Components and phenomena in the climate system

In this section, we introduce some examples of phenomena within the major components of the climate system and some of the ways they interact. In attempting to understand this complex system it is useful to introduce the notion of characteristic time and space scales of a phenomenon. One of the fundamental difficulties faced by climate models is that a huge range of scales turns out to be important. The examples here set the stage for later discussion of how this range of scales affects climate models.

Figure 2.1 summarizes some of main features of the climate system. A common way of listing the components of the climate system is: the atmosphere, the ocean, land surfaces, the cryosphere, the biosphere and the lithosphere. The cryosphere consists of land ice (including ice shelves and glaciers), snow and sea ice. The biosphere, the sum total of all living things on the planet, is obviously spread throughout the oceans and land surfaces. Indeed when considering land surfaces as a climate component, a leading effect is the vegetation type. The lithosphere, i.e. the “solid” Earth, creates the distribution of ocean basins, mountain ranges etc., not to mention the occasional volcanic eruption. Chemical composition can be viewed as a component of the climate system as well. One could view the chemical composition to be an additional set of variables associated with each of the other climate system components, but chemical interactions relevant for climate often involve interactions across these traditional boundaries.