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MIDTERM II STUDY GUIDE
METO 1010 INTRODUCTION TO METEOROLOGY
SPRING 2009
READ THIS FIRST: the outline below is not meant to be fully comprehensive. It lists the major topics that we discussed in
class, but it does not completely cover everything involved with every topic. You should use this as a guide to your
notes, and to what to look at in the text.
WHAT THE EXAM WILL COVER: The midterm will cover chapters 4, 5 and 6; chapters 5 and 6 will be emphasized.
WHEN THE EXAM WILL TAKE PLACE: Ednet & section 002: The midterm will take place on Tuesday March 10.
Distance site students will take the exam during the regular class time, on-campus students (section 002) will take the
exam in the CTC and it will be available all day there. YOU MUST TAKE THE EXAM ON 3/10 UNLESS YOU
HAVE MADE OTHER ARRANGEMENTS WITH PROF. BUNDS. Ednet and section 002 will not have a lecture on
3/10.. Section 003: The exam will be available in the CTC on Tuesday 3/10 and Wednesday 3/11. A $3 late fee will
be charged on 3/10. Section 003 will not meet for lecture on 3/10 (that’s right, no lecture; I changed my mind – use
the time to take the exam).
INSURANCE: As noted on the syllabus, you must complete all the recommended questions from the textbook (for chapters
4, 5 and 6) as well as the questions attached to this study guide and hand them in by Tuesday 3/10. You can turn your
work in to me, the College of Science and Health main office (a secretary will put it in my mailbox) or your facilitator.
For more information, see the course syllabus.
Outline of what we have covered:
1. Moisture and atmospheric stability (Chapter 4)
a. The hydrologic cycle. This is an important general concept, because the movement of water between the air,
oceans, snow, ice, rivers and lakes is a key component of weather
b. States of matter –
i) solid – coolest temperatures, closest packing of atoms/molecules for most substances (but not water), least
movement of atoms/molecules, rigid arrangement of atoms/molecules (crystalline), etc.
ii) liquid – warmer than solid state; close packing but not as close as solids (but water has closer packing than ice),
more movement of atoms/molecules, conforms to shape of container its put in, etc.
iii) vapor. higher temps, atoms/molecules are widely spaced and move very rapidly, virtually no bonding between
molecules, easily compressed, etc.
c. heat capacity – know what this is, what the heat capacity is for water (i.e., a number), etc.
d. latent heat – know what this is, how big it is for melting (or fusion) and vaporization (or condensation) for water.
this is a critical concept to weather.
e. You should be familiar with the concepts of vapor pressure, water vapor in the air and saturation.
f. Humidity – know about the following things, and be able to apply the ideas:
i) absolute humidity
ii) mixing ratio
iii) saturation mixing ratio
iv) relative humidity
v) You should know what the above ideas are (i.e., be able to define them), know how they relate to each other,
how they relate to temperature, how they change with temperature, what other factors can cause them to change,
etc. You should be able to do simple calculations of relative humidity. You should know how humidity relates to
the way the air feels and affects your body.
g. Dew point. know what it is, how it relates to humidity and temperature, how it is often used instead of mixing
ratio to describe the water vapor content of air, etc.
h. Adiabatic temperature changes
i) Basic concept of changes in pressure changing air temperature in a closed system, with no addition or removal
of heat or other forms of energy. Know what a closed system is (see Ch. 1 if necessary).
ii) Dry adiabatic rate: 5.5 oF / 1000 feet.
iii) Wet adiabatic rate 2.75 to 5.5 oF / 1000 feet.
iv) Why are there two adiabatic rates?
v) Why is the wet rate lower?
vi) Why is wet rate not a single value, but a range of possible values?
i. Lifting condensation level. Know what this is, how it relates to dew point, humidity, adiabatic cooling, clouds,
etc.
j. Causes of lifting (or air).
i) orographic
ii) frontal wedging
iii) convergence
METO 1010, Introduction to Meteorology, Midterm 2 Study Guide, Prof. Bunds, UVU
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2.
iv) solar heating/convection
v) be able to explain all of these causes of lifting, know under what conditions each is important, which is
important near mountains, etc.
k. Rain shadow desert.
i) know and be able to explain what this is, in relation to
(1) wet and dry adiabatic cooling
(2) condensation and precipitation
(3) prevailing winds
(4) mountains
ii) Be able to give an example of one and explain how your example relates to the prevailing winds and mountains
near your example
l. Atmospheric stability
i) General concept – what is atmospheric stability and instability?
ii) Why is atmospheric stability so important?
iii) Environmental lapse rate. Be able to explain what this is.
iv) Three types of stability. You need to know them, and be able to sketch graphs that illustrate them (in relation to
the environmental lapse rate).
(1) Absolute stability
(2) Absolute instability
(3) Conditional instability
v) How does each type of stability arise from the wet and dry adiabatic rates and the environmental lapse rate?
vi) Be able to apply your knowledge of stability. For example, if given and environmental lapse rate, you should
be able to determine if the air is absolutely stable, unstable, or conditionally stable.
vii) Know the importance of atmospheric stability! It helps us understand and predict whether air will rise on its
own (without being forced up, for example by frontal wedging). Of course, rising air leads to the formation of
clouds and precipitation.
Clouds, Fog, and Precipitation (Chapter 5).
a. Clouds. You should know the 10 most common types and their characteristics. You should also understand the
methodology for naming clouds (clouds names are based on height and shape) (see table 5-1 in your text).
i) High clouds
(1) cirrus
(2) cirrostratus
(3) cirrocumulus
ii) Middle clouds
(1) altocumulus
(2) altostratus
iii) Low clouds
(1) stratus
(2) stratocumulus
(3) nimbostratus
iv) Clouds of vertical development
(1) cumulus
(2) cumulonimbus
b. Fog
i) basic concept of a cloud(s) in, nor nearly in, contact with the ground
ii) The several types, based on how the fog formed
(1) radiation – radiation (ir) cooling of the ground at night produces cold ground that cools the air above it to
below its dew point. The cold air tends to collect in low spots.
(2) advection – forms when moist air is blown over a colder surface that cools it below its dew point.
(3) upslope – forms when moist air is blown uphill, causing it to expand and cool below its dew point
(4) steam fog (evaporation fog) – forms when cool air moves over water and enough water evaporates to saturate
the air above it. As the rising warm moist air off the water meets the cold air above, it forms cloud droplets
that look like steam. When you see your breath, you are creating steam fog.
(5) frontal or precipitation fog – if rain falls through cold, moist air, enough of the relatively warm rain may
evaporate into the cold air to form fog. Fog can reach from the ground up into the rain clouds.
c. Dew and frost
i) dew – liquid condensation on objects formed when air drops to (or a tiny bit below) its dew point, and water
vapor in air condenses onto objects
ii) frost – ice on objects, formed when air drops to (or a tiny bit below) its dew point and its dew point is below
freezing, so water vapor in the air freezes onto objects. Can form beautiful crystal pattens.
d. Formation of clouds
METO 1010, Introduction to Meteorology, Midterm 2 Study Guide, Prof. Bunds, UVU
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i)
3.
formation of liquid droplets in clouds near or above freezing point
(1) there are plenty of dust particles in air onto which water vapor can condense to form tiny droplets. These
droplets are so small that they can’t fall to the ground.
(2) If there were fewer dust particles on which water droplets could form, larger drops would form, and the
larger drops might fall to the ground so a cloud might not form.
ii) Formation of ice clouds
(1) It needs to be below freezing for tiny ice particles to form and make clouds. Ice will not form on just any
particle of dust unless it is much below freezing temperature. Very high clouds (cirrus) are almost always
made of tiny ice crystals because it is so cold at those high elevations. However, many clouds are made
primarily of tiny droplets of water even though they are below the freezing point because the correct solid
matter for ice to form on is not present. Water that remains a liquid below its freezing point is said to be
supercooled.
e. Formation of precipitation
i) First – what is precipitation??
ii) Precipitation from warm clouds – collision and coallesence
(1) large droplets from large condensation nuclei or very hygroscopic nuclei
(2) large droplets fall, collide with smaller droplets, become larger, fall faster, it rains.
(3) thick clouds and vertical updrafts that cause droplets to circulate and undergo more collisions.
(4) Other factors: electricity.
(5) Only effective in the correct environment where all the above factors can work in tandem – probably mostly
over tropical oceans, although it may be important at times over land.
iii) Precipitation from cold clouds – the Bergeron Process
(1) cold clouds (below freezing) consist mostly of supercooled water droplets
(2) a few nucleation sites for ice exist, ice crystals form
(3) individual water molecules migrate from supercooled water droplets onto ice crystals
(4) Ice crystals grow in size, become large enough, fall to the ground
(5) In many cases snow particles increase in size through collision and coalescence – producing large snow
flakes that may contain many individual ice crystals.
(6) The ice crystals or snow flakes that fall towards the ground may land on the ground in a variety of forms
(snow, rain, etc.) depending on the temperature profile of the air beneath the clouds.
(7) Most precipitation forms by this process.
f. Forms of precipitation (be familiar with them).
i) rain
ii) snow
iii) sleet and glaze
iv) hail
v) graupel
vi) rime
Air Pressure and Winds, Chapter 6
a. Air pressure
i) Cause of air pressure - weight of air above
ii) Behavior of air pressure - acts in all directions
iii) Change in air pressure with altitude
iv) Measurement of air pressure
(1) mercury barometer
(2) aneroid barometer
(3) barograph
v) Reporting of air pressure
(1) millibars, inches
(2) isobars - be able to sketch isobars given pressure at several or more locations
(3) adjustment for elevation - 'sea level equivalent' this is important
vi) Typical air pressures - normal, high, low (highest ever recorded = 1084; highest in U.S. 1064; standard sea level
pressure = 1013.2 mb [know this!], lowest ever recorded (as a sea level equivalent) 870mb in Typhoon Tip 1979).
vii) influences of temperature and humidity on air pressure
b. Winds
i) cause (horizontal differences in air pressure)
ii) influences or controls on winds:
(1) air pressure gradient (know what this is!) (including 'vertical gradients')
(a) this is the force that makes wind blow.
(b) larger gradient, faster wind blows
(c) larger gradients are visible as more closely spaced isobars on a weather map
METO 1010, Introduction to Meteorology, Midterm 2 Study Guide, Prof. Bunds, UVU
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(d)
pushes wind in the direction of the gradient, which is perpendicular to the isobars (but coriolis force and
friction deviate the wind from this direction)
(e) vertical gradients exist when air is not exactly in balance with gravity (in balance with gravity is called
'hydrostatic equilibrium'). Vertical gradients cause air to rise or sink.
(2) coriolis force
(a) very very important to understanding wind
(b) results from rotation of the earth
(c) in N. Hemisphere, deflects wind (and other free-floating objects) to the right. Deflection is to the left in S.
Hemisphere. Understand this, be able to draw it and interpret it from pictures. Curve is to the right when
seen as if you were following the air mass.
(d) Stronger at higher latitudes, virtually no effect exactly on the equator.
(e) Bends winds so they blow nearly (or completely) parallel to isobars!
(f) significantly effects paths of projectiles like missiles and artillery, slightly deflects a home-run baseball,
but does not cause water to rotate counter-clockwise when you flush the toilet.
(3) friction
(a) Effect of wind blowing over topography (hills, mountains etc.), flora (plants, trees, etc.), even buildings.
(b) slows the wind; wind near ground moves more slowly than air higher up
(c) keeps wind near ground from blowing completely parallel to isobars - surface winds generally move
slightly across isobars towards low pressure areas
(4) you need to understand each of these and be able to relate them to the speed and direction in which wind
blows.
iii) Geostrophic winds - high level air flow
(1) at high elevations (generally above 10,000 to 20,000 feet, depending on mountains), winds are not
significantly affected by friction
(2) pressure gradient pushes wind perpendicular to isobars but coriolis bends winds; a balance is reached and
winds blow parallel to isobars.
(3) in N. Hemisphere, winds blow in the direction with lower pressure to the left, higher to the right. Opposite is
true in S. Hemisphere
(a) This is more-or-less true of surface winds also - stand with your back to the wind and the low pressure will
be to your left.
iv) Cyclonic and anti-cyclonic flow around Low and High pressure centers
(1) Understand the terms
(2) Be able to sketch isobars and wind flow around highs and lows
(3) Understand why the cyclonic and anti-cyclonic flow develops (i.e., relation to pressure gradients and coriolis
force).
(4) Know flow is opposite in Australia.
v) Surface winds
(1) friction is a factor
(2) friction slows winds
(3) friction prevents winds from blowing parallel to isobars - instead, they tend to make a 10 to 20o angle to
isobars, cutting across them towards lower pressure areas.
vi) Relationships of horizontal winds and vertical air movement (be able to explain the following ideas)
(1) horizontal convergence at surface can cause air to rise
(2) divergence aloft can create surface lows and upward vertical movement of air
(3) Mountains
(a) direct orographic effects - air blows horizontally into mountains, must rise to flow over them
(b) divergence on downwind sides of mountains
vii) Concept of 'prevailing winds'
viii) Measurement of wind
(1) cup anemometer
(2) aerovane
ix) Given isobars, you should be able to sketch wind directions and estimate where stronger winds will occur (and
of course, you should be able to sketch isobars from air pressure measurements at specific places)
METO 1010, Introduction to Meteorology, Midterm 2 Study Guide, Prof. Bunds, UVU
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STUDY QUESTIONS
If you want to turn these in forinsurance, please be sure to neatly answer them in complete sentences on separate
sheets of paper and staple everything together (you can do the last question on the study guide). Note that if you score
below C- on the exam you can receive points equivalent to a C- by doing these questions AND the suggested problems
from the back of the appropriate chapters AND turning them all in before the end of the testing period. The suggested
chapter and web problems are listed on the course syllabus.
1.
Explain adiabatic cooling. Be sure to discuss both wet and dry adiabatic cooling, and explain the difference between
them.
2. What is the dew point? Why do meteorologists often state the dew point of air instead of its mixing ratio (how are the
two related)?
3. What is the lifting condensation level?
4. If there are a bunch of flat-bottomed clouds in the sky, how high must the lifting condensation level be relative to the
clouds?
5. Explain how rain shadow deserts form, and give an example of one. Use a sketch in your explanation. Be sure to
include adiabatic cooling in your explanation.
6. Where is there a rain shadow desert near Utah?
7. Explain, using a sketch, how frontal wedging causes lifting.
8. Explain what the environmental lapse rate is.
9. Name and explain the 3 types of atmospheric stability/instability, and state the type of weather that is usually
associated with each.
10. If the air at the ground, which is at 4500 feet elevation, is 41oF and the air at 14,500 feet elevation is -19oF, what is the
environmental lapse rate, given as degrees F per 1000 feet?
11. In the example in the question above, what is the stability of the air? What type of weather would you expect to occur?
12. If the air at the ground, which is at 4500 feet elevation, is 41oF and the air at 14,500 feet elevation is -9oF, what is the
environmental lapse rate, given as degrees F per 1000 feet?
13. In the example in the question above, what is the stability of the air? What type of weather would you expect to occur?
14. If the air at the ground, which is at 4500 feet elevation, is 41oF and the air at 14,500 feet elevation is 21oF, what is the
environmental lapse rate, given as degrees F per 1000 feet?
15. In the example in the question above, what is the stability of the air? What type of weather would you expect to occur?
16. If a weatherperson said the air is in a state of conditional instability, what would you estimate the environmental lapse
rate to be?
17. If absolute instability occurs, what type of weather would you expect to result?
18. This question refers to the figure A on the last page of the study guide, which shows the environmental lapse rate for an
area along with the dry and wet adiabats for comparison. What type of stability (or instability) exists for the area?
What type of weather would you expect to ensue?
19. This question refers to the figure B on the last page of the study guide, which shows the environmental lapse rate for an
area along with the dry and wet adiabats for comparison. What type of stability (or instability) exists for the area?
What type of weather would you expect to ensue?
20. This question refers to the figure C on the last page of the study guide, which shows the environmental lapse rate for an
area along with the dry and wet adiabats for comparison. What type of stability (or instability) exists for the area?
What type of weather would you expect to ensue?
21. This question refers to the figure D on the last page of the study guide, which shows the environmental lapse rate for an
area along with the dry and wet adiabats for comparison. What type of stability (or instability) exists for the area?
What type of weather would you expect to ensue?
Note: you should be able to draw and explain graphs like those used for the last four questions.
22. List and describe the 10 common types of clouds.
23. Would you expect radiation fog to form on a cloudy night or on a clear night? Explain.
24. List the 5 types of fog and explain how each type forms.
25. What does it mean for water to be ‘supercooled?’
26. Are there more condensation nuclei or freezing nuclei in the atmosphere?
27. How does the presence of supercooled water in the atmosphere affect aviation? Under what temperature conditions
are aircraft susceptible to icing if they fly through clouds?
28. What process produces most precipitation from clouds? Carefully explain the process.
29. If a cloud is at a temperature of 28oF, would the cloud be made primarily of water droplets or ice crystals or a
combination of both?
30. If a cloud is at a temperature of 18oF, would the cloud be made primarily of water droplets or ice crystals or a
combination of both?
31. If a cloud is at a temperature of 8oF, would the cloud be made primarily of water droplets or ice crystals or a
combination of both?
METO 1010, Introduction to Meteorology, Midterm 2 Study Guide, Prof. Bunds, UVU
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32. If a cloud is at a temperature of -8oF, would the cloud be made primarily of water droplets or ice crystals or a
combination of both?
33. Explain how frost forms. How is frost different from simply being frozen dew?
34. What is riming? Explain how it happens; be sure you include the idea of supercooled water in your explanation!
35. Describe the special conditions necessary for collision and coalescence to produce rain at temperatures above water’s
freezing point.
36. Describe rain, snow, sleet, freezing rain, hail and gaupel.
37. Explain how the Bergeron process can produce rain, snow, sleet, and glaze. In particular, explain what the
temperatures in the air beneath the cloud must be to produce rain, snow, sleet or glaze.
38. What is standard sea level air pressure?
39. What are the highest and lowest air pressures ever recorded?
40. Is it easy to notice changes in air pressure (while staying at a constant elevation)? In what ways is air pressure
important?
41. Explain what a cup anemometer and an aerovane are.
42. Explain how and why air pressure varies with altitude.
43. Orem is at 4500 feet elevation, where air pressure is much less than sealevel, yet meteorologists refer to the pressure
here as close to 1013 mb or 30 inches - why and how do they do that?
44. What is 'hydrostatic equilibrium?' Explain.
45. Explain what isobars are.
46. Explain what an equal potential surface and isoheights are.
47. Explain what a pressure gradient is, and how it relates to the strength of wind.
48. Where on earth is the coriolis force most and least strong?
49. Which direction does the coriolis force bend winds in the Northern and Southern Hemispheres?
50. Sketch a high pressure center and the winds around it.
51. Sketch a low pressure center and the winds around it.
52. What are anti-cyclonic and cyclonic flow? How do they relate to high and low pressure centers and to stormy and fair
weather?
53. Explain what geostrophic winds are (be sure to describe where they occur, why they occur, how they move in relation
to air pressure variations (i.e., isobars)).
54. What are 'troughs' and 'ridges'? Draw a sketch that illustrates your answer.
55. Explain how upper level winds can support surface level low pressure areas and upward flow of air.
56. What is the prevailing wind direction in Utah?
57. Where in the atmosphere is friction important to winds?
58. In what ways does friction affect winds?
59. The figure below-left shows a low pressure center with isobars. Draw in arrows of the type used by meteorologists on
it (see your class notes or better yet your textbook) to illustrate which way the wind would blow around the low
pressure, and put hatchures on the arrows to show relative windspeed. You aren’t expected to know the actual speed of
the winds, but you should illustrate where the wind would blow faster and where it would be slower.
60. The figure below-right shows isoheights (in meters above sea level) of the 500mb equal pressure surface. Draw in
arrows of the type used by meteorologists on it as you did for the previous question.
METO 1010, Introduction to Meteorology, Midterm 2 Study Guide, Prof. Bunds, UVU
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