Scales of processes and observations

Scales are more applicable to processes in the spatial and temporal domains than to those in the spectral domain. For a number of important Earth system processes, their corresponding scales are roughly indicated in Figure 1, which has logarithmic X- and Y-axes in order to accommodate the large ranges to be considered in the spatial and temporal domains. In the spatial domain this goes from 1 mm to 40,000 km (the circumference of the Earth), and in the temporal domain from one second to a century.

Spatial and temporal scales can not only be attached to processes, but also to observations. An example is given in Table 1, which summarizes the spatial and temporal scales of a few well-known Earth observation systems.