Studies on the Earth's climate dynamics essentially cover phenomena that occur in the atmosphere, at the most different altitudes and proportions. In addition to the atmosphere, the climate system involves transformations related to ice and snow, plant formations, the land surface and the oceans. As the Earth is mainly formed by oceanic mass, which is equivalent to approximately 2/3 of the planet, the transformations in the seas and oceans have a major impact on the distribution of heat and moisture across the globe.
Even if we consider factors external to the climate system, such as changes in the planet's orbit, the strength of the sun's rays and the energy coming from the Earth's inner layers (such as volcanoes), the oceans are among the main agents acting in climate dynamics. Comparing the role of the oceans with that of the atmosphere, we must remember that the oceans are limited by portions. and therefore the heat transported by the oceans is established more specifically in certain regions.
sea currentsrepresent the movement of the waters of seas and oceans, they can be cold or hot. Cold currents lower temperatures, cause drought due to lower evaporation and also contribute to the attraction of shoals, due to the higher concentration of phytoplankton. Warm currents promote heating and evaporation of water, contributing to the formation of wet masses. The Warm Gulf Stream (Gulf Stream) is one of the great heat and humidity distribution systems due to the reach of its effects to the North Atlantic.
Formation of Currents
Winds, atmospheric pressure and the sun's heat are the primary sources that move ocean currents. According to analyzes carried out by the Swedish oceanographer Vagn Walfrid Ekman, in the beginning of the 20th century, the water movement is forced by large scale winds that produce a pattern of movement across the water. world. Through a simple observation of the displacement of icebergs in the Arctic region, Ekman found that in the Northern Hemisphere the waters move to the right, taking the direction of the winds. In the Southern Hemisphere, the waters move to the left.
In fact, surface waters have, in principle, a displacement in the same direction as the winds. Over time, the Earth's rotation shifts particles to the right (Northern Hemisphere) and to the left (Southern Hemisphere) as a result of the Coriolis effect. O Coriolis effect produces a clockwise spiral movement in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. The standards established by Ekman's analyzes became known as Ekman's spiral, one of the most important mechanisms that make up ocean circulation.
The Gulf Stream
Even before the colonization of North America, the first explorers knew the effects of Gulf Stream, which was first documented by Spanish conqueror Ponce De Leon in 1513. The navigator found during a voyage across the Atlantic Ocean that the vessels were pushed back by a current that was stronger than the winds. This knowledge was widely disseminated and used for the navigation routes of the Atlantic.
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THE gulf stream it is about 80 km wide. It originates in the Gulf of Mexico and extends towards the United Kingdom, near Scotland. It has a warmer upper layer that moves to the North, providing heat to the atmosphere, in a total path of approximately 6,750 km, then heading south at a depth of 2-3 km below the sea surface, in the deep waters of the North Atlantic.
The initial flow of water from the Gulf Stream is 23.8 °C off the coast of Florida. For this reason, the current has an immense capacity to intensify hurricanes and tropical storms, which gain strength when passing over warmer waters. The Southern and Southeastern regions of the United States are constantly hit by these storms. tropical, as they are located exactly on the route of the most powerful hurricanes and at the beginning of the path of the current.
The contact of cold, moist air that moves over the Cold Labrador Current - further north of the coast of the United States - with the warm surface waters of the Gulf Stream causing condensation widespread. This climatic condition means that the region has one of the highest levels of fog in the world. In Europe, the Gulf Stream contributes to the maintenance of mild winter temperatures, especially in the UK and Scandinavia. Changes in the climate in England caused by warming waters help to develop subtropical vegetation and with greater diversity in the southwest region. The Norwegian Sea can be navigable throughout the winter, with intense port activity. The coast of the eastern portion of Sweden, for example, does not receive the heat of the Gulf Stream and has some of its ports closed during the winter.
The heat that is given off by the heated water causes the climate in the eastern border regions of the North Atlantic to remain warmer than at similar latitudes elsewhere. If we compare some locations in Europe with locations at similar latitudes on the North American continent, the effect becomes quite evident. Bodo, Norway, has an average temperature of -2°C in January and 14°C in July. On the Pacific and Alaska coasts, at the same latitude, there is a cold of -15°C in January and only 10°C in July.
Julio César Lázaro da Silva
Brazil School Collaborator
Graduated in Geography from Universidade Estadual Paulista - UNESP
Master in Human Geography from Universidade Estadual Paulista - UNESP
