The Hydrological Cycle theme is a component of Encyclopedia of Water Sciences, Engineering and Technology Resources in the global Encyclopedia of Life Support Systems (EOLSS), which is an integrated compendium of twenty one Encyclopedias.
The Hydrological Cycle is a process of constant water exchange or water circulation in the hydrosphere, i.e. in the system of the atmosphere - Earth's surface – soil cover - upper lithosphere (to a depth of 2000 m). Water in the hydrosphere is liquid, solid or gaseous; during the hydrological cycle it moves under the effect of heat energy, gravitation and capillary forces, converting from a liquid to its solid state or gas, and back. The hydrological cycle is one of the major geophysical processes on the planet providing relative stability of natural conditions and continuous distribution of water between ocean, land and atmosphere. The content of the Theme on The Hydrological Cycle is organized with state-of-the-art presentations covering several topics: Exchanges of Water in the Hydrosphere; Hydrosphere Components; World Water Balance; evaporation; Precipitation; Surface Water Runoff; Groundwater Hydrogeology; Glaciers and Their Significance for the Earth Nature, which are then expanded into multiple subtopics, each as a chapter. These four volumes are aimed at the following five major target audiences: University and College students Educators, Professional practitioners, Research personnel and Policy analysts, Managers, and Decision makers and NGOs
Igor Alexeevich Shiklomanov was born on 28 February 1939. In 1961 he graduated from the Leningrad Hydrometeorological Institute (Hydrological Faculty). Since 1961 to the present time he has been working at the State Hydrological Institute in St. Petersburg (Russia) in different appointments. Since 1981 he has been the director of the State Hydrological Institute. In 1967 Igor Shiklomanov defended his thesis for a candidate’s degree and in 1975 a thesis for a doctor’s degree on the specialty “Hydrology and Water Resources”. Since 1985 he has been a professor of “Water Resources”. Since 1991 he has been a Corresponding Member and, since 2000, Academician of the Russian Academy of Natural Sciences with the specialty”Hydrology”. His scientific interests include water resources, water balance, water use, the global hydrological cycle, effects of human activity and anthropogenic climate change on water resources and hydrological regime.
He has published about 200 scientific papers, including 9 monographs.
He has made a notable contribution to international cooperation within the framework of UNESCO, WMO, IAHS, and IPCC. During 1992-1994 he was Chairman of the Inter-Governmental Council for the IHP (UNESCO). Since 1992 to the present he is a member of the Advisory Working Group, Commission of Hydrology WMO, and since 2000 he has been Chairman of the Working Group on Water Resources for the Commission of Hydrology (WMO).