GEOG 111 1st Edition Lecture 19 Outline of Last Lecture I Measures of water vapor in the atmosphere II Conclusion of temperature lecture Outline of Current Lecture I Temperature a Altitude b Soil Moisture c Global temperature patterns II Vertical air motions Current Lecture I Temperature a Altitude i Generally speaking the higher the altitude the cooler it gets ii However the low lying areas of Chapel Hill are usually cooler than the top of the hill b Soil Moisture i Evaporation sensible energy to latent energy ii Ex Sandhills v Piedmont 1 When it rains large sand grains allow openings for rain water to readily go through the soil 2 Sandhills dries out much quicker than clay particles in the Piedmont 3 Less evaporation it gets hotter c Global temperature patterns i Isotherms lines of equal temperature 1 Lines closer together represent rapid temperature drops II Vertical Air Motions a Review i Wind circulations are driven by the pressure gradient force ii Differences in air pressure are driven by differences in temperature b Responsible for clouds and precipitation i Upward motion clouds and precipitation 1 When air converges it has to lif ii Lots of thunderstorms in equator area 1 Many lush rainforests in this area iii Mid latitudes warm winds coming from south and cool fronts from the north iv Downward motion clear dry conditions 1 Air sinks 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 c Adiabatic processes changes in the temperature of the air but no changes in energy heat i Ex Inflation and deflation of a tire Air always feels cool when coming out of the tire because of the instantaneous change from high to low pressure environment ii In the atmosphere 1 An air parcel is forced upward it expands and cools no heat has been removed continued lifing it continues to expand and cool 2 When air is lifed in the atmosphere it cools adiabatically 3 In contrast sinking air compresses iii Why 1 Air pressure decreases with increasing altitude a Rising air expands due to AP decrease b Sinking air compresses due to AP increase c These changes in volume affect temperature d Recall the ideal gas law PV NRT i P down V up T down ii P up V down T up iv Significance 1 Rising air cools SVP decreases RH increases a Eventually air is saturated condensation must occur forming a cloud 2 Sinking air warming SVP increases RH decreases d Lifing condensation level LCL the altitude to which you must lif the air to bring it to saturation distance from surface to clouds i Surface temperature increases RH decreases LCL increases 1 Example fog lifing in the morning ii Surface temperature decreases RH increases LCL decreases 1 Cloud bases lowering during precipitation
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