Download or read book The Role of High latitude Oceans in Transient Climate Change written by Yavor Krasimirov Kostov and published by . This book was released on 2016 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we explore the role of the large-scale ocean circulation in the North Atlantic and the Southern Ocean (SO) in setting the regional and globally averaged sea surface temperature (SST) response to atmospheric forcing. We focus on the impact of anthropogenic greenhouse gases (AGHGs) and the Antarctic ozone hole and use output from general circulation models (GCMs) to estimate the corresponding climate response functions (CRFs). We show that the strength and the vertical extent of the time-mean Atlantic Meridional Overturning Circulation (AMOC) set the effective heat capacity of the World Ocean and affect the global CRF to greenhouse gas (GHG) forcing. A large fraction of the anomalous surface heat uptake induced by GHGs takes place over the North Atlantic. However, the SO also plays a significant role in removing excess heat from the atmosphere. Compared to the rest of the World Ocean, the SO warms at a much slower rate under GHG forcing. In this region the background Meridional Overturning Circulation (MOC) upwells unmodified deep water masses to the surface where they take up atmospheric heat. The modified water masses are then advected northward and subducted in the mid-latitudes. This geographical imprint of the MOC is reflected in the regional CRFs to GHGs, as seen in idealized numerical experiments with GCMs. However, GHGs are not the only major source of anthropogenic forcing on the SO. Stratospheric ozone depletion around Antarctica gives rise to an atmospheric pattern similar to the positive phase of the Southern Annular Mode (SAM): a strengthening and a southward shift of the westerlies. This poleward intensification of the winds changes the ocean circulation and gives rise to an SST response. We examine the SO CRF to a SAM pattern that arises either in the form of natural variability in unforced control experiments or as a result of imposed ozone perturbations. We analyze the SO SST response to SAM on multiple timescales and across an ensemble of GCMs from the Climate Modeling Intercomparison Project phase 5 (CMIP5). We show that the corresponding SO CRF is governed by the anomalous wind-driven MOC redistributing the background heat reservoir. The intermodel diversity in the fast and slow SST responses to SAM is partly explained by differences in the climatological thermal stratification across the ensemble of GCMs. Furthermore, we demonstrate that the sea ice response to SAM in models is very well correlated with the geographic pattern of the SST anomalies. Finally, we convolve our estimated CRFs with timeseries of historical forcing to recover the SO SST trends in numerical simulations and in observations. We contrast the multidecadal SO cooling trends against the SST warming rate in the Northern Hemisphere high latitudes. Our results imply that the recent cooling in the SO may be explained by the Antarctic ozone hole projecting on a positive SAM trend. We furthermore attempt to understand why CMIP5 models have been unable to reproduce the observed negative SST trends in the SO and instead predict regional warming. Many GCM simulations underestimate the historical SAM evolution. Another subset of CMIP5 models have biases in their climatological SO stratification, which affects their SO CRFs to SAM. The successful application of the CRF framework in the context of observed and simulated SST trends validates the results of our analysis. We are thus able to interpret the CRFs as inherent characteristics of the climate system and elucidate the importance of the high latitude oceans in transient climate change.

Download or read book Abrupt Climate Change written by National Research Council and published by National Academies Press. This book was released on 2002-04-23 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: The climate record for the past 100,000 years clearly indicates that the climate system has undergone periodic-and often extreme-shifts, sometimes in as little as a decade or less. The causes of abrupt climate changes have not been clearly established, but the triggering of events is likely to be the result of multiple natural processes. Abrupt climate changes of the magnitude seen in the past would have far-reaching implications for human society and ecosystems, including major impacts on energy consumption and water supply demands. Could such a change happen again? Are human activities exacerbating the likelihood of abrupt climate change? What are the potential societal consequences of such a change? Abrupt Climate Change: Inevitable Surprises looks at the current scientific evidence and theoretical understanding to describe what is currently known about abrupt climate change, including patterns and magnitudes, mechanisms, and probability of occurrence. It identifies critical knowledge gaps concerning the potential for future abrupt changes, including those aspects of change most important to society and economies, and outlines a research strategy to close those gaps. Based on the best and most current research available, this book surveys the history of climate change and makes a series of specific recommendations for the future.

Download or read book Flexible Global Ocean Atmosphere Land System Model written by Tianjun Zhou and published by Springer Science & Business Media. This book was released on 2013-11-19 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coupled climate system models are of central importance for climate studies. A new model known as FGOALS ( the Flexible Global Ocean-Atmosphere-Land System model), has been developed by the Sate Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP, CAS), a first-tier national geophysical laboratory. It serves as a powerful tool, both for deepening our understanding of fundamental mechanisms of the climate system and for making decadal prediction and scenario projections of future climate change. "Flexible Global Ocean-Atmosphere-Land System Model: A Modeling Tool for the Climate Change Research Community” is the first book to offer systematic evaluations of this model’s performance. It is comprehensive in scope, covering both developmental and application-oriented aspects of this climate system model. It also provides an outlook of future development of FGOALS and offers an overview of how to employ the model. It represents a valuable reference work for researchers and professionals working within the related areas of climate variability and change. Prof. Tianjun Zhou, Yongqiang Yu, Yimin Liu and Bin Wang work at LASG, the Institute of Atmospheric Physics, Chinese Academy of Sciences, China.

Download or read book The Oceans and Rapid Climate Change written by Dan Seidov and published by John Wiley & Sons. This book was released on 2001-01-09 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 126. Until a few decades ago, scientists generally believed that significant large-scale past global and regional climate changes occurred at a gradual pace within a time scale of many centuries or millennia. A secondary assumption followed: climate change was scarcely perceptible during a human lifetime. Recent paleoclimatic studies, however, have proven otherwise: that global climate can change extremely rapidly. In fact, there is good evidence that in the past at least regional mean annual temperatures changed by several degrees Celsius on a time scale of several centuries to several decades.

Download or read book Understanding Earth s Deep Past written by National Research Council and published by National Academies Press. This book was released on 2011-08-02 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is little dispute within the scientific community that humans are changing Earth's climate on a decadal to century time-scale. By the end of this century, without a reduction in emissions, atmospheric CO2 is projected to increase to levels that Earth has not experienced for more than 30 million years. As greenhouse gas emissions propel Earth toward a warmer climate state, an improved understanding of climate dynamics in warm environments is needed to inform public policy decisions. In Understanding Earth's Deep Past, the National Research Council reports that rocks and sediments that are millions of years old hold clues to how the Earth's future climate would respond in an environment with high levels of atmospheric greenhouse gases. Understanding Earth's Deep Past provides an assessment of both the demonstrated and underdeveloped potential of the deep-time geologic record to inform us about the dynamics of the global climate system. The report describes past climate changes, and discusses potential impacts of high levels of atmospheric greenhouse gases on regional climates, water resources, marine and terrestrial ecosystems, and the cycling of life-sustaining elements. While revealing gaps in scientific knowledge of past climate states, the report highlights a range of high priority research issues with potential for major advances in the scientific understanding of climate processes. This proposed integrated, deep-time climate research program would study how climate responded over Earth's different climate states, examine how climate responds to increased atmospheric carbon dioxide and other greenhouse gases, and clarify the processes that lead to anomalously warm polar and tropical regions and the impact on marine and terrestrial life. In addition to outlining a research agenda, Understanding Earth's Deep Past proposes an implementation strategy that will be an invaluable resource to decision-makers in the field, as well as the research community, advocacy organizations, government agencies, and college professors and students.

Download or read book Effects of Climate Change Across Ocean Regions written by Ove Hoegh-Guldberg and published by Frontiers Media SA. This book was released on 2018-07-05 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: The IPCC Fifth Assessment Report (AR5) highlighted that conditions within Earth’s ocean are changing more rapidly than any of the time during the past 65 million years, and as a consequence, major changes are occurring in natural and human systems. While this major report as enhanced our understanding of the complexity of ocean issues, we propose this research topic as an opportunity to expand discussion on past, present and future changes across oceans regions.

Download or read book High latitude climate change in a global coupled ocean atmosphere sea ice model with increased atmospheric CO2 written by W.M. WASHINGTON and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Role of the Ocean in the NOAA Program Climate and Global Change written by Edward S. Sarachik and published by . This book was released on 1989 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Ocean and Cryosphere in a Changing Climate written by Intergovernmental Panel on Climate Change (IPCC) and published by Cambridge University Press. This book was released on 2022-04-30 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.

Download or read book Climate Stabilization Targets written by National Research Council and published by National Academies Press. This book was released on 2011-02-11 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emissions of carbon dioxide from the burning of fossil fuels have ushered in a new epoch where human activities will largely determine the evolution of Earth's climate. Because carbon dioxide in the atmosphere is long lived, it can effectively lock the Earth and future generations into a range of impacts, some of which could become very severe. Emissions reductions decisions made today matter in determining impacts experienced not just over the next few decades, but in the coming centuries and millennia. According to Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia, important policy decisions can be informed by recent advances in climate science that quantify the relationships between increases in carbon dioxide and global warming, related climate changes, and resulting impacts, such as changes in streamflow, wildfires, crop productivity, extreme hot summers, and sea level rise. One way to inform these choices is to consider the projected climate changes and impacts that would occur if greenhouse gases in the atmosphere were stabilized at a particular concentration level. The book quantifies the outcomes of different stabilization targets for greenhouse gas concentrations using analyses and information drawn from the scientific literature. Although it does not recommend or justify any particular stabilization target, it does provide important scientific insights about the relationships among emissions, greenhouse gas concentrations, temperatures, and impacts. Climate Stabilization Targets emphasizes the importance of 21st century choices regarding long-term climate stabilization. It is a useful resource for scientists, educators and policy makers, among others.

Download or read book The Ocean s Role in Climate Change written by Alexander Polonsky and published by Cambridge Scholars Publishing. This book was released on 2019-05-21 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: The principal focus of this book is the physical processes in the World Ocean which regulate the interannual-to-multidecadal natural variability of the climate system, and some key atmospheric and marine manifestations of this variability. It analyses a number of Atlantic and Indo-Pacific signals, and describes their regional atmospheric and marine manifestations. The role of the Ocean in the recent hiatus of global warming and the probability of abrupt climate change due to thermohaline catastrophe are also assessed. The book pays special attention to the change of parameters of synoptic atmospheric disturbances over the Northern Hemisphere and its sub-regions in different phases of the natural quasi-periodical climatic signals. It will appeal to oceanographers, climatologists, meteorologists, hydrologist, geographers and the general reader interested in the problem of climate change all over the globe, especially with regards to Eastern Europe and the Black Sea region.

Download or read book Climate Ocean Interaction written by M.E. Schlesinger and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Preface This book is the culmination of a workshop jointly organized by NATO and CEC on Climate-Ocean Interaction which was held at Lady Margaret Hall, Oxford University during 26-30 September 1988. The objective of the ARW was to assess the current status of research on climate-ocean interaction, with a major focus on the development of coupled atmosphere-ocean-ice models and their application in the study of past, present and possible future climates. This book contains 16 chapters divided into four parts: Introduction; Observations of the Climate of the Ocean; Modelling the Atmospheric, Oceanic and Sea Ice Components of the Climatic System; and Simulating the Variability of Climate on Short, Medium and Long Time Scales. A fifth part contains the reports of the five Working Groups on: Climate Observations, Modelling, ENSO Modelling and Prediction, Climate-Ocean Interaction on TIme Scales of Decades to Centuries, and Impact of Paleoclimatic Proxy Data on Climate Modelling. Preface ix Acknowledgements I thank Howard Cattle and Neil Wells for their guidance and assistance as members of the Workshop Organizing Committee. I particularly thank Michael Davey for all his efforts as Local Organizer to make the ARW a success. I also thank the staff of Lady Margaret Hall, Oxford University, for their help with the arrangements for the ARW.

Download or read book Ocean Temperature Variability During the Late Pleistocene written by Jeremy Scott Hoffman and published by . This book was released on 2016 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation explores one overarching question relevant to the paleoclimate of the latest Pleistocene glacial cycle (approximately the last 130,000 years): “How did spatial and temporal evolution of ocean temperature, both at the surface and interior, relate to other parts of the climate system in the late Pleistocene?” Results from three studies are presented that seek to address longstanding questions in paleoceanography and paleoclimatology for the late Pleistocene using a combination of novel and accepted statistical and geochemical analysis techniques and leveraging comparisons with available global climate model data. The last interglaciation (LIG; ~129-116 ka) was the most recent period in Earth’s history with higher-than-present global sea level (≥6-9 m) under similar-to-preindustrial concentrations of atmospheric CO2. This suggests that additional feedbacks related to albedo, insolation, and ocean overturning circulation may have resulted in the apparent warming required to cause the higher sea level. Our understanding of how much warmer the LIG was relative to the present interglaciation remains uncertain, however, with current estimates suggesting that sea-surface temperatures (SSTs) were 0-2°C warmer than late-20th century average global temperatures. We present a global compilation of proxy-based annual SST spanning the LIG. Using Monte Carlo and Bayesian techniques to propagate uncertainties in age-model and proxy-based SST reconstructions, our results quantify the spatial timing, amplitude, and uncertainty in global and regional SST change during the LIG. Our conclusions suggest that the LIG surface ocean was indistinguishable from the average surface ocean temperatures observed for the last two decades (1995-2014). This may ultimately imply that the Earth is currently committed to ≥6-9m of equilibrium sea-level rise. Although the LIG is not an analogue for present and future climate change due to the large differences in seasonal orbital insolation and absence of anthropogenic greenhouse gas radiative forcing, it provides an opportunity to test the ability of global climate models to simulate the mechanisms and climate feedbacks responsible for the warmer climate and higher global mean sea level during the LIG. However, when forced only by LIG greenhouse gas concentrations and insolation changes, climate models suggest that the annual mean temperature response was not significantly different from preindustrial control simulations. We present the first multi-model and multiscenario ensemble of transient and equilibrium global climate modeling results spanning the LIG. We show, using a novel model-data comparison framework, that these scenario-specific model results exhibit regionally independent agreement with ocean basin-specific proxy-based SST stacks. This result ultimately implies structural uncertainties and/or misrepresentations of climate feedbacks in the existing suite of climate model simulations, or underestimations of additional proxy-based SST uncertainties. Our conclusions suggest a new target LIG time period for future model-data comparisons and highlight the need for higher resolution transient climate modeling of the LIG and its dependence on meltwater input to the high latitude oceans during the preceding deglaciation. Few discoveries have stimulated the paleoclimate community more so than Heinrich events. Nevertheless, the cause of Heinrich events, characterized by a large flux of icebergs sourced from the Hudson Strait Ice Stream into the North Atlantic, remains debated. Commonly attributed to internal ice-sheet instability, the occurrence of Heinrich events during the coldest intervals of the last glacial cycle instead suggests an external climate control. We expand on recent studies that have shown that incursions of warm subsurface waters into the intermediate depth North Atlantic Ocean destabilized an ice shelf fronting the Hudson Strait Ice Stream, causing a Heinrich event. We present new surface- and bottom-water stable isotope, trace metal, and sedimentary records from two cores taken along the Labrador margin that further support subsurface warming as a trigger of Hudson Strait Heinrich events. We further relate these changes to other sediment core records from the North Atlantic and transient deglacial climate modeling results to show that subsurface warming was ubiquitous across the intermediate North Atlantic during the early part of the last deglaciation and was most likely caused by a preceding reduction in the Atlantic Meridional Overturning Circulation.

Download or read book Climate Variability of Southern High Latitude Regions written by Neloy Khare and published by CRC Press. This book was released on 2022-04-07 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to provide a comprehensive overview of climate change–related investigations carried out by Indian researchers through initiatives in southern high latitude regions. It explains climate variability over the Southern Ocean and Antarctica; air, sea, ice, and atmosphere interactions; and the impact of climate variability on sea ice and the polar atmosphere. The data were gathered at two Indian research bases, Maitri and Bharti, which are ideal sites to study and understand climatic evolution in Antarctic in the past and recent changes. This book helps to understand climatological perspectives and to evaluate some of the most pressing issues in the south polar region. FEATURES Highlights the achievements of India in the contemporary field of Antarctic climatology Presents four decades of research by Indian scientists in Antarctica, which is now shared for the first time with the global community Includes case studies on climatological and environmental conditions of natural archives to shed light on climate scenarios in the Southern Ocean and Antarctic regions Covers various aspects of climate variability and induced air-sea-ice-atmosphere interactions This book is edited by one of the top scientists and researchers of India in the field of paleoclimatology, and the contributors are experts in the Antarctic region.

Download or read book Natural Climate Variability on Decade to Century Time Scales written by National Research Council and published by National Academies Press. This book was released on 1996-08-30 with total page 645 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reflects the current state of scientific knowledge about natural climate variability on decade-to-century time scales. It covers a wide range of relevant subjects, including the characteristics of the atmosphere and ocean environments as well as the methods used to describe and analyze them, such as proxy data and numerical models. They clearly demonstrate the range, persistence, and magnitude of climate variability as represented by many different indicators. Not only do natural climate variations have important socioeconomic effects, but they must be better understood before possible anthropogenic effects (from greenhouse gas emissions, for instance) can be evaluated. A topical essay introduces each of the disciplines represented, providing the nonscientist with a perspective on the field and linking the papers to the larger issues in climate research. In its conclusions section, the book evaluates progress in the different areas and makes recommendations for the direction and conduct of future climate research. This book, while consisting of technical papers, is also accessible to the interested layperson.

Download or read book Decomposing Atmospheric Versus Oceanic Contributions to the High To Low Latitude Teleconnection During a Freshwater Triggered Abrupt Climate Change written by Guanglin Tang and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation we study the high-to-low latitude teleconnection during Younger Dryas-like abrupt climate events using models. The teleconnection considered here is between climate change induced by a freshwater input in high-latitude North Atlantic and global response over the Northern Hemisphere and in the tropics. We focus on three primary questions: (1) What is the relative importance of oceanic vs. atmospheric processes in the teleconnection? (2) What are the respective mechanisms of the atmospheric and oceanic controlled teleconnection? (3) How important is sea surface temperature to the teleconnection, particularly in tropical climate responses. To answer these questions we performed a series of model experiments using an Atmospheric General Circulation Model coupled to a thermodynamic slab ocean model. Previous studies identified a teleconnection between the high-latitude fresh-waterforced abrupt climate change and the low-latitude climate response during a Younger Dryas-like abrupt climate change using coupled Atmosphere-Ocean General Circulation Models. In this study we attempt to separate and compare the atmospheric and oceanic contributions to this teleconnection. The results show that these contributions have comparable climate response magnitudes, but different spatial characteristics with the atmospheric contribution being more zonally symmetric than the oceanic counterpart. Physical atmospheric and oceanic processes are also analyzed to address the second question. It is found that the equator ward propagation of the high-latitude surface cooling is induced by increasing surface sensible heat flux in northern mid-latitudes and subtropics and surface latent heat flux in northern equatorial region. The increase in sensible heat flux is due to cooling of near surface air temperatures, whereas latent heat response is caused by strengthening of the surface trade winds linked to an increase in meridional surface temperature gradient. The oceanic contribution in the North Atlantic is through changes in the oceanic circulation caused by freshwater forcing. To address the third question, we performed additional modelling experiments with same high-latitude forcing but different oceanic mixed layer depths. It is found that change in sea surface temperature is necessary for the high-to-low latitude teleconnection and the tropical precipitation response. To determine the importance of sea surface temperature in Intertropical Convergence Zone (ITCZ) response, we further performed an experiment using a simple model developed by Lindzen and Nigam (1987) and found that the change in sea surface temperature, in concert with lower-tropospheric vertical mixing and surface drag, largely contributes to the simulated ITCZ shift. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155500

Download or read book Toward an Understanding of Global Change written by and published by National Academies Press. This book was released on 1988-01-01 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: