Solar energy is the fundamental driving force of the water cycle, leading to a three-state change in water. Evaporation is one of the most important aspects of the water cycle. Water vapor from evaporation enters the atmosphere and moves with atmospheric activity. Atmospheric water vapor comes mainly from the oceans and partly from evaporation from continental surfaces. The cycle of water vapor in the atmosphere is a cycle of evaporation - condensation - precipitation - evaporation.
The main role of the water cycle
① water is the medium of all nutrients, nutrient cycling and water cycle inextricably linked together;
② water is a good solvent for substances, in the ecosystem plays the role of energy transfer and utilization;
③ water is one of the driving forces of geologic change, the loss of mineral elements of a place, and the deposition of mineral elements in another place. The loss of mineral elements in one place and the deposition of mineral elements in another place is often accomplished through the water cycle.
The geographical significance of the water cycle
1, water in the water cycle, a huge system of constant movement, transformation, so that water resources are constantly renewed (the so-called renewal, to a certain extent, decided that water is a renewable resource).
2. The water cycle maintains the dynamic balance of global water.
3. The water cycle carries out energy exchange and material transfer. Land runoff to the ocean constantly transport sediment, organic matter and salts; on the surface of the solar radiation absorption, transformation, transmission, alleviate the contradiction between different latitudes between the heat balance imbalance, for the regulation of the climate is of great significance.
4, causing erosion, handling, accumulation and other external forces, constantly shaping the surface morphology.
5, the water cycle can have an impact on the quality of the soil.