What are the main aspects of the ocean's influence on climate?

The ocean is an important link in the global climate system. It plays a decisive role in regulating and stabilizing the climate by exchanging energy and materials with the atmosphere and water cycle, and is called the "regulator" of the earth's climate. The ocean, which accounts for 7 1% of the earth's area, is the main provider of atmospheric heat. If the global surface seawater with a thickness of 100 m cools 1 celsius, the released heat can warm the global atmosphere by 60 celsius. The ocean is also the main source of water vapor in the atmosphere. When seawater evaporates, it will bring a lot of water vapor from the ocean into the atmosphere. The evaporation of the ocean accounts for about 84% of the total evaporation, and 3.6 trillion cubic meters of water can be converted into steam every year. Therefore, the thermal state and evaporation of the ocean directly affect the content and distribution of heat and water vapor in the atmosphere. At the same time, the ocean absorbs 40% of carbon dioxide in the atmosphere, which is considered as one of the greenhouse gases that cause climate change.

On the other hand, climate change has also had a great impact on the ocean. Rising temperature leads to rising sea level and seawater temperature, and excessive absorption of carbon dioxide by the ocean leads to acidification of seawater, which has caused damage to marine and coastal ecosystems and is considered to be the root of a series of problems such as coral bleaching, death and island flooding. Take Indonesia as an example. The Minister of Ocean Affairs and Fisheries said that many islands in Indonesia will sink into the sea in the coming decades due to rising sea levels. The environmentalist Ovi of the University of Queensland in Australia also published a report saying that if we don't act immediately, the coral reefs on the earth will all disappear by the end of this century. In addition, climate change has also changed the marine climate patterns and ocean currents, thus increasing the degree of marine disasters. In particular, the backward flow of seawater after acidification will have a great impact on estuaries, estuaries and other ecosystems after entering the land.

Marine climate is the most basic climate type on the earth. The general feature is that it is less influenced by the mainland and more influenced by the ocean. Under the condition of maritime climate, the annual and daily variations of temperature are relatively gentle, and the daily variation of annual variation is smaller than that of continental climate. The temperature in spring is lower than in autumn. The annual maximum and minimum temperatures appear later than continental climate; The hottest month is in August and the hottest month in Leng Yue is in February.

The main factors affecting marine climate are solar radiation, marine environment and atmospheric circulation. Solar radiation is the main energy source of seawater and atmospheric warming, and it is the basic driving force of many physical processes in the atmosphere. Sea surface is the underlying surface of the lower atmosphere. Seawater has high specific heat and low solar radiation reflectivity. In addition, the ocean is vast and bulky, so it has become a huge reservoir of heat and water on the earth. About half of the solar radiation energy reaching the earth's surface is absorbed and stored by seawater, and then seawater transfers heat to the atmosphere in the form of long-wave radiation, latent heat and sensible heat, which promotes atmospheric movement. The ocean provides a lot of water to the atmosphere in the water cycle. Environmental factors such as land and sea distribution, cold and warm air flow affect the heat balance, water balance and atmospheric circulation, resulting in climate differences in different sea areas. Atmospheric circulation can promote the exchange of heat and water between north and south or between east and west, so that the climate is not only restricted by the nearby marine environment, but also affected by other non-marine environments.

The climate formed by the action of huge water bodies in the ocean. Including the ocean surface or island and the climate of the offshore part of the mainland where the main airflow comes from the ocean. The maritime climate has the following characteristics: ① The annual and diurnal variations of temperature are very small, and even the diurnal variations are not observed on the ocean surface. The annual extreme value is generally 1 month later than that of Chinese mainland, such as February in Leng Yue and August in the warmest month. At high latitudes, Leng Yue may be in March and the hottest month may be in September. Autumn is warmer than spring. (2) The seasonal distribution of precipitation is relatively uniform, with more precipitation days but less intensity. Cloudy weather and high humidity. (3) There are many tropical ocean storms, such as the southwest of the North Pacific and the South China Sea of China, where typhoons have a strong influence. Tropical storm is a very important meteorological disaster. Most of the mainland areas near the ocean have maritime climate characteristics, and the coastal areas of western Europe are typical maritime climate areas on the mainland.

Trade (trade)

(Wind) In the lower atmosphere on both sides of the equator, northeast wind blows in the northern hemisphere and southeast wind blows in the southern hemisphere. The direction of these winds rarely changes. They appear like this year after year, which is very trustworthy. This is trade.

Wind is translated into Chinese "trade wind".

The formation of trade winds is related to the earth's circulation. Under the long-term irradiation of the sun, the equator is heated to the greatest extent, and the air near the equator is heated, forming an equatorial low pressure area near the ground and a relative high pressure at high altitude. The upper-air high pressure moves to the south-north low pressure direction, and due to the influence of geostrophic deflection, it deflects to 30 degrees north-south latitude parallel to the isobar, where the atmosphere accumulates and is forced to sink, forming a subtropical high pressure area near the surface. At this time, there is a pressure difference between the equatorial low pressure area and the subtropical high pressure area, and the airflow flows from the subtropical high pressure area to the equatorial low pressure area. Under the influence of geostrophic bias, when the air in the subtropical high in the northern hemisphere moves southward, the air moves to the right of the pressure gradient force, forming the northeast wind, that is, the northeast trade wind. On the contrary, the southern hemisphere forms the southeast trade wind.

Monsoon is a wind system prevailing in a wide range due to the temperature difference between the mainland and the adjacent ocean, and the wind direction changes significantly with the seasons. The wind with this characteristic of atmospheric circulation is called monsoon.

Monsoon is a large-scale convection phenomenon with a period of one year, which is caused by land and sea distribution, atmospheric circulation, continental topography and other factors. Asia is the most famous monsoon region in the world, and its monsoon characteristics are mainly manifested in the existence of two main monsoon circulations, namely, the northeast monsoon prevailing in winter and the southwest monsoon prevailing in summer, and their transformation has an explosive mutation process with a short transition period. Generally speaking, 1 1 is the winter monsoon period, June-September is the summer monsoon period, and April-May and 10 are the transition periods between summer monsoon and winter monsoon. However, the seasonal differences in different regions are different, so the division of monsoon is not completely consistent. Monsoon is a widely prevailing wind system, and the wind direction changes significantly with the seasons. Like the wind belt, it belongs to the planetary circulation system, and its formation is caused by the temperature difference between the ocean and the land in winter and summer. Summer monsoon blows from the ocean to the mainland, and winter monsoon blows from the mainland to the ocean.

Monsoon is formed by the difference between the sun's heating of the ocean and the land. In summer, the ocean has a large heat capacity, slow heating, cold sea surface and high air pressure, while the mainland has a small heat capacity, fast heating and low temperature, so the summer monsoon blows from the cold ocean surface to the warm continent. In winter, on the other hand, the winter wind blows from the cold continent to the warm ocean surface.

Southwest wind blows in summer and northeast wind blows in winter. This is because when the air flow crosses the equator from the southern hemisphere to the northern hemisphere in summer, due to the rotation effect of the earth, the air flow will be subjected to an inertial force to the right, which is the geostrophic bias force (Coriolis force). Due to the geostrophic bias, the airflow deviates to the right in the process of moving northward, forming a southwest wind. In addition, influenced by the topography of the Qinghai-Tibet Plateau and other factors, the East Asian monsoon is more complicated than that of South Asia.

The horizontal range of sea-land breeze can reach tens of kilometers, the vertical height can reach 1 ~ 2 kilometers, and the cycle is one day and night. During the day, the surface of the earth is heated by solar radiation. Because the heat capacity of land soil is much less than that of sea water, and the temperature on land is much faster than that on the ocean, the temperature on land is obviously higher than that on the nearby ocean. The air column on the land expands due to heating, so the sea breeze starts every morning until the evening, and the wind is strongest in the afternoon. After sunset, the land cools faster than the ocean; At night, when the sea water temperature is higher than the land temperature, there will be a thermal circulation opposite to that during the day, resulting in the formation of low-level land wind and land wind circulation on the vertical section. During the day, the temperature difference between land and sea is greater than at night, so the sea breeze is greater than the land breeze. If the sea breeze is forced to rise along the hillside, it often produces clouds. In larger lakes, lake-land wind similar to sea-land wind circulation can also be generated at the junction of lake and land. Sea breeze and lake breeze have the effect of cooling off summer heat for coastal residents. On the big island, the sea breeze gathers on the island during the day and the land breeze diverges from the island at night. So the island is rainy during the day and sunny at night. For example, in Hainan Island, China, the biggest precipitation intensity in a day occurs in the afternoon when the sea breeze is the biggest.

Typhoon (hurricane) is a tropical cyclone formed on the vast sea surface with tropical or subtropical sea surface temperature above 26℃. According to the definition of the World Meteorological Organization, tropical cyclone centers with sustained wind speeds of 12 to 13 (that is, 32.7 meters to 4 1.4 meters per second) are called typhoons or hurricanes, and the name of hurricanes is used in the North Atlantic and the East Pacific. The western part of the North Pacific (north of the equator, west of the international international date line, east of east longitude 100 degrees) is called a typhoon. In summer and autumn, many violent storms called typhoons will be generated in the northwest Pacific Ocean adjacent to China. Some of these storms will dissipate in the ocean, while others will land and bring storms.

Tropical cyclone (tropical)

Cyclone is a low-pressure vortex that occurs on the surface of tropical or subtropical oceans, and it is a powerful and profound tropical weather system. Like a vortex moving forward in a flowing river, it rotates around its center and moves forward with the surrounding atmosphere. In the tropical cyclone in the northern hemisphere, the airflow rotates counterclockwise around the center, but in the southern hemisphere, it is the opposite. This situation is mainly affected by the Coriolis force generated by the earth's rotation.

The life history of tropical cyclones can be divided into three stages: generation, maturity and extinction. Its average life span is about a week, the shortest is only 2-3 days, and the longest is about a month. The generation and development of tropical cyclones need huge energy, so they are formed on the tropical ocean surface with suitable meteorological conditions such as high temperature and high humidity. According to statistics, tropical cyclones are generated in tropical oceans all over the world except the southeast Pacific Ocean.

There are at least two conditions for the formation of typhoon: 1 and relatively high temperature.

2. Sufficient water. When boiling water, the water at the bottom of the pot will rise, because the water at the bottom of the pot will expand when heated. So is the air. When the air at the bottom is heated, it will rise. In areas with high temperature, some disturbed air in the atmosphere will rise, which will reduce the ground pressure. At this time, the air outside the rising area will continue to flow into the rising area, and the inflow of air will rotate like a wheel because of the rotation of the earth, which is one of the reasons for the typhoon. After the rising air expands and cools, the water vapor in it cools and condenses into water droplets, releasing heat, which in turn promotes the rise of low-level air, makes the ground pressure drop lower, and the air rotates more violently, thus forming a typhoon.

Where are these two conditions simultaneously? Only on the surface of tropical oceans. The sea surface temperature there is very high, so that the lower air can fully accept the water on the sea surface. It is also the place with the richest water vapor on the earth, which is the main driving force for the formation and development of typhoons. Without this motivation, typhoons will dissipate even if they form. Secondly, it is close to the equator, and the deflection force generated by the earth's rotation plays a certain role, which is conducive to the development of cyclone circulation and the strengthening of airflow convergence. Third, the latitude is simple in the case of tropical ocean surface. Therefore, the air over the same sea area can often remain stable for a long time, so that typhoons have enough time to accumulate energy and brew a wind. Under this condition, typhoons will form and strengthen in some tropical marine areas as long as there is a suitable trigger mechanism, such as divergent airflow in the upper air or the encounter of trade winds in the northern and southern hemispheres slightly north of the equator. According to statistics, in tropical oceans, typhoons often occur in areas where the sea surface temperature exceeds 26 or 7 degrees. Mainly distributed in the ocean east of the Philippines, the South China Sea, the West Indies and the east coast of Australia. The seawater temperature in these places is relatively high, and it is also the place where the trade winds in the northern and southern hemispheres meet, so more than 20 typhoons are often born in a year.

Ocean current, also known as ocean current, refers to the large-scale and relatively stable flow of surface seawater in a certain direction all the year round. Ocean current is the main regulator of the thermal environment on the earth's surface, and the huge ocean current system promotes the energy exchange in high and low latitudes of the earth. The environmental characteristics between ocean currents and the areas they pass through are also changed through energy exchange. The ocean current around the subtropical high becomes the subtropical circulation. The center of circulation is about 25~30 degrees north and south latitude. Near the equator, the northeast trade winds and the southeast trade winds work together to form an equatorial airflow flowing from east to west, separating the equatorial airflow in the northern and southern hemispheres.

Ocean currents can be divided into warm currents and cold currents. If the water temperature of ocean current is higher than the water temperature reaching the sea area, it is called warm current; If the water temperature of the ocean current is lower than the water temperature reaching the sea area, it is called a cold current. Generally, the ocean current from low latitude to high latitude is warm current, and the ocean current from high latitude to low latitude is cold current. Sailing along ocean currents can save fuel and speed up. When cold and warm air currents meet, sea fog often forms, which is not conducive to maritime navigation. In addition, ocean currents carry icebergs south from the Arctic, posing a great threat to maritime shipping.

Since 1970s, global abnormal weather has the characteristics of wide range, heavy disasters and long time. In this series of abnormal weather, scientists have discovered the El Nino phenomenon, which is one of the important phenomena in the ocean and atmospheric system.

Nino) "Trends play an important role." "el Nino" is a transliteration of Spanish, El is a masculine definite article, and Nino originally means "prodigy" or "son of a wise man". According to legend, long ago, ancient Indians living along the coast of Peru and Ecuador paid great attention to the relationship between the ocean and the weather. They found that if the sea around Christmas is warmer than usual, it will rain heavily soon, accompanied by strange phenomena such as seabirds migrating in groups. Out of superstition, ancient Indians called this unusually warm trend "prodigy" trend, that is, "El Nino" trend.

El Nino warm current is an abnormal natural phenomenon in the Pacific Ocean, and it is a famous Peruvian cold current flowing from south to north on the west coast of South America and the eastern part of the South Pacific. Every June 1 1 to March of the following year is the summer in the southern hemisphere. The water temperature in the southern hemisphere generally rises, and the equatorial warm current flowing eastward strengthens. At this time, the global pressure belt and wind belt move south, and the northeast trade wind passes through the equator and is deflected to the left by the self-deflection force (also called rotational deflection force) in the southern hemisphere to enter the northwest monsoon. The northwest monsoon not only weakens the southeast trade wind, which is near the west coast of Peru, but also weakens or even disappears the cold water flooding of Peru's cold current. It also blows the equatorial warm current with higher water temperature to the south, which makes the water temperature of Peru's cold current abnormally rise. This quiet and unstable ocean current is called "El Nino Warm Current".

La Nina means "La" in Spanish.

The transliteration of Nia ",La is a negative definite article, Nia means little girl and saint, which is also called" anti-El Nino "or" cold event "as opposed to El Nino phenomenon. It refers to the abnormal drop of water temperature in the eastern Pacific near the equator, which is characterized by obvious cooling in the eastern Pacific, accompanied by global climate chaos, and always appears after the El Ni? o phenomenon.

China has a long coastline, vast territorial waters and numerous

Islands, in order to develop marine fishing and aquaculture, develop marine resources, develop maritime trade, and defend the coast of the motherland, we should vigorously develop marine research, develop islands, increase island meteorological observation points, establish telemetry meteorological stations, and do a good job in military and civilian meteorological services.