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Key Vocabulary
1. What are the top 3 gases in the atmosphere? List in order and give percentages.
2. What is the dew point when the dry-bulb temperature is 24°C and the wet-bulb
temperature is 15°C? 80C
3. What terms are used to describe the moisture content of an air mass? What does each
term mean? Continental = dry, Maritime = moist
4. What terms are used to describe the temperature of an air mass? What does each term
mean? Polar = cold, Arctic = extreme cold, Tropical = warm
5. Explain what happens to water vapor in the air when the air temperature and dew
temperature are the same? How is this shown in the “sweating” of a drink glass on a hot
July afternoon? When the air temperature and dew temperature are the same, water
vapor condenses into water droplets, because the air can not support the amount of
water vapor at a certain temperature. The warm the temperature, the more water
vapor it can hold(support). When a glass of ice water is set on the table, the air around
begins to cool.
6. What type of weather is associated with high pressure systems?Fair calm weather Low
pressure systems?rainy/stormy weather Explain why using the ideas of air density and
air movement. The movement of air mass is driven by the density of air. The warmer
the air, the lighter the air mass becomes, the colder the air, the more dense the air mass
becomes. Air around a high pressure system moves clockwise, causing the pressure to
be heavy and prevent the movement(evaporation) of water vapor. Air around a low
pressure system moves counterclockwise, allowing water vapor to release into the
atmosphere creating a ideal situations for the formation of clouds and unstable
atmospheric conditions which leads to rain and stormy weather.
7. What direction does wind travel at the ground at a high pressure system?clockwise Low
pressure system?counterclockwise
8. The most severe weather occurs at which type of front?when a cold front moves in an
area where a warm front exists.
9. What are “source regions” of air masses? areas where the air mass is formed How does
the source region determine the properties of the air mass? if an air mass forms over
land, it will be dry, if it forms over water, it will be moist. If an air mass forms near the
north or south poles it will be polar(cold), and if it forms near the tropics(equator) it will
be warm.
10. Study your weather stations, and know how to draw a weather station model including
temperature, dew point, wind speed, wind direction, pressure, and cloud cover. (see
your weather station packet and practice worksheets)
11. Hurricanes gain strength over (warm water/land) and dissipate or lose strength over
(water/land). Circle the correct answers.
12. Which type of storm is the largest and most powerful: Tornado, Hurricane,
Thunderstorm?
13. What is a storm surge?a rising of the sea as a result of atmospheric pressure changes and
wind associated with a storm. What type of storm causes a storm surge? Hurricanes
14. What are sea and land breezes? a sea breeze -a breeze blowing toward the land from the
sea, especially during the day owing to the relative warmth of the land. A land breeze-a breeze
blowing toward the sea from the land, especially at night, owing to the relative warmth of the
sea. How does heating and cooling of land versus water create these breezes? As warm
air rises, it is replaced by air from the sea; you have now created a sea breeze. Sea
breezes tend to be much stronger and can produce gusty winds as the sun can heat the
land to very warm temperatures, thereby creating a significant temperature contrast to
the water.
15. What direction does air flow in a sea breeze? towards the land Land breeze? towards
the sea
16. Draw a convection current over the following land based on the regional temperatures:
(Atmosphere)
______________________________________________
Warm
Cold
Warm
Cold (Earth’s Surface)
17. Compare the densities of high and low pressure air masses. High pressure air mass will
have a greater density than a low pressure air mass
18. What is the greenhouse effect? the trapping of the sun's warmth in a planet's lower
atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun
than to infrared radiation emitted from the planet's surface.Is it a good or bad thing? Explain.
life as we know it evolved from the process of the greenhouse effect. It is a naturally
occurring process. The greenhouse effect helped to structure our atmosphere to
support life. The impact of human activity has created (global warming) which limits the
positive process of the greenhouse effect, creating increase in heat on the surface of the
earth as well as many other negative things such as pollution.
19. What are the main greenhouse gases? The presence of four major greenhouse gases,
namely water vapor (H2O), carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)
in the Earth's atmosphere keeps the average temperature of 15º C (59º F), whereas
without the greenhouse effect the average temperature would be a frosty -18º C (0º F).
20. What is the ozone layer, and what does it do? a layer in the earth's stratosphere at an
altitude of about 6.2 miles (10 km) containing a high concentration of ozone, which absorbs
most of the ultraviolet radiation reaching the earth from the sun.What chemical(s) cause
damage to the ozone layer? Chlorofluorocarbons (CFCs) and other halogenated ozone
depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion. The
total amount of effective halogens (chlorine and bromine) in the stratosphere can be calculated
and are known as the equivalent effective stratospheric chlorine (EESC
21. What are some negative effects of a damaged ozone layer? If this ozone becomes
depleted, then more UV rays will reach the earth. Exposure to higher amounts of UV radiation
could have serious impacts on human beings, animals and plants, such as the following:
● Harm to human health:
○ More skin cancers, sunburns and premature aging of the skin.
○ More cataracts, blindness and other eye diseases: UV radiation can damage
several parts of the eye, including the lens, cornea, retina and conjunctiva.
○ Cataracts (a clouding of the lens) are the major cause of blindness in the
world. A sustained 10% thinning of the ozone layer is expected to result in
almost two million new cases of cataracts per year, globally (Environment
Canada, 1993).
○ Weakening of the human immune system (immunosuppression). Early
findings suggest that too much UV radiation can suppress the human
immune system, which may play a role in the development of skin cancer.
● Adverse impacts on agriculture, forestry and natural ecosystems:
○ Several of the world's major crop species are particularly vulnerable to
increased UV, resulting in reduced growth, photosynthesis and flowering.
These species include wheat, rice, barley, oats, corn, soybeans, peas,
tomatoes, cucumbers, cauliflower, broccoli and carrots.
○ The effect of ozone depletion on the Canadian agricultural sector could be
significant.
○ Only a few commercially important trees have been tested for UV (UV-B)
sensitivity, but early results suggest that plant growth, especially in
seedlings, is harmed by more intense UV radiation.
● Damage to marine life:
○ In particular, plankton (tiny organisms in the surface layer of oceans) are
threatened by increased UV radiation. Plankton are the first vital step in
aquatic food chains.
○ Decreases in plankton could disrupt the fresh and saltwater food chains, and
lead to a species shift in Canadian waters.
○ Loss of biodiversity in our oceans, rivers and lakes could reduce fish yields for
commercial and sport fisheries.
● Animals:
○ In domestic animals, UV overexposure may cause eye and skin cancers.
Species of marine animals in their developmental stage (e.g. young fish,
shrimp larvae and crab larvae) have been threatened in recent years by the
increased UV radiation under the Antarctic ozone hole.
●
Materials:
Wood, plastic, rubber, fabrics and many construction materials are degraded
by UV radiation.
○ The economic impact of replacing and/or protecting materials could be
significant.
22. How does relative humidity measure water content in the air? When the humidity is high it
feels oppressive outside because sweat doesn't evaporate and provide cooling. When the
humidity is low you feel cooler, but your skin dries out and you get dehydrated more easily
because more moisture is being evaporated from your body. The same thing applies to crops in
high and low humidity. A high water vapor content is necessary to produce clouds and
precipitation. Relative humidity and dew point are the two main ways to describe humidity. If
the water vapor content stays the same and the temperature drops, the relative humidity
increases. If the water vapor content stays the same and the temperature rises, the relative
humidity decreases. This is because colder air doesn’t require as much moisture to become
saturated as warmer air.
○
23. Dew point is always less than or equal to the ambient temperature. If it is 70F outside,
which dew point temperature would mean there is more water vapor in the air: 45F or
65F?
24. Describe the process of forming a cloud beginning with warm air above land rising.
Consider dew point, condensation, condensation nuclei, cooling, and decreasing air
pressure. Clouds are formed when air containing water vapor is cooled below a critical
temperature called the dew point and the resulting moisture condenses into droplets on
microscopic dust particles (condensation nuclei) in the atmosphere. The air is normally cooled by
expansion during its upward movement. Upward flow of air in the atmosphere may be caused by
convection resulting from intense solar heating of the ground; by a cold wedge of air (cold front)
near the ground causing a mass of warm air to be forced aloft; or by a mountain range at an
angle to the wind. Clouds are occasionally produced by a reduction of pressure aloft or by the
mixing of warmer and cooler air currents.
25. Read more: cloud: Formation of Clouds http://www.infoplease.com/encyclopedia/weather/cloudformation-clouds.html#ixzz3ZqKlJ4LU
26. Describe how the air masses interact as a cold front moves through. A cold front separates
a cold, dry air mass from a warm air mass. The cold air mass pushes under the warm air mass
because of its higher density, forcing this warm air to rise. If enough moisture exists in the
atmosphere at this time, then clouds and possibly thunderstorms could develop. Cold fronts move
much faster than warm fronts. Cold fronts are represented as blue triangles on a weather map
and move in the direction that the “teeth” are pointing. Cold fronts are usually accompanied with
areas of low pressure. Winds blow counterclockwise around an area of low pressure in the
Northern Hemisphere. With this in mind, the wind direction before a cold front passes would
usually be out of the south or southwest with warm air temperatures. After the cold front passes,
the winds would shift to out of the west or northwest and the air temperature would steadily
drop. A narrow band of precipitation is likely ahead of the cold front boundary. Depending on the
amount of moisture in the air and the speed of the approaching cold front, the area of
precipitation could in fact range from no precipitation to heavy precipitation. During the summer
months, an approaching cold front is likely to bring thunderstorms with the possibility of severe
storms. This occurs in the warm sector between the warm and cold fronts where severe
thunderstorms and tornadoes are likely to occur.
27. Describe how the air masses interact as a warm front moves through. A warm front is the
surface boundary between a warm air mass and a cold air mass it is overtaking. The warm air
moves into an area of colder, drier air. The air masses do not readily mix; therefore the warm air
rises slowly over the colder air because it is less dense. This produces clouds and precipitation
well ahead of the approaching warm front, since warm air in the southeastern US usually has
higher water vapor content than cool air. Steady precipitation usually persists along the boundary
of a warm front. This amount of precipitation, however, depends on the amount of moisture in
the air ahead of the surface front. If the warm air is relatively dry and stable, precipitation would
not be likely to occur. If the air is moist and conditionally unstable, heavy precipitation could occur
over a broad area.During the winter, an approaching warm front is likely to bring about hazardous
winter weather conditions. Along the warm front, near the surface, where temperatures are
relatively warm, rain will be the likely precipitation form. Outside of this rain area ahead of the
warm front, sleet or freezing rain will persist in an area that is at or just below freezing. Snow will
be the likely precipitation component further ahead of the warm front where the temperature
profiles are completely below freezing.Precipitation increases over an area as the front
approaches. Winds ahead of the approaching warm front will be out of the south or southeast in
the Northern Hemisphere. After the warm front has passed, the winds will shift to out of the south
or southwest and the air temperatures will have warmed and leveled off. Behind the warm front
is a warm sector, where the air mass is usually relatively warm and moist. Severe storms could
possibly be located in this warm sector that is ahead of the approaching cold front if the air mass
is unstable.
28. Describe how the air masses interact at a stationary front. A stationary front is the boundary
between two different air masses with different densities when neither is advancing. The air
masses are not moving strongly enough to overtake each other, so the front remains in one place.
Winds along a stationary front are usually parallel to the front blowing in opposite directions on
either side which is one reason why the front does not move. Stationary fronts essentially have
no surface movement, or very slow movement of less than 5 mph at the surface. However, warm
air from the warm air mass can still be moving over the top of the colder air farther up in the
atmosphere. When one of the air masses moves into the other air mass, the stationary front will
begin to move. When this transition occurs, the front will then either be classified as a warm front
or a cold front, depending on which air mass is pushing ahead. Along some stationary fronts, the
weather is clear to partly cloudy. If both of the air masses are relatively dry, then no precipitation
will fall. However, in some stationary fronts where there is a lot of water vapor in the warmer air
mass, significant rain or freezing rain can occur. Some of the worst ice storms and flooding in the
Southeast occur in these conditions because rain falls continuously over an area for several days
as the front stays in one place.
29. Describe how the air masses interact at an occluded front. Occluded fronts form when a
cold front catches up to a warm front because cold fronts move along much faster than warm
fronts do. The cold front overtakes the warm front and cold air moves into cooler air ahead of the
warm front. Occluded fronts are represented on weather maps as alternating warm and cold front
symbols in purple pointing in the direction the front is moving. Occluded fronts are not particularly
common in the southeast US. The low pressure centers may begin in the south, but will typically
move to the northeast and form an occlusion farther north. The precipitation patterns for an
occluded front typically follow the same patterns as a cold front. Temperature will vary after the
occluded front passes depending on the different air masses that are interacting with the
occlusion. The colder, drier air is moving in to replace the cooler air above the warm front. The
cooler air will rise up over the colder, drier air and the front will move in the direction the purple
symbols are pointing.
30. How does temperature change as altitude increases from the surface of the earth
through the thermosphere layer? temperature rises and falls according to the layer of
the atmosphere. As you go up in elevation in the troposphere, the temperature drops,
it rises as you go upward in the stratosphere, drops upward in the mesosphere, and
rises as you go upward in the thermosphere.
31. What layer has increasing temperature but decreasing pressure? Mesosphere
32. What layer(s) have a direct relationship between temperature and pressure?
troposphere
33. At what altitude does pressure stop changing? 45
34. What is the coldest temperature in the atmosphere?-800C
35. What is the warmest temperature in the atmosphere? 100C
36. What is the atmospheric pressure at 100 km altitude? 0 50 km altitude? 0
37. What is the altitude of the ozone layer? 19