Climatic characteristics of the Atlantic Ocean

The Atlantic Ocean extends from north to south, and the equator passes through the middle. The climate is symmetrical from north to south, and the climate zone is complete. At the same time, influenced by ocean currents, atmospheric circulation, land and ocean contours and other factors, the climate in different sea areas is different. The equatorial belt of the Atlantic Ocean is a low-pressure area, and it is also the intersection of the north and south trade winds. The wind is weak and the direction is uncertain, so it is called windless area. At the same time, the updraft is strong, and there is a lot of convective cloud precipitation, with an annual precipitation of 2000 mm, which is a rainy area in the Atlantic Ocean. The subtropical zone is a high-pressure area, where the airflow is mainly subsiding and diverging, with less clouds and rain, sunny weather and strong evaporation. Generally, the precipitation is 500- 1000 mm, and the annual precipitation in the high-pressure center (near the Azores in the eastern ocean) is only 100-250 mm, which is much less than the evaporation. It is a dry zone in the Atlantic Ocean. The air flow sinking from the subtropical high pressure area to the equatorial low pressure area is called the trade wind area, with the northeast trade wind in the northern hemisphere and the southeast trade wind in the southern hemisphere. The trade winds have stable wind direction and strong wind force (3-4), which has become an important wind belt in the Atlantic Ocean and is the driving force for the formation and maintenance of ocean surface currents. The airflow sinking from the subtropical high to the subtropical low is called prevailing westerly belt, which is a powerful planetary wind belt in the middle and high latitudes and the driving force for the formation of west wind drift at 40-60 degrees north and south latitudes. The westerlies also often merge with cold air from the polar regions. The formation of fronts and tornadoes leads to changeable weather and more precipitation, especially in winter, which often brings snowstorms, causing strong winds and waves in high latitudes, seriously affecting shipping, offshore fisheries and oil industry production. The high latitude sea area north of 60 in the northern hemisphere (mainly in the east) is affected by warm current and cyclone, and the annual precipitation can reach about 1000 mm; In the sea area south of 60 in the southern hemisphere, due to the adjustment of dry cold air and no warm current, the precipitation is very small, generally between 100-250 mm.

The temperature distribution in the Atlantic Ocean is basically similar to that in the Pacific Ocean, extending along the latitude direction and decreasing from the equatorial region to the high latitude. The equatorial region has the highest temperature. The annual average temperature is 25-26℃, and the annual change of temperature is very small (generally not more than 3℃). Near 20 north latitude and 20 south latitude, the temperature in the hottest month is about 25℃, and that in Leng Yue is about 20℃. Near 40 north latitude, due to the influence of warm current, the temperature in the North Atlantic is higher than that in the South Atlantic, with the hottest month of 20℃, the South Atlantic is only 15℃, and Leng Yue is 13℃ and 10℃ respectively. Near 60 north latitude, the warming effect of the North Atlantic warm current is more obvious. The temperature in the hottest month is 10℃, while the temperature in the South Atlantic is 0℃, and the temperature in Leng Yue is 0℃ and-10℃ respectively, so the air in the North Atlantic is warmer than that in the South Atlantic. At the same time, due to the different effects of cold and warm air currents on the east and west coasts of the Atlantic Ocean, the temperature in the West Sea between 30 north and south latitudes is about 5℃ higher than that in the east. The temperature in the eastern part of the ocean north of latitude 30 is about 5- 10℃ higher than that in the west, while in the south of latitude 30, due to the narrowing of land and the widening of sea area, and the influence of west wind drift, the temperature difference between the eastern and western parts of the Atlantic Ocean is not obvious.

The climate in the Atlantic Ocean is very different from north to south, and there are also differences between east and west. The annual temperature is not high, which is below 1℃ in equatorial region, below 5℃ in subtropical region, below 10℃ in northern latitude and below 60℃ in southern latitude, only exceeding 25℃ in the northwest and southernmost part of the ocean. Northeastern trade winds prevail in the northern part of the Atlantic Ocean and southeast trade winds prevail in the southern part. The temperate zonal belt is located in the transition zone between cold and warm airflow and westerly belt, and the wind force is the largest. There are many storms between 40-60 degrees north and south latitude; From May to June, hurricanes often occur in the tropical areas of the northern hemisphere. The precipitation in the Atlantic Ocean is 500- 1000 mm at high latitudes, 1000- 1500 mm at mid latitudes,1000 mm from east to west in subtropical and tropical regions, and over 20000 mm in equatorial regions. The average sea surface temperature near the equator of the Atlantic Ocean is about 25-27℃, and it is colder in the east than in the west between 30 north and south latitude, but the opposite is true to the north of 30 north latitude. In the Atlantic Ocean, the summer ice floes in the southern hemisphere and the northern hemisphere can reach about 40 degrees north and south latitude respectively.

There is little change in the annual temperature in the Atlantic Ocean, and the annual temperature difference in the equatorial region is less than 65438 0℃. The subtropical zone is 5℃, the mid-latitude zone is 10℃, and only the northwest and extreme south exceed 20℃. The average temperature of seawater is 65438 07℃, which is slightly lower than that of the Pacific Ocean. However, the salinity is slightly higher than that in the Pacific Ocean, with an average of 35.4‰. In the North Atlantic, the subtropical high lies between north latitude 15-30, and the northeast trade wind lies in the south. The main westerlies lie between 40 and 60 degrees north latitude. In the South Atlantic, the tropical high pressure zone is located near 30 south latitude, and the prevailing westerly belt extends almost from 40 south latitude to Antarctica. In the Atlantic Ocean with a latitude of 5-20 from north to south, there are frequent hurricanes in July-10 every year. There is often sea fog along the coast of Newfoundland in summer; In winter, the Atlantic coast of Europe is foggy; The southwest coast of Africa is foggy all the year round. The Atlantic Ocean current forms a circulation in the north and south. The northern circulation consists of the North Equatorial Warm Current, the Gulf Warm Current and the Canary Cold Current. The southern circulation warms from the southern equator. Brazil Warm Current, west wind drift and Benjira Current. The Gulf Stream is the most powerful warm current in the Atlantic Ocean and plays an important role in regulating the climate in northwest Europe.