1-11: Global Hydrological Cycle

Pre-Class Preparation

Objectives

• To understand the global distribution of water substance (water, water vapor, and ice).
• To understand how these reservoirs of water substance influence global temperature patterns.

Procedure

1. Read the learning unit.

   Class images

2. Take the learning unit quiz. Quizzes are available from your portfolio. You may access your portfolio via the list of students participating in this years course, as represented by the icon below.
   
   
3. Additional Required 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.

   Houghton, J. T., G. J. Jenkins, and J. J. Ephraums, 1990: Climate Change, The IPCC Scientific Assessment. Cambridge University Press. p. 47-51, 75-79.

Class Discussion

• Problem to ponder...

  The chemical H-O-H is responsible for several hundred deaths each year in the US due to suffocation when exposed improperly to its concentrated form. It also causes billions of dollars in damage annually to steel structures and machines. Furthermore, it is known to be a greenhouse gas. Why is this chemical not banned by the EPA?

• Class Discussion Summary: by classmates Kelli Lotz and Mark Nauman

  Global energy balance was covered in a chart that showed the cycle of solar energy allotments to different parts of the environment. This is important because it affects the way in which solar energy is absorbed by the earth. It is then distributed by weather systems and ocean currents. Ocean currents are influenced by energy gradients within the atmosphere and driven by differences in temperature and salinity. The next topic discussed how the hydrological cycle regulates global vegetation patterns. Water determines the type of vegetation that evolves within a climatic region. The hydrological cycle plays a role in ecosystem functioning. Dr. Takle showed a simple chart of the hydrological cycle based on natural landscape and water systems. There are multiple components of the hydrological cycle such as oceans, ice sheets, lakes and rivers. Human interactions affect the natural hydrological cycle. Dr. Takle made a reference to the New York water system and the natural purification of water.

Post-Class Activities

• Participate in the electronic dialog. Use this forum for:
  • continuing class discussion;
  • posing new questions to students or the instructor;
  • responding to issues/questions raised by students in class/electronic dialog.

  Visitor Access (Visitors are welcome to participate in the dialog. Just click on the icon below)	Student Access (Students must post all dialog from their portfolio. Click on the icon below to access the student list.)

• Recommended Reading Materials

  	CIESIN Thematic Guides: Freshwater Resources.
  	Global Energy and Water Cycle Experiment (GEWEX) Home Page
  	National Climactic Data Center
  	The Water Planet- Meteorological, Oceanographic and Hydrologic Applications of Remote Sensing (From the Applied Information Sciences Branch, NASA)
  	USGS Water Resources Information
  	Chahine, Moustafa T., 1992: The hydrological cycle and its influence on climate. Nature 359, 373-381.
  	Lau, K. M., C. H. Sui, and W. K. Tao, 1993: A preliminary study of the tropical water cycle and its sensitivity to surface warming. Bulletin of the American Meteorological Society 74, 1313-1321.
  	Peterson, D., et. al., 1995: The role of climate in estuarine variability. American Scientist 83, 58-67.
  	Shuttleworth, William James. 1994: Large-scale experimental and modeling studies of hydrological processes. Ambio 23, 82-86

• References

  	Irrigated land, technical atlas, WFS. (To download Adobe Acrobat Reader, go to http://www.adobe.com/prodindex/acrobat/readstep.html).
  	National Ground Water Association
  	Water utilization intensity, technical atlas, WFS.