 |
|
Catastrophic 'lake burst' chills climate
June 30, 2006Ocean circulation changes during the present warm interglacial were more extensive than previously thought, according to new research by the University of East Anglia (UEA) and Cardiff University.
The findings, reported in this week's edition of the international journal Science (30 June 2006), prove for the first time that sudden North American 'lake bursts' slowed ocean circulation and cooled the climate approximately 8200 years ago. The groundbreaking research increases our understanding of the complex link between ocean circulation and climate change and highlights the sensitivity of the Atlantic overturning circulation to freshwater forcing.
Christopher Ellison and Dr Mark Chapman, of UEA's School of Environmental Sciences, and Dr Ian Hall, of Cardiff University's School of Earth, Ocean and Planetary Sciences, investigated whether there was a connection between the catastrophic freshwater release from glacial lakes in North America, ocean circulation changes and the dramatic cooling seen in many climate records approximately 8200 years ago. The research team studied a sediment core taken from the seabed of the North Atlantic.
"The core contains sediments representing the warm interval since the last Ice Age," said Christopher Ellison of the University of East Anglia. "The sediment includes a variety of small animals called foraminifera that record surface water conditions in their shells when living. We analysed changes in the abundance of different species of foraminifera and the chemistry of the shells to examine past patterns of climate change. We also analysed the sediment grain size to gauge the speed of deep ocean currents and therefore the strength of ocean circulation."
The new findings provide direct evidence of both the freshwater forcing and the climate response.
"The 8200-year-old event is the most recent abrupt climate change event and by far the most extreme cooling episode in the last 10,000 years, but up until now we knew comparatively little about its impact, if any, on the ocean circulation," said Dr Mark Chapman of the University of East Anglia. "Our records show a sequenced pattern of freshening and cooling of the North Atlantic sea surface and an associated change in the deep ocean circulation, all key factors that are involved in controlling the state of northern hemisphere climate."
Dr Ian Hall of Cardiff University said: "The impact of large-scale pulsed inputs of freshwater on ocean circulation and climate during the time of the last Ice Age are well documented, but our results clearly demonstrate that these sorts of abrupt reorganisations also can occur during periods of warm climate. These findings have important implications for future research because they aid our understanding of the magnitude of forcing involved in rapid climate changes and the mechanisms involved. This provides a useful target for assessing the models that are used to predict future patterns of climate change".
University of East Anglia
"The core contains sediments representing the warm interval since the last Ice Age," said Christopher Ellison of the University of East Anglia. "The sediment includes a variety of small animals called foraminifera that record surface water conditions in their shells when living. We analysed changes in the abundance of different species of foraminifera and the chemistry of the shells to examine past patterns of climate change. We also analysed the sediment grain size to gauge the speed of deep ocean currents and therefore the strength of ocean circulation."
The new findings provide direct evidence of both the freshwater forcing and the climate response.
"The 8200-year-old event is the most recent abrupt climate change event and by far the most extreme cooling episode in the last 10,000 years, but up until now we knew comparatively little about its impact, if any, on the ocean circulation," said Dr Mark Chapman of the University of East Anglia. "Our records show a sequenced pattern of freshening and cooling of the North Atlantic sea surface and an associated change in the deep ocean circulation, all key factors that are involved in controlling the state of northern hemisphere climate."
Dr Ian Hall of Cardiff University said: "The impact of large-scale pulsed inputs of freshwater on ocean circulation and climate during the time of the last Ice Age are well documented, but our results clearly demonstrate that these sorts of abrupt reorganisations also can occur during periods of warm climate. These findings have important implications for future research because they aid our understanding of the magnitude of forcing involved in rapid climate changes and the mechanisms involved. This provides a useful target for assessing the models that are used to predict future patterns of climate change".
University of East Anglia
Ocean Circulation Current Events and Ocean Circulation News RSSAquatic creatures mix ocean water
Understanding mixing in the ocean is of fundamental importance to modeling climate change or predicting the effects of an El Niño on our weather. Modern ocean models primarily incorporate the effects of winds and tides. However, they do not generally take into account the mixing generated by swimming animals.
Oceans' uptake of manmade carbon may be slowing
The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air.
Iron controls patterns of nitrogen fixation in the Atlantic
Scientists including researchers from the National Oceanography Centre, Southampton and the University of Essex have discovered that interactions between iron supply, transported through the atmosphere from deserts, and large-scale oceanic circulation control the availability of a crucial nutrient, nitrogen, in the Atlantic.
Soil moisture and ocean salinity satellite ready for launch
A new European Earth observation satellite will be launched in the early hours of Monday morning (2 November 2009) from the Plesetsk Cosmodrome in northern Russia.
Final look at ESA's SMOS and Proba-2 satellites
As preparations for the launch of SMOS and Proba-2 continue on schedule, the engineers and technicians at the Russian launch site say goodbye as both satellites are encapsulated within the half-shells of the Rockot fairing.
Key new ingredient in climate model refines global predictions
For the first time, climate scientists from across the country have successfully incorporated the nitrogen cycle into global simulations for climate change, questioning previous assumptions regarding carbon feedback and potentially helping to refine model forecasts about global warming.
Arctic Sea ice extent is third lowest on record
U.S. satellite measurements show Arctic sea ice extent in 2009 - the area of the Arctic Ocean covered by floating ice - was the third lowest since satellite measurements were first made in 1979.
Satellites and submarines give the skinny on sea ice thickness
This summer, a group of scientists and students - as well as a Canadian senator, a writer, and a filmmaker - set out from Resolute Bay, Canada, on the icebreaker Louis S. St-Laurent.
Researchers link jellyfish, other small sea creatures to large-scale ocean mixing
The ocean's smallest swimming animals, such as jellyfish, can have a huge impact on large-scale ocean mixing, researchers have discovered.
Scientists report first remote, underwater detection of harmful algae, toxins
Scientists at NOAA's National Centers for Coastal Ocean Science and the Monterey Bay Aquarium Research Institute (MBARI) have successfully conducted the first remote detection of a harmful algal species and its toxin below the ocean's surface.
More Ocean Circulation Current Events and Ocean Circulation News Articles
 |
Ocean Circulation, Second Edition by Open University (Author) This second edition retains the general structure of the first edition, but has been updated in the light of recent oceanographic research, and improved as a teaching text on the basis of feedback from past students and other readers. Notable additions include new sections addressing the topic of numerical modelling, and more discussion of natural oscillations in the ocean-atmosphere system (previously confined to the El Niño phenomenon). In particular, the Chapter on the North Atlantic now includes a discussion of the North Atlantic Oscillation, as well as of the Great Salinity Anomaly. In the final Chapter, treatment of water mass formation has been updated to reflect recent ideas about the processes involved and how they relate to climatic... |
 |
Waves, Tides and Shallow-Water Processes, Second Edition by Open University (Author) Completely revised and updated for its second edition, this volume belongs to the Open University series on oceanography. It is designed so that it can be read on its own or studied as part of the Open University third-level course, S330 Oceanography. The book begins by describing the characteristics of waves and tides, and their behaviour in shallow water. After outlining the sources of sediment supply to the oceans, some theoretical aspects of sediment movement and deposition by currents are considered. After looking at wave action in the littoral zone, the interplay of tidal currents, river flow and wave action in estuaries and deltas are explored. The final chapter provides an overview of shelf processes. This is a vital book for all oceanography undergraduate... |
 |
The Ocean Circulation Inverse Problem by Carl Wunsch (Author) This book addresses the problem of inferring the state of ocean circulation, understanding it dynamically, and forecasting it through a quantitative combination of theory and observation. It focuses on so-called inverse methods and related methods of statistical inference. The author considers both time-independent and time-dependent problems, including Gauss-Markov estimation, sequential estimators and adjoint/Pontryagin principle methods. This book is intended for use as a graduate level text for students of oceanography and related fields. It will also be of interest to working physical oceanographers. |
 |
Ocean Circulation and Climate, Volume 77: Observing and Modelling the Global Ocean (International Geophysics) by Gerold Siedler (Author), John Church (Author), John Gould (Author) The book represents all the knowledge we currently have on ocean circulation. It presents an up-to-date summary of the state of the science relating to the role of the oceans in the physical climate system. The book is structured to guide the reader through the wide range of World Ocean Circulation Experiment (WOCE) science in a consistent way. Cross-references between contributors have been added, and the book has a comprehensive index and unified reference list. The book is simple to read, at the undergraduate level. It was written by the best scientists in the world who have collaborated to carry out years of experiments to better understand ocean circulation. |
 |
Circulation of the Ocean Ubud (Primary Contributor) |
 |
Botanic Choice Super EPA (Pack of 4) by Botanic Choice Omega 3 EFAs (Essential Fatty Acids) are essential for healthy arteries, blood pressure already in normal range, and triglycerides. The EFAs in cold water fish oil are believed to be the reasons why Greenland Eskimos (whose diet is mainly fish) are known for having such good heart and circulatory health. Two softgels of our high potency Super EPA Omega 3 fish oil give you 2000 mg. of fish oil and 1398 mg. of other beneficial fatty acids, 360 mg. of EPA and 240 mg. of DHA |
 |
The Turbulent Ocean by S. A. Thorpe (Author) The subject of ocean turbulence is in a state of discovery and development with many intellectual challenges. This book describes the principal dynamic processes that control the distribution of turbulence, its dissipation of kinetic energy and its effects on the dispersion of properties such as heat, salinity, and dissolved or suspended matter in the deep ocean, the shallow coastal and the continental shelf seas. It focuses on the measurement of turbulence, and the consequences of turbulent motion in the oceanic boundary layers at the sea surface and near the seabed. Processes are illustrated by examples of laboratory experiments and field observations. The Turbulent Ocean provides an excellent resource for senior undergraduate and graduate courses, as well as an introduction and general... |
 |
Numerical Modeling of Ocean Circulation by Robert N. Miller (Author) The modelling of ocean circulation is important not only for its own sake, but also in terms of the prediction of weather patterns and the effects of climate change. This book introduces the basic computational techniques necessary for all models of the ocean and atmosphere, and the conditions they must satisfy. It describes the workings of ocean models, the problems that must be solved in their construction, and how to evaluate computational results. Major emphasis is placed on examining ocean models critically, and determining what they do well and what they do poorly. Numerical analysis is introduced as needed, and exercises are included to illustrate major points. Developed from notes for a course taught in physical oceanography at the College of Oceanic and Atmospheric Sciences at... |
 |
An Introduction to Ocean Turbulence by S. A. Thorpe (Author) This textbook provides an introduction to turbulent motion occurring naturally in the ocean on scales ranging from millimetres to hundreds of kilometres. It describes turbulence in the mixed boundary layers at the sea surface and seabed, turbulent motion in the density-stratified water between, and the energy sources that support and sustain ocean mixing. Little prior knowledge of physical oceanography is assumed. The text is supported by numerous figures, extensive further reading lists, and more than 50 exercises that are graded in difficulty. Detailed solutions to the exercises are available to instructors online at www.cambridge.org/9780521859486. This textbook is intended for undergraduate courses in physical oceanography, and all students interested in multidisciplinary aspects of... |
 |
Nonlinear Physical Oceanography: A Dynamical Systems Approach to the Large Scale Ocean Circulation and El Niño, (Atmospheric and Oceanographic Sciences Library) by Henk A. Dijkstra (Author) In this book, methodology of dynamical systems theory is applied to investigate the physics of the large-scale ocean circulation. Topics include the dynamics of western boundary currents such as the Gulf Stream in the Atlantic Ocean and the Kurosio in the Pacific Ocean, the stability of the thermohaline circulation, and the El Niño/Southern Oscillation phenomenon in the Tropical Pacific. The book also deals with the numerical methods to apply bifurcation analysis on large-dimensional dynamical systems, with tens of thousands (or more) degrees of freedom, which arise through discretization of ocean and climate models. The novel approach to understand the phenomena of climate variability is through a systematic analysis of the solution structure of a hierarchy of models using these... |
| © 2009 BrightSurf.com |