The water on the surface of the earth. Some 74% of the earth’s surface is covered with water, 97% (or some 1.3×1021 kilograms) of which is in the oceans. Icecaps and glaciers contain about 2.6×1019 kg, rivers about 1015 kg, lakes and inland seas about 2×1017 kg, and groundwater (down to 4000 metres) about 1.5×1019 kg. Water in the atmosphere contains only about 1.3×1016 kg.
Geology and Earth Sciences
The whole of that body of water which exists on or close to the surface of the Earth. The hydrosphere formed as the Earth cooled and atmospheric water condensed.
Geography
All the water on, or close to, the surface of the Earth. Some 97% of this water is in the Earth’s seas and oceans; of the rest, about 75% is in ice-caps and sheets, about 25% in surface drainage and groundwater, and about 0.03% in the atmosphere.