Brief introduction to the change and distribution of precipitation

The introduction and answer about the change and distribution of precipitation are as follows:

Introduce precipitation.

Precipitation refers to the condensation of water vapor from the atmosphere on the ground. Natural phenomena such as rain, snow, dew, frost, graupel and hail all belong to the category of precipitation. It is the product of the comprehensive influence of geographical location, atmospheric circulation, weather system conditions and other factors. It is the most basic link in the water cycle and the basic parameter in the water balance equation.

Precipitation is the general name of rain, snow, dew, frost, graupel, hail and other phenomena that occur in nature. Precipitation is the source of surface runoff and the main source of groundwater recharge. The uneven spatial distribution of precipitation and the instability of time change are the direct causes of floods and droughts. Urbanization is an important factor affecting precipitation.

2. Precipitation formation

Precipitation is the phenomenon that water in the cloud falls to the ground in liquid or solid form, including rain, snow, sleet, rice snow, frost, hail, ice particles, ice needles and so on. There are three conditions for precipitation: there must be enough water vapor; Raising the air block, cooling and condensing; There should be more condensation nuclei.

When a large amount of warm and humid air is continuously input into the rain area, if there is a mechanism that makes the ground air rise strongly, such as a rainstorm weather system, the warm and humid air will rise rapidly, and the rising air will be cooled due to the internal energy consumed by expansion work. When the temperature is lower than the dew point, water vapor will condense into larger and larger cloud droplets, which will increase the condensation, merger and collision, and increase mutual attraction, resulting in precipitation when the updraft cannot float. Warm and humid air on the ground → lifting and cooling → condensing into a large number of cloud drops → falling into rain.

Artificial precipitation is a necessary condition to artificially supplement some precipitation according to the principle of natural precipitation formation. Promote the rapid condensation of cloud droplets, collide with other cloud droplets, and increase precipitation. For different clouds, different catalytic methods are needed.

3. Precipitation type

According to different physical characteristics, precipitation can be divided into liquid precipitation and solid precipitation. Liquid precipitation includes rain, rainstorm, thunderstorm, freezing rain and showers in Mao Mao. Solid precipitation includes snow, hail and graupel. And liquid-solid mixed precipitation such as sleet.

Liquid water falling to the ground is called rain, which is divided into: continuous precipitation, long time and medium scale; Array precipitation, short time and high strength; The rain in Mao Mao is like a cow's hair. According to its intensity, it can be divided into light rain, moderate rain, heavy rain, heavy rain, heavy rain, heavy rain and so on. And can be distinguished by precipitation.