux goes in opposite direction and heat is conducted into your skin from the atmosphere the faster the wind the hotter it gets 3 Relative humidity an expression of how close the air is to being saturated percent of water vapor in the atmosphere
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