>>>>>>>>WHEN YOU FINISH <<<<<<<< Hand in the answer sheet separately.

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1 Instructor: Prof. Seiberling PHYSICS DEPARTMENT MET nd Midterm Exam October 28, 2002 Name (print, last rst): Signature: On my honor, I have neither given nor received unauthorized aid on this examination. YOUR TEST NUMBER IS THE 5-DIGIT NUMBER AT THE TOP OF EACH PAGE. (1) Code your test number on your answer sheet (use 76{80 for the 5-digit number). Code your name on your answer sheet. DARKEN CIRCLES COMPLETELY. Code your student number on your answer sheet. (2) Print your name on this sheet and sign it also. (3) Do all scratch work anywhere on this exam that you like. At the end of the test, this exam printout is to be turned in. No credit will be given without both answer sheet and printout with scratch work most questions demand. (4) Blacken the circle of your intended answer completely, using a #2 pencil or blue or black ink. Do not make any stray marks or the answer sheet may not read properly. If you believe there is no correct answer listed, leave the answer spaces blank. (5) The answers are rounded o. Choose the closest to exact. There is no penalty for guessing. >>>>>>>>WHEN YOU FINISH <<<<<<<< Hand in the answer sheet separately. There are 32 multiple choice questions. Clearly mark the one best answer for each question. If more than one answer is marked, no credit will be given for that question, even if one of the marked answers is correct. Guessing an answer is better than leaving it blank. All questions are worth 3 points, except for 4 questions, which are worth 4 points. The 4-point questions are clearly indicated. Good Luck! 1. The reversal of the positions of surface high and low pressure at opposite ends of the Paci c Ocean is called: (1) upwelling (2) the Ekman Spiral (3) El Ni~no (4) La Ni~na (5) the Southern Oscillation 2. The winter monsoon in eastern and southern Asia is characterized by: (1) wet weather and strong, variable winds (2) dry weather and winds blowing from sea to land (3) wet weather and winds blowing from land to sea (4) dry weather and winds blowing from land to sea (5) wet weather and winds blowing from sea to land 3. Which below does not describe the polar front jet stream? (1) is above a region of rising air (2) forms approximately above the boundary called the polar front (3) moves farther south in winter (4) is normally found at a higher elevation than the subtropical jet (5) is strongest in winter 4. A wind reported as 315 ± would be a wind blowing from the: (1) SW (2) NW (3) SE (4) NE (5) W

2 5. Chicago, Illinois (latitude 42 ± N) is located in the. (1) westerlies (2) southeast trades (3) northeast trades (4) horse latitudes (5) doldrums 6. The wind's speed generally increases with height above the earth's surface because: (1) air parcels expand and become less dense as they rise above the surface (2) wind instruments are not accurate at the earth's surface (3) only the highest layer of air rotates with the earth (4) friction with the earth's surface slows the air near the ground (5) air temperature normally decreases with height 7. (4 pts) I have a parcel of air at some pressure, P, temperature, T and volume, V. If I increase the temperature from 20 ± C to 40 ± C, while keeping the pressure constant, what happens to the volume? (Hint: add 273 to temperature in ± C to get temperature in K) (1) V increases by 50% (2) V remains constant (3) V decreases by less than 10% (4) V doubles (5) V increases by 50% 8. For a golf-ball sized hailstone to develop, it must remain in the cloud for about: (1) 6 hours (2) 1 hour (3) 10 minute (4) 24 hours (5) 1 minutes 9. (4 pts) What is the dew point inside the cloud at 2000 m? (1) 9 ± C (2) 8 ± C (3) 10 ± C (4) 11 ± C (5) 12 ± C 10. Radar gathers information about precipitation in clouds by measuring the: (1) amount of sunlight scattered o the precipitation (2) energy emitted by the precipitation particles (3) amount of solar energy passing through the cloud (4) absorption characteristics of falling precipitation (5) amount of energy re ected back to a transmitter 11. A pressure plate anemometer determines by measuring the. (1) wind speed, angular de ection of a plate (2) wind speed, deformation of a membrane (3) air pressure, deformation of a membrane (4) wind direction, angular orientation of a plate (5) altitude, deformation of a membrane 12. During the summer in humid climates, nighttime clouds tend to form over water during a: (1) monsoon (2) sea breeze (3) land breeze (4) chinook wind (5) Santa Ana wind

3 13. Why are clouds generally con ned to the troposphere? (1) gravity is too weak above the tropopause (2) there is an inversion in the stratosphere (3) ozone in the stratosphere charges the cloud droplets (4) mountains don't extend up into the stratosphere (5) clouds are not usually con ned to the troposphere 14. During the summer, ocean water is colder near the northern California coast than it is further north along the coast near Seattle mainly because of: (1) oceanic fronts (2) upwelling (3) evaporation (4) the California current (5) cold air moving over the water 15. The average winds aloft are strongest in: (1) wind speeds aloft do not vary with season (2) winter (3) spring (4) summer (5) fall 16. In a certain area, the surface temperature and dew point are 28 ± C and 18 ± C, respectively. The environmental lapse rate is 12 ± C from the surface up to 1000m, then is 8 ± C for the next 1000m, then is 4 ± C from 2000m upward. (The dry adiabatic rate is 10 ± C/1000m, the moist adiabatic rate is 6 ± C/1000m and the dew point drops by 2 ± C/1000m.) Use these data to answer the following four questions. What is the overall stability of this atmosphere from the surface up to 3000m? (1) neutrally stable (2) conditionally unstable (3) absolutely unstable (4) absolutely stable (5) conditionally stable 17. Which of the forces below can never change the speed of a wind? (1) centripetal and pressure gradient (2) friction and pressure gradient (3) centripetal and Coriolis (4) pressure gradient and Coriolis (5) Coriolis only 18. Which type of precipitation would most likely form if snow falls through an above-freezing layer, then enters a shallow freezing layer near the ground? (1) hail (2) freezing rain (3) snow (4) drizzle (5) rain 19. A small crystal of pure ice and a small droplet of pure water are both suspended in a cloud maintained at a temperature of 10 ± C. What is likely to happen? (1) both the ice crystal and the water droplet will grow by accretion (2) the ice will grow and the water droplet will shrink (3) neither the ice crystal nor the water droplet will change size (4) the water droplet will freeze and the ice crystal will not change (5) the water droplet will grow and the ice crystal will shrink 20. Which of the following might be mistaken for hail? (1) dendrite (2) supercooled droplet (3) ice nuclei (4) graupel (5) virga

4 21. A knowledge of air stability is important because: (1) it determines how much moisture is in the air (2) it determines the vertical motion of air (3) it determines seasonal weather patterns (4) it determines the direction of movement of storms (5) it determines the movement of high pressure areas 22. In the Northern Hemisphere, ocean currents in the Atlantic and the Paci c move in a generally circular pattern. The direction of this motion is in the Atlantic and in the Paci c. (1) counterclockwise, counterclockwise (2) neither; the direction of the ocean currents depends on the season (3) counterclockwise, clockwise (4) clockwise, counterclockwise (5) clockwise, clockwise 23. If in the Northern Hemisphere the clouds high above you are blowing from south to north, then it is a good bet that an upper-level trough of low pressure is to the of you. (1) south (2) west (3) east (4) north (5) right above 24. The world's deserts are found at about 30 ± latitude because: (1) of the sinking air of the subtropical highs (2) of the convergence of the prevailing westerlies and the Northeast Trades (3) the intertropical convergence zone is located there (4) of the sinking air of the polar front (5) of the doldrums 25. (4 pts) The net force acting on air which is blowing parallel to straight contours at constant speed is: (1) in the direction of wind motion (2) in a direction opposite the wind's motion (3) in the direction of the pressure gradient (4) to the right of the wind's motion in the Northern Hemisphere (5) zero 26. A strong wind is blowing past an obstacle. On the downwind (leeward) side of the obstacle, the wind is likely to be: (1) reduced to zero (2) reversed from the original direction (3) much the same as on the upwind side (4) lighter and more steady (5) strong and steady 27. The name commonly used to describe the drier region observed on the downwind (leeward) side of a mountain range is: (1) inversion region (2) dryline (3) orographic (4) compression region (5) rain shadow

5 28. At what height above the surface of the earth would a convective cloud base form? (1) 1250 m (2) 1000 m (3) 1500 m (4) 2000 m (5) 1750 m 29. One day, the 500 mb surface above your city was at 5620 m. A week later, the 500 mb surface above the same city was at 5740 m. What most likely happened in your city during that week? (1) a cold front passed through (2) the temperature increased (3) a full moon occured (4) the winds aloft became geostrophic (5) the atmosphere became more unstable 30. What supports the weight of the column of mercury in a mercury barometer (so that the mercury does not ow out of the column)? (1) surface tension (2) the mercury in the dish below the column (3) capillary action (4) the gravitational force on the mercury (5) the pressure of the atmosphere 31. Large raindrops fall than smaller raindrops, and have a terminal velocity than small raindrops. (1) faster, smaller (2) slower, smaller (3) slower, larger (4) faster, larger (5) the speed of raindrops is independent of size 32. (4 pts) What is the temperature inside the cloud at 2000 m? (1) 11 ± C (2) 8 ± C (3) 10 ± C (4) 12 ± C (5) 9 ± C