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How does the risk of death from weather compare with other risks in life?
It is extremly small (2 out of 1,000,000)
On averge in the United States, which weather-related event takes most lives annually?
In the state in which you currently live, which weather event poses the greatest risk for weather related fatality?
flooding (in order top to bottom flooding/lightning/tornados)
List the two most abundent gases in today's atmosphere. What percentage does each one occupy in a volume of dry air near the earth's surface?
Nitrogen (N2) 78.08%, Oxygen (O2) 20.96%
List the most abundent greenhouse gases in the earth's atmosphere. What makes them greenhouse gases?
Water vapor, carbon dioxide, methane, nitrous oxide, chlorofluorocarbons. They are greenhouse gases because they absorb a portion of the earth's outgoing infrared radiation and radiate it back to earth.
What are some of the important roles that water vapor okays in our atmosphere?
Water vapor is an extremely important gas in our atmosphere. Not only does it form into both liquid and solid cloud particles that grow in size and fall to earth as precipitation, but it also releases large amounts of heat—called latent heat—when it changes from vapor into liquid water or ice. Latent heat is an important source of atmospheric energy, especially for storms, such as thunderstorms and hurricanes. Moreover, water vapor is a potent greenhouse gas because it strongly absorbs a portion of the earth's outgoing radiant energy.
Briefly explain the production and natural destruction of carbon dioxide near the earth's surface. Give two reasons for the increase in carbon dioxide over the past 100 years or so.
Carbon dioxide enters the atmosphere mainly from the decay of vegetation, but it also comes from volcanic eruptions, the exhalations of animal life, from the burning of fossil fuels (such as coal, oil, and natural gas), and from deforestation. The removal of CO2 from the atmosphere takes place during photosynthesis, as plants consume CO2 to produce green matter. The CO2 is then stored in roots, branches, and leaves. The ocean acts as a huge reservoir for CO2, as phytoplankton (tiny drifting plants) in surface water, fix CO2 into organic tissues. Carbon dioxide that dissolves directly into surface water mixes downward and circulates through greater depths. The increase in atmospheric CO2 appears to be due mainly to the burning of fossil fuels, such as coal and oil; however, deforestation also plays a role as cut timber, burned or left to rot, releases CO2 directly into the air, perhaps accounting for about 20 percent of the observed increase.
Explain how ozone is a needed gas in the stratosphere, but an unwanted gas near the earth's surface.
At the surface, ozone (O3) is the primary ingredient of photochemical smog, which irritates the eyes and throat and damages vegetation. But the majority of atmospheric ozone (about 97 percent) is found in the upper atmosphere—in the stratosphere—where it is formed naturally, as oxygen atoms combine with oxygen molecules. Here, the concentration of ozone averages less than 0.002 percent by volume. This small quantity is important, however, because it shields plants, animals, and humans from the sun's harmful ultraviolet rays.
How would waether differ from climate?
When we talk about the weather, we are talking about the condition of the atmosphere at any particular time and place. Climate represents the accumulation of daily and seasonal weather events (the average range of weather, including extremes) over a long period of time.
How does the average speed of air molecules relate to theair temperature?
Higher temperatures correspond to faster average speeds, and lower temperatures to slower average speeds.
How does the Kelvin temperature scale differ from the celsius scale? On a day when the outside temperature is 273 Kelvin, would the air be considered warm or cold?
Each degree on the Kelvin scale is exactly the same size as a degree Celsius, and a temperature of 0 K is equal to -273°C. Converting from °C to K can be done by simply adding 273 to the Celsius temperature. A temperature of 273K is the same as 0°C or 32°F, which most people would consider cold.
On the basis of temperature, list the layers ofthe atmosphere from the lowest layer to the highest. Which layer would be coldest? Which layer would be warmest? Which layer contains all of our weather?
Lowest to highest: troposphere, stratosphere, mesosphere, thermosphere. Coldest: mesosphere. Warmest: thermosphere. Contains our weather: troposphere.
What is the average (standard) temperature lapse rate in the tropososphere?
6.5 degrees Celsius for every 1,000 meters or about 3.6°F for every 1,000-foot rise in elevation.
Explain the concept of air pressure in terms of mass of air above some level.
The pressure at any level in the atmosphere may be measured in terms of the total mass of the air above any point.
Why does air pressure always decrease with increasing height above the surface?
As we climb in elevation, fewer air molecules are above us; hence, atmospheric pressure always decreases with increasing height.
What is the standard atmospheric pressure at sea level in
a. 29.92 inches of mercury. b. 1013.25 millibars. c. 1013.25 hectopascals.
Describe the three scales of motion when discussing wind and give an example of each.
At the microscale, eddies with diameters of a few meters or less not only disperse smoke, they also sway branches and swirl dust and papers into the air. The circulation of city air constitutes the next largest scale—the mesoscale (meaning middle scale). Typical mesoscale winds range from a few kilometers to about a hundred kilometers in diameter. Generally, they last longer than microscale motions, often many minutes, hours, or in some cases as long as a day. Thunderstorms and tornadoes fall under the heading of mesoscale winds. In the largest scale, or macroscale, circulations dominate regions of hundreds to even thousands of square kilometers, typically lasting days and sometimes weeks.
What causes the wind to blow?
The wind blows due to horizontal differences in atmospheric pressure. The greater the difference in pressure, the stronger the wind.
Does a north wind blow from north toward the south or south towards the north?
A north wind blows from the north toward the south.
Describe how the wind blows around areas of surface low-and high-pressure in the Northern Hemisphere.
In the Northern Hemisphere, surface winds blow counterclockwise and in toward an area of low pressure; they blow clockwise and outward around an area of high pressure.
Why are cloufs more common with areas of low pressure?
As the surface air spins inward, toward the area of low pressure, it flows together and rises much like toothpaste does when its open tube is squeezed. The rising air cools and water vapor in the air condenses into clouds. Hence, above areas of surface low pressure, we often find clouds and precipitation. As the surface air flows outward away from the area of surface high pressure, sinking air from above gradually replaces the laterally spreading surface air. Since sinking air does not usually produce clouds, we find generally clear skies and fair weather associated with regions of high atmospheric pressure.
Explain why condensation is more likely when the air temperature lowers.
Condensation is more likely to happen as the air cools because the speed of the vapor molecules decreases. As the air temperature increases, condensation is less likely because most of the molecules have sufficient speed (sufficient energy) to remain as a vapor.
Define Relative humidity
The relative humidity is the ratio of the amount of water vapor actually in the air to the maximum amount of water vapor required for saturation at that particular temperature (and pressure).
Define Dew Point
The dew-point temperature (or simply dew point) represents the temperature to which air must be cooled (with no change in moisture content or air pressure) in order for saturation to occur.
If the air temperature is close to the dew point, would the relative humidity be high or low? Explain.
When the air temperature and dew point are close together, the air is nearly saturated and the relative humidity is high. When the air temperature and dew point are far apart, the air is far from being saturated, and the relative humidity is low. When the air temperature equals the dew point, the air is saturated and the relative humidity is 100 percent.
Breifly describe the movement of water in the hydrologic cycle.
The hydrologic cycle can be thought of as beginning over the ocean, where the sun's energy transforms enormous quantities of liquid water into water vapor. Winds then transport this invisible moist air to other regions, where the water vapor condenses back into liquid, forming cloud. Under certain conditions, the liquid (or solid) cloud particles may grow in size and fall to the surface as precipitation—rain, snow, or hail. If the precipitation falls into an ocean, the water is ready to begin its cycle again. If, on the other hand, the precipitation falls on a continent, a great deal of the water returns to the ocean in a complex journey. This cycle of moving and transforming water molecules from liquid to vapor and back to liquid again is called the hydrologic (water) cycle. In the form with which we are most concerned, water molecules travel from ocean to atmosphere, to land, and then back to the ocean.
List some of the ays extreme weather and climate can influence our lives.
Weather and climate often dictates the type of clothing we buy and wear. Climate determines when to plant crops as well as what type of crops can be planted. Weather determines if these same crops will grow to maturity. Perhaps their most immediate effect is on our comfort. In order to survive the cold of winter and heat of summer, we build homes, heat them, air condition them, insulate them—only to find that when we leave our shelter, we are at the mercy of the weather elements. Even when we are dressed for the weather properly, wind, humidity, and precipitation can change our perception of how cold or warm it feels. On a cold, windy day the effects of wind chill tell us that it feels much colder than it really is and, if not properly dressed, we run the risk of frostbite or even hypothermia. On a hot, humid day we normally feel uncomfortably warm and blame it on the humidity. If we become too warm, our bodies overheat and heat exhaustion or heat stroke may result.
In a volume of air near the earth's surface, __________ occupies 78 percent
and __________ nearly 21 percent.
The gas that shows the most variation from place to place and from time to time in the lower atmosphere is:
water vapor (H2O)
The only substance near the earth's surface that is found naturally in the atmosphere as a solid, liquid, and a gas is:
Much of Tibet lies at altitudes over 18,000 feet where the pressure is about 500 mb. At such altitudes, the Tibetans are above roughly:
50% of the air molecules in the atmosphere
Which of the following weather elements always decreases as we climb upward in the atmosphere?
The gas that absorbs most of the harmful ultraviolet radiation in the stratosphere is:
At night, when the weather is extremely cold and dry,
atmospheric pressure decreases with increasing altitude
Where cold surface air is replacing warm air, the boundary separating the different bodies of air is termed a:
Which relates to weather rather than climate?
the lowest temperature ever recorded in Frozenlake, Minnesota is -57 oF
At the 500 mb level, the amount of oxygen inhaled in a single breath is __________ of that inhaled at sea-level.
about one half
Referring to Table 1.3: If you were to take a breath of pure oxygen, from a tank, you'd be getting about __________ the amount of oxygen you'd get by taking a normal breath of our atmosphere.
Standing at the top of a tall mountain, a breath of air would contain a lot fewer molecules than a breath of air taken at sea level, but the proportion of oxygen in the two breaths of air, relative to the other constituents, would remain the same.
Referring to Figure 1.12 (page 15): There is a lot of mixing and overturning of air in the mesosphere.
Heat waves are generally considered to be little more than a nuisance and are not responsible for considerable loss of life.
Water vapor shows more variation from place to place and from time to time than any other atmospheric gas.
Under what circumstances might a person breathe stratospheric air? How often is it likely to happen in a student's lifetime?
If there is an airplane that breaches while it is flying in the stratosphere a person might breathe in stratospheric air. This is likely to never happen in a student's life time.
What causes air pressure? Why does air pressure decrease with increasing altitude?
Air molecules are held near the earth by gravity. This strong, invisible force pulling down on the air above squeezes air molecules closer together, which causes their number in a given volume to increase. The more air above a level, the greater the squeezing effect or compression. Since air density is the number of air molecules in a given space, it follows that air density is greatest at the surface and decreases as we move up in the atmosphere.
The weight of air molecules acts as a force upon the earth. The amount of force exerted over an area of surface is called atmospheric pressure or air pressure. The pressure at any level in the atmosphere may be measured in terms of the total mass of the air above any point. As we climb an elevation, fewer air molecules are above us hence, atmospheric pressure always decreases with increasing height, rapidly at first, then more slowly at higher levels.
Why is there very little water vapor above the tropopause?
The gas ozone plays a major part in heating the air at this altitude. The ozone is important because it absorbs energetic ultraviolet solar energy. Some of this absorbed energy warms the stratosphere. If the ozone were not present, the air would probably become colder with height like it does in the troposphere and continue to have greater amounts of water vapor.
Describe the relationship between gravity and weight.
Air molecules are held near the earth by gravity. This strong, invisible force pulling down on the air above squeezes air molecules closer together, which causes their number in a given volume to increase. The more air above a level, the greater the squeezing effect or compression. Since air density is the number of air molecules in a given space, it follows that air density is greatest at the surface and decreases as we move up in the atmosphere. The weight of air molecules acts as a force upon the earth. The amount of force exerted over an area of surface is called atmospheric pressure or air pressure. The pressure at any level in the atmosphere may be measured in terms of the total mass of the air above any point. As we climb an elevation, fewer air molecules are above us hence, atmospheric pressure always decreases with increasing height, rapidly at first, then more slowly at higher levels.
How likely are you to die from a weather-related event?
2 out of 1,000,000 people die from weather related events.
Only a tiny fraction of the atmosphere is carbon dioxide. Why is it so important?
It traps a portion of the earth's outgoing energy. Consequently, with everything else being equal, as the atmospheric concentration of CO2 increases so should the average global surface air temperature. In fact, over the last hundred years or so the earth's average surface temperature has warmed by more than 1.4 degrees Fahrenheit. Estimated that if Co2 increases at its current rate then at the end of the century the earth's surface will be warmed by an additional 5 degrees Fahrenheit with consequences such as rising sea levels and the rapid melting of polar ice.
Could air pressure ever increase with increasing altitude? Why or why not?
Since air density is the number of air molecules in a given space, it follows that air density is greatest at the surface and decreases as we move up in the atmosphere. The weight of air molecules acts as a force upon the earth... When decreasing altitude the amount of air molecules decreases so the less air molecules there are, you are going to get the decreasing air pressure because of the fewer molecules.
Why does air pressure change much more with vertical distance than it does with horizontal distance?
Atmospheric pressure normally changes much more quickly when we move upward than it does when we move sideways. Because air pressure changes so rapidly with increasing height, cities located different elevations will have much different pressure readings.
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