Introduction - The Global Climate System: Patterns, Processes, and Teleconnections - page 1

Chapter 1
Introduction
1.1 The climate system
Climate is a function not only of the atmosphere but is rather the response to
linkages and couplings between the atmosphere, the hydrosphere, the biosphere,
and the geosphere. Each of these realms influences any prevailing climate and
changes in any one can lead to changes in another. Figure 1.1 provides in
schematic form the major couplings between the various components of the
climate system. A climate-systems approach avoids the isolation of considering
only individual climatic or atmospheric components. This approach recognizes
the importance of forcing factors, which create changes on scales from long-
term transitional to short-term sudden, and that the climate system is highly non-
linear. According to Steffen ( 2001 ), a systems approach also recognizes the
complex interaction between components, and links between the other great
systems of the Earth, and the ways in which humans affect climate through the
socioeconomic system. Ignoring such interactions may create inaccuracies and
misinterpretations of climate system impacts at different spatial scales.
In examining any component of the Earth's atmosphere, its systems and
its couplings, basic knowledge of the energy and mass budgets is critical.
Information concerning these is given in most introductory texts (Oliver and
Hidore 2002 ; Barry and Chorley 1998 ) and they are not reiterated in detail here.
Rather, the following provides a brief summary of major concepts.
1.1.1 Energy and mass exchanges
Energy
Every object above the temperature of absolute zero 273 8C radiates energy to
its environment. It radiates energy in the form of electromagnetic waves that
travel at the speed of light. Energy transferred in the form of waves has
characteristics that depend upon wavelength, amplitude, and frequency.
The characteristics of the radiation emitted by an object vary as the fourth
power of the absolute temperature (degrees Kelvin). The hotter an object, the
greater the flow of energy from it. The Stefan-Boltzmann Law expresses this
1