Briefly describe the process and characteristics of the global water cycle.

Water cycle

The process of repeated movement of water on earth in the form of evaporation, precipitation and runoff under the influence of solar radiation and gravity is also called water cycle and hydrological cycle. The water cycle is one of the most important and active material cycles in the geographic environment.

Water cycle process The three-state transformation characteristics of water (solid, liquid, gas) are the internal causes of the water cycle, while solar radiation and gravity are the external causes or driving forces of this process. The sun radiates a large amount of thermal energy into space. About 23% of the total heat reaching the Earth is consumed by the evaporation of water from the surface of oceans and land masses. Each year, an average of 5,000 cubic kilometers of water enters the atmosphere through evaporation. , and returns to the oceanand on the earth thanks to precipitation. The water cycle process generally includes four links: ① Evaporation, which refers to the evaporation of water from ocean and land surfaces by solar radiation, and is emitted from the surface of plants in steam of water and becomes part of the atmosphere; vapor transport, which refers to the movement of water vapor from an area with air flow. Being transported to another area, or from low altitude to high altitude ③ Condensation precipitation, refers to water vapor entering the atmosphere which condenses under appropriate conditions; and falls under the action of gravity in the form of rain, snow, hail, etc. ; ④ Runoff, refers to During the falling process, part of the precipitation evaporates and returns to the atmosphere, while the other part is intercepted by plants, infiltrated, filled and retained on the ground. Heforms surface runoff, surface flow and subsurface runoff through different channels and merges into rivers, lakes and seas.

Types of water cycles include the greater water cycle and the lesser water cycle. ① The great circulation of water, that is to say the circulation between the sea and the land. Water vapor evaporated from the ocean is carried to the continent by air currents, condenses and falls to the surface as precipitation. Some of it seeps into the ground and is transformed into groundwater; part of it evaporates into the sky; the remaining water flows to the surface to form rivers and is injected into the ocean. ② Small moisture cycle, that is, the vertical exchange process between precipitation and evaporation in the ocean or continent. These include two local processes of the water cycle: the small marine circulation (internal circulation of the sea) and the smalle land circulation (internal circulation).

Velocity of water circulation The total amount of water participating in the water cycle on earth each year is approximately 5,000 cubic kilometers (equivalent to a water depth of 1,130 mm). The total amount of water in the troposphere of the atmosphere is approximately 129,000 cubic kilometers (equivalent to a water depth of 25 mm). This water is replaced by evaporation and precipitation on average about 45 times per year, i.e. the renewal period is about 8 days. The river flow update period is approximately 16 days. Swamps and lakes have longer cycle renewal periods, 5 and 17 years, respectively. Other water bodies have longer renewal periods: 1,400 years for deep groundwater, 25 years for the ocean, and 9,700 years for polar glaciers. It can be seen that the speed of circulation of different bodies of watervaries considerably.

(Selected from “Middle School Encyclopedia Geography Volume” edited by Cao Qi)

Can I use natural forces to establish an infinite water circulation system on the surface of Earth ?

Due to the self-cleaning ability of water, the water on earth will not expire because the water on earth has undergone a water cycle and the organisms present in water we also maintain the water. Cleanliness is also me. This is why we say that “water has the ability to clean itself”.

We know that there are many organisms in water, which can be roughly divided into three categories based on their types: producers, consumers, and decomposers. Producers are mostly plants that produce energy through photosynthesis. Most consumers are animals that cannot produce energy themselves and needto obtain energy from the outside world. Decomposers, mainly microorganisms, break down organic matter into simple inorganic matter.

In addition to the self-cleaning capacity of water, water also participates in the water cycle. Water on earth evaporates all the time. After evaporation, water vapor is lighter and rises to high altitude. When enough water vapor accumulates in the sky, the water vapor condenses with dust, particles, etc. to form small water droplets. Although these small water droplets fall downward, their diameter is small enough, they evaporate again along the way. down. Only small water droplets of larger diameter will drip onto the ground and form rain.

In addition to the atmospheric water cycle, "Nature" magazine also reported that the water cycle also takes place ininterior of the earth. There is a trench near Japan that is currently the deepest known trench in the world: the Great Marigana Trench. The Marigana Trench is located at the subduction limit, where seawater penetrates the interior of the earth. According to statistics, hundreds of millions of tons of seawater are swallowed into the earth's interior every year. But this swallowed seawater will also flow to the surface during the volcanic eruption, thus completing the water cycle.

In fact, the drinking water in the bottle also comes from water from rivers and lakes, but this water is "raw water" and must go through a series of processes such as precipitation, impurity removal, disinfection and filtration to clean impurities from raw water. It is tested to meet human drinking water standards beforeto be poured into bottles. Compared to rivers, lakes and seas, the water contained in the bottle is a closed system. Only certain microorganisms can survive in this system, which also means that they have no natural enemies and can reproduce in large numbers. Although the bottle is sealed and stored, the microorganisms are very small and many microorganisms reproduce asexually. The reproduction time is relatively short and can multiply from one microorganism to thousands of microorganisms in just 6 hours. As a result, over time, the number of microorganisms in the bottle will increase significantly and it will no longer be suitable for human consumption. Therefore, mineral water or purified water generally has a shelf life.

What everyone said is not entirely correct. In fact, the great circulation between maritime routes is a s“infinite” water circulation system. The energy for the water cycle comes from the sun. When the sun is present, the water cycle continues. Of course, when the sun disappears, the water cycle stops. As the Sun still has 6 billion years to live, we can consider the water cycle on Earth to be “infinite”.

I don't know if LZ is satisfied with this explanation