This book gives a comprehensive presentation of our present
understanding of the Earth's Hydrological cycle and the problems,
consequences and impacts that go with this topic. Water is a central
component in the Earth's system. It is indispensable for life on Earth
in its present form and influences virtually every aspect of our
planet's life support system. On relatively short time scales,
atmospheric water vapor interacts with the atmospheric circulation and
is crucial in forming the Earth's climate zones. Water vapor is the most
powerful of the greenhouse gases and serves to enhance the tropospheric
temperature. The dominant part of available water on Earth resides in
the oceans. Parts are locked up in the land ice on Greenland and
Antarctica and a smaller part is estimated to exist as groundwater. If
all the ice over the land and all the glaciers were to melt, the sea
level would rise by some 80 m. In comparison, the total amount of water
vapor in the atmosphere is small; it amounts to 25 kg/m2, or
the equivalent of 25 mm water for each column of air. Yet atmospheric
water vapor is crucial for the Earth's energy balance. The book gives an
up to date presentation of the present knowledge.
Previously published in Surveys in Geophysics, Volume 35, No. 3, 2014