Thermal Physics of the Atmosphere (Ambaum/Thermal Physics of the Atmosphere) || General Applications

✍ Scribed by Ambaum, Maarten H. P.

• Publisher: John Wiley & Sons, Ltd
• Year: 2010
• Tongue: English
• Weight: 227 KB
• Edition: 1
• Category: Article
• ISBN: 0470745150
• DOI: 10.1002/9780470710364.ch3

✦ Synopsis

Now that we have reviewed the first and second laws of thermodynamics we can start to look at some of their basic consequences. This will provide us with relationships that will be used throughout the rest of the book and that are also applicable outside the field of atmospheric physics.

In this chapter we only consider simple substances. Simple substances have only one constituent, or are accurately described as if made up of one constituent, as opposed to compound substances where variations in composition would contribute to variations in internal energy through their chemical potentials. Dry air is a good example of a simple substance: the bulk composition of dry air is constant up to great heights. Sea water would be a simple substance if we discarded any variation in the salinity. However, variation in salinity is an important driver of the ocean currents, so any approximation of sea water as a simple substance has limited applicability.

The developments in this chapter are largely of general validity. We often apply these results specifically to an ideal gas. But the more general approach will be advantageous, for example when considering the more complex situation of a vapour-dry air mixture in Chapter 5.