How does La Ni a cause flooding? And it can cause a drought??

This involves ocean currents, there is a kind of ocean current in the waters around Cuba off the coast of Central and South America in the Pacific Ocean, which is the alternating movement of cold water in Haiti and warm water on the sea surface, because the sea water over there has a periodic movement, that is, when the water temperature of the seabed drops sharply and causes it to rise, it affects the original circulation, which just meets the warm current at the equator. Therefore, this cold water follows the equatorial circulation movement all the way to the east coast of Australia, so it has a serious impact on the local climate, and precipitation is the biggest factor, which is also called the reverse El Niño phenomenon.

Because the La Niña phenomenon will lead to high SST and strong subtropical high and northerly rain belt in the western tropical Pacific, the phenomenon of drought in the south and flooding in the north and cold winter in China will be formed.

La Niña is a condition in which the waters of the central and eastern Pacific Ocean become abnormally cold. The southeast trade winds blow the sun-scorched sea water to the western part of the Pacific Ocean, causing the sea level in the west to rise by nearly 60 centimeters compared with the eastern one, and the sea temperature in the west increases, the air pressure drops, and the moist air accumulates to form typhoons and tropical storms, and the bottom sea water in the east rises, causing the sea water in the eastern Pacific Ocean to become colder.

La Niña often alternates with El Niño, but occurs less frequently than El Niño. When the La Niña phenomenon occurs, China is prone to cold winters and hot summers, and the number of tropical cyclones that make landfall in China is more than normal, and the phenomenon of "drought in the south and flooding in the north" occurs. Indonesia, eastern Australia, northeastern Brazil and other places have more rainfall; The equatorial regions of Africa and the southeastern United States are prone to drought.

La Niña is a condition in which the waters of the central and eastern Pacific Ocean become abnormally cold. The southeast trade winds blow the sun-scorched sea water to the western part of the Pacific Ocean, causing the sea level in the west to rise by nearly 60 centimeters compared with the eastern one, and the sea temperature in the west increases, the air pressure drops, and the moist air accumulates to form typhoons and tropical storms, and the bottom sea water in the east rises, causing the sea water in the eastern Pacific Ocean to become colder.

La Niña is the opposite of El Niño, and with the disappearance of El Niño and the arrival of La Niña, weather and climate disasters in many parts of the world will also shift. Overall, La Niña is not very mild, and its climate impact is roughly opposite to that of El Niño, which is less intense and less severe than El Niño, but its arrival could also bring disaster to many parts of the world.

The above information reference: Encyclopedia-La Niña.

1. The movement of the ocean surface is mainly controlled by the sea surface wind. The presence of trade winds causes a large amount of warm water to be blown into the western equatorial Pacific, where the warm water is blown away and is mainly replenished by cold water below the sea surface, and the sea surface temperature in the eastern equatorial Pacific is significantly lower than that in the western Pacific.

When the trade winds strengthen, the upward upside of the deep sea water in the eastern equatorial Pacific Ocean becomes more intense, resulting in abnormally low sea surface temperatures, which causes the airflow to sink in the eastern equatorial Pacific Ocean, and the upward movement of the airflow in the western part of the country is more intensified, which is conducive to the strengthening of the trade winds, which further exacerbates the development of cold water in the eastern equatorial Pacific Ocean, causing the so-called La Niña phenomenon.

Impact: Impacts on the east and west shores of the Pacific Ocean near the equator: The east coast is drier and the west coast is wetter, which is prone to flooding. Impact on the global climate: Causes climate anomalies. Impact on China's climate: Relative to the impact of El Niño.

2. When the earth's rotation decelerates, the "brake effect" causes the atmosphere and sea water in the equatorial belt to gain an eastward inertia, the equatorial ocean current and trade winds weaken, the warm water of the western Pacific Ocean flows eastward, and the cold water of the eastern Pacific Ocean is blocked, and the El Niño phenomenon of sea water warming and sea level elevation occurs due to the accumulation of warm water.

Impact: The most certain impact is that an El Niño event results in significantly higher global precipitation than normal years. As a result, frequent floods in the central and eastern Pacific and Pacific coastal countries in South America, as well as severe droughts in India, Indonesia and Australia, will affect many crops in the world.

When La Niña occurs, it should be that the western United States should be more prone to drought.

The impact of El Niño on the climate is usually contrary to the usual climatic characteristics of a place;

La Niña is the opposite of El Niño, and its occurrence does not distort the climatic characteristics of a region, but on the contrary, it strengthens the climatic characteristics of the region, i.e., arid areas are drier and humid areas are wetter. Specifically, when La Niña occurs, places such as Peru, Ecuador, the equatorial Pacific, the western United States, and equatorial Africa are prone to drought.

a. Distillation is the purification of water through the operation of condensation after evaporation, and the water obtained after distillation is pure water, which has the highest degree of purification in the operation of purified water; therefore a is correct;

b. Activated carbon has adsorption and can remove pigments and odors in water; Therefore b is correct;

c. Soapy water needs to be used to distinguish between hard water and soft water, soft water is rich in foam, and salt water cannot achieve the purpose of distinguishing hard water from soft water; Therefore c is incorrect;

d. One water for multiple purposes can make full use of water resources and achieve the purpose of water conservation; Therefore d is correct, so choose c