Terrestrial Hydrometeorology and the Global Water Cycle - Terrestrial Hydrometeorology - page 13

Hydrosphere :
— Extent and importance : Oceans cover ~70% of the Earth and the solar
energy they intercept is mainly used to evaporate water vapor into the
atmosphere; they have a large thermal capacity and act as 'memory' in the
Earth system that influences season climate.
— Structure : Oceans have a surface layer 10s-100s m deep warmed by the
Sun's energy in which there are wind-driven ocean currents, this layer
being separated by a strong thermal gradient from the deep ocean which
moves very slowly in response to changes in temperature and salinity.
— Currents : Upper ocean currents move heat from the tropics to polar
regions: ocean flow is east to west in the tropics, poleward on the eastern
side of continents, then back toward the equator on the western side of
continents.

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Cryosphere : comprises the polar ice fields and glaciers that change slowly
and transient continental snow/ice fields with a strong seasonal influence on
climate.

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Lithosphere : organized topography perpendicular to atmospheric flow can
inhibit penetration of maritime air into continents, and aerosols from volca-
noes can alter the radiation balance over extensive areas.

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Biosphere : vegetation cover affects aerodynamic roughness and reflection of
solar energy and by intercepting rainfall and accessing water in the soil
through roots, also whether precipitation leaves as evaporation or runoff.

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Anthroposphere : human population is now large enough to influence cli-
mate, mainly by changing the concentrations of gases in the atmosphere and
by modifying land cover over large areas.

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References

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Sellers, P.J., Mintz, Y., Sud, Y.C. & Dalcher, A. (1986) A simple biosphere model (SiB) for use
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