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The ocean component of the global water cycle
Author(s) -
Schmitt Raymond W.
Publication year - 1995
Publication title -
reviews of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.087
H-Index - 156
eISSN - 1944-9208
pISSN - 8755-1209
DOI - 10.1029/95rg00184
Subject(s) - water cycle , precipitation , environmental science , ocean current , annual cycle , atmosphere (unit) , evaporation , oceanography , water mass , climatology , geology , meteorology , geography , ecology , biology
The distribution of evaporation and precipitation over the ocean (its hydrologic cycle) is one of the least understood elements of the climate system. However, it is now considered one of the most important, especially for ocean circulation changes on decadal to millennial time‐scales. The ocean covers 70% of the Earth's surface and contains nearly all (97%) of its free water, thus, it plays a dominant role in the global water cycle. The atmosphere only holds a few centimeters of liquid water, or 0.001% of the total. However, most discussions of the water cycle focus on the rather small component associated with terrestrial processes [Chahine, 1992]. This is understandable, since the water cycle is so vital to agriculture and all of man's activities. Yet current estimates indicate that 86% of global evaporation and 78% of global precipitation occurs over the oceans [ Baumgartner and Reichel , 1975]; (Figure 1 ). Since the oceans are the source of most rainwater, it behooves us to work toward a better understanding of the ocean hydrologic cycle; small changes in ocean evaporation and precipitation patterns may have dramatic consequences for the much smaller terrestrial water cycle. For example, if less than 1% of the rain falling on the Atlantic Ocean were to be concentrated in the central US, it would double the discharge of the Mississippi river!