Download or read book Relation Between Tropical Easterly Wave Convection and Tropical Cyclogenesis Over the Atlantic and East Pacific written by Kenneth D. Leppert (II.) and published by . This book was released on 2012 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tropical Cyclogenesis Within the Critical Layer of Tropical Easterly Waves written by Ali Asaadi and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This study provides new insight into the longstanding problem in tropical cyclogenesis involving the transformation of tropical easterly waves (EWs) into coherent cyclonic vortices. Observation indicates that only a small fraction of EWs in a single hurricane season become tropical cyclones. However, this small fraction accounts for a large portion of intense hurricanes. Some recent studies proposed the "Marsupial" paradigm and showed that named storms over the Atlantic and eastern Pacific basins are almost all associated with a cyclonic Kelvin cat's eye of an EW critical layer, located equatorward of the easterly jet axis. Yet no definitive study on the mechanism for the formation of the cat's eye has appeared in the literature. It is the purpose of this study to fill this gap. A climatological study of 54 developing EWs during 1998-2001 over the Atlantic and eastern Pacific was conducted using the European Centre for Medium-Range Weather Forecasts(ECMWF) reanalysis data. Time-lagged composites in a translating reference frame following the disturbances indicate a weak meridional potential vorticity (PV) gradient of the easterly jet, and a cyclonic critical layer located slightly south of the weak PV gradient. Using closed PV contour as a criterion for the formation of the cat's eye, it was shown that on average, it takes ~2.6 days for open contours to transform to a closed coherent structure. Additionally, it is found that EW train over the Atlantic and eastern Pacific is oriented in a southeast-northwest direction, due to the observed tilt in the easterly jet. Bootstrap analysis was then applied to determine the reliability of the EW train-like pattern in the composite perturbation PV analysis. The results indicate that the coexistence of a nonlinear critical layer and a region of weak meridional PV gradient over several days occurred in only ~25% of the EWs due to the aforementioned geometrical tilt. This geometric criterion may distinguish developing and non-developing disturbances and may constitute a necessary condition for EWs to develop into named storms. It also offers an explanation as to why only a small fraction of EWs contribute to tropical cyclogenesis. Additionally, using asymptotic theory we obtained an analytic time scale that governs the onset of nonlinearity for forced disturbances on a parabolic jet critical layer. This time scale is consistent with that found in 54 cases of EWs that developed into named storms, highlighting the importance of nonlinear and diabatic processes in cat's eye formation. A shallow water model is then used to study forced and unforced problems of disturbances on a parabolic jet and the observed jet in the composite. The nonlinear forced simulations, with the convective heating represented by a mass sink, produced a realistic time scale for cat's eye formation, and confirm our above-mentioned analytic solution. The modeling results further confirm the synergic role of the dynamical mechanisms of wave breaking and PV redistribution within the nonlinear critical layer, and the thermodynamical mechanism of convectively generated PV anomalies, in the formation of the cat's eye in tropical cyclogenesis. Finally, an objective tracking technique is used to track both developing and nondeveloping EWs. Composite analysis of the large scale structure and characteristics of nondeveloping EWs show that ~91% of non-developing waves are not located on a critical layer with weak PV gradient, while the remaining ~9% indicates characteristics similar to the developing waves. Examination of the composite OW parameter indicates that the nondeveloping waves are characterized by negative values implying that they are dominated by deformation, unlike developing waves which are dominated by vorticity. Our analysis and modeling results thus lend support to the proposed geometric criterion for cat's eye formation in tropical cyclogenesis." --
Download or read book A Multi scale Analysis of Tropical Cyclogenesis Within the Critical Layer of Tropical Easterly Waves in the Atlantic and Western North Pacific Sectors written by Louis L. Lussier and published by . This book was released on 2010 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: A newly proposed tropical cyclogenesis sequence that describes the transition of a tropical wave's critical layer to a tropical cyclone is used to examine two formation cases in the western North Pacific basin. Typhoon Nuri (2008), formed from a precursor easterly wave during the Tropical Cyclone Structure 2008 field experiment, and Typhoon Man-yi (2007), formed within an equatorial Rossby wave as it interacted with a monsoon trough. In each case, i) the critical layer of the parent wave protects a proto-vortex from an external hostile environment and allows it to strengthen until it becomes a self-sustained entity and ii) the intersection between the wave trough and critical latitude, within the Kelvin cat's eye, is the preferred location for tropical cyclogenesis. Numerical simulations suggest that the so-called "bottom-up" pathway to tropical cyclogenesis is favored within Typhoon Man-yi's critical layer. Additionally, Tropical Rainfall Measurement Mission (TRMM) composite analyses of 55 developing easterly waves indicate that as genesis approaches, i) convection is favored in the Kelvin cat's eye circulation, ii) the convective contribution to total rain rate becomes dominant, iii) the radius of maximum convection decreases, and iv) a convective-type heating profile is present. These findings support the "bottom-up" development model within easterly wave critical layers.
Download or read book Tropical Cyclogenesis and Its Relation to Interactions Between African Easterly Waves and Mesoscale Convective Systems written by Kelly Nunez Ocasio and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tropical cyclogenesis remains a challenging research topic, in part due to the limited understanding of the interactions between the mesoscale processes and the TC-seedling synoptic-scale vortex. The interactions between African easterly waves (AEWs) and mesoscale convective systems (MCSs) over Africa and east Atlantic and how they pertain to the formation of tropical cyclone (TCs) are documented. First, an algorithm that objectively tracks MCSs over Africa is developed to analyze the morphology and climatology of these systems over Africa. It is shown that realistic MCS propagation over Africa is attained when the tracker accounts for the African Easterly Jet (AEJ) mean background flow in which the MCSs propagate on. With an MCS dataset in place, a climatology AEW-MCS dataset is developed to perform a wave-relative analysis of AEW-MCS systems over Africa and over the Main Development Region. It is found that the MCSs of developing AEW-MCS systems (those that develop into TCs) are more likely to be in phase with and propagate at the same speed as the AEW trough. In contrast, the MCSs of non-developing AEW-MCS systems are more likely to be positioned south of the AEW trough and do not necessarily propagate at the same speed. In addition, it is found that developing AEWs over West Africa are associated with a larger number of Convective Cloud Clusters (CCCs; squall line-type systems) than non-developing AEWs. Over West Africa, the fraction of extremely large MCS areas associated with developing AEWs is larger than for non-developing AEWs. These findings support the notion that both the position of moisture and latent heating relative to the AEW trough are essential for cyclogenesis. At the synoptic-scale, significant differences between developing and non-developing AEWs are identified over eastern Africa (region of AEW onset) that can inform tropical cyclogenesis prediction. TC precursors when compared to non-developing AEWs experience: anomalously active West African Monsoon, stronger northerly flow, more intense zonal Somali jet, anomalous convergence over the Marrah Mountains (region of AEW forcing), and a more intense and elongated African easterly jet (AEJ). These more favorable large scale condition for developers reflect in their initial 850-hPa dynamic and thermodynamic structure over eastern Africa. It is found that AEWs that initiate over eastern Africa and cross the west coast of Africa are more likely to undergo tropical cyclogenesis than those initiating over central or west Africa. Developing AEWs are also more likely to be southern-track AEWs than non-developers.
Download or read book Meteorology of Tropical West Africa written by Douglas J. Parker and published by John Wiley & Sons. This book was released on 2017-02-13 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: Meteorology of tropical West Africa: the Forecasters’ Handbook presents the science and practice of weather forecasting for an important region of the tropics. Connecting basic theory with forecasting practice, the book provides a unique training volume for operational weather forecasters, and is also suitable for students of tropical meteorology. The West African region contains a number of archetypal climatic zones, meaning that the science of its weather and climate applies to many other tropical regions. West Africa also exhibits some of the world’s most remarkable weather systems, making it an inspiring region for students to investigate. The weather of West Africa affects human livelihoods on a daily basis, and can contribute to hardship, poverty and mortality. Therefore, the ability to understand and predict the weather has the potential to deliver significant benefits to both society and economies. The book includes comprehensive background material alongside documentation of weather forecasting methods. Many examples taken from observations of West African weather systems are included and online case-studies are referenced widely.
Download or read book Practical Meteorology written by Roland Stull and published by Sundog Publishing, LLC. This book was released on 2018 with total page 942 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantitative introduction to atmospheric science for students and professionals who want to understand and apply basic meteorological concepts but who are not ready for calculus.
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 Remote Sensing and Global Environmental Change written by Sam J. Purkis and published by John Wiley & Sons. This book was released on 2011-03-03 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Remote Sensing plays a key role in monitoring the various manifestations of global climate change. It is used routinely in the assessment and mapping of biodiversity over large areas, in the monitoring of changes to the physical environment, in assessing threats to various components of natural systems, and in the identification of priority areas for conservation. This book presents the fundamentals of remote sensing technology, but rather than containing lengthy explanations of sensor specifications and operation, it concentrates instead on the application of the technology to key environmental systems. Each system forms the basis of a separate chapter, and each is illustrated by real world case studies and examples. Readership The book is intended for advanced undergraduate and graduate students in earth science, environmental science, or physical geography taking a course in environmental remote sensing. It will also be an invaluable reference for environmental scientists and managers who require an overview of the use of remote sensing in monitoring and mapping environmental change at regional and global scales. Additional resources for this book can be found at: http://www.wiley.com/go/purkis/remote.
Download or read book Storm and Cloud Dynamics written by William R. Cotton and published by Academic Press. This book was released on 2010-12-21 with total page 826 pages. Available in PDF, EPUB and Kindle. Book excerpt: Storm and Cloud Dynamics focuses on the dynamics of clouds and of precipitating mesoscale meteorological systems. Clouds and precipitating mesoscale systems represent some of the most important and scientifically exciting weather systems in the world. These are the systems that produce torrential rains, severe winds including downburst and tornadoes, hail, thunder and lightning, and major snow storms. Forecasting such storms represents a major challenge since they are too small to be adequately resolved by conventional observing networks and numerical prediction models. Provides a complete treatment of clouds integrating the analysis of air motions with cloud structure, microphysics, and precipitation mechanics Describes and explains the basic types of clouds and cloud systems that occur in the atmosphere-fog, stratus, stratocumulus, altocumulus, altostratus, cirrus, thunderstorms, tornadoes, waterspouts, orographically induced clouds, mesoscale convection complexes, hurricanes, fronts, and extratropical cyclones Summarizes the fundamentals, both observational and theoretical, of atmospheric dynamics, thermodynamics, cloud microphysics, and radar meteorology, allowing each type of cloud to be examined in depth Integrates the latest field observations, numerical model simulations, and theory Supplies a theoretical treatment suitable for the advanced undergraduate or graduate level, as well as post-graduate
Download or read book Simulations Of Tropical Cyclone In Regional Climate Models written by Zhong Zhong and published by World Scientific. This book was released on 2018-02-01 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book studies the pitfalls of regional climate models in simulating track and intensity of tropical cyclone over western North Pacific for the East Asian summer monsoon climate.A number of sensitivity experiments related to tropical cyclone simulation with different model configurations and model physical schemes, including model resolution, model lateral boundary condition, effect of sea surface temperature, cumulus parameterization scheme and model microphysics scheme, as well as the features and the failure of tropical cyclone simulation in regional climate models were carefully analyzed with model output with high temporal resolution, to investigate shortcomings of the models, so as to come up with better models to simulate and study tropical cyclone track and intensity.The book is suitable for graduate students in meteorology with focuses in the tropical cyclone simulation, as well as professionals devoted to model development and study of tropical cyclone activities.
Download or read book Climate Extremes written by S.-Y. Simon Wang and published by John Wiley & Sons. This book was released on 2017-06-15 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although we are seeing more weather and climate extremes, individual extreme events are very diverse and generalization of trends is difficult. For example, mid-latitude and subtropical climate extremes such as heat waves, hurricanes and droughts have increased, and could have been caused by processes including arctic amplification, jet stream meandering, and tropical expansion. This volume documents various climate extreme events and associated changes that have been analyzed through diagnostics, modeling, and statistical approaches. The identification of patterns and mechanisms can aid the prediction of future extreme events. Volume highlights include: Compilation of processes and mechanisms unique to individual weather and climate extreme events Discussion of climate model performance in terms of simulating high-impact weather and climate extremes Summary of various existing theories, including controversial ones, on how climate extremes will continue to become stronger and more frequent Climate Extremes: Patterns and Mechanisms is a valuable resource for scientists and graduate students in the fields of geophysics, climate physics, natural hazards, and environmental science. Read an interview with the editors to find out more: https://eos.org/editors-vox/how-does-changing-climate-bring-more-extreme-events
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Perspectives On Tropical Cyclones From Science To Mitigation written by Johnny C L Chan and published by World Scientific. This book was released on 2010-04-30 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a completely rewritten, updated and expanded new edition of the original Global Perspectives on Tropical Cyclones published in 1995. It presents a comprehensive review of the state of science and forecasting of tropical cyclones together with the application of this science to disaster mitigation, hence the tag: From Science to Mitigation.Since the previous volume, enormous progress in understanding tropical cyclones has been achieved. These advances range from the theoretical through to ever more sophisticated computer modeling, all underpinned by a vast and growing range of observations from airborne, space and ocean observation platforms. The growth in observational capability is reflected by the inclusion of three new chapters on this topic. The chapter on the effects of climate change on tropical cyclone activity is also new, and appropriate given the recent intense debate on this issue. The advances in the understanding of tropical cyclones which have led to significant improvements in forecasting track, intensity, rainfall and storm surge, are reviewed in detail over three chapters. For the first time, a chapter on seasonal prediction is included. The book concludes with an important chapter on disaster mitigation, which is timely given the enormous loss of life in recent tropical cyclone disasters.World Scientific Series on Asia-Pacific Weather and Climate is indexed in SCOPUS.
Download or read book The Encyclopedia of Climatology written by J.E. Oliver and published by Springer. This book was released on 1987 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today's greater public awareness of how climate affects our quality of life and environment has created an increasing demand for climatological information. Now this information is available in one convenient, accessible source, The Encyclopedia of Climatology. This comprehensive volume covers all the main subfields of climatology, supplies data on climates in major continental areas and explains what is known about the causes of climatic processes and changes. Contents include articles on bioclimatology, El Niño, climatic models, world regional climates, civilization and climate, climatic variations and the greenhouse effect.
Download or read book Dynamics of the Tropical Atmosphere and Oceans written by Peter J. Webster and published by John Wiley & Sons. This book was released on 2020-06-08 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a unique and comprehensive view of the fundamental dynamical and thermodynamic principles underlying the large circulations of the coupled ocean-atmosphere system Dynamics of The Tropical Atmosphere and Oceans provides a detailed description of macroscale tropical circulation systems such as the monsoon, the Hadley and Walker Circulations, El Niño, and the tropical ocean warm pool. These macroscale circulations interact with a myriad of higher frequency systems, ranging from convective cloud systems to migrating equatorial waves that attend the low-frequency background flow. Towards understanding and predicting these circulation systems. A comprehensive overview of the dynamics and thermodynamics of large-scale tropical atmosphere and oceans is presented using both a “reductionist” and “holistic” perspectives of the coupled tropical system. The reductionist perspective provides a detailed description of the individual elements of the ocean and atmospheric circulations. The physical nature of each component of the tropical circulation such as the Hadley and Walker circulations, the monsoon, the incursion of extratropical phenomena into the tropics, precipitation distributions, equatorial waves and disturbances described in detail. The holistic perspective provides a physical description of how the collection of the individual components produces the observed tropical weather and climate. How the collective tropical processes determine the tropical circulation and their role in global weather and climate is provided in a series of overlapping theoretical and modelling constructs. The structure of the book follows a graduated framework. Following a detailed description of tropical phenomenology, the reader is introduced to dynamical and thermodynamical constraints that guide the planetary climate and establish a critical role for the tropics. Equatorial wave theory is developed for simple and complex background flows, including the critical role played by moist processes. The manner in which the tropics and the extratropics interact is then described, followed by a discussion of the physics behind the subtropical and near-equatorial precipitation including arid regions. The El Niño phenomena and the monsoon circulations are discussed, including their covariance and predictability. Finally, the changing structure of the tropics is discussed in terms of the extent of the tropical ocean warm pool and its relationship to the intensity of global convection and climate change. Dynamics of the Tropical Atmosphere and Oceans is aimed at advanced undergraduate and early career graduate students. It also serves as an excellent general reference book for scientists interested in tropical circulations and their relationship with the broader climate system.
Download or read book The Influence of Equatorial Rossby Waves on the Flow Convection and Tropical Cyclones Over the Australian Tropics and Southeastern Indonesia written by Joan Patricia Fernon and published by . This book was released on 2014 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines Equatorial Rossby Waves (ERWs) and their modulation of the low to middle level flow, convection and tropical cyclogenesis associated with the passage of over northern Australia, southeastern Indonesia and adjoining waters during the Austral summer wet season. ERWs are equatorially trapped, convectively coupled, westward propagating waves, which are symmetric about the equator. In the Southern Hemisphere the enhanced (suppressed) convective phase of these waves is associated with northwesterly (southeasterly) low to middle level wind anomalies. In the western Pacific, in the absence of dominating low to middle level easterly flow, ERWs manifest themselves as twin cyclonic circulations on either side of the equator. In this thesis ERWs are identified using 9.7 to 48 day band pass filtered outgoing long-wave radiation (OLR) data. Nine strong ERW events, and also thirteen tropical cyclone (TC) genesis events where the initial circulation formed in the Banda Sea, are investigated using a case study and compositing approach. Principal component analysis was employed to investigate all Austral wet season ERW events from January 1979 to 30 April 2011. These data indicated that on average there were 11 ERW events moving through Australian longitudes each wet season. Conclusions reached in this thesis are based on the two sets of events/case studies and the principle component analysis.Analysis of the data over Australian longitudes indicates that there are two classes of ERW events, in which both the propagation of the ERWs and the modulation of the flow, convection and TC genesis differ. These classes are associated with the pre-existing synoptic situation over the region. The first class is characterised by a pre-existing monsoon trough. Four of the nine case studies fall into this class, the remaining five case studies fall into the second class. This class is characterised by a pre-existing, near equatorial trough and easterly low to middle level mean flow extending southward over northern Australia. For the first class of ERW event the focus of enhanced convection and precipitation is over northern Australia and the Coral Sea with the monsoon trough moving south and the flow to its north strengthening and becoming more northerly. Pre-existing circulations within the trough can intensify or new circulations can form. These circulations sometimes reach tropical cyclone intensity. Over the northern Australian, southeastern Indonesian region during the mid wet season months of January through March the monsoon trough is the persistent synoptic feature. Hence over this region during these months most ERW events fall into the first class of event. During these months ERWs propagate to the southwest and tend to weaken. They have an average wave length of 6090km, with an average westward ground based phase speed of 4.4ms-1. For the second class of ERW event a typical scenario occurs when the Southern Hemisphere member of the ERW twin moves westward from the Pacific basin and loses its structure as it traverses the Papua New Guinea (PNG) highlands then rapidly reforms to the west of PNG, thus initiating the formation of the monsoon trough to the north of Australia. In individual events the subsequent development and movement of this system and the trough affect the deep layer flow and precipitation over northern Australia and southeastern Indonesia. In a number of scenarios investigated in this thesis the circulation reached tropical cyclone intensity. In these scenarios the system initially moved to the west and then generally recurved towards the southeast, making landfall on the northwest Australian coast.During the early and late wet season months of November, December and April the near equatorial trough is the typical synoptic situation, so most ERW events fall into the second class of event. During these months ERWs have an average wave length of 6570km, with an average westward phase speed of 4.8ms-1. On average during these months ERWs propagate parallel to the equator and maintain their strength as they move through Australian/Indonesian longitudes.ERWs were found to modulate tropical cyclogenesis (TC genesis) over the Australian/eastern Indonesian region. During the mid wet season months ERWs modulate TC genesis in the east and central parts of the region and in far west. During the early and late wet season ERWs modulate TC genesis in the central parts of the region.Thirteen TCs were found to have initially formed as circulations in the Banda Sea. Eleven of these systems formed in the early or late wet season. The initial formation and movement of each of these eleven systems were intimately associated with the passage of active ERW phases. Subsequent to their initial formation as cyclonic circulations most of the thirteen systems rapidly intensified to tropical cyclone strength and beyond in a favourable environment provided by an active phase of a Madden Julian Oscillation (MJO). These systems can bring severe weather to the eastern Indonesian Archipelago with heavy rainfall and landslides due to steep topography and very deep soil profiles.
Download or read book Tropical and Extratropical Air Sea Interactions written by Swadhin Kumar Behera and published by Elsevier. This book was released on 2020-11-18 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tropical and Extratropical Air-Sea Interactions: Modes of Climate Variations provides a thorough introduction to global atmospheric and oceanic processes, as well as tropical, subtropical and mid-latitude ocean-atmosphere interactions. Written by leading experts in the field, each chapter is dedicated to a specific topic of air-sea interactions (such as ENSO, IOD, Atlantic Nino, ENSO Modoki, and newly discovered coastal Niños/Niñas) and their teleconnections. As the first book to cover all topics of tropical and extra-tropical air-sea interactions and new modes of climate variations, this book is an excellent resource for researchers and students of ocean, atmospheric and climate sciences. Presents case studies on the ocean-atmosphere phenomena, including El Nino Southern Oscillation (ENSO), Indian Ocean Dipole and different Nino/Nina phenomena Provides a clear description of air-sea relationships across the world’s ocean with an analysis of air-sea relations in different time scales and a focus on climate change Includes prospects for air-sea interaction research, thus benefiting young researchers and students
