The Ocean's Role in Global Change Progress of Major Research Programs (1994) / Chapter Skim
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THE CONTEMPORARY SYSTEM
THE CONTEMPORARY SYSTEM
Pages 7-38
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can have immediate economic and societal impacts. Agricultural production, and therefore food supplies and economies, is directly affected by climate variations.
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Formation of deep water in the North Atlantic Ocean can be diminished and reestablished over decadal time scales. There is increasing evidence that anomalously hot summers or cold winters in the United States are related to particular ocean conditions that cause distortions in weather patterns across the country for weeks at a time.
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From page 9... ...
, the consequent rainfall and temperature patterns, and observations needed for detection of global change due to greenhouse warming, such as absolute sea level and average ocean temperatures. GOOS is planned to have five application modules, including climate, living marine resources, marine weather and operational ocean services, health of the ocean, and the coastal zone.
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The U.S. TOGA program has been concerned primarily with studies of the ENSO cycle in the tropical Pacific Ocean and its effect on global climate.
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The TOGA Program on Seasonal to Interannual Prediction (T-POP) , a research program, has been instituted to develop the models and methods needed to provide socially useful predictions of aspects of ENSO a month to a year in advance using data provided by the TOGA Observing System (Box 21.
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Internationally, the World Climate Research Program is planning the Climate Variability and Predictability (CLIVAR) program whose designated Focus 1 will be on seasonal to interannual global variations and predictability.
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A TOGA Observing System has been established in the tropical Pacific to relay surface and subsurface information to the GTS in real time. Data collected with the TOGA Observing System has helped develop coupled atmosphere-ocean models for the simulation of ENSO events.
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From page 15... ...
World Ocean Circulation Experiment Ocean circulation is related to climate on a decades-to-centuries scale, through the transfer of heat, momentum, and greenhouse gases between the atmosphere and the ocean. Thus, in order to understand and predict global climate change, on these time scales improved understanding of ocean circulation is crucial.
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Core Project 3 focuses on specific processes important to ocean circulation and modeling. The Subduction Experiment (1991-93)
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Enhanced sampling of the North Atlantic Ocean (especially with repeat hydrography, floats, and drifters) is planned through international cooperation and joint work with the Atlantic Climate Change Program (ACCP)
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From page 19... ...
A major initiative for the North Atlantic is proposed to begin in 1996, and studies of variability elsewhere will continue for some time. WOCE's second goal is to determine whether specific WOCE data sets are representative of the long-term behavior of the ocean and to find methods for quantifying decadal changes in ocean circulation.
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From page 20... ...
Additionally, WOCE research is leading to continued improvements in global ocean modeling as scientists begin to use the largest computers at fine model scales. While providing new insights into ocean circulation, these data and models will also form the large-scale physical framework for studies of chemistry and biology being carried out through programs such as Joint Global Ocean Flux Study (JGOFS)
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From page 21... ...
a mid-depth ocean reference level with horizontal velocity estimates. Joint Global Ocean Flux Study Observations demonstrating a continuing increase in the concentration of atmospheric CO2, linked with numerous model-based forecasts, have led the nations of the world to consider controlling of CO2 emissions.
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The second process study was carried out in the equatorial Pacific Ocean in 1991 and 1992. Process studies are scheduled for the Arabian Sea (1994-95)
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The time-series studies at Bermuda and Hawaii provide a sense of the range of seasonal and interannual variability in carbon cycle processes characteristic of the vast oligotrophic areas of the world oceans. The various process studies have provided and will continue to reveal details of key carbon cycle controls in globally significant ocean areas.
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the planning of sitespecific process studies. Toward that end, several modeling investigations and projects to develop molecular techniques were funded, and a process study on the Georges Bank ecosystem in the northwest Atlantic Ocean was planned (Box 61.
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The stated goal of GLOBEC-Intemational is "to understand the effects of physical processes on predator-prey interactions and population dynamics of zooplankton, and their relation to ocean ecosystems in the context of the global climate system and anthropogenic change." GLOBEC is endorsed by Scientific Committee on Oceanic Research, Intergovernmental Oceanographic Commission, International Council for the Exploration of the Sea (ICESy, and Pacific ICES (PICKS)
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The second involves the development of coupled numerical, physical-biological models and observational systems that will involve a significant planning effort and international cooperation. Coupled models and observations are central to determining present oceanic conditions and predicting future conditions.
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Much of the early emphasis of ACCP is directed at middle and high latitudes of the North Atlantic for several reasons. First, the subarctic North Atlantic is the only site in the northern hemisphere where convection in the ocean extends from the surface to deeper levels, providing a mechanism for creating persistent sea-surface temperature anomalies one decade to century time scales.
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From page 29... ...
Similarly, the relatively cool climate of the late 1960s and early 1970s was associated with very low sea-surface temperature in the western Subarctic North Atlantic. Finally, in the context of assessing global climate change due to anthropogenic causes, understanding the very low frequency, apparently natural variability of climate will help answer the question: Can we discriminate natural climate variability of very long time scale from the possible effects of human-induced greenhouse warming?
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From page 30... ...
Ocean models with boundary conditions which mimic the effects of air-sea interaction provide the simplest illustration of how changes in the ocean's thermohaline circulation and in high-latitude ocean convection provide an explanation for low-frequency climate variability in the North Atlantic. Rapid progress has been made in clarifying the early results obtained with these models, which showed that two very different solutions could exist for the same boundary conditions.
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The records from the Greenland ice cap appear to have enormous potential for the study of North Atlantic climate variability. Plans for field activities in ACCP are guided by the results of the data analysis and modeling elements of the program.
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The Arctic comprises a mosaic of precariously balanced ecosystems that interact intimately with climate. Global climate models have shown that the largest temperature changes may occur in the Arctic.
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Several key research areas have been identified, including the effects of energy exchange (for example, from wind or the sun) on temperature, salinity, and density distributions in the water column and carbon removal from the atmosphere and surface waters to the deep ocean and sediments via plant material.
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34 THE OCEAN'S ROLE IN GLOBAL CHANGE ~ BOx~ 8~i~jor ARCSS~A¢¢o~n0's~ei~s~ ~ = ................................................
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From page 35... ...
Following a successful 1991 demonstration of the viability of acoustic travel time measurements over trans-oceanic paths (the Heard Island Experiment) , ATOC was funded in early 1993 to establish a Pacific Ocean network of sound path measurements to test the feasibility of a future global network for monitoring ocean climate trends.
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for Seasonal-toInterannual Climate Prediction Program was conceived as the U.S. contribution to the Climate Variability and Predictability (CLIVAR)
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The process studies will concentrate on the monsoonal forcing of the atmosphere in the eastern Pacific and Indian oceans and the transmission of these signals to higher latitudes. It is anticipated that two major ongoing TOGA activities, the TOGA Observing System and the TOGA Program on Seasonal to Interannual Prediction (T-POP)
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From page 38... ...
. Because existing global change research lacks strong components focused specifically on the coastal zone, the International Geosphere-Biosphere Program developed the Land-Ocean Interactions in the Coastal Zone (LOICZ)
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