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Variability And Trends In The Tropical Pacific And The El Nino Southern Oscillation Inferred From Coral And Lake Archives
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Book Synopsis Variability and Trends in the Tropical Pacific and the El Niño-Southern Oscillation Inferred from Coral and Lake Archives by : Diane Marie Thompson
Download or read book Variability and Trends in the Tropical Pacific and the El Niño-Southern Oscillation Inferred from Coral and Lake Archives written by Diane Marie Thompson and published by . This book was released on 2013 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Reconstructing Past Changes in El Niño-Southern Oscillation Variability Using Geochemical Proxies from Corals by : Allison E. Lawman
Download or read book Reconstructing Past Changes in El Niño-Southern Oscillation Variability Using Geochemical Proxies from Corals written by Allison E. Lawman and published by . This book was released on 2020 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: The El Niño-Southern Oscillation (ENSO) is the leading mode of interannual (>1-9 year) climate variability and has far-reaching impacts on global temperature and rainfall patterns. That said, the instrumental record of ENSO does not have the temporal coverage necessary to characterize the full range of natural variability. Uncertainties about how ENSO variability may change in the future with anthropogenic warming motivates the study of past climate conditions when the Earth experienced different climate conditions compared to the warm, rapidly changing climate of today. Climate scientists use two primary tools to study past climate. First, general circulation models use mathematical equations based on physical principles to simulate different aspects of the climate system, including the ocean, atmosphere, land, and ice sheets. Second, various geological archives like corals, cave stalagmites and lake and ocean sediment also provide clues about how the climate varied in the past. The paleoclimate proxy records generated from geological archives thus provide independent validation of paleoclimate model simulations. Geochemical proxy records from corals are particularly well-suited for investigating past (paleo) ENSO variability as corals can provide decades to hundreds of years of climate information from the tropics at sub-annual resolution. This dissertation seeks to quantify changes in paleo-ENSO variability using geochemical proxies from corals. I first generate replicated coral records from Vanuatu in the southwest Pacific to investigate the range of ENSO variability during the 20th century and ~900 years during a time interval called the Medieval Climate Anomaly. The paleo-temperature records are based on the ratio of strontium to calcium (Sr/Ca) of massive Porites corals from Vanuatu. Next, I develop various computational algorithms to investigate how different uncertainties inherent to the coral archive impact the ability of a coral to capture changes in ENSO variability. The algorithms incorporate the impact of variable growth rates, analytical and calibration errors, and age model assumptions, and are collectively referred to a coral proxy system model (PSM). The utility of the coral PSM is demonstrated using unforced climate model output for the last millennium. I then use the PSM and apply the analytical techniques developed in the first two projects to investigate simulated and coral proxy-inferred changes in paleo-ENSO variability during the Holocene (11.65 thousand years ago to the present). The resulting model-data comparison provides a new perspective on long-term changes in ENSO variability
Book Synopsis El Niño Southern Oscillation in a Changing Climate by : Michael J. McPhaden
Download or read book El Niño 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.
Book Synopsis Coral Records of the El Niño-southern Oscillation and Tropical Pacific Climate Over the Last Millennium by : Kim M. Cobb
Download or read book Coral Records of the El Niño-southern Oscillation and Tropical Pacific Climate Over the Last Millennium written by Kim M. Cobb and published by . This book was released on 2002 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis El Niño-Southern Oscillation (ENSO) and Tropical Pacific Climate Across the 4.2 Ka BP Climate Excursion by : Karen V. Gutierrez
Download or read book El Niño-Southern Oscillation (ENSO) and Tropical Pacific Climate Across the 4.2 Ka BP Climate Excursion written by Karen V. Gutierrez and published by . This book was released on 2021 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin and influence of the "4.2 kyr event"--a climate excursion characterized by century-long drought hypothesized to have affected civilizations throughout the northern subtropics--is uncertain, despite its registration in multiple paleoclimatic archives. As the dominant source of global interannual climate variability, the El Niño-Southern Oscillation (ENSO) might be expected to have shaped the expression of global precipitation and temperature across the 4.2 kyr event. However, the role of ENSO has not been explored, owing to a general lack of temporally extended observations in the tropical Pacific. Here I analyze a number of tropical Pacific Porites coral fossils spanning this interval, between ~4600 and 4100 years B.P., building on the previously published record of ENSO activity as well as the prevailing mean state of the tropical Pacific climate. Monthly resolved oxygen isotopic records of three corals from Fanning Island and one from Christmas Island overlap with and extend existing records to produce a nearly-continuous sequence that spans several hundred years. Oxygen isotopic values of the overlapping segments of the fossil corals strengthen the reliability of the paleoclimate record and the radiometric dating. The new coral data generated in this study confirm the previous inference of low ENSO activity over an extended time interval encompassing the 4.2 kyr event. Additionally, the new coral data show that the interannual variability, though reduced in amplitude relative to the modern climate, was expressed as repeated episodes of prolonged and intense La Niña conditions. This characterization stands in contrast with a single multi-decadal excursion, as initially hypothesized for the 4.2 kyr event. Finally, the mean values of overlapping coral segments from Fanning and Christmas Islands are similar, suggesting that the modern temperature and salinity gradient was not present during the interval of the 4.2 kyr event. The simplest explanation for this lack of temperature/salinity gradient is that the southern boundary of the North Equatorial Counter Current was shifted north of Fanning Island.
Book Synopsis An Introduction to the Dynamics of El Nino and the Southern Oscillation by : Allan J. Clarke
Download or read book An Introduction to the Dynamics of El Nino and the Southern Oscillation written by Allan J. Clarke and published by Elsevier. This book was released on 2008-01-28 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many scientists either working on the El Niño/Southern Oscillation (ENSO) problem or its many applications have not been trained in both the equatorial ocean and atmospheric dynamics necessary to understand it. This book seeks to overcome this difficulty by providing a step by step introduction to ENSO, helping the upper level graduate student or research scientist to learn quickly the ENSO basics and be up to date with the latest ENSO research. The text assumes that the reader has a knowledge of the equations of fluid mechanics on a rotating earth and emphasizes the observations and simple physical explanations of them. Following a history of ENSO and a discussion of ENSO observations in Chapters 1 and 2, Chapters 3-5 consider relevant equatorial ocean dynamics, Chapters 6 and 9 relevant atmospheric dynamics, and Chapters 7 and 8 the main paradigms for how the Pacific Ocean and atmosphere couple together to produce ENSO. Chapter 8 also discusses the old mystery of why ENSO tends to be locked in phase with the seasonal cycle. Successful dynamical and statistical approaches to ENSO prediction are discussed in Chapters 10 and 11 while Chapter 12 concludes the book with examples of how ENSO influences marine and bird life. Quick reference guide and step by step introduction to El Niño/Southern Oscillation dynamics Keep informed and up to date on El Niño/Southern Oscillation research and how El Niño and the Southern Oscillation can be predicted Understand how El Niño can affect marine and bird life
Book Synopsis The El Niño-Southern Oscillation Phenomenon by : Edward S. Sarachik
Download or read book The El Niño-Southern Oscillation Phenomenon written by Edward S. Sarachik and published by Cambridge University Press. This book was released on 2010-02-18 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many climatic extremes around the globe, such as severe droughts and floods, can be attributed to the periodic warming of the equatorial Pacific sea surface, termed the El Niño or Southern Oscillation (ENSO). Advances in our understanding of ENSO, in which Edward S. Sarachik and Mark A. Cane have been key participants, have led to marked improvements in our ability to predict its development months or seasons, allowing adaptation to global impacts. This book introduces basic concepts and builds to more detailed theoretical treatments. Chapters on the structure and dynamics of the tropical ocean and atmosphere place ENSO in a broader observational and theoretical context. Chapters on ENSO prediction, past and future, and impacts, introduce broader implications of the phenomenon. This book provides an introduction to all aspects of this most important mode of global climate variability, for research workers and students of all levels in climate science, oceanography and related fields.
Book Synopsis Influence of Mean Climate Change on Climate Variability from a 155-Year Tropical Pacific Coral Record by :
Download or read book Influence of Mean Climate Change on Climate Variability from a 155-Year Tropical Pacific Coral Record written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. National Oceanic and Atmospheric Administration (NOAA) presents an abstract for the article entitled "Influence of Mean Climate Change on Climate Variability from a 155-Year Tropical Pacific Coral Record," by F.E. Urban, J.E. Cole, and J.T. Overpeck. The article was published in the October 2000 issue of "Nature." The article discusses the El Nino/Southern Oscillation (ENSO) system and the influence of increasing atmospheric concentrations of greenhouse gases on ENSO variability.
Book Synopsis El Niño, Southern Oscillation & Climatic Variability by : Rob Allan
Download or read book El Niño, Southern Oscillation & Climatic Variability written by Rob Allan and published by CSIRO Publishing. This book was released on 1996 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accompanied by a CD-ROM; El Nino and La Nina, Southern Oscillation and SOI, ENSO - ENSO structure, nature and physical characteristics - Data and methods - Oceanic, atmospheric and hydrological variable responses to ENSO - Patterns in historical records - Wider terrestrial and marine environmental impactst_____________
Book Synopsis Learning to Predict Climate Variations Associated with El Nino and the Southern Oscillation by : National Research Council
Download or read book Learning to Predict Climate Variations Associated with El Nino and the Southern Oscillation written by National Research Council and published by National Academies Press. This book was released on 1997-01-12 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: The TOGA (Tropical Ocean and Global Atmosphere) Program was designed to study short-term climate variations. A 10-year international program, TOGA made El Nino a household word. This book chronicles the cooperative efforts of oceanographers and meteorologists, several U.S. government agencies, many other nations, and international scientific organizations to study El Nino and the Southern Oscillation (ENSO). It describes the progression from being unable to detect the development of large climate variations to being able to make and use rudimentary climate predictions, especially for some tropical countries. It examines the development of the TOGA Program, evaluates its accomplishments, describes U.S. participation in the program, and makes general recommendations for developing better understanding and predictions of climate variations on seasonal to interannual time scales.
Book Synopsis Tropical Pacific Decadal Variability and ENSO Amplitude Modulation in a CGCM by : Sang-Wook Yeh
Download or read book Tropical Pacific Decadal Variability and ENSO Amplitude Modulation in a CGCM written by Sang-Wook Yeh and published by . This book was released on 2004 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis El Niño-Southern Oscillation Variability During the Little Ice Age and Medieval Climate Anomaly Reconstructed from Fossil Coral Geochemistry and Pseudoproxy Analysis by : Kelly Ann Hereid
Download or read book El Niño-Southern Oscillation Variability During the Little Ice Age and Medieval Climate Anomaly Reconstructed from Fossil Coral Geochemistry and Pseudoproxy Analysis written by Kelly Ann Hereid and published by . This book was released on 2012 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: The El Niño-Southern Oscillation (ENSO) dominates global interannual climate variability. However, the imprint of anthropogenic climate change hinders understanding of natural ENSO variability. Model predictions of the response of future ENSO variability to anthropogenic forcing are highly uncertain. A better understanding of how ENSO operates during different mean climate states may improve predictions of its future behavior. This study develops a technique to quantify the response of tropical Pacific sea surface temperature and salinity to ENSO variations. This analysis defines expected regional relationships between ENSO forcing and the tropical Pacific climate response. For example, the western tropical Pacific records El Niño events with greater skill than La Niña events; whereas the oceans near the South Pacific Convergence Zone (SPCZ) preferentially record La Niña events. This baseline understanding of regional skill calibrates interpretations of both modern and pre-instrumental coral geochemical climate proxy records. A suite of monthly resolved [delta]18O variations in a fossil corals (Porites spp.) from the tropical western Pacific (Papua New Guinea) and the SPCZ (Vanuatu) are used to develop case studies of ENSO variability under external forcing conditions that differ from the modern climate. A record from Misima, Papua New Guinea (1411-1644 CE) spans a period of reduced solar forcing that coincides with the initiation of the Little Ice Age. This record indicates that the surface ocean in this region experienced a small change in hydrologic balance with no change in temperature, extended periods of quiescence in El Niño activity, reduced mean El Niño event amplitudes, and fewer large amplitude El Niño events relative to signals captured in regional modern records. Several multidecadal (~30-50 year) coral records from Tasmaloum, Vanuatu during the Medieval Climate Anomaly (~900-1300 CE), a period of increased solar forcing, depict ENSO variability that is generally lower than modern times. However, these records often cannot be distinguished from 20th century ENSO variability due to ENSO variability uncertainty associated with record lengths. Neither record can be tied to concurrent changes in solar or volcanic forcing, calling into question the paradigm of ENSO variability being predominantly mediated by external forcing changes on multidecadal time scales.
Book Synopsis Mechanisms of Tropical Pacific Climate Change During the Holocene by : Alyssa Regine Atwood
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.
Book Synopsis West Pacific Warm Pool, South Pacific Convergence Zone and El Niño by : Christopher Robert Maupin
Download or read book West Pacific Warm Pool, South Pacific Convergence Zone and El Niño written by Christopher Robert Maupin and published by . This book was released on 2014 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observations and reconstructions of climate variability are necessary to place predictions of future global climate change into temporal context (Goddard et al., 2012). I focus here on the western tropical Pacific (Solomon Islands; ~9.5°S, ~160°E), a region directly influenced by: the South Pacific Convergence Zone (SPCZ), the West Pacific Warm Pool, the Pacific Walker Circulation, and the Hadley Circulation. The West Pacific Warm Pool (WPWP) is an integral source of heat and moisture to the atmosphere. It is part of both Walker and Hadley circulations, and the El Niño-Southern Oscillation (ENSO), which is the largest source of interannual climate variability on Earth. Modern observations of changes in the mean state of the WPWP, Walker circulation, and ENSO are limited in temporal scale and overprinted with the signal of anthropogenic climate change; hence, proxy-based observations in the pre-instrumental period are needed to place any future changes in these systems, and attribution of these changes, into context. I present evidence for large (~1.5 m), abrupt, and periodic changes in total annual rainfall amount on decadal to multidecadal timescales since 1423±5 CE (Year Common Era) in the Solomon Islands utilizing a fast growing (>2 mm yr−1) stalagmite sample and an empirical relationship developed between stalagmite [delta]18O and local rainfall amount. The ~600-yr Solomon Islands stalagmite [delta]18O record indicates that decadal oscillations in rainfall are a persistent characteristic of SPCZ-related climate variability, and available evidence points to these changes arising from internal forcing. Such changes have important implications to water resource management in this region, in addition to contextualizing models and future predictions of rainfall amount changes and latent heat release into the atmosphere via anthropogenic climate change. I also present a reconstruction pre-instrumental variability utilizing a monthly [delta]18O time series generated series from the long lived, slow-growing coral species Diploastrea heliopora spanning 1716-2008 CE. The record demonstrates strong coherence with modern instrumental variability, and in addition, demonstrates variance in centennial-multicentury, decadal-multidecadal and interannual bands. Quantitative comparison of the interannual component of the record to instrumental ENSO indices, and application of the resulting metrics to previously undocumented, potentially extreme ENSO events occurring during the early eighteenth and nineteenth centuries. These extreme events are absent from existing multiproxy reconstructions due to temporal limitations of extant proxies that have the greatest ENSO sensitivity. The intensity of these events may rival or exceed the largest in the instrumental record. The record also contains significant but transient decadal to multidecadal variability. The coral record exhibits a trend toward isotopic depletion, implying significant changes in SST and/or SSS over the entirety of the record. I also document the unique behavior of the SPCZ and the Intertropical Convergence Zone (ITCZ) over the past six centuries, present evidence of influence by decadal-scale advection processes on Solomon Islands SSS, and explore basin-scale changes in the tropical Pacific conditions potentially related to global average temperature change over the past three centuries.
Book Synopsis A Collection of Studies on the Effects of the 1997-98 El Niño-Southern Oscillation Event on Corals and Coral Reefs in the Eastern Tropical Pacific by : Peter W. Glynn
Download or read book A Collection of Studies on the Effects of the 1997-98 El Niño-Southern Oscillation Event on Corals and Coral Reefs in the Eastern Tropical Pacific written by Peter W. Glynn and published by . This book was released on 2001 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Tropical Ocean-atmosphere Newsletter by :
Download or read book Tropical Ocean-atmosphere Newsletter written by and published by . This book was released on 1980 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Long-term Change of El Niño Southern Oscillation in an Ensemble Reanalysis and Climate Coupled Models by : Chunxue Yang
Download or read book The Long-term Change of El Niño Southern Oscillation in an Ensemble Reanalysis and Climate Coupled Models written by Chunxue Yang and published by . This book was released on 2013 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-term changes of El Niño/Southern Oscillation (ENSO) are studied with the ensemble run of Simple Ocean Data Assimilation (SODA 2.2.6) and the Coupled Model Intercomparison Project Phase 5 (CMIP5). An eight member ocean reanalyses (SODA 2.2.6) from 1871 to 2008 is produced by using forcing from eight ensemble members of an atmospheric reanalysis. The ensemble reanalysis shows that El Niño has prominent decadal variability. Weak El Niños occur throughout the entire record whereas the occurrence of strong El Niños varies, with strong El Niño at the beginning and end of the record. The strength of La Niña is weaker than for El Niño, and has less variability. Although for any given El Niño year all ensemble members show the occurrence of El Niño, in some ensemble members the El Niño is strong while in others it is weak. When the timing of the onset of Westerly Wind Bursts (WWBs) occurs earlier in the year and the strength of WWBs is stronger, strong El Niño occurs. To study the importance of the background state in the tropical Pacific Ocean on ENSO, long-term trends of tropical Pacific SST, wind stress, subsurface temperature and the sub-tropical cells (STCs) are analyzed. The reanalysis shows that there is a slight cooling trend of SST in the central tropical Pacific due to an enhanced tropical Pacific circulation. Subsurface temperature also has a cooling trend. The STCs, which consist of equatorial upwelling, Ekman transport, extra-tropical subduction and pycnocline transport from the sub-tropical to the tropical region, strengthen from 1900 to 2008. When the STCs are accelerated, equatorial upwelling increases bringing cold water from the subsurface that cools the surface. ENSO variability is also analyzed in the CMIP5 historical experiments. Results show that most of the models have a realistic representation of the strength of ENSO; however, the location of warming generally extends too far to the west. Overall, properties of ENSO do not show a significant change in most of the CMIP5 models. One distinguishing difference between the CMIP5 models and SODA 2.2.6 is that ENSO in SODA 2.2.6 has prominent asymmetry between El Niño and La Niña, whereas ENSO in the CMIP5 models tends to have fairly symmetric El Niño and La Niña. In contrast with the reanalysis most of the CMIP5 models have warming trends at the surface and the transport of the STCs has a decreasing trend. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148283
