Download or read book Simulated Response of the Tropical Pacific Climate and ENSO Teleconnections to Glacial Conditions written by Thomas M. Foster and published by . This book was released on 2004 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Climate Change Science A Modern Synthesis written by G. Thomas Farmer and published by Springer Science & Business Media. This book was released on 2013-01-12 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: An introduction to the principles of climate change science with an emphasis on the empirical evidence for climate change and a warming world. Additional readings are given at the end of each chapter. A list of "Things to Know" opens each chapter. Chapters are arranged so that the student is first introduced to the scientific method(s), examples of the use of the scientific method from other sciences drawn from the history of science with an emphasis on climate science. Climate science is treated in each chapter based on the premise of global warming. Chapter treatments on the atmosphere. biosphere, geosphere, hydrosphere, and anthroposphere and their inter-relationships are given.
Download or read book Analyses of the Response of Tropical Pacific Mean State and ENSO Variability to External Forcing Factors in the Early and Mid holocene written by Yihua Luan and published by . This book was released on 2013 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this PhD was to bring some insight on the link between changes in the characteristics of the El Niño-Southern Oscillation and change in the mean climate state. Using the IPSL_CM4 and FGOALS_g1.1 coupled ocean-atmosphere model, we have performed sensitivity experiments to analyze the response of the mean state and interannual variations in the tropical Pacific to Holocene variations in orbital parameters and to remote forcing originated from a remnant ice sheet or ice sheet melting in the Atlantic, as well as teleconnections with the Indian Ocean. Composite analyses of these simulations indicate that 1) Orbital forcing and freshwater flux both dampen the seasonal cycle in the east Pacific in the early and mid-Holocene. 2) The orbital forcing also dampens the interannual variability whereas the freshwater flux enhances it. 3) ENSO amplitude could be affected not only by the ocean mean state, but also by the atmosphere mean state. 4) The ocean dynamics in the Indonesian Sea plays an important role in the interaction between IOD and ENSO. Compared to previous studies this work established that air-sea interaction and clouds in the tropical Pacific could enlarge the impact of the external forcing factors. It also highlight that the tropical air-sea coupling system is very sensitive to the seasonal phasing of the external forcing signals and the development of internal anomalies, but that the magnitude of the response depends on the annual mean state. This may help understand model biases in simulating the modern ENSO amplitude and period. It also provides guidelines to refine the interpretation of high resolution proxy records.
Download or read book Wind Stress Over the Ocean written by Ian S. F. Jones and published by Cambridge University Press. This book was released on 2001-09-24 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive 2001 volume for researchers and graduate students in oceanography, meteorology, fluid dynamics and coastal engineering.
Download or read book El Ni o Southern Oscillation in a Changing Climate written by Michael J. McPhaden and published by John Wiley & Sons. This book was released on 2020-11-24 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive and up-to-date information on Earth’s most dominant year-to-year climate variation The El Niño Southern Oscillation (ENSO) in the Pacific Ocean has major worldwide social and economic consequences through its global scale effects on atmospheric and oceanic circulation, marine and terrestrial ecosystems, and other natural systems. Ongoing climate change is projected to significantly alter ENSO's dynamics and impacts. El Niño Southern Oscillation in a Changing Climate presents the latest theories, models, and observations, and explores the challenges of forecasting ENSO as the climate continues to change. Volume highlights include: Historical background on ENSO and its societal consequences Review of key El Niño (ENSO warm phase) and La Niña (ENSO cold phase) characteristics Mathematical description of the underlying physical processes that generate ENSO variations Conceptual framework for understanding ENSO changes on decadal and longer time scales, including the response to greenhouse gas forcing ENSO impacts on extreme ocean, weather, and climate events, including tropical cyclones, and how ENSO affects fisheries and the global carbon cycle Advances in modeling, paleo-reconstructions, and operational climate forecasting Future projections of ENSO and its impacts Factors influencing ENSO events, such as inter-basin climate interactions and volcanic eruptions The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Find out more about this book from this Q&A with the editors.
Download or read book A Comparison of Climate Prediction and Simulation Over Tropical Pacific written by Vasubandhu Misra and published by . This book was released on 2007 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation and Prediction of North Pacific Sea Surface Temperature written by Fabian Lienert and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of this thesis is an assessment of the ability of global climate models to reproduce observed features of the leading Empirical Orthogonal Function (EOF) mode of North Pacific sea surface temperature (SST) anomalies known as the Pacific Decadal Oscillation (PDO). The simulations from 13 global climate models I am analyzing were performed under phase 3 of the coupled model intercomparison project (CMIP3). In particular, I am investigating whether these climate models capture tropical influences on the PDO, and the influences of the PDO on North American surface temperature and precipitation. My results are that 1) the models as group produce a realistic pattern of the PDO. The simulated variance of the PDO index is overestimated by roughly 30%. 2)The tropical influence on North Pacific SSTs is biased systematically in these models. The simulated response to El Nino-Southern Oscillation (ENSO) forcing is delayed compared to the observed response. This tendency is consistent with model biases toward deeper oceanic mixed layers in winter and spring and weaker air-sea feedbacks in the winter half-year. Model biases in mixed layer depths and air-sea feedbacks are also associated with a model mean ENSO-related signal in the North Pacific whose amplitude is overestimated by roughly 30%. Finally, model power spectra of the PDO signal and its ENSO-forced component are?redder? than observed due to errors originating in the tropics and extratropics. 3) The models are quite successful at capturing the influence of both the tropical Pacific related and the extratropical part of the PDO on North American surface temperature. 4) The models capture some of the influence of the PDO on North American precipitation mainly due to its tropical Pacific related part. In the second part of this thesis, I investigate the ability of one such coupled ocean-atmosphere climate model, carefully initialized with observations, to dynamically predict the future evolution of the PDO on seasonal to decadal time scales. I am using forecasts produced by the Canadian climate data assimilation and prediction system employing the Canadian climate model CanCM3 for seasonal (CHFP2) and CanCM4 for decadal (DHFP1) predictions. The skill of this system in predicting the future evolution of the PDO index is then inferred from a set of historical?forecasts? called hindcasts. In this manner, hindcasts are issued over the past 30 years (seasonal), or over the past 50 years (decadal) when they can be verified against the observed historical evolution of the PDO index. I find that 1) CHFP2 is successful at predicting the PDO at the seasonal timescale measured by mean-square skill score and correlation skill. Weather?noise? unpredictable at the seasonal time scale generated by substantial North Pacific stormtrack activity that coincides with a shallow oceanic mixed layer in May and June appear to pose a prediction barrier for the PDO. PDO skill therefore depends on the start season of the forecast. PDO skill also varies as a function of the target month. Variations in North Pacific storminess appear to impact PDO skill by means of a lagged response of the ocean mixed layer to weather noise. In CHFP2, times of increasing North Pacific storm track activity are followed by times of reduced PDO skill, while the North Pacific midwinter suppression of storm track ...
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 Coral Reefs of the Eastern Tropical Pacific written by Peter W. Glynn and published by Springer. This book was released on 2016-08-12 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book documents and examines the state of health of coral reefs in the eastern tropical Pacific region. It touches on the occurrence of coral reefs in the waters of surrounding countries, and it explores their biogeography, biodiversity and condition relative to the El Niño southern oscillation and human impacts. Additionally contained within is a field that presents information on many of the species presented in the preceding chapters.
Download or read book Mechanisms of Tropical Pacific Climate Change written by Pedro Di Nezio and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanisms of tropical Pacific climate variability and change are studied in numerical experiments of future anthropogenic global warming (AGW), the Last Glacial Maximum (LGM) 21,000 years ago, and decadal variability (PDV). According to these mechanisms the equatorial Pacific does not become either El Niño- or La Niña-like as the tropics warm up in response to increasing greenhouse gases. Because humidity increases much faster than precipitation as the tropical atmosphere warms up, theory and models anticipate a slowing-down of the Walker circulation in order to keep a balanced flow of water vapor into areas of convection. On long time scales characteristic of climate change, ocean dynamics oppose these changes in the Walker circulation. First, equatorial adjustment theory indicates that changes in the Walker circulation are not amplified via the Bjerknes feedback, as during El Niño or La Niña events. Second, during AGW, the ocean becomes more thermally stratified resulting in enhanced cooling of the equatorial cold tongue opposing the warming there. These ideas can be applied to interpret proxies of the LGM for which El Niño and La Niña analogies have been made. However, the LGM tropics are not an opposite analogue to future AGW because the Walker circulation is also sensitive to changes in the geography of the Maritime continent associated with lower sea level. Models simulate a stronger Walker circulation when the tropics cool in order to compensate for the decrease in moisture due to a cooler/drier atmosphere. However, this response is opposed by a weakening of the ascending branch of the Walker circulation because convection is suppressed over vast areas of the Maritime Continent exposed due to lower sea level. In general, the patterns of warming or cooling for AGW and LGM are not El Niño- or La Niña-like because of the opposing mechanisms presented here. As such, adherence to an ENSO analogy for interpreting tropical Pacific climate change can lead to serious misconceptions. However, proxies of the thermocline tilt can provide unequivocal evidence of changes in the Walker circulation because the pressure gradient associated with the thermocline tilt has to be in balance with the trade winds at all timescales.
Download or read book Decade to Century Scale Climate Variability and Change written by National Research Council and published by National Academies Press. This book was released on 1998-12-24 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Society today may be more vulnerable to global-scale, long-term, climate change than ever before. Even without any human influence, past records show that climate can be expected to continue to undergo considerable change over decades to centuries. Measures for adaption and mitigation will call for policy decisions based on a sound scientific foundation. Better understanding and prediction of climate variations can be achieved most efficiently through a nationally recognized "dec-cen" science plan. This book articulates the scientific issues that must be addressed to advance us efficiently toward that understanding and outlines the data collection and modeling needed.
Download or read book Past Climate Variability in South America and Surrounding Regions written by Francoise Vimeux and published by Springer Science & Business Media. This book was released on 2009-08-04 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: South America is a unique place where a number of past climate archives are ava- able from tropical to high latitude regions. It thus offers a unique opportunity to explore past climate variability along a latitudinal transect from the Equator to Polar regions and to study climate teleconnections. Most climate records from tropical and subtropical South America for the past 20,000 years have been interpreted as local responses to shift in the mean position and intensity of the InterTropical Conv- gence Zone due to tropical and extratropical forcings or to changes in the South American Summer Monsoon. Further South, the role of the Southern Hemisphere westerly winds on global climate has been highly investigated with both paleodata and coupled climate models. However the regional response over South America during the last 20,000 years is much more variable from place to place than pre- ously thought. The factors that govern the spatial patterns of variability on millennial scale resolution are still to be understood. The question of past natural rates and ranges of climate conditions over South America is therefore of special relevance in this context since today millions of people live under climates where any changes in monsoon rainfall can lead to catastrophic consequences.
Download or read book Assessment of Intraseasonal to Interannual Climate Prediction and Predictability written by National Research Council and published by National Academies Press. This book was released on 2010-09-08 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: More accurate forecasts of climate conditions over time periods of weeks to a few years could help people plan agricultural activities, mitigate drought, and manage energy resources, amongst other activities; however, current forecast systems have limited ability on these time- scales. Models for such climate forecasts must take into account complex interactions among the ocean, atmosphere, and land surface. Such processes can be difficult to represent realistically. To improve the quality of forecasts, this book makes recommendations about the development of the tools used in forecasting and about specific research goals for improving understanding of sources of predictability. To improve the accessibility of these forecasts to decision-makers and researchers, this book also suggests best practices to improve how forecasts are made and disseminated.
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 Deep time Perspectives on Climate Change written by Mark Williams and published by Geological Society of London. This book was released on 2007 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Validating ENSO Simulation in Coupled Climate Models written by and published by . This book was released on 2006 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanisms of Tropical Pacific Climate Change During the Holocene written by Alyssa Regine Atwood and published by . This book was released on 2015 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel set of hydroclimate reconstructions is presented from the eastern equatorial Pacific that spans the last 9100 years. Past changes in total climatological rainfall and rainfall associated with El Niño events were reconstructed using the sedimentary distribution, accumulation rate, and hydrogen isotope composition of four lipid biomarkers in the sediment of El Junco Lake, San Crist??bal Island. Possible mechanisms of the multi-decadal to millennial scale rainfall variations inferred at El Junco Lake are evaluated in light of tropical hydroclimate and global climate reconstructions through the Holocene. Tropical hydroclimate changes are further investigated during the so-called "8.2 ka event" and the Little Ice Age (LIA) using climate model simulations. We propose that rainfall changes at El Junco Lake ca. 8500-8000 yr BP were produced by a large meltwater pulse in the North Atlantic that caused a southward shift of the ITCZ (via reduced northward ocean heat transport and expanded Arctic sea ice) and weakened El Niño/Southern Oscillation (ENSO) variability (via tropical Pacific mean state changes that increased the stability of the coupled ocean-atmosphere system). We provide support for this concept using simulations with a fully coupled global climate model (CESM) and a linearized ocean-atmosphere model of the tropical Pacific (LOAM), Tropical hydroclimate changes and their mechanisms during the LIA were investigated in the CMIP5/PMIP3 last millennium simulations. Climate forcings and feedbacks were quantified using the Approximate Partial Radiative Perturbation and radiative kernel methods, highlighting the role of volcanic forcing and the water vapor, lapse rate, and surface albedo feedbacks during the LIA. A weak southward shift in zonally averaged tropical precipitation was found during the LIA in the model simulations in association with anomalous northward cross-equatorial atmospheric energy transport that was driven by greater volcanic forcing and greater snow and sea ice response in the Northern (versus Southern) Hemisphere. A second theme of this dissertation is the influence of tropical Pacific mean state changes on ENSO variability. This concept is explored through simulations of the 8.2 ka event, as well as through analysis of the large, unforced, multi-decadal changes in ENSO variability in the General Circulation Model GFDL CM2.1. Experiments using LOAM suggest that a two-way feedback operates between ENSO and the mean state of the tropical Pacific in CM2.1, whereby random forcing and nonlinear dynamics produce low frequency changes in ENSO variance that are then counteracted by mean state feedbacks.
