GEOG 111 1st Edition Lecture 17 Outline of Last Lecture I. Winda. Wind systemsb. Factors affecting windOutline of Current Lecture I. Review from last lectureII. Water in the atmospherea. Phase changes of waterb. Effects/examplesIII. HumidityCurrent LectureI. Review from last lecture:a. Winds blow from higher to lower pressurei. Pressure gradient force- the rate of change of pressure across a distanceb. Valley mountain breeze: suns rays hit a slope directly (so it’s receiving the most solar insolation in the valley, warming more quickly than the other side of the valley). Air warms up and convection occurs, making the air rise and a pressure gradient force developsi. Upslope flow- ridge/mountain tops receive more radiation than the valleys which createsii. First storms of the day occur on the ridge topsc. Cold air drainage: As air becomes cooler it becomes more dense/heavy on the slopes; coolest air drains to the lowest elevation (the valley)d. Factors affecting windi. Pressure gradient1. The closer together the isobars (the greater the change in pressure) the stronger the winds2. Hurricanes/tornados have a very large pressure gradient and therefore high windse. Winds get turned due to the Coriolis Effectf. Friction i. Gust factor- the variation in wind speed with respect to time1. How much does the wind change from one second/minute to the nextii. Wind fetchII. Water in the atmospherea. Phase changes of wateri. Melting/evaporation (sublimation) is a cooling process/absorbs heat and creating latent energyThese 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.ii. Condensation/freezing (deposition)- latent heat released b. Effects/examplesi. Melting- cools- snow melt inhibits temperature rises; warming not observed in Arctic until snow has melted (around July)ii. Freezing- warming- latent heat going back to sensible energy; surface temperature hangs at 32 until all of the water has frozen and then the temperature continues to dropiii. Evaporation- cooling- cooling when it starts to rain; falling through an atmosphere that’s not saturatediv. Condensation- warming – convection/lifting; adds buoyancy to updrafts in thunderstorm or hurricane. Nocturnal temperature drop decreases/stops when dew formsv. Sublimation- cooling – cooling when it starts to snowvi. Deposition – warming – ice fogs which are common in high latitudes; contrails III. Humidity a. Vapor pressure- expression of how much water vapor is in the atmosphere; the partial pressure exerted by water vapor in the atmosphereb. Saturation vapor pressure- how much water vapor the atmosphere can hold; once the air is 100% saturated condensation occursi. At extremely low temperatures the air has no capacity for water vapor; as temperature rises the capacity of the atmosphere to hold water vapor increases (but not
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