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MEASURING AND MONITORING


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OVERVIEW

Measurement and monitoring, in combination with theory, are vital in understanding how
environmental systems are put together, how they work and how they change. Several
questions are crucial to the process of measuring and monitoring and need thinking through before an investigation starts.

First, it is essential to establish what will be measured and monitored and why. Second, it must be decided how the measuring and monitoring will be done, and third, when and where. Finally, it is advisable to appreciate the limitations of the techniques being used. This chapter begins with a general discussion of these questions. By taking examples from each of the key environmental media – air, water, soil, sediments and land cover – it then shows how measuring and monitoring help in the understanding of how the Earth system and its components work.


LEARNING OUTCOMES

Reading this chapter should help you understand the overall purpose of measuring and monitoring
and you will learn how to measure and monitor:

• Air, especially urban air
• Water
• Soil
• Earth’s surface processes
• Land cover and land cover change.

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SUMMARY

Measuring and monitoring are essential tools for understanding the environment and environmental change. Before undertaking measurements or setting up a monitoring programme, it is necessary to give thought to several questions – what, why, how, when and where. All these matters require an appreciation of several ideas, including the scientific method, the nature of data, sampling
techniques, scales of measurement, precision and accuracy and a host of field and laboratory techniques.

In addition, it is prudent to recognize the limitations of the techniques employed. A wide range of equipment measures and monitors the chief atmospheric variables (temperature, wind speed and so on) and atmospheric composition at climatic stations and other sites. In the hydrosphere, measurements focus on flows in the water cycle – evaporation, precipitation,
runoff and so on – as well as water quality. Soil scientists measure nutrient status, acidity and other soil variables, especially those relevant to agriculture. A host of measurement techniques facilitate the study of geomorphic processes, including weathering, erosion, transport and deposition. Measurement techniques allow land cover to be mapped and land cover change to be monitored.


QUESTIONS

1. What are the problems of measuring air    quality? 4. Discuss the issues to consider when    setting up a study of a geomorphic    process. 2. Compare and contrast the problems of     measuring evaporation and precipitation. 5. Compare and contrast the use of ground-     based surveys, aerial photography, digital     airborne remote sensing and space-borne     remote sensing in land-cover mapping. 3. Why is it useful to measure soil    properties?

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FURTHER READING

Good texts that cover the topics introduced in this chapter include:

• Arnell, N. (2002) Hydrology and Global Environmental Change. Harlow: Prentice Hall.
  Full of useful information and ideas.
  
• Brutsaert, W. (1982) Evaporation into the Atmosphere: Theory, History and Applications. Dordrecht: D. Reidel Publishing Co.
  Rather old, but still worth reading.
  
• Fetter, C. W. (1994) Applied Hydrogeology, 3rd edn. Englewood Cliffs, New Jersey: Prentice Hall.
  As the title suggests, it covers applied aspects of groundwater.
  
• Goudie, A. (1995) The Changing Earth: Rates of Geomorphological Process. Oxford, UK and Cambridge, USA: Blackwell.
  A valuable source on geomorphic processes.