Sunday , February 28 2021

Ocean circulation that has been the weakest in the North Atlantic for 1,500 years and can trigger an Ice Age



The researchers' water in the North Atlantic has dramatically weakened & # 39; they discovered it.

The study shows that levels are at the lowest levels for 1,500 years and that climate change is responsible.

The researchers warn that currents will have a "deep impact" on both North American and European climate.

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The weakening ocean: This is a scheme of circulation in the western North Atlantic during the strong (left) and weak (right) west of the Labradorian Current (LC). The oceanography of this region is characterized by the interaction of the water bodies formed in the Labrador and the interactions of water bodies moving eastward (LC and Labrador Sea Tilt Water (LSSW)) and Gulf Stream (GS) and the Atlantic Temperate Tilt. Water (ATSW). The place where these two water mass systems come together (yellow dashed lines) is then determined by the force of the north recirculation grease (white arrows) that control the temperature.

The weakening ocean: This is a scheme of circulation in the western North Atlantic during the strong (left) and weak (right) west of the Labradorian Current (LC). The oceanography of this region is characterized by the interaction of the water bodies formed in the Labrador and the interactions of water bodies moving eastward (LC and Labrador Sea Tilt Water (LSSW)) and Gulf Stream (GS) and the Atlantic Temperate Tilt. Water (ATSW). The place where these two water mass systems come together (yellow dashed lines) is then determined by the force of the north recirculation grease (white arrows) that control the temperature.

The weakening ocean: This is a scheme of circulation in the western North Atlantic during the strong (left) and weak (right) west of the Labradorian Current (LC). The oceanography of this region is characterized by the interaction of the water bodies formed in the Labrador and the interactions of water bodies moving eastward (LC and Labrador Sea Tilt Water (LSSW)) and Gulf Stream (GS) and the Atlantic Temperate Tilt. Water (ATSW). The place where these two water mass systems come together (yellow dashed lines) is then determined by the force of the north recirculation grease (white arrows) that control the temperature.

WHY ARE OCEAN DAYS IMPORTANT?

Ocean currents play a critical role in regulating the planet.

Slower circulation in the North Atlantic, North American and European climate as well as African and Asian summer monsoon precipitation can also create a great change.

The transfer of this heat and energy not only has a direct impact on the climate in Europe and North America, but it can also affect the African and Asian monsoon system with its impact on sea surface temperature, hydrological cycle, atmospheric circulation, and variation in the intertropical convergence region.

The researchers brought the North Pole Patrol (AMOC), the arm of the North Atlantic movement, to the North Pole with hot surface water and cold water towards the equator.

Research, Dr. Christelle Not and Benoit Thibodeau from the World Sciences Department and the Swire Institute from the Institute of Marine Sciences at the University of Hong Kong are interpreted as a direct result of the global warming and the related melting of the Greenland Ice Mold.

Slower circulation in the North Atlantic, North American and European climate as well as African and Asian summer monsoon precipitation can also create a great change.

Lar AMOC plays a very important role in regulating the global climate, but scientists find it difficult to find reliable indicators of their intensity in the past.

Dr. I The discovery of this new AMOC record will enhance our understanding of drivers and ultimately help us better understand the future potential for global warming,, said Thibodeau.

The research team also found a weak signal at a time called the Small Ice Age (a cold spell observed between 1600 and 1850 AD).

WHAT IS SMALL ICE AGE?

The reconstructed depth of the Small Ice Age varies between different studies.

The reconstructed depth of the Small Ice Age varies between different studies.

The reconstructed depth of the Small Ice Age varies between different studies.

The Little Ice Age occurred between 1300 and 1850.

The Little Ice Age had two stages, first started in 1290 and continued until the end of the 1400s.

In the 1500s, there was a slightly warmer period, then in the cold periods between 1645 and 1715 the climate was significantly deteriorated.

In this coldest period of the Little Ice Age, there are indications that the average winter temperatures in Europe and North America have fallen to 2 ° C at present.

The Baltic Sea froze like most of the rivers and lakes in Europe.

Frozen Thames, 1677, The original picture in the collection of the Museum of London

Frozen Thames, 1677, The original picture in the collection of the Museum of London

Frozen Thames, 1677, The original picture in the collection of the Museum of London

The winters were bitterly cold and summers were generally cool and wet.

These conditions have led to widespread crop failure, famine and population decline.

There were social unrest, which increased because of the reduction of large sections of the population to hunger and poverty.

Although not as clear as the tendency of the 20th century, this period can also confirm that there is a weaker movement in the North Atlantic, which means a decline in heat transfer towards Europe and contributes to the cold temperature of this period.

However, further studies are needed to confirm this hypothesis.

"20. It is not possible to do temperature reconstruction for instrumental measurements.

& # 39; Therefore, we need to do more analysis to reinforce this hypothesis & # 39; dedi Dr. Note.

The findings have recently been published in prestigious geophysical research letters.

The Atlantic Meridian Rollover Cycle (AMOC) is a branch of the North Atlantic circulation, bringing the cold surface water towards the Arctic region and cold deep water towards the equator.

The transfer of this heat and energy not only has a direct impact on the climate in Europe and North America, but it can also affect the African and Asian monsoon system with its impact on sea surface temperature, hydrological cycle, atmospheric circulation, and variation in the intertropical convergence region.

Dr. Not and Thibodeau used microfossils called foraminifers in a precipitate nucleus to estimate the past temperature of the ocean. Foraminifer type used in illustration

Dr. Not and Thibodeau used microfossils called foraminifers in a precipitate nucleus to estimate the past temperature of the ocean. Foraminifer type used in illustration

Dr. Not and Thibodeau used microfossils called foraminifers in a precipitate nucleus to estimate the past temperature of the ocean. Foraminifer type used in illustration

Many climate models have predicted the weakening or even collapse of this branch of circulation under global warming, partly due to the release of fresh water from Greenland Ice Plate.

This fresh water has a lower density than the salty water and thus prevents the formation of deep water by slowing down the entire circulation.

However, this slimming is still strongly debated due to the lack of AMOC's long-term record.

Dr. Not and Thibodeau used microfossils called foraminifers in a precipitate nucleus to estimate the past temperature of the ocean.

The sediment core used is the Laurentian Channel, where two major currents meet on the shore of Canada.

The strength of these streams will control the temperature of the water in the corrosion zone, indicating that the re-generated temperature from this center is indicative of the strength of the North Atlantic circulation.

With their collaborators in the United States, they confirmed their results using instrumental data and two numerical models that could simulate the climate and the ocean.


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