Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Modeling Ocean Behavior: The Key to Understanding Our Future Climate


Scientists have long recognized the importance of oceans in our climate. In fact, the unique physical characteristics of our oceans are largely responsible for making the Earth a livable environment. Oceans are major “climate-controllers” because of their large heat capacity. For instance, it requires four times the amount of energy to raise the temperature of water by one degree than it does soil. As a result, over a long period, oceans can store and transport heat from one location to another. Furthermore, water reacts slowly to the surrounding atmosphere. While this means our oceans may exert relatively little influence in short-term weather, they have a large effect on long-term climate.

Of particular interest is the ocean’s Conveyor Belt or thermohaline circulation, since both temperature and salinity are at the root of its existence. People in the U.S. know it as part of the “Gulf Stream” that carries warm waters north along the U.S. eastern seaboard and across the north Atlantic Ocean.

It then flows south from the European side of the Atlantic, crosses the equator, joins another ocean circulation, and eventually reaches the Pacific, a trip that lasts 1000 years! At high latitudes, cold, dry air from land lowers the average temperature of the warm waters coming from the equator. Evaporation then removes water free of salt and ice formation leaves behind the salty ocean waters. These processes go to increase the ocean’s water density, forcing it to sink, leading to the formation of what is known as the North Atlantic Deep Water (NADW)..

A major player in the thermohaline circulation is a process known as “deep convection,” or DC, that mixes very efficiently warm and cold waters, affects sea ice melting and how much solar radiation is absorbed. DC forms in the Labrador Sea during winter when polar air blows from Canada, removes heat and salt from the waters, and causes it to sink and mix. It is a key feature since it represents the initial stages of the global-scale ventilation loops of the world’s oceans.Outside of the Labrador Sea, DC is confined to small portions of the Weddell and Western Mediterranean Seas.

Computer models are the tools employed by scientists to simulate present oceanic-atmospheric behavior as well as future and past climates. But, due to the limitations of today’s computers, it is not possible to explicitly represent all the important physical processes that govern the climate. Deep convection is one such process that must therefore be modeled in ocean general circulation models (OGCM).

While lab and numerical simulations have brought to light several key features of DC, the translation of this information into a reliable model usable in OGCMs has not yet been achieved, with the result that Deep Convection is still poorly understood.

Dr. Vittorio M. Canuto, a senior scientist at NASA’s Goddard Institute for Space Studies (GISS) and Columbia University’s department of applied physics in New York, has recently focused on how well DC is represented, or modeled, in OGCMs. In a research paper, “Modeling Ocean Deep Convection,” published in the April 2004 issue of Ocean Modelling, Canuto and several colleagues assessed the accuracy of several well-known mixing models widely used by the scientific community to represent DC in the Labrador Sea. They compared the model predictions with data on Labrador DC that has recently become available.

Canuto and colleagues examined three specific mixing models. They foundthat while their NASA-GISS mixing model simulated the observed DC data more faithfully than the other models, it still suffered from problems. For example, it overestimated the depth of DC. Canuto and collaborators are presently trying to determine how the inclusion of rotation may improve the model’s performance.

This study is particularly timely since in recent years, considerable concern has been expressed about the fragility of the thermohaline circulation to climate change. Increased greenhouse gases would add fresh water to our oceans by melting glaciers. Increased rainfall at high latitudes, as predicted by OGCMs, would further lower ocean’s salinity, inhibiting water from sinking. The net result would be a slow-down of the NADW, depriving much of Europe and eastern North America of warmth. The Younger Dryas, a period of ice-age-like conditions characterized by a partial collapse of the Conveyor Belt around 11,000 years ago, is believed to have been initiated in this manner.

Whether or not human-induced greenhouse gases will affect the thermohalinecirculation is strongly dependent on the future temperature distributionand fresh water supply over the North Atlantic. Most models predictan increase in precipitation in high latitudes and some warming over the North Atlantic within the next 70 years, assuming a doubling of carbon dioxide. However, the extent of projected weakening of the thermohaline circulation varies considerably among the models, with some even indicating little to no change. The details and long-term effect - more than 100 years - of such changes to the ocean circulation have only been explored by a few studies.

"While it is unlikely that climate change will lead to a collapse of thethermohaline circulation, it is possible that DC in the Labrador Sea mightbe severely affected," said Canuto. "Such an event would have a significantimpact on the climate in Europe," he added.

One thing is for certain: the climate system is extremely complex, and many questions remain. Current computer climate models offer a "best guess" as to how scientists believe different climate processes interact. Since scientists do not know exactly how human industry, including transportation and agriculture, will change over the next 100 years, the uncertainty associated with computer climate models will not be much reduced even if today’s climate models were perfect.

Other changes to our oceans, spawned by climate change, may also have a considerable impact on human populations. "If we recall that nearly 100 million people live within one meter of the mean sea level, we can easily understand the societal and economic impacts of a rising sea," said Canuto. "One of the most immediate consequences will be a huge migration of people in the tens of millions, a phenomenon that will seriously burden the host nations."

Inevitably, the discussion turns back to the influence of human behavior. A few scientists believe that the changes we are seeing, such as those in theArctic, are consistent with large, slow natural cycles in the oceans. But many scientists believe there is a greater human component that is also impacting climate. The one overwhelming question is how significant greenhouse gases are against the backdrop of larger climate changes, and how ’self-correcting’ the Earth system will be to these changes. Scientists hope that improved climate and ocean models will provide clearer answers to such questions in the near future.

Rob Gutro | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht New technologies and computing power to help strengthen population data
22.03.2018 | University of Southampton

nachricht New interactive map shows climate change everywhere in world
22.03.2018 | University of Cincinnati

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Modular safety concept increases flexibility in plant conversion

22.03.2018 | Trade Fair News

New interactive map shows climate change everywhere in world

22.03.2018 | Earth Sciences

New technologies and computing power to help strengthen population data

22.03.2018 | Earth Sciences

Science & Research
Overview of more VideoLinks >>>