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What is the difference between humidity and relative humidity?

Why does relative humidity increase at night?

As air temperature rises, does relative humidity increase, decrease, or stay the same?

What does saturation point have to do with dew point?

What happens to the water vapor in saturated air as the air cools?

What factors are responsible for condensation?

Does condensation occur more readily at high temperatures or low temperatures? Explain.

When water vapor condenses to liquid water, is heat absorbed or released?

Distinguish between condensation and precipitation.

Explain why warm air rises and cools as it expands.

When a parcel of air rises, does it become warmer, become cooler, or remain the same temperature?

What is an adiabatic process?

Name at least two ways that thermal energy in air can be increased.

Name at least two ways that thermal energy in air can be decreased.

What is a temperature inversion? Give one location where these inversions often occur.

What happens to the air pressure and temperature of an air parcel as it flows up the side of a mountain?

How do clouds form?

Name the cloud form associated with (a) the hazy shade of winter, (b) a mackerel sky, (c) floating cotton, and (d) snowfall.

Name the cloud group to which each of the following cloud types belongs: (a) altocumulus, (b) cirrostratus, (c) nimbostratus, and (d) cumulus.

Rain or snow is most likely to be produced by which of the following cloud forms: (a) cirrostratus, (b) nimbostratus, (c) altocumulus, or (d) stratocumulus?

Are clouds that have vertical development characteristic of stable air, stationary air, unstable air, or dry air?

Which type of cloud can become a thunderhead?

Explain how convectional lifting plays a role in the formation of cumulus clouds.

Explain how a convection cycle is generated.

Does a rain shadow occur on the windward or leeward side of a mountain range? Explain.

Differentiate between a cold front and a warm front.

What are the three main atmospheric lifting mechanisms?

Under what conditions does orographic precipitation occur?

How do downdrafts form in thunderstorms?

Briefly describe how thunder and lightning develop.

What happens when water vapor in a can suddenly condenses? Put a small amount of water in an aluminum soft-drink can, then heat the can on a stove until steam comes out of the opening. With a pair of tongs, invert the can into a pan of cool water. Air is driven from the can so that only water vapor molecules remain inside. When the can is inverted into the pan of water, the water vapor condenses. The condensation of molecules in the can leaves behind a vacuum. The pressure of the atmosphere, with nothing inside pushing back, crushes the can.

Search the sky for passing jets and look for the condensation trailcontrailthat the jet leaves behind. Because jet exhaust is mainly carbon dioxide and water vapor, when the water vapor mixes with the cold environment of the upper troposphere, it can condense into small water droplets to form a line of white clouds. Study the length and thickness of the contrails. You may even take a photo. After about 10 minutes, reexamine the contrails. Are they still there? Have they dissipated, or have they grown thicker? If they have disappeared, or if the jet did not leave a contrail, the humidity of the atmosphere is too low to create clouds and produce rain. So it is safe to say that tomorrows weather will probably be very similar to todays weather. If the contrails are still present and have grown thicker, the humidity of the atmosphere is high enough for cloud formation. And with clouds can come precipitation. So tomorrows weather may be very different from todays weather.

At 50F the maximum amount of water vapor in air is 9 g/m3. If the relative humidity is 40%, what is the mass of water vapor in 1 m3 of air?

The relative humidity of an air parcel is 50%, and the pressure is 1000 millibars (mb). If the pressure increases to 1053 mb without changing the temperature or the water-vapor content of the air, what is the relative humidity? Hint: Use Boyles law from Chapter 5.

The cooling rate of a rising air parcel depends on the type of air mass. From the greatest to the least temperature change, rank the following lapse rates for each kilometer of rising air: (a) environmental lapse rate, (b) moist adiabatic lapse rate, (c) dry adiabatic lapse rate.

Several steps need to happen for a cloud to fully develop. Going from first to last, rank these steps: (a) air rises to the lifting condensation level, (b) air rises and the condensation rate exceeds the evaporation rate, (c) air rises to a level where the condensation rate equals the evaporation rate.

Several steps need to happen before precipitation forms. Going from first to last, rank the steps in the collision coalescence process: (a) cloud droplets form, (b) water vapor condenses on small particles, (c) cloud droplets are floated upward, (d) cloud droplets are bombarded by updraft droplets, (e) raindrops form.

Rank, from beginning to end, the stages in the formation of a warm front: (a) light to moderate rain and wind, (b) air warms and rain turns to drizzle, (c) cirrus cloud formation, (d) altocumulus and altostratus clouds darken the sky.

Rank, from beginning to end, the stages in the formation of a cold front: (a) warm air is forced upward where it cools; (b) air cools and sinks, pressure rises, rain stops; (c) formation of cumulonimbus or nimbostratus clouds; d) thunderstorms with heavy showers and gusty winds.

Rank, from beginning to end, the stages in the formation of a hurricane: (a) central low pressure area intensifies, (b) sufficient warm air and high humidity, (c) inward flowing air spirals, (d) rising warm air creates a central low-pressure area, (e) increase in rotation and speed of wind.

What is the difference between weather and climate?

Which produces precipitation: a rising moist air mass, a descending moist air mass, or both?

Why do clouds tend to form above mountain peaks?

Why does warm, moist air blowing over cold water result in fog?

Why does dew form on the ground during clear, calm summer nights?

Why does a July day in the Gulf of Mexico generally feel appreciably hotter than a July day in Arizona, even when temperatures are the same?

Would you expect a glass of water to evaporate more quickly on a windy, warm, dry, summer day or on a calm, cold, dry, winter day? Defend your answer.

Why does the surface temperature rise on a clear, calm night as low cloud cover moves overhead?

During a summer visit to Cancun, Mexico, you stay in an air-conditioned room. Getting ready to leave your room for the beach, you put on your sunglasses. The minute you step outside, your sunglasses fog up. Why?

After a day of skiing in the Rocky Mountains, you decide to go indoors to get a warm cup of cocoa. As you enter the ski lodge, your eyeglasses fog up. Why?

Can the temperature of an air mass change if no heat is added or subtracted? Explain.

Why must an air mass rise in order to produce precipitation?

As an air mass moves first upslope and then downslope over a mountain, what happens to the airs temperature and moisture content?

Why are saturation and condensation more likely to occur on a cold day than on a warm day?

The sky is overcast, and it is raining. What type of cloud is above you: nimbostratus or cumulonimbus?

Distinguish between dew and frost.

What accounts for the large spaces of blue sky between cumulus clouds?

Why dont cumulus clouds form over cool water?

Which cloud form is associated with a stable air mass?

What cloud form is associated with thunderstorms?

What is the relationship between saturation vapor pressure and humidity?

When the condensation rate is greater than the evaporation rate, what happens to the air?

Cite at least four types of information needed to predict the weather.

The accuracy of weather forecasts depends on great quantities of data and thousands of calculations. If the number of data points were decreased, would accuracy also decrease?

What is the difference between rainfall that accompanies the passage of a warm front and rainfall that accompanies the passage of a cold front?

When does an adiabatic process happen in the atmosphere?

How can a layer of altostratus clouds change into altocumulus clouds?

Antarctica is covered by glaciers and large ice sheets. Is the snowfall in Antarctica therefore heavy or light? Why?

How do fronts cause clouds and precipitation?

Explain why freezing rain is more commonly associated with warm fronts than with cold fronts.

What steps need to happen before precipitation occurs?

In simplest terms, what is an occluded front?

How does a rain-shadow desert form?

Sinking air warms, and yet the downdrafts in a thunderstorm are cold. Why?

Tornadoes form in the regions of a strong updraft, and yet they descend from the base of a cloud. Explain.

Why are hurricanes more likely to occur on the East Coast of the United States than on the West Coast?

Why are clouds that form over water more efficient in producing precipitation than clouds that form over land?

What is the source of the enormous amount of energy released by a hurricane?

What part of the United States has the highest frequency of tornadoes?

In which atmospheric layer does all our weather occur?

Clouds can act like a blanket around Earththey can trap terrestrial radiation to warm Earths surface, and they can block incoming solar radiation to cool Earths surface. Which cloud type is a better warmer and which is a better cooler: high, thin cirrus clouds or low, thick stratus clouds?

In old-growth redwood forests, some trees have survived for well over a thousand years. As such, they provide a record of climate change. By studying tree rings, scientists have discovered that redwoods have played a significant role in removing CO2 from the atmosphere. They have also learned that the bigger the tree, the more it grows and hence the more carbon it sequesters. What other information can tree rings from these huge redwoods tell us about climate? By studying what has happened in the past, will we be better prepared for the future?

Our global climate is changing. There are many contributing factors to this change. One often ignored factor is soot: black and brown particles emitted by burning fossil fueldiesel, coal, gasoline, and jet fueland from burning solid biofuelswood, manure, and dung (used for heating homes and cooking in many locations). Just like wearing a black shirt on a sunny day, soot in the atmosphere absorbs solar radiationheating the surrounding air. It also absorbs light reflecting off Earths surfacea double whammy for further warming. Unlike CO2, which lingers in the atmosphere for decades, soot lingers for only a few weeks before being washed out. So, reducing soot emissions can be very helpful in slowing the trend toward global warming. How can soot emission be reduced?

The year 2010 had several extreme weather eventsthe Moscow heat wave, disastrous flooding in Pakistan, Vietnam, and the South Pacific; drought in the Amazon; and several devastating winter storms throughout the Northern Hemisphere. Are these severe weather events related to global warming? What type of weather has been happening where you live?