Earth’s Atmosphere

PART #1 – Earth’s Atmosphere

1. Browse through any weather-related Web sites and find an example of each of the following:
   1. a surface analysis
   2. an upper-air analysis (e.g., 850-mb, 700-mb, 500-mb, 300-mb, and so on) (only one type of upper-air analysis is required)

Print and label each analysis. Discuss, to the best of your understanding, what the different lines and symbols represent in each analyses. Be sure to submit a copy or printout of your analyses and clearly indicate their Web site addresses.

2. A weather map is dated 2100Z, 01 March 2006. What was the local time in:
   1. Greenwich, England?
   2. Albany, New York?
   3. Houston, Texas?
   4. Seattle, Washington?

Would any of the local times be different if the date were July 28, 2006? Explain.
If the local times did change, what would be the new times?

3. Go to the American Meteorological Society DataStreme Atmosphere Project Web site’s S. Data Map.

1. Make a copy of the map, highlight four stations of your choice, and describe the conditions as best as you can at each station.
2. What is the “universal time” on the U.S. map? For each of your chosen stations, indicate its “local time.” Be sure to use the proper suffixes such as EST, EDT, PST, and so forth.

Part #2 – Temperature, Heat Energy, and Heat Transfer

1. The amount of solar radiation (in Watts per square meter) incident on the top of the atmosphere at local noon is given as a function of latitude in the table below, for June 22 and December 22.

Table 2.1

1. On graph paper, plot the amount of radiation received on June 22 and December 22 as a function of latitude (plot both curves on the same sheet). Plot latitude along the x-axis and amount of radiation along the y-axis. You may use a graphing program such as Microsoft Excel if you like. (Be sure to label your axes with the proper variables and units.)
2. At what latitude does the amount of radiation vary the least from winter to summer?
   At what latitude does the amount of radiation vary the most from winter to summer?
3. Based solely on this radiation information, at what latitude would you expect the largest temperature swing from winter to summer? At what latitude would you expect the smallest temperature swing from winter to summer?

2. In this activity, the map in Figure 2.3 shows air temperatures, in degrees Fahrenheit, over a portion of the United States (time: 2000Z; date: 27 Dec 2004).
3. Table 2.2 below shows the relationship of the “average” air temperature (in units of degrees Celsius) as a function of air pressure (in units of millibars).

Table 2.2
Air Temperature as a Function of Air Pressure

1. Complete the rest of the table by converting temperature values from ºC to K, and from ºC to ºF.

2. In the graph below (figure 2.4), plot the average air temperature as a function of air pressure.

Source: American Meteorological Society’s DataStreme Project
http://www.ametsoc.org/dstreme/images/maxt.gif

2. Which axis on the figure 2.4 graph is linear, and which is nonlinear? (The x-axis is the horizontal axis, and the y-axis is the vertical axis.)
3. Based on your plotted graph, at what pressure level is the tropopause located? Explain how you came to your conclusion. (The tropopauseis the boundary between the troposphere and the stratosphere.)
4. Does your plotted graph represent weatheror climate? Explain your reasoning. (Hint: The data you plotted are average values.)

PART #3 – Seasonal and Daily Temperature Variations

1. From the American Meteorological Society Atmosphere Web site, view and print the temperature profile diagram (Stüve) for Dulles Airport, Washington, D.C. (IAD). (If IAD data are not available, use any station of your choice.) Answer the following questions and be sure to submit your printout.
   1. What variables do the horizontal and vertical axes represent?
   2. What are the units of the horizontal and vertical axes?
   3. Which of the axes displays linear data; which displays nonlinear data?
   4. What do the two black, plotted curves on the Stüve represent?
   5. From the plotted air-temperature data, where is the tropopause (the boundary between the troposphere and stratosphere)? Explain.
2. Table 3.1 below lists elevation above sea level (in feet) and mean annual temperature (in °F) for several locations at approximately the same latitude along a line from central Tennessee eastward across the Appalachian Mountains to central North Carolina.
   1. On a graph, plot the mean annual temperature along the y axis and elevation along the x axis for these stations.

Your points will not lie precisely on a straight line. Because air temperature generally decreases with elevation in the troposphere, however, the points should tend to orient themselves in a linear fashion. Draw a straight line of best fit to your plotted data and compute the slope of your line, thereby providing a numerical estimate of the average environmental lapse rate.

1. How close is your estimate to the average environmental lapse rate cited in Key Concept 1 of this lesson? (Hint: To draw a straight line of best fit through a set of points, think of the points as exhibits scattered in a large room of a museum. You want to get as close as possible to all the exhibits, but you are constrained to walk through the museum in a straight line. The most efficient path for you to accomplish your goal would be a good estimate of a straight line of best fit through the points.)

Table 3.1

3. Review your data and graph from Activity #1 of the lesson 2 lab. Based on your understanding of seasonal Earth-Sun geometry (Earth’s axis tilt of 23.5º), at what latitude would you expect:
   1. the greatest amount of radiation difference from winter to summer?
   2. the greatest amount of temperature difference from winter to summer?

4. Using the instruments found in your “weather kit,” take one daytime and one nighttime weather observation (or ob) of as many of the seven weather elements as you can (air temperature, air pressure, humidity, sky condition, wind speed and direction, precipitation, and visibility).
   1. Record your obs in a simple text format, and then put it in “station model” format.
   2. Indicate the location of your ob (city) and the time in both local and Z-time references.
   3. Were there any data that you were unable to measure or observe at this time?
   4. Discuss any differences or particular challenges between taking your day ob and taking your night ob.
   5. If you are in the United States, immediately after taking your obs, go to the WeatherbugWeb site. Call up the station closest to your location and record the current weather data. Compare the Weatherbug readings with your personal obs, and discuss possible reasons for the Weatherbug readings being different from yours.