The Global Water Cycle

Which processes shown in this figure involve the phase transition H20(/)- H20(g)  

AU the water on Earth is connected in a global water cj cle ( FIGURE 18.15). Most of the processes depicted here rely on the phase changes of water. For in.stance, warmed by the Sun, liquid water in the oceans evaporates into the atmosphere as water vapor and condenses into liquid water droplets that we see as clouds. Water droplets in the clouds can crystallize to ice, which can precipitate as hail or snow. Once on the ground, the hail or snow melts to liquid water, which soaks into the ground. If conditions are right, it is also possible for ice on the ground to sublime to water vapor in the atmosphere. 

The vast layer of salty water that covers so much of the planet is in actuality one large connected body and is generally constant in composition. For this reason, oceanographers speak of a world ocean rather than of the separate oceans we learn about in geography books. 

Seawater is often referred to as saline water. The salinity of seawater is the mass in grams of dry salts present in 1 kg of seawater. In the world ocean, salinity averages about 35. To put it another way, seawater contains about 3.5% dissolved salts by mass. The list of elements present in seawater is very long. Most, however, are present only in very low concentrations. T TABLE 18.5 lists the 11 ionic species most abundant in seawater. 

TABLE 18.5 Ionic Constituents of Seawater Present in Concentrations Greater Than 0.001 g/kg (1 ppm) 

Look at the trend in density as a function of depth does it mirror the trend in salinity or in temperature  

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E. K. Berner and R. A. Berner, The Global Water Cycle Geochemistry and Environment Prentice-HaH, Inc., Englewood Cliffs, N.J., 1987. 

To this point, direct human impacts on the hydrosphere have remained restricted to the regional scale. Although they can still be important, particularly in terms of water supply, these direct manipulations of the hydrologic cycle are unlikely to affect the global water balance significantly. However, this is not to suggest that the global water cycle is immune to human influence its close ties to other physical and... 

Berner, E. K. and Berner, R. A. (1987). "The Global Water Cycle." Prentice-Hall, Englewood Cliffs, New Jersey. 

Sabater S (2008) Alterations of the global water cycle and their effects on river structure, function and services. Ereshw Rev 1 75-88... 

Berner EK, Berner RA (1987) The global water cycle Geochemistiy and environment. Prentince-Hall, New Jersey... 

The presence of water as solid, liquid, and gas is a feature that makes Earth unique in the solar system and that makes life possible as we know it. The transport of water and the energy exchanged as it is converted from one state to another are important drivers in our weather and climate. One of the key missions is to develop a better understanding of the global water cycle at a variety of scales so that we can improve model forecasts of climate trends,... 

ABSTRACT The locations, magnitudes, variations and mechanisms responsible for the atmospheric C02 sink are uncertain and under debate. Previous studies concentrated mainly on oceans, and soil and terrestrial vegetation as sinks. Here, we show that there is an important C02 sink in carbonate dissolution, the global water cycle and photosynthetic uptake of DIC by aquatic ecosystems. The sink constitutes up to 0.82 Pg C/a 0.24 Pg C/a is delivered to oceans via rivers and 0.22 Pg C/a by meteoric precipitation, 0.12 Pg C/a is returned to the atmosphere, and 0.23 Pg C/a is stored in the continental aquatic ecosystem. The net sink could be as much as 0.70 Pg C/a, may increase with intensification of the global water cycle, increase in C02 and carbonate dust in atmosphere, reforestation/afforestation, and with fertilization of aquatic ecosystems. Under the projection of global warming for the year 2100, it is estimated that this C02 sink may increase by 22%, or about 0.18 Pg c/a. 

Previous studies addressed oceans and terrestrial vegetation as C02 sinks. Here, we describe an important C02 sink in carbonate dissolution, the global water cycle (GWC), and uptake of dissolved inorganic carbon (DIC) by aquatic. The sink is larger than previous estimates (Meybeck 1993 Gombert 2002). 

Fig. 1. The global water cycle and its C02 sinks (italic numbers, in Pg C/a water fluxes from Shiklomanov 1993).

Huntington, T. G. 2006. Evidence for intensification of the global water cycle Review and synthesis. Journal of Hydrology, 319, 83-95. 

Liu, Z., et al. 2008. A possible important C02 sink by the global water cycle. Chinese Science Bulletin, 53, 402-407. 

Hydrological cycle The global water cycle involving the transport of this substance between the atmosphere, hydrosphere, and lithosphere. 

As the world s water towers, mountains will continue to play an essential role in meeting increased demands for food, drinking water, energy supplies, and industrial production in the twenty-first century. Thanks to their specific climatic and hydro-logical characteristics, mountains play a key role in the global water cycle. Water... 

Land-atmosphere exchange processes include the evaporation of soil moisture, from the leaf surface, stems, and trunks of plants, as well as transpiration, precipitation, and evaporation olf the surface of unstable water accumulations low in the ground (Figure 4.11). The water flow from the soil through the plant is the least studied link in this chain. The importance of the process of transpiration in the global water cycle cam be judged from available estimates, according to which the process of... 

The atmospheric processes of moisture transport that are directly connected with the temporal variations of meteorological elements, play an important role in the global water cycle. Global atmospheric circulation can be described by the Monin model (Monin and Krasnitsky, 1985) ... 

Numerical model of global water balance 4.6.4.1 Modeling the global water cycle... 

Within the MBWB, small corrections for the water exchange between the Earth and space are not taken into account. A model of the global water cycle can be based on describing the hydrology of comparatively large territories. In this case the basic unit of such a territory is compartment Qy of the Earth surface of size Aby latitude and AXj by longitude. 

In what way is the control of interactions between the global water cycle and other cycles (carbon, energy, etc.) accomplished by feedback processes and how do these processes change over time ... 

Let us discuss the education aspect of the global water cycle in two steps first the extended list of potential topics, and then how these topics can be integrated into water and man science museums (section 18.4.2), local exhibitions (section 18.4.3), teaching at schools (section 18.4.4), and teaching at universities (section 14.4.5). The topics are by and large elucidated in the present book. 

List of key topics of the global water cycle. Water—the unique fluid... 

Such institutions are a must in major cities, and it will be most interesting to see how diverse they can be. The wide topic of the global water cycle and the close relation of man to water provide a master outline for a specific type of geological science museum. 

At the kindergarten and primary school class level the active water cycle is a suitable topic, along with simple measures by which we can save water. In middle school classes the man and water topic may be developed and visits to neighboring natural water assets as well as coverage of the water supply issues are appropriate. At the high school level the global water cycle can be tackled, and mini research projects are suitable. A list of examples may be drawn from section 18.4.1. 

Oki, T., 1999. The global water cycle. Chapter 1.2, Global Energy and Water Cycles, Eds. K. Browning and R Gurney, Cambridge University Press, pp. 10-27. 

Eecuyer C., Gillet P., and Robert F. (1998) The hydrogen isotope composition of seawater and the global water cycle. Chem. Geol. 45, 249-261. 

Berner, K.B. Berner, R.A. (1987) The Global Water Cycle. Prentice Hall, Englewood Cliffc, NJ. 

Figure 8.9 Average pH of annua) precipitation in the northeastern United States and adjacent Canada in 1955 to 1956 and 1972 to 1973, and for the contiguous United States and Canada in 1980. From E. K. Berner and R. A. Berner. The global water cycle, geochemistry and environment. Copyright 1987. Used by permission of Prentice Hall, Inc, Upper Saddle River, NJ.

Berner, E. K., and R. A. Berner. 1987. The global water cycle, geochemistry and environment. Englewood CliflFs, NJ (Yentice-Hall, Inc. 

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