Main Characteristics of Atlantic Climate

The main characteristics of the Atlantic climate: the Atlantic Ocean extends from north to south, and the equator runs through the middle. The north-south climate symmetry and complete climate zones are obvious features. At the same time, affected by factors such as ocean currents, atmospheric circulation, and the contours of sea and land, the climate in each sea area is different. The Atlantic equatorial zone is a low pressure zone and the convergence zone of the north and south trade winds. The wind is weak and the wind direction is uncertain, which is called the windless zone. At the same time, the updrafts are strong and there are many convective cloud systems with precipitation. The annual precipitation is as much as 2000 mm, making it a rainy belt in the Atlantic Ocean. The subtropical zone is a high-pressure zone with mainly sinking and divergent airflow. There are few clouds and rain, sunny weather and strong evaporation. The general precipitation is 500-1000 mm. The annual precipitation in the high pressure center (near the Azores Islands in the eastern ocean) is only 100-250 mm, which is much less than the evaporation, making it a dry zone in the Atlantic Ocean. The airflow that sinks from the subtropical high pressure belt to the equatorial low pressure belt is called the trade wind belt as the northeast trade wind in the northern hemisphere and the southeast trade wind in the southern hemisphere. The trade wind has a stable wind direction and strong wind (level 3-4). It 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 air flow from the subtropical high pressure to the subpolar low pressure zone is called the prevailing westerly belt. It is a powerful planetary wind belt in the middle and high latitudes, and is also the driving force behind the westerly drifts between 40° and 60° north and south latitudes. The westerlies often meet with cold air from the polar regions. Fronts and cyclones are formed, resulting in changeable weather and heavy precipitation, especially in winter, which often brings blizzards, causing strong winds and huge waves in high-latitude sea areas, 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 currents and cyclones, and the annual precipitation can reach about 1000 mm; while the sea area south of 60° in the Southern Hemisphere has very little precipitation due to dry and cold air and no warm current adjustment. Generally between 100-250 mm.

The temperature distribution in the Atlantic Ocean is basically similar to that in the Pacific Ocean. It extends along the latitude direction and decreases from the equatorial region to high latitudes, with the highest temperature in the equatorial region. The average annual temperature is 25-26°C, with a small annual temperature variation (generally no more than 3°C). Near 20° north and south latitude, the temperature in the hottest month reaches about 25°C, and the coldest month is about 20°C. Near 40° north and south latitude, the temperature in the North Atlantic is higher than that of the South Atlantic due to the influence of warm currents. The hottest month is 20°C, while the South Atlantic is only 15°C. The coldest months are 13°C and 10°C respectively. Near 60° north and south latitude, the warming effect of the warm current in the North Atlantic is more obvious. The temperature in the hottest month reaches 10℃, while in the South Atlantic it is 0℃ and the coldest month is 0℃ and -10℃ respectively. Therefore, the temperature in the North Atlantic is warm. in the South Atlantic. At the same time, the east and west coasts of the Atlantic Ocean are affected by cold and warm currents, causing the temperature in the western part of the ocean between 30° north and south latitude to be about 5°C higher than that in the east. The temperature in the eastern part of the ocean north of 30° north latitude is about 5-10°C higher than that in the west. However, south of 30° south latitude, due to the narrowing of the land and the wideness of the sea and the influence of westerly drift, the temperature difference between the eastern and western parts of the Atlantic is not obvious.

The climate of the Atlantic Ocean is very different between the north and the south, and there are also differences between the east and west sides. The annual temperature range is small, less than 1°C in the equatorial region, 5°C in the subtropical latitudes, 10°C in the north and 60° south latitudes, and only exceeds 25°C in the northwest and extreme south of the ocean. The northeast trade wind prevails in the northern part of the Atlantic Ocean, and the southeast trade wind prevails in the south. Temperate latitudes are located in the transition zone between cold and warm currents and in the westerly belt. The winds are strongest between 40-60° north and south latitudes and there are many storms; in the tropical latitudes of the northern hemisphere, hurricanes are common from May to October. The precipitation in the Atlantic region is 500-1000 mm in high latitudes, 1000-1500 mm in most mid-latitudes, more than 100-1000 mm in subtropical and tropical latitudes from east to west, and more than 2000 mm in the equatorial region. The average water surface temperature of the Atlantic Ocean is about 25-27°C near the equator. The east is cooler than the west between 30° north and south latitude, and the opposite is true north of 30° north latitude. Within the Atlantic Ocean, summer ice floes in the southern and northern hemispheres can reach approximately 40° south and north latitude respectively.

The temperature in the Atlantic Ocean does not change much throughout the year, and the annual temperature difference in the equatorial region is less than 1°C. 5℃ in the subtropics, 10℃ in the mid-latitudes, and only exceeds 20℃ in the northwest and extreme south. The average seawater temperature is 17°C, slightly lower than the Pacific Ocean. The salinity is slightly higher than that of the Pacific Ocean, with an average of 35.4‰. In the North Atlantic, between 15° and 30° north latitude is the subtropical high pressure belt, and to the south is the northeast trade wind belt. The prevailing westerly wind zone is between 40° and 60° north latitude. In the South Atlantic, the tropical high pressure belt is located near 30° south latitude, and the prevailing westerly belt extends from 40° south latitude almost to Antarctica. On the Atlantic Ocean at latitudes 5°-20° north and south, there are many hurricanes from July to October every year. Sea fog is common along the coast of Newfoundland in summer; sea fog is common along the Atlantic coast of Europe in winter; and the southwest coast of Africa is foggy all year round. The Atlantic Ocean currents form a gyre in the north and south. The northern circulation consists of the North Equatorial Warm Current, the Gulf Stream, and the Canary Cold Current. The southern circulation consists of the South Equatorial Warm Current. The Gulf Stream composed of the Brazilian Current, the Westerly Drift, and the Benguela Current is the strongest warm current in the Atlantic Ocean and plays a significant role in regulating the climate in northwest Europe.