Water in the biosphere

Reservoir Volume (103 km3) Part of total volume (%) Regeneration time 

An important block of the MBWB is the methods of determination of various parameters of the water cycle. Such methods are based on the use of surface, satellite, and airborne measurements. The MBWB used as a global model makes it easier to understand the role of the oceans and land in the hydrological cycle, to identify the main factors that control it, as well as to trace the dynamics of its interaction with plants, soil, and topographic characteristics of the Earth surface. It is based on the interaction between the elements of the water cycle, and takes natural and anthropogenic factors into account by means of information interfaces with other units of the global model (Krapivin and Kondratyev, 2002). 

Let us consider a block scheme of global water exchange and write respective equations for it. The basic regularity of global water exchange is the invariability of water supplies on Earth over time periods of hundreds of years (i.e., we can reliably write the balance equation WE -f Ws I W0, where WE, Ws, and WQ are water supplies on Earth, on land and in the oceans, respectively). A compartment of the atmosphere is related to the respective region of water basin. Such a relationship is valid 

With water supply in the atmosphere WA = WAO + WAS, we obtain W/, = WA + lVst + W01, where WAO and WAS are water supplies in the atmosphere over the oceans and land, respectively Wsl = Ws — WAS and Wai = Wa — WAO, The balance equation will be  

As can be seen, the structure of trends in the ratios of water supplies is complicated and to analyze it additional considerations are needed. This complication becomes considerable as we further subdivide the biosphere. 

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