The natural circulation of water near the surface of the Earth is shown by the graph above.

1 The hydrological cycle are considered as beginning with the direct effect of the sun’s radiation on this reservoir.

The heating of the sea surface and the movement of the sea water is called evaporation.

2 The water vapor changes back to liquid state again through the process of condensation to form cloud.?

3 With the certain atmospheric condition , Precipitation occurs to return directly to the ocean. Some of the precipitation may return to the ocean through land surface.

4 When rainfall reach the ground , the water may form the surface runoff and infiltrate into ground.

5 The groundwater and the surface runoff flow may join together in surface stream and rivers and finally flow into the ocean.