GEOG120 Unit 1 (Lutgen/Tarbuck- Atmosphere intro to meteorology 12/13 ed)
What are the major components of clean, dry air?
The major components of clean, dry air are nitrogen (about 78.084%) and oxygen (about 20.946%) gases. These gases make up 99% of the volume of clean, dry air. The remaining 1% of dry air is mostly the inert gas argon, plus tiny quantities of a number of other gases. Pg. 17
State the relationship between the heating and cooling of land versus water
Land-surface temperatures are much higher than water-surface temperatures. In side-byside bodies of land and water, land heats more rapidly and to higher temperatures than water, and it cools more rapidly and to lower temperatures than water. Variations in air temperatures are much greater over land than over water. There are many factors that collectively cause water to warm more slowly, store greater quantities of heat, and cool more slowly than land. Pg. 68, 70
The coolest temperature of the day occurs about sunrise. Why?
During the night the atmosphere and the surface of Earth cool as they radiate away heat that is not replaced by incoming solar energy. Therefore, the minimum temperature occurs about the time of sunrise, after which the sun heats the ground, which in turn heats the air. Pgs. 81-82
How might this sharp change be related to changes in cloudiness during the period?
During this time of the dramatic change of incoming longwave radiation, the clouds cleared the skies. Cloudy days have higher incoming longwave radiation than clear days.
Which station has the higher surface temperature?
Florida
Which station has the higher temperature at 10 kilometers?
Florida
Why does the temperature increases in stratosphere?
Higher temperatures occur in the stratosphere because it's in this layer that the atmosphere's ozone is concentrated. The ozone absorbs ultraviolet radiation from the sun, therefore the stratosphere's temperatures increase. Pg. 27
Which station has the higher temperature at 16 kilometers?
Alaska
Describe the "negative net radiation" after sunset.
The amount of incoming radiation is not balanced with the amount of radiation that is emitting from the Earth. When the sun sets, the Earth is not receiving radiation from the sun's rays, yet is emitting radiation that it had received and absorbed earlier. Pg. 82
Using the rule above, indicate the % of the atmosphere above at each height.
Using the rule above, indicate the % of the atmosphere above at each height. Height (km) % of atmosphere above 33.6 1.5625% 28.0 3.125% 22.4 6.25% 16.8 12.5% 11.2 25% 5.6 50% Sea level (Surface) 100%
What fraction is above Mt. Everest (8.5 km)? Use the graph above.
about 34 % and pressure is _314 mb
What is the difference between convection and advection?
Meteorologists often use the term convection to describe the part of the atmospheric circulation that involves upward and downward heat transfer- heat transfer that involves the actual movement or circulation of a substance .However the term advection is used to indicate the primarily horizontal component of convective flow ("wind" is the term commonly used for advection). Pgs.45-46
What is meant by net radiation?
Net radiation is the balance that exists between the amount of incoming solar radiation and the amount of radiation emitted back into space- the annual balance of incoming and outgoing radiation. The quantity of incoming solar radiation is, over time, balanced by the quantity of longwave radiation that is radiated back to space. Pgs. 56-57
Can the annual variation in Earth-Sun distance adequately explain seasonal temperature changes? Explain
No, it cannot adequately explain. For instance, in the winter (particularly January 3), the Earth is closest to the sun (perihelion), and in July- about 6 months later- the Earth is farthest away from the sun (aphelion). Although the Earth receives up to 7% more energy and is closer to the sun in January than in July, the difference only plays a small role in producing variations in seasonal temperatures. This is shown through the fact that Earth is closest to the sun during the winter in the Northern Hemisphere. The change in day length and the angle of the sun above the horizon adequately explain seasonal temperature changes. The seasonal variation in the angle of the sun above the horizon affects the amount of energy that is received by Earth in two ways: the level of concentration of the rays determines their intensity, and the angle of the sun, which determines the path that the solar rays take through the atmosphere. Latitude determines solar angle which controls intensity of solar radiation and daylength. The tilt, rather than distance determines seasonality-location in orbit, as well, determines seasonality. Pg. 36
Distinguish between kinetic energy and temperature.
Kinetic energy is energy that is associated with an object by virtue of its motion. Temperature, however, is a measure of the average kinetic energy of the atoms or molecules in a substance. Pgs. 43-44
Complete the table below indicating the number of hours of daylight on each of the following dates at the given latitudes: (Hint: Sum of daylengths of Summer Solstice and Winter Solstice will be 24 hours. Also refer to your note)
66.5S 23.5S 0 40N 61N Summer Solstice- 0hrs 10.5 hrs 12 hrs 15 hrs 18.75 hrs Equinox -12hrs 12hrs 12hrs 12hrs 12hrs Winter Solstice -24hrs 13.5hrs 12hrs 9hrs 5.25hrs
Why would the solar intensity at 40.0N is greater than that at 61.0N on June 21?
At 61 Degrees N, the sun's rays arrive at more of an acute angle; the rays are more diffuse. The lower the latitude or the closer one is to the equator, the more intensity there is because the rays are arriving more directly (the more the intensity is concentrated). On June 21st, at 40 Degrees N, the sun angle is higher than at 61 Degrees N; therefore, the larger the concentration of insolation is per unit area. With a higher sun angle, the surface receives more intense and more solar radiation; therefore, the solar intensity is higher at 40 Degrees N.
The magnitude of the daily temperature range can vary significantly from place to place and from time to time. List and describe at least three factors that might cause such variations.
1. Variations in sun angle are relatively great during the day in the middle and low latitudes. Points near the poles experience a low sun angle all day. The temperature change experienced during a day in the high latitudes is small. 2. An overcast day is responsible for a flattened daily temperature curve. By day, clouds blocking incoming solar radiation and so reduce daytime heating. At night the clouds retard the loss of radiation by the ground and air. Therefore, nighttime temperatures are warmer than they otherwise would have been. 3. A windward coast is likely to experience only modest variations in the daily cycle. During a typical 24-hour period the ocean warms less than 1 Degree C. As a result, the air above it shows a correspondingly slight change in temperature. 4. The amount of water vapor in the air influences daily temperature range because water vapor is one of the atmosphere's important heat absorbing gases. Pg. 83
Describe the relationship between the temperature of a radiating body and the wavelength it emits.
All bodies/objects continually radiate energy over a range of wavelengths. Both the rate and the wavelength of radiation emitted depend on the temperature of the radiating body. Hotter objects radiate more total energy per unit area than do colder objects. Hotter objects also radiate more energy in the form of short-wavelength radiation than do cooler objects. Pgs.47-48
Although the intensity of incoming solar radiation is greatest at local noon, the warmest part of the day is most often mid-afternoon. Why?
Although the intensity of solar radiation drops in the afternoon, it still exceeds outgoing energy from Earth's surface for a period of time. This produces an energy surplus for up to several hours in the afternoon and contributes much to the lag of the maximum. As long as the solar energy gained exceeds the rate of Earth radiation lost, the air temperature continues to rise. The warmest part of the day is generally in midafternoon because it takes time for Earth's surface to absorb and release radiation. Pgs. 81-82
During which hours of the day is the earth's emitted radiation (LW ) highest? Why?
Around mid- to late afternoon it is highest (most likely around 5-6 p.m.). Outgoing longwave radiation is highest at this time because it is when the surface temperature is the highest. The higher that the surface temperature is, the more radiation that the surface can emit.
Which portions of the earth's surface experience the greatest changes in daylength during the year? Where is the change smallest?
At higher latitudes, Earth's surface experiences the greatest changes in day length. The smaller the latitude, the less change in day length there is. Therefore, locations at 66 ½ degrees N and S can experience zero to 24 hours of daylight- depending primarily on what time of year it is, along with the sun angle. Locations near the equator barely see a variation of day length, if at all. The equator typically sees 12 hours of daylight.
Explain why the energy from the sun decreases as solar angle decreases.
At lower sun angles, the sun's rays are more spread out/less direct and, therefore, are less intense. Also, the angle of the sun determines the path that the solar rays take as they pass through the atmosphere. Solar angles less than 90 degrees have to travel farther to reach the surface, therefore, the Earth at those latitudes/locations receive less energy from the sun
Based on the radiation fluxes, when was surface temperature highest? And how did you make your estimates?
Based on the diagram, the highest surface temperatures occurred around mid to late afternoon for all four days. During the time that their highest surface temperatures occurred, they had their highest levels of outgoing longwave radiation. The higher the surface temperature is the more outgoing longwave radiation is emitted. The day that had the highest surface temperature was November 10th, because on this day, the highest outgoing longwave radiation was emitted.
How does the daily march of temperature on a completely overcast day compare with that on a cloudless, sunny day?
Clear days are often warmer than cloudy ones. Since many clouds have a high albedo, they reflect a significant proportion of the sunlight that strikes (reflects) them (solar energy) back to space. By reducing the amount of incoming solar radiation, daytime temperatures will be lower than of clouds were absent and the sky was clear. An overcast day is responsible for a flattened daily temperature curve. By day, clouds block incoming solar radiation and so reduce daytime heating. At night the clouds retard the loss of radiation by the ground and air. Therefore, nighttime temperatures are warmer than they otherwise would have been. Pg. 54, 83
Which of the following is responsible for absorbing the largest portion of incoming solar radiation, Earth's surface or the atmosphere?
Earth's surface is responsible for absorbing the largest portion of incoming solar radiation.
Are temperatures in the lower stratosphere cooler at Alaska or at Florida?
Essentially Florida
What factors determines the amount of radiation that will be reflected by a surface?
Factors that determine the amount of radiation that will be reflected are primarily: sun angle, surface color, and surface texture. Notes
What is meant by heat? How is it different from temperature?
Heat is energy that is transferred into or out of an object because of temperature differences between that object and its surroundings. Temperature, however, is a measure of the average kinetic energy of the atoms or molecules in a substance. Temperature is essentially a measurement, whereas heat is a transferrable energy. Temperature essentially describes the presence or absence of heat. Pg. 44
Compare land and sea differences in latent heat loss.
Latent heat is responsible for transporting considerable amounts of energy from Earth's land-sea surface to the atmosphere. Pg. 44.The energy loss to Earth's surface through the process of evaporation is latent heat. Land has a limited amount of water supply, whereas the sea has abundance. Land is shallow; therefore heat does not penetrate deeply into it. However, water is highly mobile and as it is heated, convection distributes the heat through a considerably large mass. Water undergoes more evaporation than land; therefore more energy occurs or comes from the water than land. Land has a less amount of heat loss, whereas water has a bigger amount of heat loss. Pg. 68-69
Use Analemma to determine "solar declination" on:
March Equinox Equator Summer Solstice About 23 ½ degrees N January 20 20 degrees S Fall Equinox Equator Winter Solstice About 23 ½ degrees S March 15 2 degrees S
Based on the amounts of incoming shortwave radiation, which days between November 9 and November 12 were clear and which were cloudy?
November 9th and 10thwere cloudy days; their incoming solar radiation amounts are somewhat lower than the other two days and their incoming longwave radiation levels were high. November 11th and 12th were more likely clear days; their incoming solar radiation levels (shortwave radiation) are high and their incoming longwave radiation levels were low. Cloudy days have higher incoming longwave radiation than clear days.
What vertical temperature change occurs within the troposphere?
Since the atmosphere is largely transparent to solar radiation but more absorptive of the of the longwave radiation emitted by Earth, the Earth is heated from the ground up. This explains the general drop in temperature when the altitude increases in the troposphere. The farther from the Earth's surface, the colder it gets. On average, the temperature drops 6.5 Degrees C for each kilometer increase in altitude-a figure called the normal lapse rate. The temperature decrease in the troposphere is called the environmental lapse rate. The temperature decrease continues to an average height of about 12 kilometers. The thickness of the troposphere is not the same everywhere. It reaches heights in excess of 16 kilometers in the tropics, but in polar regions it is more subdued, extending to 9 kilometers or less. Warm surface temperatures and highly developed thermal mixing are responsible for the greater vertical extent of the troposphere near the equator. As a result, the environmental lapse rate extends to great heights. The lowest tropospheric temperatures are found in the tropics. Pg. 27
Calculate the noon sun angle for Macomb, IL (40N) and Anchorage (61N) on each of the following dates.
Solar Declination Macomb (40N) Key West (24N) March 21- 0 deg 50 Deg 66 Deg June 21- 23.5 N 73.5 Deg 89.5 Deg September 22- 0 Deg 50 Deg 66 Deg December 22- 23.5 Deg S 26.5 Deg 42.5 Deg
Use the figure above to complete the table and to calculate the net radiation (Q*) and Albedo () at the surface. Formula for Q* and are in your note.
Time a (%) 02:00 p.m. - (SWUP) 140W/m^2 (SWDN) 800 W/m^2 (LWUP)460 W/m^2 (LWDN)400 W/m^2 Q* (Wm-2) 600 Wm^(-2) a (%) 17.5% 06:00 p.m. - (SWUP) 40 W/m^2 (SWDN)260 W/m^2 (LWUP)500 W/m^2 (LWDN)380 W/m^2 Q* (Wm-2)100 Wm^(-2) a (%) 15.38 or 15.4% 03:00 a.m. - (SWUP) 0 W/m^2 (SWDN)0 W/m^2 (LWUP)420 W/m^2 (LWDN)360 W/m^2 Q* (Wm-2) -60 Wm^(-2) a (%) 0%
Compare visible, infrared, and ultraviolet radiation. For each indicate whether it is considered shortwave or longwave
Visible light is often referred to as white because it appears "white" in color. The white light is really an array of colors, each color corresponding to a specific range of wavelengths. By using a prism, white light can be divided into the colors of the rainbow, from violet with the shortest wavelength, to red with the longest wavelength. The retinas of our eyes are sensitive to visible light. Visible light is roughly in the middle of the range of short and long wavelengths. Infrared radiation, which cannot be seen by the human eye but is detected by heat, is located adjacent to the color red. Infrared radiation has a longer wavelength. Only the infrared energy that is nearest the visible part of the spectrum is intense enough to be felt as heat and is referred to as near infrared. Ultraviolet radiation is located on the opposite side of the visible range, next to violet. It consists of wavelengths that are shorter and that can cause sunburned skin. All wavelengths of radiation behave similarly, although they are divided into categories based on our ability to perceive them. The sun emits all forms of radiation. Pgs. 46-47
We are studying the atmosphere, so why are we concerned with the heating characteristics at Earth's surface?
We are concerned because the atmosphere is primarily heated by what energy the Earth emits. The atmosphere is not an effective absorber of the short wavelengths that are given off of the sun, yet are good absorbers of the longer wavelengths that are emitted by Earth. The atmosphere is heated from the ground up. The atmosphere and the Earth affect one another. How the Earth and the atmosphere affect the other contributes in causing weather. The fact that the atmosphere does not acquire the bulk of its energy directly from the sun but is heated by Earth's surface is of utmost importance to the dynamics of the weather machine. Pg. 54
Distinguish between the terms "weather" and "Climate"
Weather refers to the state of the atmosphere at a given time and place, and is constantly changing. Climate, however, is a description of aggregate weather conditions; the sum of all statistical weather information that helps to describe a place or region. Pg. 4
Describe the phenomenon of temperature inversion.
When the temperature in a layer of air increases with altitude, rather than decreases, a temperature inversion occurs. Pg. 118
A commercial airplane travels at 11.2 km above sea level. What fraction of the atmosphere is above the airplane? Use Table 1.
25 % and pressure is _250 mb
What happens to heat during the process of condensation?
Condensation occurs when water vapor changes to the liquid state. During condensation, water vapor molecules release energy (latent heat of condensation) in an amount equivalent to what was absorbed during evaporation. When condensation occurs in the atmosphere, it results in the formation of clouds and fog. Latent heat plays an important role in many atmospheric processes. When water vapor condenses to form cloud droplets, latent heat is released, which warms the surrounding air and gives it buoyancy. When the moisture content of air is high, this process can spur the growth of storm clouds. The evaporation of water over the tropical oceans and the subsequent condensation at higher latitudes results in significant energy transfer from equatorial to more poleward locations. Pg. 102
List and explain the factors that cause the difference between the heating and cooling of land and water. Reasons for the differential heating of land and water include the following:
1. Water is highly mobile. As water is heated, convection distributes the heat through a considerably larger mass. Daily temperature changes occur to depths of 6 meters or more below the surface. Heat does not penetrate deeply into soil or rock-it remains near the surface. No mixing can occur on land because it is not a fluid. Heat must be transferred through the slow process of conduction. Daily temperature changes are small below a depth of 10 centimeters, and some change can occur to about 1 meter. Annual temperature variations usually reach depths of 15 meters or less. Asa result of the mobility of water and the lack of mobility in the solid Earth, a relatively thick layer of water is heated to moderate temperatures during the summer. On land only a thin layer is heated but to much higher temperatures. Water bodies cool slowly as they draw on the reserved heat stored within. As the water surface cools, vertical motions are established, and the dense, chilled surface water sinks and is replaced by the less dense, warmer water from below. 2. Heat is absorbed only at the surface because land surfaces are opaque. Since water is more transparent, it allows some solar radiation to penetrate to a depth of several meters. 3. The specific heat is more than three times greater for water than for land. Thus, water requires considerably more heat to raise its temperature the same amount as an equal volume of land. 4. Evaporation from water bodies is greater than from land surfaces. Energy is required to evaporate water. When energy is used for evaporation, it is not available for heating. Pgs. 68-70
Why are water vapor and dust important constituents of our atmosphere?
4. Why are water vapor and dust important constituents of our atmosphere? Water vapor is significant because it is the source of all clouds and precipitation. It also has the ability to absorb heat given off by Earth, as well as some solar energy. Water vapor in the atmosphere transports latent heat (hidden heat) from one region to another, and is the energy source that drives many storms. Aerosols (dust particles) are important because many act as surfaces on which water vapor may condense, which is an important function in the formation of clouds and fog. Aerosols can also absorb or reflect incoming solar radiation. Aerosols contribute to the varied tints of red and orange at sunrise and sunset. Pgs. 19-21
A balloon travels at 5.6 km above sea level. What fraction of the atmosphere is above the balloon? Use Table 1.
50 % and pressure is _500 mb
What role do clouds paly in determining radiant heat input?
Clouds that are composed of tiny liquid droplets are excellent absorbers of the energy in the atmospheric window. Clouds absorb outgoing radiation and radiate much of this energy back to Earth's surface. They effectively block the atmospheric window and lower the rate at which Earth's surface cools. Pg. 54 Cloud cover is important because many clouds have a high albedo and therefore reflect a significant proportion of the sunlight that strikes them back to space. By reducing the amount of incoming solar radiation, daytime temperatures will be lower than if the clouds were absent and the sky was clear. At night,clouds have the opposite effect. They absorb outgoing radiation and emit a portion of it toward the surface. The effect of cloud cover is to reduce the daily temperature range by lowering the daytime maximum and raising the nighttime minimum. Pg. 75
Why does the daytime sky usually appear blue?
Sunlight appears white, but is made up of all colors. Gas molecules more effectively scatter blue and violet light that have shorter wavelengths than they scatter red and orange. This is why the sky is blue and the why red and orange are colors seen at sunrise and sunset. On clear days, if one looks in any direction away from the direct sun and sees a blue sky, the wavelength of light is more readily scattered by the atmosphere. The color of the sky gives an indication of the number of large or small particles present. Large particles produce white, gray skies, so the bluer the sky, the less polluted, or dryer the air. Pgs. 51-52
Why are temperatures in the thermosphere not strictly comparable to those experiences near Earth's surface?
Temperature is defined as the average speed at which molecules move. Because the gases of the thermosphere are moving at very high speeds, the temperature is very high. However, the gases are so sparse that collectively they possess only an insignificant amount of heat. Because of this, the temperature of a satellite orbiting Earth in the thermosphere is determined primarily by the amount of solar radiation it absorbs and not by the high temperature of the almost nonexistent surrounding air. Pgs. 28-29
How is the atmosphere heated?
Terrestrial radiation is the primary heat source for the atmosphere. The atmosphere does not absorb direct radiation from the sun very well (largely transparent to short wavelengths of solar radiation); however it does absorb long wavelengths of radiation that are emitted from the Earth's surface. The atmosphere is heated from the ground up. The ozone layer in the stratosphere does absorb ultraviolet rays, which is primarily why that part of the stratosphere has higher temperatures. Pg.54 Atmospheric heating is a function of the ability of atmospheric gases to absorb radiation, the amount of solar radiation that reaches Earth's surface, and the nature of the surface material. (Notes)
How does Earth's atmosphere act as a "Greenhouse"?
The "Greenhouse effect" is the extremely important role that the atmosphere plays in heating Earth's surface. Earth's atmosphere "traps" some of the outgoing radiation, which makes our planet habitable. Cloudless air is largely transparent to incoming shortwave solar radiation and, hence, transmits it to Earth's surface. By contrast, a significant fraction of the longwave radiation emitted by Earth's land-sea surface is absorbed by water vapor, carbon dioxide and other traces of gases in the atmosphere. This energy heats the air and increases the rate at which it radiates energy, both back out to space and back toward Earth's surface. Without this phenomenon, Earth's average temperature would be -18 Degrees C, rather than the current temperature of 15 Degrees C. Greenhouses are heated in a similar manner. Pgs. 54-55
Which hemisphere has the greatest interior landmass temperature range? And why?
The Northern Hemisphere, with its large continents, has larger annual temperature ranges than the ocean-dominated Southern Hemisphere. Continental locations must endure hotter summers and colder winters than a coastal location. Outside the tropics, the annual range of temperature will increase with continentality. Temperatures do not fluctuate as much over water as over land, partially because water is mobile and is denser than land. Pg. 80
What makes a difference in the surface albedo between 2:00 p.m. and 6:00 p.m.?
The albedo is less because the incoming short wavelength radiation that is coming in is sharply declining (The sun is on the verge of setting, and eventually does). The shortwave radiation that is being emitted is declining as well, but not near as much as the incoming shortwave radiation. At 2 p.m., the albedo is higher than at 6 p.m., by about 2%. The angle of the sun changes as the day goes on, which would affect the albedo because of the angle that the radiation is being reflected/received.
Why does the amount of solar energy received at Earth's surface change when the angle of the Sun changes?
The amount of solar energy that is received changes because when the sun angle changes, so does the concentration of the rays that are hitting Earth's surface. The higher the sun angle is, the larger the concentration of insolation per unit area. The lower the sun angle is, the smaller the concentration of insolation per unit area. Backscattering also plays a part of the changing of sun angles affecting the amount of solar energy received by Earth. The lower the sun angle and thicker the atmosphere, there is a longer distance for the energy to travel and more backscattering occurs,resulting in less radiation reaching the Earth. The higher the sun angle and thinner the atmosphere, there is a shorter distance to travel and less backscattering occurs, resulting in more radiation reaching Earth's surface. Pg. 50 and Notes
What factors influence albedo from time to time and from place to place?
The angle of the sun and the thickness of the clouds are a couple of factors. In general, light-colored surfaces tend to be more reflective then dark-colored surfaces, and thus have higher albedos. Surface texture also influences albedo. There is a high albedo when there are light colored objects/areas involved, such as snow, desert sands, and clouds. There is a lower albedo when dark-colored objects/areas are involved, such as grass, forests, volcanic rock, and farm land. Pg. 50 and Notes
Explain why the atmosphere is heated primarily by radiation from Earth's surface rather than by direct solar radiation.
The atmosphere is nearly transparent to incoming solar radiation; therefore, direct solar energy is not an effective "heater" of Earth's atmosphere. The atmosphere is a less effective absorber because gases are selective absorbers (and emitters) of radiation. Much of the short-wavelength radiation from the sun passes through the atmosphere and is absorbed by the Earth's surface. This energy is then emitted from the surface as longer-wavelength radiation, which is absorbed by the greenhouse gases in the atmosphere. The atmosphere is generally a relatively efficient absorber of longwave radiation emitted by Earth. Since the atmosphere is more absorptive of the longwave radiation emitted by Earth, the atmosphere is heated from the ground up. Pg. 54
What are the basic elements of weather and climate?
The basic elements of weather and climate are: the temperature of the air, the humidity of the air, the type and amount of cloudiness, the type and amount of precipitation, the pressure exerted by the air, and the speed and direction of the wind. Pg. 6
How are the following temperature data calculated: daily mean, daily range, monthly mean, annual mean, and annual range?
The daily mean temperature is determined by averaging the 24 hourly readings or by adding the maximum and minimum temperatures for a 24-hour period and dividing by 2. From the maximum and minimum, the daily temperature range is computed by finding the difference between these figures. The monthly mean temperature is calculated by adding together the daily means for each day of the month and dividing by the number of days in the month. The annual mean temperature is an average of the 12 monthly means. The annual temperature range is computed by finding the difference between the warmest and coldest monthly mean temperatures. Pg. 66
On which day and during what hours did the incoming longwave radiation from the atmosphere change most dramatically? And how did you make your estimates?
The incoming longwave radiation changed most dramatically on November 11th, from about midnight to around 3 or 4 a.m. Through looking at the diagram, it was easy to see that this was the lowest level of incoming longwave radiation that occurred throughout the four days. This dramatic change most likely happened because the clouds were cleared the skies. Cloudy days have higher incoming longwave radiation than clear days.
On which day and at what time was surface temperature lowest? And how did you make your estimates?
The lowest surface temperature occurred on November 12th, between around 6 and 8 a.m. This day had the lowest amount of outgoing longwave radiation, which occurred around 6-8 a.m. The lower the amount of longwave radiation that is emitted from the Earth, the lower its surface temperature.
Which gases are the primary heat absorbers in the lower atmosphere? Which one is most influential in weather?
The only significant absorbers of incoming solar radiation are water vapor, oxygen and ozone, which account for most of the energy absorbed directly by the atmosphere. However, water vapor and carbon dioxide are the principal absorbing gases (of radiation emitted by the Earth's surface), with water vapor absorbing about 60% of radiation emitted by Earth's surface. Therefore, water vapor, more than any other gas, accounts for warm temperatures of the lower troposphere, where it is most highly concentrated. It is in the lower troposphere where essentially all important weather phenomena occur. Pg. 54
5. Why is ozone important to life on Earth? And what are the effects on human health of a decrease in the stratosphere's ozone?
The ozone absorbs the potentially harmful ultraviolet radiation from the sun. If the ozone didn't filter a great deal of the ultraviolet radiation, and if the sun's UV rays reached the surface of Earth undiminished, land areas on Earth would not be habitable for most of life. Anything that reduces the amount of the ozone in the atmosphere could affect the well-being of life on Earth. Ultraviolet radiation is known to induce or raise the risk of skin cancer, it can negatively impact the human immune system, as well as promote cataracts. Pgs. 21-23
Why does the sky appear red or orange tint near sunrise or sunset?
The sun seems to have a reddish-orange tint when seen near the horizon. This is the result of the great distance solar radiation has to travel through the atmosphere before it reaches one's eyes. During its travel, the majority of the blue and violet wavelengths are scattered out. The light that reaches one's eyes consists mostly of reds and oranges. The color of the sky gives an indication of the number of large or small particles present. Numerous small particles create sunsets. The reddish appearance of clouds during sunrise and sunset also results because the clouds are illuminated by light from which the blue color has been removed by scattering. Pgs. 51-52
How would you characterize the relationship between average temperature and the thickness of the troposphere?
The thickness of the troposphere is not the same everywhere. It reaches heights in excess of 16 kilometers in the tropics, but in polar regions it is more subdued, extending to 9 kilometers or less. Warm surface temperatures and highly developed thermal mixing are responsible for the greater vertical extent of the troposphere near the equator. Because of this, the environmental lapse rate extends to great heights. The lowest tropospheric temperatures are found aloft in the tropics and not at the poles, although the surface temperatures are warmer in the tropics and colder at the poles. Pg. 27
Describe the three basic mechanisms of energy transfer. Which mechanism is least important meteorology?
The three basic mechanisms of energy transfer are: conduction, convection and radiation. Conduction is the transfer of heat through electron and molecular collisions from one molecule to another. Conduction is important only between Earth's surface and the air immediately in contact with the surface. As a means of heat transfer for the whole atmosphere, conduction is the least important when it comes to meteorology. Convection is heat transfer that involves the actual movement or circulation of a substance. It takes place in fluids, where the material is able to flow. Radiation is the only mechanism of heat transfer that can travel through the vacuum of space. Therefore, it is responsible for solar energy reaching Earth. There are various types of radiation, and when they pass through space at the speed of light, they come in various sizes/wavelengths. Radiation is often identified by the effect that it produces when it interacts with an object. Pgs. 44-46
How does the annual temperature range near the equator compare with the annual temperature ranges in the middle to high latitudes?
The tropics experience small annual temperature variations, whereas the highest temperature variations occur in the middle of large landmasses in the subpolar latitudes. Locations near the equator have very small annual ranges of temperature because they experience little variation in the length of daylight, and they always have a relatively high sun angle. In mid to high latitudes, locations experience wide variations in sun angle and length of daylight and hence have larger variations in temperature. Annual temperature range increases with an increase in latitude. Pgs. 79-80
On this date, the solar noon solar radiation values at the top of the atmosphere and at the surface at this place are 1317 Wm-2 and 920 Wm-2, respectively. Why is the surface value lower than the value at the top of the atmosphere?
The value at the top of the atmosphere is higher because the sun's rays do not have as many obstacles to go through to reach it. Less of the sun's rays have the chance of being deflected as well. The surface value is lower because the sun's rays have to travel through the atmosphere and endure through many obstacles before they reach the Earth's surface; therefore, the radiation values are higher at the top of the atmosphere.
The warmest temperature occurs at ____________ and why does the warmest daily temperature occur in mid-to-late afternoon rather than at the time of the highest sun angle?
The warmest temperature occurs at about the 17th hour of the day, or, respectively, around 5 P.M., according to the diagram. Although the intensity of solar radiation drops in the afternoon, it still exceeds outgoing energy from Earth's surface for a period of time. This produces an energy surplus for up to several hours in the afternoon and contributes much to the lag of the maximum. As long as the solar energy gained exceeds the rate of Earth radiation lost, the air temperature continues to rise. The lag of the daily maximum is also a result of the process by which the atmosphere is heated. Air is a poor absorber of most solar radiation, so it is heated primarily by energy reradiated from Earth's surface. The rate at which Earth supplies heat to the atmosphere is not in balance with the rate at which the atmosphere radiates away heat. Generally, for a few hours after the period of maximum solar radiation, more heat is supplied to the atmosphere by Earth's surface than is emitted by the atmosphere to space. Pg. 81-82
The atmosphere is divided vertically into four layers on the basis of temperature. List the names of these layers and their boundaries in order (from lowest to highest), and list as many characteristics of each as you can
There are four layers of the atmosphere: the troposphere, stratosphere, mesosphere and thermosphere. Troposphere: It is the bottom layer in which we live, where temperature decreases with an increase in altitude. The term troposphere means the region where air "turns over," a reference to the appreciable vertical mixing of air in this lowermost zone. The temperature decrease that occurs here is called the environmental relapse, which average value is 6.5 degrees C per kilometer. The temperature decrease continues to an average height of about 12 kilometers. The thickness the troposphere is not the same everywhere. It reaches heights in excess of 16 kilometers in the tropics, but in polar regions it is more subdued, extending to 9 kilometers, or less. The warm surface temperatures and highly developed thermal mixing are responsible for the greater vertical extent of the troposphere near the equator. The troposphere is the chief focus of meteorologists- it is in this layer that essentially all important weather phenomena occur. The troposphere is often called the "weather sphere" because it is here where almost all clouds, and all precipitation, as well as storms are born. Stratosphere: The boundary between the troposphere and the stratosphere is the tropopause. Atmospheric properties are not readily transferred by large-scale turbulence and mixing in this layer. The temperature here at first remains nearly constant to a height of about 20 kilometers before it begins a sharp increase that continues until the stratopause is encountered at a height of about 50 kilometers above Earth's surface. Higher temperatures happen here because it is where the ozone is concentrated, and the ozone absorbs the ultraviolet radiation from the sun. Although the maximum ozone concentration is between 15 and 30 kilometers, the smaller amounts of ozone above this absorb enough UV energy to cause the higher observed temperatures. Mesosphere: The stratopause is the boundary between this layer and the stratosphere. This is the third layer of the atmosphere in which the temperatures again decrease with height until at the mesopause (about 80 kilometers above the surface), where the average temperature is around -90 degrees C. The coldest temperatures anywhere in the atmosphere occur at the mesopause. The pressure at the base of the mesosphere is only about one-thousandth that at sea level. The atmospheric pressure at the mesopause drops to just one-millionth that at sea level. The mesosphere is one of the least explored regions of the atmosphere because accessibility is difficult. Thermosphere: The fourth layer that extends outward from the mesopause and has no well-defined upper limit. This is a layer that contains only a tiny fraction of the atmosphere's mass. Temperatures again increase in the extremely rarified air of this layer due to the absorption of very shortwave, high-energy solar radiation by atoms of nitrogen and oxygen. Temperatures can rise extremely high up to values of more than 1000 degrees C. These temperatures are not comparable to those that are experienced on Earth. The gases of this layer move at very high speeds, causing the temperature to be high. The gases are so sparse that collectively they possess only an insignificant amount of heat. Pgs. 27-29
Why are values of LW higher in summer than in winter?
They are higher in the summer because during the summer (in the Northern Hemisphere), the sun's rays hit more directly than they do in the winter (the sun angles are higher). This being the case, the energy (sun's rays) are more concentrated, which causes the surface of the Earth to experience more intensity from that energy. The surface is receiving more energy, therefore can emit/reflect more. During the summer, the surface temperature is warmer than in the winter; therefore, more outgoing long wavelengths of radiation are emitted from Earth's surface. The higher the surface temperature, the more outgoing long wave radiation can be emitted.
