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Chapter 27
interactions between terrestrial surfaces and the atmosphere, in particular
through the exchange of biogeochemicals, including trace gases such as
carbon dioxide and methane
the productivity of the different ecosystems
the state and dynamics of land cover/land use.
The energy and water fluxes are determined by the biophysics of the
surface, the carbon and nitrogen fluxes are controlled by its biochemistry.
The interrelations are shown in Figure 1.
In summary, without entering into the requirements of all land-related
applications, it is possible to identify a set of basic land features and
characteristics, which must represent the focus of attention in a space
observation strategy for the next decade. They are related to:
surface characteristics and conditions (type and condition of land cover,
terrain characteristics, soil, surface – and subsurface water, and changes
in those conditions, including environmental degradation and pollution);
surface processes such as primary productivity, biochemical cycles,
energy and matter interactions (e.g., evapotranspiration, radiation
balance).
Knowledge of the surface/atmospheric exchange processes for trace
gases, together with the exchange processes for energy and water, are
determining factors for furthering our understanding and the modeling of
ecosystems. The links between the biospheric interactions in the time
domain are displayed in Figure 2.