Download or read book Aspects of Moat Formation in Tropical Cyclone Eyewall Replacement Cycles written by Christopher Michael Rozoff and published by . This book was released on 2007 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impacts of Asymmetric Dynamics on Tropical Cyclone Eyewall Replacement Cycles written by Tsz Kin Lai and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In mature tropical cyclones (TCs), secondary eyewall formation (SEF) is a frequently observed feature associated with the formation of an outer (secondary) eyewall outside the existing (primary) eyewall. The two eyewalls are separated by a moat region of convective minimum and vorticity minimum. An SEF is often followed by an eyewall replacement cycle (ERC) during which the contracting outer eyewall gradually intensifies while the inner eyewall dissipates. Throughout this period, significant changes in the size and the intensity of the TC usually occur. Therefore, a better understanding of ERC is desired for better TC forecasts. Nevertheless, the mechanisms underlying inner eyewall decay (IED) and outer eyewall intensification (OEI) are not well-understood. It is widely accepted that the cutoff effect associated with the OE makes the main contribution to the IED. However, radar imagery of some double-eyewall TCs showed that the TC vortices became elliptic prior to and during the IED. This kind of elliptic development could result from the dynamic (barotropic) instability across the moat, which is a region of sign reverse of vorticity gradient and satisfies the Rayleigh necessary condition for barotropic instability. Hence, the instability across the moat (known as the type-2 instability) may also make contributions to IED. As the first part of the thesis (Chapter 2), a study of the simulated Hurricane Wilma (2005) is conducted by using a three-dimensional (3D) cloud-resolving full-physics numerical model. It is found that the timing of the onset of the type-2 instability is coincident with the start of the rapid decrease of the low-level IE circulation, indicating that the circulation of the IE is likely weakened by the vorticity mixing associated with the type-2 instability. In the second part of the thesis (Chapter 3), two 3D numerical experiments are performed to further explore the underlying dynamics. The detailed budget analyses of azimuthally averaged absolute angular momentum (AAM) in the moist full-physics experiment clearly show that the eddy radial flux of vorticity associated with the type-2 instability makes significant contributions to the decrease in AAM of the IE and the increase in AAM of the OE. It is also found that the type-2 instability can work with the cutoff effect to accelerate the IED process. Similar patterns of the AAM budget analyses are also obtained from the dry experiment in which all physics parameterisation schemes are switched off. It is thus suggested that the type-2 instability is a fundamental process responsible for the IED and OEI in these two experiments. In the third part of the thesis (Chapter 4), unforced shallow water (SW) experiments further reveal that the intensity changes in the eyewalls through the eddy radial flux of vorticity are intrinsic nonlinear features of the type-2 instability. In addition, a detailed analysis of the most unstable eigenmode of a double-eyewall TC-like vortex shows evidence of substantial divergence of angular momentum flux over the IE and significant convergence of angular momentum flux over the OE. This further demonstrates that the origin of the intensity changes of the eyewalls is the angular momentum transport from the IE to the OE by the eddy processes associated with the type-2 instability. The last part of the thesis (Chapter 5) discusses the long-term effect of the type-2 instability on the eyewall intensity changes during ERCs. A series of forced and unforced SW experiments, which are initialised with different parameters of the vortex and convective heating, show repeated cycles of decay-intensification after the type-2 instability has been excited for a longer time. It is found that the oscillation results from the periodic elongation and contraction of the vortices associated with the long-term nonlinear evolution of the type-2 instability. These results suggest that predicting the eyewall intensity changes during ERCs may be a challenge"--

Download or read book Analyzing Tropical Cyclone Structures During Secondary Eyewall Formation Using Aircraft In situ Observations written by Katharine Wunsch and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the evolution of mature tropical cyclones (TCs), intensity and structural changes canoccur due to a process called an eyewall replacement cycle (ERC). Secondary eyewall formation(SEF) is the initial phase of an ERC, in which a ring of convection forms outside of the preexistingprimary eyewall of the TC. The dynamical mechanisms for SEF remain unclear, but mosthypotheses rely on the early presence of persistent and widespread rainband convection outside ofthe primary eyewall. The evolving rainband convection has both axisymmetric and asymmetricstructures that play a role in SEF processes. This project uses aircraft reconnaissance observationsfrom the FLIGHT+ dataset to examine the evolution of these structures. We create compositesfrom this dataset which includes USAF C-130 and NOAA P-3 aircraft observations of Atlanticbasin TCs from 1999-2015. The axisymmetric structures of TCs undergoing SEF are firstcompared to intensifying TCs that did not experience an ERC. Tangential wind and angularmomentum profiles show a broadening of the outer wind field prior to SEF, whilethermodynamic observations indicate features consistent with strengthening eyewall convection.Next, the ERC TCs are analyzed in quadrants relative to the deep-layer environmental wind shearto examine the evolution of asymmetric kinematic and thermodynamic structures. We utilize anew normalization technique based on the radii of both eyewalls to isolate structures thatsurround the secondary eyewall before and during SEF. We found that the kinematic structures ofthe developing secondary eyewall were most prominent in the storm half left of the wind shearvector. The thermodynamic structures of the secondary eyewall became more axisymmetric overtime during SEF, but those of the primary eyewall became more asymmetric as it began toweaken prior to being fully replaced. Analyzing observations from Hurricane Earl as a case studyillustrates variations in convective coverage that are captured in the composite study.Understanding the structures observed by aircraft reconnaissance and their relation tomechanisms that lead to SEF will improve our ability to predict the resultant changes in TC intensity and structure.

Download or read book Analysis of Environmental Factors Contributing to the Eyewall Replacement Cycle of Hurricanes written by Martha Christino and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Even the most advanced hurricane forecast models have difficulty predicting eyewall replacement cycles (ERCs) in tropical cyclones. Most research has attempted to solve this problem by working to understand the dynamic and kinematic drivers of an ERC. This project proposes an alternative approach focused on analyzing the changes in measurable environmental factors and utilizing a machine learning algorithm to predict the ERC. The aim of the first phase of this project is to establish which environmental factors are linked to the initial development of a secondary eye wall. Thirty-seven occurrences of secondary eyewall formation (SEF) in hurricanes between 1984 and 2018 were selected based on the criteria used in Sitkowski, et al. (2011). Each SEF event was matched with a similarly intensifying hurricane that did not experience a subsequent SEF event based on the year and storm intensity. Using environmental data from the Statistical Hurricane Intensity Prediction Scheme (SHIPS) predictor files, the change in each environmental variable at six-hour intervals for twenty-four hours before the start of SEF was analyzed. The environmental variables that experience the most significant change prior to SEF will determine which variables should be used as predictors in a machine learning program designed to predict SEF onset. The goal of this research is to create an algorithm capable of predicting a SEF event twenty-four hours in advance. This algorithm will be compared to existing statistical SEF prediction schemes. Predicting ERC events will allow hurricane track and intensity models to produce more accurate forecasts and emergency response centers to accordingly alter evacuation zones, resulting in decreased economic loss and fatalities.

Download or read book Cloud Dynamics written by Robert A. Houze Jr. and published by Elsevier. This book was released on 1994-06-28 with total page 605 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clouds play a critical role in the Earth's climate, general atmospheric circulation, and global water balance. Clouds are essential elements in mesoscale meteorology, atmospheric chemistry, air pollution, atmosphericradiation, and weather forecasting, and thus must be understood by any student or researcher in the atmospheric sciences. Cloud Dynamics provides a skillful and comprehensive examination of the nature of clouds--what they look like and why, how scientists observe them, and the basic dynamics and physics that underlie them. The book describes the mechanics governing each type of cloud that occurs in Earth's atmosphere, and the organization of various types of clouds in larger weather systems such as fronts, thunderstorms, and hurricanes.This book is aimed specifically at graduate students, advanced undergraduates, practicing researchers either already in atmospheric science or moving in from a related scientific field, and operational meteorologists. Some prior knowledge of atmospheric dynamics and physics is helpful, but a thorough overview of the necessary prerequisites is supplied. 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 Presents a photographic guide, presented in the first chapter, linking the examination of each type of cloud with an image to enhance visual retention and understanding 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

Download or read book The Representation of Cumulus Convection in Numerical Models written by Kerry Emanuel and published by Springer. This book was released on 2015-03-30 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents descriptions of numerical models for testing cumulus in cloud fields. It is divided into six parts. Part I provides an overview of the problem, including descriptions of cumulus clouds and the effects of ensembles of cumulus clouds on mass, momentum, and vorticity distributions. A review of closure assumptions is also provided. A review of "classical" convection schemes in widespread use is provided in Part II. The special problems associated with the representation of convection in mesoscale models are discussed in Part III, along with descriptions of some of the commonly used mesoscale schemes. Part IV covers some of the problems associated with the representation of convection in climate models, while the parameterization of slantwise convection is the subject of Part V.

Download or read book Convectively generated Potential Vorticity in Rainbands and Secondary Eyewall Formation in Hurricanes written by Falko Judt and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Concentric eyewall formation and eyewall replacement cycles are intrinsic processes that determine the intensity of a tropical cyclone, as opposed to purely environmental factors such as wind shear or the ocean heat content. Although extensive research has been done in this area, there is not a single widely accepted theory on the formation of secondary eyewall structures. Many previous studies focused on dynamic processes in the inner core of a tropical cyclone that would precede and ultimately lead to the formation of a secondary eyewall. Hurricanes Katrina and Rita in 2005 were frequently sampled by research aircraft which gathered a copious amount of data. During this time, Rita developed a secondary eyewall which eventually replaced the original eyewall. This thesis will investigate the formation of a secondary eyewall with particular emphasis on the rainband region, as observations show that an outer principal rainband transformed into the secondary ring. A high resolution, full physics model (MM5) initialized with global model forecast fields correctly predicted the secondary eyewall formation in Rita. The model output will be used to investigate both Katrina and Rita in terms of their PV generation characteristics since PV and vorticity maxima correlate well with wind maxima that accompany the eyewall and rainbands. Furthermore, dynamical processes such as vortex Rossby wave (VRW) activity in the inner core region will be analyzed. Comparison of the differences in the two storms might shed some light on dynamics that can lead to structure changes. Comparison of the model data with aircraft observation is used to validate the results. Doppler radar derived wind fields will be used to calculate the vertical vorticity. The vorticity field is closely related to PV and thus a manifestation of the PV generation process in the rainband. The investigation has shown that Rita2s principal rainband features higher PV generation rates at radii beyond 80 km. Both the azimuthal component and the projection of asymmetric PV generated by convection onto the azimuthal mean connected with the principal band are hypothesized to be of importance for the formation of the secondary eyewall. VRW were found not to be important for the initial formation of the ring but might enhance convective activity once the outer eyewall contracts.

Download or read book Satellite Climatology of Tropical Cyclone with Concentric Eyewalls written by Yi-Ting Yang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An objective method is developed to identify concentric eyewalls (CEs) for tropical cyclones (TCs) using passive microwave satellite imagery from 1997 to 2014 in the western North Pacific (WNP) and Atlantic (ATL) basin. There are 91 (33) TCs and 113 (50) cases with CE identified in the WNP (ATL). Three CE structural change types are classified as follows: a CE with the inner eyewall dissipated in an eyewall replacement cycle (ERC, 51 and 56% in the WNP and ATL), a CE with the outer eyewall dissipated first and the no eyewall replacement cycle (NRC, 27 and 29% in the WNP and ATL), and a CE structure that is maintained for an extended period (CEM, 23 and 15% in the WNP and ATL). The moat size and outer eyewall width in the WNP (ATL) basin are approximately 20-50% (15-25%) larger in the CEM cases than that in the ERC and NRC cases. Our analysis suggests that the ERC cases are more likely dominated by the internal dynamics, whereas the NRC cases are heavily influenced by the environment condition, and both the internal and environmental conditions are important in the CEM cases. A good correlation of the annual CE TC number and the Oceanic Niño index is found (0.77) in WNP basin, with most of the CE TCs occurring in the warm episodes. In contrast, the El Niño/Southern Oscillation (ENSO) may not influence on the CE formation in the ATL basin. After the CE formation, however, the unfavorable environment that is created by ENSO may reduce the TC intensity quickly during warm episode. The variabilities of structural changes in the WNP basin are larger than that in the ATL basin.

Download or read book Dynamics and Predictability of Large Scale High Impact Weather and Climate Events written by Jianping Li and published by Cambridge University Press. This book was released on 2016-03-24 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the dynamical processes between high-impact weather and climate events, and between atmospheric and ocean phenomena.

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 Atmospheric Science written by John M. Wallace and published by Elsevier. This book was released on 2006-03-24 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric Science, Second Edition, is the long-awaited update of the classic atmospheric science text, which helped define the field nearly 30 years ago and has served as the cornerstone for most university curricula. Now students and professionals alike can use this updated classic to understand atmospheric phenomena in the context of the latest discoveries, and prepare themselves for more advanced study and real-life problem solving. This latest edition of Atmospheric Science, has been revamped in terms of content and appearance. It contains new chapters on atmospheric chemistry, the Earth system, the atmospheric boundary layer, and climate, as well as enhanced treatment of atmospheric dynamics, radiative transfer, severe storms, and global warming. The authors illustrate concepts with full-color, state-of-the-art imagery and cover a vast amount of new information in the field. Extensive numerical and qualitative exercises help students apply basic physical principles to atmospheric problems. There are also biographical footnotes summarizing the work of key scientists, along with a student companion website that hosts climate data; answers to quantitative exercises; full solutions to selected exercises; skew-T log p chart; related links, appendices; and more. The instructor website features: instructor’s guide; solutions to quantitative exercises; electronic figures from the book; plus supplementary images for use in classroom presentations. Meteorology students at both advanced undergraduate and graduate levels will find this book extremely useful. Full-color satellite imagery and cloud photographs illustrate principles throughout Extensive numerical and qualitative exercises emphasize the application of basic physical principles to problems in the atmospheric sciences Biographical footnotes summarize the lives and work of scientists mentioned in the text, and provide students with a sense of the long history of meteorology Companion website encourages more advanced exploration of text topics: supplementary information, images, and bonus exercises

Download or read book Tropical cyclone intensity and structure changes Theories observations numerical modeling and forecasting written by Eric Hendricks and published by Frontiers Media SA. This book was released on 2023-09-29 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sensitivity of Simulated Hurricane Eyewall Replacement Cycles to Horizontal Turbulent Mixing written by Joanne Michelle Kennell and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eyewall replacement cycles (ERCs) are naturally occurring phenomena in some intense tropical cyclones. The exact mechanisms of ERCs are currently not known and successful numerical simulations of ERCs are also rare. The objectives of this thesis are to 1) validate the current ERC theories for a set of numerical simulations which resolved ERC processes, 2) investigate the role of boundary layer turbulence in ERCs, and 3) propose a mechanism for ERCs. Using the Advanced Research and Weather Forecasting (WRF-ARW) model, Hurricane Danielle (2010) was simulated. The ERCs that occurred in simulated Danielle are sensitive to parameterized horizontal turbulent mixing. Five theories on the initiating mechanisms of eyewall replace cycles are discussed with respect to each of our simulations and based on the results, a new idea of how the eyewall replacement process formed in our simulations is proposed. Two sensitivity experiments are performed to test the validity of this mechanism.

Download or read book Hurricanes written by Paul V. Kislow and published by Nova Publishers. This book was released on 2008 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: A hurricane is a tropical storm with winds that have reached a constant speed of 74 miles per hour or more. Hurricane winds blow in a large spiral around a relative calm centre known as the "eye." The "eye" is generally 20 to 30 miles wide, and the storm may extend outward 400 miles. As a hurricane approaches, the skies will begin to darken and winds will grow in strength. As a hurricane nears land, it can bring torrential rains, high winds, and storm surges. A single hurricane can last for more than 2 weeks over open waters and can run a path across the entire length of the eastern seaboard. August and September are peak months during the hurricane season that lasts from 1 June to 30 November. This book presents the facts and history of hurricanes.

Download or read book Encyclopedia of Atmospheric Sciences written by Gerald R. North and published by Elsevier. This book was released on 2014-09-14 with total page 2874 pages. Available in PDF, EPUB and Kindle. Book excerpt: Encyclopedia of Atmospheric Sciences, Second Edition, Six Volume Set is an authoritative resource covering all aspects of atmospheric sciences, including both theory and applications. With more than 320 articles and 1,600 figures and photographs, this revised version of the award-winning first edition offers comprehensive coverage of this important field. The six volumes in this set contain broad-ranging articles on topics such as atmospheric chemistry, biogeochemical cycles, boundary layers, clouds, general circulation, global change, mesoscale meteorology, ozone, radar, satellite remote sensing, and weather prediction. The Encyclopedia is an ideal resource for academia, government, and industry in the fields of atmospheric, ocean, and environmental sciences. It is written at a level that allows undergraduate students to understand the material, while providing active researchers with the latest information in the field. Covers all aspects of atmospheric sciences—including both theory and applications Presents more than 320 articles and more than 1,600 figures and photographs Broad-ranging articles include topics such as atmospheric chemistry, biogeochemical cycles, boundary layers, clouds, general circulation, global change, mesoscale meteorology, ozone, radar, satellite remote sensing, and weather prediction An ideal resource for academia, government, and industry in the fields of atmospheric, ocean, and environmental sciences

Download or read book Global Perspectives on Tropical Cyclones written by Johnny C. L. Chan and published by World Scientific. This book was released on 2010 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: Make God's Word your everyday traveling companion. Thin and lightweight, Thomas Nelson's KJV Compact UltraSlim™ Bible boasts a complete and easy-to-read Bible that is ready to go when you are! A Bible you can be comfortable taking with you every day and everywhere you go, the Compact UltraSlim Bible is thin enough to tuck into your purse, briefcase, backpack, or glove compartment, yet large enough for easy readability. The Compact UltraSlim Bible is the perfect gift and ideal companion for today's Christian on the move. Features include: Presentation page Self-pronouncing text Words of Jesus in red Concordance Full-color maps Type size: 6 Part of the CLASSIC SERIES line of Thomas Nelson Bibles Compact UltraSlim Bibles sold to date: More than 135,000 The King James Version-The most successful Bible translation in history with billions of copies published Thomas Nelson Bibles is giving back through the God's Word in Action program. Donating a portion of profits to World Vision, we are helping to eradicate poverty and preventable deaths among children. Learn more and discover what you can do at www.seegodswordinaction.com.

Download or read book Investigation and Prediction of Hurricane Eyewall Replacement Cycles written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: