GEOG 111 1st Edition Lecture 20 Outline of Last Lecture I. Temperaturea. Altitudeb. Soil Moisturec. Global temperature patternsII. Vertical air motionsOutline of Current Lecture I. Types of uplifa. Convective lifi. Stability of atmosphereII. Review for Exam #2Current LectureI. Types of uplifi. Convective lif- buoyant air parcels rise as they remain relatively warmer (less dense) than their surroundings1. Warming is accompanied by expansion (decrease in density)2. Ex. Hot air balloon rises because the air in the balloon is hotter (less dense) than the surrounding aira. Cooling as it goes up, but sill warmer than surrounding air3. Thermals- air lifing on its owna. Thermals come from mountain tops and mountain sides (particularly those facing the sun)i. Late morning South East slopes are absorbing more radiation so thermals get established4. Stability of atmospherea. ELR > DALR > WALR: absolutely unstable convectionb. DALR > ELR > WALR: conditionally unstable convection IF atmosphere is saturatedc. DALR > WALR > ELR: absolutely stable no convection no matter what because thermal is cooler than surrounding air and resists vertical air motions; inversion = stability5. Instability- a. If a thermal is rising and reaches an inversion, the thermal will stop rising and atmosphere regains stability6. Rising and sinking air parcels warm and cool at the:a. Unsaturated: dry adiabatic lapse rate RH<100%b. Saturated: wet adiabatic lapse rate RH= 100%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. Not going to cool nearly as rapidly during lifingii. WALR is nearly half of the DALR1. Because water vapor must be removed by condensation or deposition (cuts cooling rate in half)a. Lots of sensible and latent heat availableb. Heat must be liberatedc. More likely to lif more quicklyc. Environmental lapse rate (ELR)– varies according to the weather7. Controls on the ELR and convectiona. ELR determines stabilityb. Daytime radiational warmingi. Lower tropospheric warming atmosphere more unstableii. Most likely to get storms when air is warm at bottom of columnc. Night time radiational coolingi. Lower tropospheric cooling stabilizes the columnii. ELR becomes less steep and may even cause an inversion on a clear, calm nightd. Approaching 500 mb trough (cool air moving in alof)i. Middle tropospheric coolingii. Steepens the ELRiii. Makes atmosphere unstableiv. Increase likelihood of stormse. Approaching 500 mb ridgei. Middle tropospheric warmingii. Makes atmosphere stableiii. No convection/convective cloudsII. Review for exam #2a. Antarctica is colder than north polar regioni. Much higher elevation and continental regionii. Little bit of heat conduction through ice at North Poleiii. Siberia is coldest place in North Americab. Sea-land breezei. Sunny day along coastal region, water is cooler than land, result of temperature difference results in pressure difference1. Moves from high pressure off coast to low pressure inlandii. What season of the year is the sea breeze strongest?1. Difference in temperature between land and water between seasons2. Speed of sea breeze results in how great the temperature difference is3. Water temperatures off our coast4. Water v. landc. Valley-mountain breezei. On a sunny day air rises on ridges, causing instability on slopes and ridge tops, upslope flow because air is risingii. Those slopes getting direct sunlight cause more convective lif (stronger rising)iii. Air is convecting and moving upsloped. Geostrophic windsi. Happening in upper levels of atmosphere where no friction is taking placeii. Moving with respect to rotating Earthiii. Winds slow down near surface is a result of friction1. Coriolis force is not as great but pressure gradient forces stays the same2. Greater friction on surface more turning
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