water cycle

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Related to water cycles: nitrogen cycle, carbon cycles

water cycle

the circulation of the earth's water, in which water evaporates from the sea into the atmosphere, where it condenses and falls as rain or snow, returning to the sea by rivers or returning to the atmosphere by evapotranspiration

Water Cycle

 

the continuous migration of water on earth (in its atmosphere, hydrosphere, and crust), accompanied by phase transitions of the water and possessing a more or less pronounced cyclical character.

The water cycle consists of the evaporation of water from the underlying surface and its transport by air currents from the evaporation site, condensation of water vapor, precipitation, and shifting of water in bodies of water over the land surface and within the earth’s crust. Most of the water evaporates from the oceans and returns to them; less is transported by air currents from the oceans to land. The transport of moisture evaporating from land to the oceans by air currents is slight. The water cycle is characterized quantitatively by the water balance.

A small cycle—sea (ocean) → atmosphere → sea (ocean)— and a large cycle—ocean → atmosphere → land — ocean—are distinguished according to the site of the evaporation and precipitation of water and the modes of its transport. Moisture repeatedly evaporates from the continents, is transported in the atmosphere, condenses, and again falls in the form of precipitation and again evaporates. This complex of processes is called the intracontinental cycle. An internal moisture cycle is characteristic of closed intermontane basins. The water cycle on the earth is part of the total complex of processes participating in the cycle of matter on the earth. (See alsoHYDROLOGIC CYCLE.)

K. G. TIKHOTSKII

water cycle

[′wȯd·ər ‚sī·kəl]
(hydrology)
References in periodicals archive ?
'The water cycle in this region ends in June and the monsoon begins in July,' the official said.
Understanding observed changes to the global water cycle is key to predicting future climate changes and their impacts.
Better management of water resources and adaptation to expected changes require reliable predictions of the water cycle. Such predictions must be grounded in the changes already observed.
We discuss how well the available observing capability can capture expected changes in the global water cycle, including the increasing water content of the atmosphere, strengthening of climatological precipitation minus evaporation (P - E) patterns, the pronounced spatial structure and sharp gradients in precipitation change, and increases of extreme precipitation.
Drawing on discussions from a workshop held at the University of Reading, United Kingdom, in June 2012, we focus on long-term large-scale changes in a few key variables that are both potentially related to climate change and are essential for diagnosing changes in the global water cycle. These include humidity, precipitation, P - E, and salinity.
We also discuss how physically consistent a picture these observations draw and conclude with recommendations to ensure continued and improved ability to document the changing water cycle. The supplement provides more information on available observational data and quality control procedures (supplemental information available online at http:// dx.doi.org/10.1175/ BAMS-D-13-00212.2).
They typically collect and/or treat water at the source and are designed to maximize efficiency by mimicking or taking advantage of natural water cycles. Decentralization has been gaining traction in low-resource regions of the world as a means of stabilizing water Intake and output, while reducing the risk of large-scale failure.
Nevertheless, huge shortages remain in many parts of the world due to the naturally uneven distribution of the water cycle (among other factors).
Because Canada has been spared the harshest impacts (so far), we are largely unprepared for major water cycle shifts.
The physical designs of these systems are founded on a set of principles--flexibility, resilience and redundancy--which act in concert to mimic the natural water cycle.
GCOM's primary goal is to better understand the state of the Earth's water cycle and climate change.