1. Pick one of the atmospheric gases listed in table 3-4 on p. 75 and do enough background research to write a page about its relative abundance in the atmosphere, recent trends, and environmental impacts. Cite any sources consulted. Post this to the discussion board - I will create a forum for this question.

2. I would like you to work with some real, current data on the vertical structure of the atmosphere. There is a bookmark on the "notes" and also on the "useful links" page, labelled "Vertical structure of the atmospher" in the first case, and  "Upper air soundings of the atmosphere" in the second case. If you visit this site you will see a map of the U.S. with a bunch of locations highlighted. You can select any of these and get a table of information derived from a weather balloon that collected the data this morning. I would like you to use the data in this table to create a plot showing the vertical temperature and pressure profiles of the atmosphere for that particular location at that particular time. In the textbook there are general profile showing global average conditions; what is interesting is to pick a particular place and time and look at the profile to see how it is similar to or different from the one in the textbook.

Follow these steps in order to complete this part of the assignment. PLEASE DO THIS FOR TWO DIFFERENT LOCATIONS, PREFERABLY LOCATED FAR FROM EACH OTHER.

- click on "upper air observations by station"

- click on one of the locations shown on the map

- after the data table appears on your screen, you can either print it  or just write down the numbers you need; or, if you know how to save files and import them into a spreadsheet program, you can save the file for this purpose.

- the data you want are from the following columns:

PRES (pressure, in millibars); HGHT (altitude, in meters above the surface); and TEMP (temperature, in degrees Celsius). Note that some rows may not have a number listed for altitude. Make certain that the station you choose has data beginning at an altitude that isn't too far above ground level; some of them have incomplete readings that start several kilometers above the ground, and those are not suitable for our purposes. (Also keep in mind, however, that some cities in the mountainous part of the western U.S. have ground elevations that are several thousand feet or more above sea level).

Plot both pressure and temperature vs. altitude, with altitude on the vertical axis and pressure or temperature on the horizontal axis. This allows you to produce vertical profiles for both of these variables that are comparable to the plots shown in the book. Comment on the comparison between the plots from your two sites and on the comparison between your two sites and the average atmospheric conditions shown on the plots in the textbook. If there are visible differences, try to think of possible explanations.  Your assignment, in addition to creating the plots, is to provide a description and an explanation of the trends shown in your plots. Although this is not a group project, feel free to discuss your observations and explanations with your colleagues.

If there are rows with missing entries for altitude, you can't plot the temperature or pressure values unless you are willing to interpolate an altitude. You might post a message to the newsgroup asking for help on how to do this if you don't know already.

While you're looking at the table, you might also examine the column labelled "SPD" or wind speed in knots. Although we won't get to this until chapter 5, it's interesting to plot wind speed vs. altitude and to see what that trend looks like.

Finally, if you use a spreadsheet and decide to use a graphing function, make sure (1) that you plot altitude on the vertical axis and the other variables on the horizontal axis; and (2) that you plot an xy or scatter plot, rather than a line graph. If you use the line graph function you will get a plot that doesn't make any sense.