Chapter 9 Wind: Small Scale and Local SystemsChapter 10 Wind: Global SystemsChapter 11 Air Masses and FrontsChapter 12 Mid-Latitude CyclonesChapter 14 Thunderstorms and TornadoesEXAM QUESTIONS HE GAVE OUT DURING CLASS:Chapter 9 Wind: Small Scale and Local SystemsWind-Wind direction is described as the direction from which wind is blowingEX: easterly wind blows from east to west A northwesterly wind means the wind is blowing:a. from northwest to southeastScales of motions-Micro scale- 2m, small spirals of wind, lasts for seconds to minutesEX: smoke from a chimney-Mesoscale- 20 km, thunderstorms, lasts for hours to daysEX: sea breeze -Synoptic scale- 2,000 km, lasts for many weeksHigh and low pressure centers are ________ weather features.b. synoptic scaleSea breezes are _________ weather features.d. mesoscalePlanetary Boundary Layer (PBL)-The layer of the atmosphere near the surface that is influence by friction-Typically the lowest 1-3km of the atmosphere, height varies on weather conditionsTurbulence-any disturbed air flow that produces wind gusts (eddies)-Mechanical turbulence- created by obstructions, irregularities on the surface lead to disrupted air flow and creates mechanical turbulence-Thermal turbulence- created by rising thermals, stronger during daytime heating => destabilization =>stronger thermals => stronger thermal turbulence-Both mechanical and thermal turbulence exist in PBLHorizontal airflow that is disturbed by obstructions (e.g., buildings, trees, mountains, etc.) is called:d. mechanical turbulencePBL-The depth of the PBL depends on three primary factors:1. Surface heating- producing a steep lapse rate and strong thermal turbulence2. Strong wind speeds- producing strong mechanical turbulence 3. Rough, hilly landscape- producing strong mechanical turbulence (strongest in cities, forests, mountains)SELECT ALL CORRECT ANSWERS. Which of the following contributes to a tall planetary boundary layer?a. strong surface windd. strong surface heatingWind and Water-Wind waves- waves formed by wind-Height depends on:-wind speed-length of time wind blows-fetch (distance), of deep water over which wind blowsEX: A sustained 58mph wind lasts 3 days over at least 1600 miles can generate waves with an average height of 49 feet.SELECT ALL CORRECT ANSWERS. Which of the following contributes to relatively low wind wave heights?a. weak wind speedb. high pressure directly overheadd. a short fetchLocal Wind Systems-By convention, we name the feature based on the origin of the airEX: sea breeze – air from seaThermal Circulations-Shallow-Weaken with height-Maintained by local surface heating and coolingSea Breeze-An example of thermal circulation-Dominant weather feature in Florida during summer-Is responsible for scattered afternoon thunderstorms that occur almost every day during the summerEX:Land: warm Ocean: cool WINDSurface low Surface high Cloud Development Aloft lowAloft HighSea Breeze Characteristics-Strongest: -At coast (strongest temperature and pressure difference)-Near time of max temperature-Anything that causes greater horizontal temperature difference causes stronger sea breezeSELECT ALL CORRECT ANSWERS. The sea breeze:b. is strongest at the coastc. is stronger when horizontal temperature changes are larged. is responsible for most of Florida's summer thunderstormsSea Breeze Front-Leading edge of sea breeze-Is the boundary between warm, drier, inland air and cooler, humid ocean air-Sea breeze front passage: cooler temperature, higher dew points, higher relative humidity, wind shift, pressure min.-As front moves inland, it collides with inland air creating convergence-Convergence causes rising motion and cloud development-Sea breeze front is often accompanied by a line of cumulus clouds-If atmosphere is conditionally unstable, these clouds along sea breeze front can grow to great depths and become thunderstormsWhich of the following is NOT a characteristic of a sea breeze front passage?d. lower relative humidityOther Factors Influencing Strength of the Sea Breeze-Ambient (synoptic scale) wind flow-Light offshore synoptic wind:-enhanced temperature gradient-sea breeze pinned to the coast-Light onshore synoptic wind:-decreased convergence-potentially weaker temperature gradient-sea breeze moves farther inland-If the synoptic wind is too strong, no true sea breeze-Shape of coastlineWhich of the following would inhibit sea breeze development?a. strong synoptic scale windsLand Breeze-Opposite of sea breeze-Caused by temperature difference in sea and land-Occurs at night-Generally weaker than sea breezes because the temperature difference is weaker at night than during the dayWhich of the following is NOT true of a land breeze?c. it is usually stronger than a sea breezeLake Breeze-Same as sea breeze, just with a lake-Large lakesEX: Lake Michigan cools Chicago, Lake Superior and Michigan cool the upper peninsula of Michigan Which of the following explains why the upper peninsula of Michigan sees scattered thunderstorms in the summer?a. colliding lake breezes causing convergence and rising motionIn the northern hemisphere, as air moves from a mountainous land surface to a large, smooth lake, the air will:d. speed up and deflect to the rightMountain and Valley Breezes-Thermal Circulation-During the day the hillside warms up faster than the surrounding air and rises (valley)-During the night the hillside cools down faster than surrounding air and sinks (mountain)Chinook Winds-Air moving down slope of a mountain and warming adiabatically-Warming windsEX: East side of the Rocky MountainsWhich of the following is NOT a thermal circulation?a. chinook breezeSanta Ana Winds-Downslope winds-Causes warm dry conditions-Can cause wild fires to spread rapidlyWhich types of winds are favorable for the development and/or spread of wildfires in southern California?c. Santa AnaMonsoon-Large scale phenomenon-Seasonal change in wind direction-Large scale sea breeze that occurs in summer and land breeze in winterThe monsoon causes areas in southeastern Asia to receive most of their rainfall during:b. summerChapter 10 Wind: Global SystemsGeneral Circulation-Large scale, average patterns-Main cause is uneven heating across Earth’s surface-Doldrums- Areas near equator with light winds-Intertropical Convergence Zone (ITCZ)- area near equator where the NE and SE trade winds converge-belt of thunderstorms and clouds-low pressure and rising airWhat causes the ITCZ?a.
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