Geog. 143 -- Global Environmental ChangeExercise 2: Recent Climate TrendsThis exercise involves examining some of the recent trends in climate as illustrated by maps and time-series plots from several web pages, focusing mainly on the monthly and annual reviews of climate done by the National Climatic Data Center (NCDC). Much of the work that goes on in understanding global change involves the preparation and subsequent analysis of the kinds of graphical displays that will be examined here. Sometimes dismissed as superficial "wiggle matching," the examination of visualization of data nevertheless provides the "first-order" description of how climate is changing. In examining the maps and plots that will be looked at here, it will be useful to get into a routine of figuratively (sorry...) deconstructing them--inferring how they were made in order to understand what they are showing. In looking at a time-series plot, such as that for global temperature, the key tasks are:
In the case of maps, the key tasks are roughly the same, only instead of the x- and y-axis frame, the "window" or regional extent of a map (e.g. globe? Pacific Northwest?), and whether the data are projected or not is an important considerations. Similarly, how the data are plotted (on a grid vs. at individual points), and how they are displayed (as points, contours, or as levels) are the key things to note. Begin by opening the "Global Analysis" section "Climate of 2007 -- Annual Report" web page by clicking on the following link. (The page will open in a new browser or window):
Answer each of the following questions (e.g. Q1, Q2, etc.) with a short sentence. It will be handy to open the images or links on the individual pages in new browser windows or new tabs as you go. 1. Global temperature trends Examine the image showing global mean temperature over land and ocean that appears at the top of the page. (Click on the "larger image" link, or right-click and open in a new tab (Firefox or IE 7). Recall that "anomalies" are differences between some observed values and a long-term mean of those values.
(It might be helpful in answering this question to look at the ways in which global temperature has been summarized by other laboratories, e.g.:
The underlying observations are basically the same, but the data have been treated and plotted in slightly different ways.) 2. Comparison of trends Back on the NCDC page, scroll down to the plots of
In interpreting these plots, it will be helpful to look at the "longwave" or right-hand side of Fig. 1.2 in the IPCC WG1 (2001) chapter on the climate system. Note that the two plots have different axes.
(You might want to close a few browser windows or tabs at this point. If you accidentally close the "Climate of 2007 -- Annual Report" you can always reopen it using the link above. 3. Comparison of anomaly (map) patterns and time series Locate and open the larger-size versions of the following
4. Temporal changes in western U.S. wildfire data Next, take a look at the summarization of wildfire incidence (number of fires) and area burned for the western United States. Here are direct links to the end-of-the-fire-season part of the page, and to the appropriate figure:
It might be useful to look at the long-term trends of temperature and precipitation around the country in interpreting the data here. Such a map can be found at: and an explanation of how such maps are created is at:
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