Download or read book Influence of Mean State on Climate Variability at Interannual and Decadal Time Scales written by Xiaojie Zhu and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation reports on studies on the role of the mean state in modulating climate variability at interannual and decadal time scales. In the atmosphere, the nonlinear superposition of mean flow and anomalous flow has important implications for many phenomena associated with variables that are nonlinear by definition, such as the vertical wind shear and surface wind speed. In the first part of this dissertation, the influence of mean flow and anomalous flow on vertical wind shear variability is studied in observations and numerical model simulations. At interannual timescales, the ENSO-shear relationship is compared between observations and numerical model simulations. It is shown that there is strong influence of mean flow on the ENSO-shear relationship. For same anomalous flow, different mean flows could give rise to a different ENSO-shear relationship. The nonlinear superposition of mean flow and anomalous flow also helps explains the dipole mode of tropical Atlantic vertical wind shear variability seen in observations and models, which implies opposite variation of vertical wind shear over the two sides of the tropical Atlantic. This has important implications for predicting phenomena such as Atlantic hurricanes, whose variations are modulated by vertical shear variability. The dissertation also addresses the role of the mean surface wind in decadal variability and predictability, as manifested through the Wind-Evaporation-SST (WES) feedback. The nonlinear superposition of anomalous surface wind on the mean trade wind can give rise to a positive WES feedback, which can amplify tropical climate variability. To study this feedback, we carried out ensembles of decadal climate predictions using the CAM3 atmospheric model coupled to a slab ocean model (CAM3- SOM) with prescribed ocean transport and simple extrapolative prescriptions of future external forcings. Mechansitic sensitivity runs using the CAM3-SOM were also carried out, where the WES feedback was switched off by prescribing climatological surface wind. Results suggest that switching off the WES feedback enhances the prediction skill over some regions, especially over the eastern tropical Pacific, by increasing the signal- to-noise ratio. To address the issue of cold bias noted in the decadal prediction experiments, we carried out additional sensitivity experiments where we used an adaptive formulation for the prescribed oceanic heat transport (Q-flux) in the slab ocean. The results from these experiments demonstrate that the mean oceanic heat transport plays a crucial role in influencing decadal predictability, by helping improve predictions of the trend component of decadal variations. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/150993
Download or read book Frontiers in Decadal Climate Variability written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2016-07-22 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many factors contribute to variability in Earth's climate on a range of timescales, from seasons to decades. Natural climate variability arises from two different sources: (1) internal variability from interactions among components of the climate system, for example, between the ocean and the atmosphere, and (2) natural external forcings, such as variations in the amount of radiation from the Sun. External forcings on the climate system also arise from some human activities, such as the emission of greenhouse gases (GHGs) and aerosols. The climate that we experience is a combination of all of these factors. Understanding climate variability on the decadal timescale is important to decision-making. Planners and policy makers want information about decadal variability in order to make decisions in a range of sectors, including for infrastructure, water resources, agriculture, and energy. In September 2015, the National Academies of Sciences, Engineering, and Medicine convened a workshop to examine variability in Earth's climate on decadal timescales, defined as 10 to 30 years. During the workshop, ocean and climate scientists reviewed the state of the science of decadal climate variability and its relationship to rates of human-caused global warming, and they explored opportunities for improvement in modeling and observations and assessing knowledge gaps. Frontiers in Decadal Climate Variability summarizes the presentations and discussions from the workshop.
Download or read book Global Environmental Change written by National Research Council and published by National Academies Press. This book was released on 1999-09-14 with total page 621 pages. Available in PDF, EPUB and Kindle. Book excerpt: How can we understand and rise to the environmental challenges of global change? One clear answer is to understand the science of global change, not solely in terms of the processes that control changes in climate and the composition of the atmosphere, but in how ecosystems and human society interact with these changes. In the last two decades of the twentieth century, a number of such research effortsâ€"supported by computer and satellite technologyâ€"have been launched. Yet many opportunities for integration remain unexploited, and many fundamental questions remain about the earth's capacity to support a growing human population. This volume encourages a renewed commitment to understanding global change and sets a direction for research in the decade ahead. Through case studies the book explores what can be learned from the lessons of the past 20 years and what are the outstanding scientific questions. Highlights include: Research imperatives and strategies for investigators in the areas of atmospheric chemistry, climate, ecosystem studies, and human dimensions of global change. The context of climate change, including lessons to be gleaned from paleoclimatology. Human responses toâ€"and forcing ofâ€"projected global change. This book offers a comprehensive overview of global change research to date and provides a framework for answering urgent questions.
Download or read book Frontiers in Decadal Climate Variability written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2016-08-22 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many factors contribute to variability in Earth's climate on a range of timescales, from seasons to decades. Natural climate variability arises from two different sources: (1) internal variability from interactions among components of the climate system, for example, between the ocean and the atmosphere, and (2) natural external forcings, such as variations in the amount of radiation from the Sun. External forcings on the climate system also arise from some human activities, such as the emission of greenhouse gases (GHGs) and aerosols. The climate that we experience is a combination of all of these factors. Understanding climate variability on the decadal timescale is important to decision-making. Planners and policy makers want information about decadal variability in order to make decisions in a range of sectors, including for infrastructure, water resources, agriculture, and energy. In September 2015, the National Academies of Sciences, Engineering, and Medicine convened a workshop to examine variability in Earth's climate on decadal timescales, defined as 10 to 30 years. During the workshop, ocean and climate scientists reviewed the state of the science of decadal climate variability and its relationship to rates of human-caused global warming, and they explored opportunities for improvement in modeling and observations and assessing knowledge gaps. Frontiers in Decadal Climate Variability summarizes the presentations and discussions from the workshop.
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 Thriving on Our Changing Planet A Decadal Strategy for Earth Observation from Space written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-06-18 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: We live on a dynamic Earth shaped by both natural processes and the impacts of humans on their environment. It is in our collective interest to observe and understand our planet, and to predict future behavior to the extent possible, in order to effectively manage resources, successfully respond to threats from natural and human-induced environmental change, and capitalize on the opportunities â€" social, economic, security, and more â€" that such knowledge can bring. By continuously monitoring and exploring Earth, developing a deep understanding of its evolving behavior, and characterizing the processes that shape and reshape the environment in which we live, we not only advance knowledge and basic discovery about our planet, but we further develop the foundation upon which benefits to society are built. Thriving on Our Changing Planet: A Decadal Strategy for Earth Observation from Space (National Academies Press, 2018) provides detailed guidance on how relevant federal agencies can ensure that the United States receives the maximum benefit from its investments in Earth observations from space, while operating within realistic cost constraints. This short booklet, designed to be accessible to the general public, provides a summary of the key ideas and recommendations from the full decadal survey report.
Download or read book Decadal Climate Variability written by David L.T. Anderson and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: On decadal time scales, climate change may result not only from man-made causes, but also from natural processes. This book brings together theoretical conceptions of the physical mechanisms of climate change with observational evidence of these changes. The following key topics are included: Observed Climatic Variability, Predictability of the Atmosphere and Oceans from Days to Decades, and Mechanisms for Decadal to Centennial Climate Variability. Further, there are specialised contributions on the role of the oceanic circulation in climate change. The authors are renowned for their pedagogical skills, and the book is primarily designed for beginners in the field, who have a background in physical science. In addition, it is an invaluable source of information for scientists seeking an overview on climate dynamics.
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 Influence of the Sea Surface Temperature Decadal Variability on Tropical Precipitation West African and South American Monsoon written by Julián Villamayor and published by Springer. This book was released on 2019-07-05 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book the Sea Surface Temperature (SST) patterns of decadal-to-multidecadal variability observed and simulated by 17 general circulation models (GCMs) are analyzed. Furthermore, their impact on precipitation in West Africa and South America and the atmospheric mechanisms involved are assessed. Through this analysis, the effect of external forcings on these impacts and the relative contribution of decadal-to-multidecadal variability patterns of SST to precipitation are presented in depth. Finally, a humid period in the West African region of the Sahel during the 19th century, previously little documented, is analyzed using an atmospheric GCM. The monsoons of West Africa and South America have shown changes in the timescales of a few decades. Previous work suggests a relationship with patterns of decadal-to-multidecadal variability of SST, such as global warming and the Atlantic and Pacific variability. However, the dynamics underlying this relationship and its simulation by current GCMs had not been addressed in a consistent manner. This is the main motivation of this book. The results of this book not only represent a great step forward in our understanding of the changes in the precipitation regimes of the studied regions, but they can also be of great help for the improvement of decadal prediction systems and the associated social consequences.
Download or read book Climate Variability and Trend on Interannual to centennial Timescales from Global Observations and Atmosphere ocean Model Simulations written by Houk Paek and published by . This book was released on 2013 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The numerical climate models have provided scientists, policy makers and the general public, crucial information for climate projections since mid-20th century. An international effort to compare and validate the simulations of all major climate models is organized by the Coupled Model Intercomparison Project (CMIP), which has gone through several phases since 1995 with CMIP5 being the state of the art. In parallel, an organized effort to consolidate all observational data in the past century culminates in the creation of several "reanalysis" datasets that are considered the closest representation of the true observation. This study compared the climate variability and trend in the climate model simulations and observations on the timescales ranging from interannual to centennial. The analysis focused on the dynamic climate quantity of zonal-mean zonal wind and global atmospheric angular momentum (AAM), and incorporated multiple datasets from reanalysis and the most recent CMIP3 and CMIP5 archives. For the observation, the validation of AAM by the length-of-day (LOD) and the intercomparison of AAM revealed a good agreement among reanalyses on the interannual and the decadal-to-interdecadal timescales, respectively. But the most significant discrepancies among them are in the long-term mean and long-term trend. For the simulations, the CMIP5 models produced a significantly smaller bias and a narrower ensemble spread of the climatology and trend in the 20th century for AAM compared to CMIP3, while CMIP3 and CMIP5 simulations consistently produced a positive trend for the 20th and 21st century. Both CMIP3 and CMIP5 models produced a wide range of the magnitudes of decadal and interdecadal variability of wind component of AAM (MR) compared to observation. The ensemble means of CMIP3 and CMIP5 are not statistically distinguishable for either the 20th- or 21st-century runs. The in-house atmospheric general circulation model (AGCM) simulations forced by the sea surface temperature (SST) taken from the CMIP5 simulations as lower boundary conditions were carried out. The zonal wind and MR in the CMIP5 simulations are well simulated in the AGCM simulations. This confirmed SST as an important mediator in regulating the global atmospheric changes due to GHG effect.
Download or read book Prediction of Interannual Climate Variations written by J. Shukla and published by Springer. This book was released on 1993 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been known for some time that the behavior of the short-term fluctuations of the earth's atmosphere resembles that of a chaotic non-linear dynamical system, and that the day-to-day weather cannot be predicted beyond a few weeks. However, it has also been found that the interactions of the atmosphere with the underlying oceans and the land surfaces can produce fluctuations whose time scales are much longer than the limits of deterministic prediction of weather. It is, therefore, natural to ask whether it is possible that the seasonal and longer time averages of climate fluctuations can be predicted with sufficient skill to be beneficial for social and economic applications, even though the details of the day-to-day weather cannot be predicted beyond a few weeks. The main objective of the workshop was to address this question by assessing the current state of knowledge on predictability of seasonal and interannual climate variability and to investigate various possibilities for its prediction.
Download or read book Under the Weather written by National Research Council and published by National Academies Press. This book was released on 2001-06-29 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the dawn of medical science, people have recognized connections between a change in the weather and the appearance of epidemic disease. With today's technology, some hope that it will be possible to build models for predicting the emergence and spread of many infectious diseases based on climate and weather forecasts. However, separating the effects of climate from other effects presents a tremendous scientific challenge. Can we use climate and weather forecasts to predict infectious disease outbreaks? Can the field of public health advance from "surveillance and response" to "prediction and prevention?" And perhaps the most important question of all: Can we predict how global warming will affect the emergence and transmission of infectious disease agents around the world? Under the Weather evaluates our current understanding of the linkages among climate, ecosystems, and infectious disease; it then goes a step further and outlines the research needed to improve our understanding of these linkages. The book also examines the potential for using climate forecasts and ecological observations to help predict infectious disease outbreaks, identifies the necessary components for an epidemic early warning system, and reviews lessons learned from the use of climate forecasts in other realms of human activity.
Download or read book Indian Summer Monsoon Variability written by Jasti S. Chowdary and published by Elsevier. This book was released on 2021-08-15 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Indian Summer Monsoon Variability: El Niño-Teleconnections and Beyond presents the improved understanding of Indian Monsoon teleconnections (ENSO and Non-ENSO), new advances, and preferred future steps. Special emphasis is given to non-ENSO teleconnections which have been poorly understood for decades. With growing monsoon rainfall extremes across the Indian Subcontinent, a new understanding of monsoon environmental factors that are driven remotely through teleconnections is a trending topic. Finally, the book reviews current understanding ofthe observational and modeling aspects of Indian monsoon teleconnections. This is a must-read for researchers and graduate students in atmospheric science and meteorology. Presents teleconnections associated with the Indian summer monsoon from a global perspective Discusses new pathways that connect the remote drivers to Indian summer monsoon variability Covers a wide range of mechanisms, processes, and science questions in relation to monsoon variability from interannual, decadal to climate change time scales
Download or read book Interacting Climates of Ocean Basins written by Carlos R. Mechoso and published by Cambridge University Press. This book was released on 2020-11-26 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive review of interactions between the climates of different ocean basins and their key contributions to global climate variability and change. Providing essential theory and discussing outstanding examples as well as impacts on monsoons, it a useful resource for graduate students and researchers in the atmospheric and ocean sciences.
Download or read book Earth s Climate written by Chunzai Wang and published by American Geophysical Union. This book was released on 2004-01-09 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 147. It is more than 30 years since the publication of Jacob Bjerknes' groundbreaking ideas made clear the importance of ocean-atmosphere interaction in the tropics. It is now more than 20 years since the arrival of a massive El Niño in the fall of 1982 set off a cascade of observational and theoretical studies. During the following decades, the climate research community has made exceptional progress in refining our capacity to observe earth's climate and theorize about it, including new satellite-based and in situ monitoring systems and coupled ocean-atmosphere predictive numerical models. Of equal importance. is the expanding scope ofresearch, which now reaches far beyond the Pacific El Niño and includes climate phenomena in other ocean basins. In order to cover the now global context of ocean-atmosphere interaction we have organized this monograph around five principal themes, each introduced by one or more broad overview papers. Theme I covers interaction and climate variability in the Pacific sector, with extensive discussion of El Niño-Southern Oscillation, and with the possible causes and consequences of variability on both shorter and longer timescales. Theme II is devoted to interaction in the Atlantic sector. This basin exhibits complex behavior, reflecting its geographic location between two major zones of convection as well as neighboring the tropical Pacific. Theme III reviews the recent, exciting progress in our understanding of climate variability in the Indian sector. Theme IV addresses the interaction between the tropics and the extratropics, which are linked through the presence of shallow meridional overturning cells in the ocean. Finally, Theme V discusses overarching issues of cross-basin interaction.
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 Climate Analysis written by Chester F. Ropelewski and published by Cambridge University Press. This book was released on 2019-01-17 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sensational images and stories about variations in Earth's climate and their impacts on society are pervasive in the media. The scientific basis for these stories is often not understood by the general public, nor even by those with a scientific background in fields other than climate science. This book is a comprehensive resource that will enable the reader to understand and appreciate the significance of the flood of climate information. It is an excellent non-mathematical resource for learning the fundamentals of climate analysis, as well as a reference for non-climate experts that need to use climate information and data. The focus is on the basics of the climate system, how climate is observed and how the observations are transformed into datasets useful for monitoring the climate. Each chapter contains Discussion Questions. This is an invaluable textbook on climate analysis for advanced students, and a reference textbook for researchers and practitioners.
