2-8: The Instrument Climate Record, Uncertainties

Unit Objectives

• To review the meteorological records taken by scientific instruments.
• To understand the difficulties in constructing representative patterns of global climate variables.

Preparation for Online and Class Discussion

1. Read the summary information.

   Class images

   Related class images

2. Print for offline review.

3. Take the summary information quiz. Quizzes are available from your portfolio.

4. Additional Related Reading. Although you are not ultimately responsible for content listed in this section, we encourage you to fully explore the links in order to provide a better scope on the upcoming class discussion.

   	Global warming and the Arctic
   	Is the Earth warming up yet? (From the United Nations Environment Programme, UNEP)
   	Houghton, J. T., L. G. Meira Filho, B. A. Callander N. Harris, A. Kattenberg, and K. Maskell, 1996: Climate Change 1995. The Science of Climate Change. Cambridge University Press, 419-423.
   	Houghton, J. T., G. J. Jenkins, and J. J. Ephraums, 1990: Climate Change, The IPCC Scientific Assessment. Cambridge University Press. p. 201-216.

Online and Class Discussion

• Social Comments
• Knowledge-building Comments
• Ethical Comments

• Unit Problem to Ponder
• Unit exam questions from previous years
• Unit discussions from previous years

Unit Wrap-up Materials

• Group Discussion Summary:

  Summary prepared by: Rustan Krentz, Ryan Kardell, and Gregory M. Cillo

  Summary section:

  This section talked about various means for measuring current conditions such as temperatures and Precipitation. Then the chapter continues to tell how this is used to determine climate change. This summary also discussed some of the errors in collecting the data.

  Meteorological measurements are taken a few feet above the earth¥s surface over the land. They are also taken by the use of weather balloons every 12 hrs to measure upper air data. The weather observations over land are taken every hour unless there are rapidly changing conditions. The upper air data is measured by using weather balloons. These balloons contain radiosonds that send the data back to the surface.

  Measurements over oceans are taken from buoys that are mounted to the sea floor or the measurements are taken from ships out at sea.

  To determine global warming one must rely on surface temperatures. These are compared to some relative base temperatures, like the 1950-1980 average temperatures for the area.

  Using this one concludes that warming has been occuring. This has been determined using the land temperatures. The patern of change is different from land to sea and the northern and southern hemisphere.

  There have been some problems when using global temp patterns.

  1. Varies greatly
  2. someone changes observing schedule
  3. Different types of ways to measure temperature
  4. change of locations
  5. growth of the city around the observing station.
  

  Number 5 is the one that causes the most problems. The temperatures tend to be warmer near urban areas then in the rural areas.

  Most of the warming that has been occuring is due to the rise in daily minimum temps.

  Besides the error in measuring temps there is an error in taking precip measurements. These errors are due to three factors.

  1. The rain gauge network is very sporatic, letting heavy rain events slip through the grid and causing overestimates when a small heavy rain event centers over one rain gauge.
  2. High winds can cause a gauge to read low.
  3. Wetting of the gauge in light precipitation events can also cause low readings.

  Despite all of these errors in measuring precip and temperatures there have been reports from upper air data that the earth is warming up. Also reports from the ocean data suggests warming too. Ice has been thinning as well.

  Lecture section:

  The only thing that has been brought up in lecture is the thinning of the ice caps. Also that a lot of energy has ben used to melt the ice so far.

  Dialog Summary:

  There were some questions from dialog. One question was about weather stations. Someone replied that the data is taken in white boxes to keep the effects of sun radiation out, and that these boxes are 4 to 6 ft above the earth¥s surface.

  Someone suggested that the reason for the precip errors could be due to the lack of data in the record booth.

  One question was brought up was why more ice loss was occuring in the southern hemisphere then the northern hemisphere. This question went unanswered.

• Recommended Reading Materials

  	Global Temperatures from Space and the Surface: Why the Discrepancy?
  	Cane, Mark A., Amy C. Clement, Alexey Kaplan, Yochanan Kushnir, Dmitri Pozdnyakov, Richard Seager, Stephen E. Zebiak, and Ragu Murtugudde, 1990: Twentieth century sea surface temperature trends. Science, 275, 957-960.
  	Global Temperature Anomolies: 1979 - Current (From UNIDATA)

• References

  	Measuring the Temperature of Earth from Space
  	Urban Heat Island
  	Climactic / Meteorologic Information Sources. Center for Global & Regional Environmental Research, University of Iowa.
  	American Association of State Climatologists
  	World Climate data average monthly and yearly rainfall, temperature, and pressure for over 85,000 sites worldwide
  	Hunt, G. L., Jr., C. L. Baduini, R. D. Brodeur, K. O. Coyle, N. B. Kachel, J. M. Napp, S. A. Salo, J. D. Schumacher, P. L. Stabeno, D. A. Stockwell, T. E. Whitledge, and S. I. Zeeman, 1999: The Bering Sea in 1998: The second consecutive year of extreme weather-forced anomalies. EOS, 80, 561.
  	Wigley, T. M. L., R. L. Smith, and B. D. Santer, 1998: Anthropogenic influence on the autocorrelation structure of hemispheric-mean temperatures. Science 282, 1676-1679.