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Book The Structural Changes of Tropical Cyclones Upon Interaction with Vertical Wind Shear

Download or read book The Structural Changes of Tropical Cyclones Upon Interaction with Vertical Wind Shear written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fourth Convection and Moisture Experiment (CAMEX-4) provided a unique opportunity to observe the distributions and document the roles of important atmospheric factors that impact the development of the core asymmetries and core structural changes of tropical cyclones embedded in vertical wind shear. The state-of-the-art instruments flown on the NASA DC-8 and ER-2, in addition to those on the NOAA aircraft, provided a unique set of observations that documented the core structure throughout the depth of the tropical cyclone. These data have been used to conduct a combined observational and modeling study using a state-of-the-art, high- resolution mesoscale model to examine the role of the environmental vertical wind shear in producing tropical cyclone core asymmetries, and the effects on the structure and intensity of tropical cyclones.The scientific objectives of this study were to obtain in situ measurements that would allow documentation of the physical mechanisms that influence the development of the asymmetric convection and its effect on the core structure of the tropical cyclone. Ritchie, Elizabeth A. Goddard Space Flight Center

Book Global Perspectives On Tropical Cyclones  From Science To Mitigation

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.

Book The Structure of Vertical Wind Shear in Tropical Cyclone Environments

Download or read book The Structure of Vertical Wind Shear in Tropical Cyclone Environments written by Peter M. Finocchio and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The vertical wind shear measured between 200 and 850 hPa is commonly used to diagnose environmental interactions with a tropical cyclone (TC) and to forecast the storm's intensity and structural evolution. More often than not, stronger vertical shear within this deep layer prohibits the intensification of TCs and leads to predictable asymmetries in precipitation. But such bulk measures of vertical wind shear can occasionally mislead the forecaster. In the first part of this dissertation, we use a series of idealized numerical simulations to examine how a TC responds to changing the structure of unidirectional vertical wind shear while fixing the 200-850-hPa shear magnitude. These simulations demonstrate a significant intensity response, in which shear concentrated in shallow layers of the lower troposphere prevents vortex intensification. We attribute the arrested development of TCs in lower-level shear to the intrusion of mid-level environmental air over the surface vortex early in the simulations. Convection developing on the downshear side of the storm interacts with the intruding air so as to enhance the downward flux of low-entropy air into the boundary layer. We also construct a two-dimensional intensity response surface from a set of simulations that sparsely sample the joint shear height-depth parameter space. This surface reveals regions of the two-parameter space for which TC intensity is particularly sensitive. We interpret these parameter ranges as those which lead to reduced intensity predictability. Despite the robust response to changing the shape of a sheared wind profile in idealized simulations, we do not encounter such sensitivity within a large set of reanalyzed TCs in the Northern Hemisphere. Instead, there is remarkable consistency in the structure of reanalyzed wind profiles around TCs. This is evident in the distributions of two new parameters describing the height and depth of vertical wind shear, which highlight a clear preference for shallow layers of upper-level shear. Many of the wind profiles tested in the idealized simulations have shear height or depth values on the tails of these distributions, suggesting that the environmental wind profiles around real TCs do not exhibit enough structural variability to have the clear statistical relationship to intensity change that we expected. In the final part of this dissertation, we use the reanalyzed TC environments to initialize ensembles of idealized simulations. Using a new modeling technique that allows for time-varying environments, these simulations examine the predictability implications of exposing a TC to different structures and magnitudes of vertical wind shear during its life cycle. We find that TCs in more deeply distributed vertical wind shear environments have a more uncertain intensity evolution than TCs exposed to shallower layers of upper-level shear. This higher uncertainty arises from a more marginal boundary layer environment that the deeply distributed shear establishes, which enhances the TC sensitivity to the magnitude of deep-layer shear. Simulated radar reflectivity also appears to evolve in a more uncertain fashion in environments with deeply distributed vertical shear. However, structural predictability timescales, computed as the time it takes for errors in the amplitude or phase of azimuthal asymmetries of reflectivity to saturate, are similar for wind profiles with shallow upper-level shear and deeply distributed shear. Both ensembles demonstrate predictability timescales of two to three days for the lowest azimuthal wavenumbers of amplitude and phase. As the magnitude of vertical wind shear increases to universally destructive levels, structural and intensity errors begin to decrease. Shallow upper-level shear primes the TC for a more pronounced recovery in the predictability of the wavenumber-one precipitation structure in stronger shear. The recovered low-wavenumber predictability of TC precipitation structure and the collapse in intensity spread in strong shear suggests that vertical wind shear is most effective at reducing TC predictability when its magnitude is near the threshold between favorable and unfavorable values and when it is deeply distributed through the troposphere. By isolating the effect of the environmental flow, the simulations and analyses in this dissertation offer a unique understanding of how vertical wind shear affects TCs. In particular, the results have important implications for designing and implementing future environmental observing strategies that will be critical for improving forecasts of these destructive storms.

Book Global Perspectives on Tropical Cyclones

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: Pt. I. Theory of tropical cyclones. ch. 1. Tropical cyclone structure and dynamics / Jeffrey D. Kepert. ch. 2. Tropical cyclone formation / Kevin J. Tory and William M. Frank. ch. 3. Air-sea interactions in tropical cyclones / Lynn K. Shay. ch. 4. Movement of tropical cyclones / Johnny C.L. Chan. ch. 5. The extratropical transition of tropical cyclones : structural characteristics, downstream impacts, and forecast challenges / Patrick A. Harr -- pt. II. Observations of tropical cyclones. ch. 6. Observing and analyzing the near-surface wind field in tropical cyclones / Mark D. Powell. ch. 7. Satellite observations of tropical cyclones / Christopher Velden and Jeffrey Hawkins. ch. 8. Aircraft observations of tropical cyclones / Sim D. Aberson [und weitere] -- pt. III. Climate variations of tropical cyclone activity. ch. 9. Tropical cyclones and climate change : a review / Thomas Knutson, Chris Landsea and Kerry Emanuel -- pt. IV. Forecasting of tropical cyclones. ch. 10. Track and structure forecasts of tropical cyclones / Julian Heming and Jim Goerss. ch. 11. The influence of natural climate variability on tropical cyclones, and seasonal forecasts of tropical cyclone activity / Suzana J. Camargo [und weitere] -- pt. V. Hydrological aspects of tropical cyclones. ch. 12. Storm surge modeling and applications in coastal areas / Shishir K. Dube [und weitere] -- pt. VI. Societal impacts of tropical cyclones. ch. 13. Disaster mitigation and societal impacts / David King, Jim Davidson and Linda Anderson-Berry

Book Tropical Cyclones

    Book Details:
  • Author : Richard Anthes
  • Publisher : Springer
  • Release : 2016-06-29
  • ISBN : 1935704281
  • Pages : 228 pages

Download or read book Tropical Cyclones written by Richard Anthes and published by Springer. This book was released on 2016-06-29 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tropical Cyclones and hurricanes, long feared for the death and destruction that often accompanies them, are among the most fascinating of atmospheric phenomena. Created by thermodynamic processes, they unleash vast amounts of energy and influence a wide variety of natural processes along their paths. Richard Anthes tells the story of tropical cyclones creation and destruction, of meteorology's successes in understanding, modeling and predicting their behavior, and of the attempts to modify them. The book begins with a lively introduction to hurricanes, their awesome power, and their effects on individuals and societies in the past and present. The characteristics of the mature hurricane are revealed by consideration of rawinsonde, aircraft and satellite data. The physical processes responsible for the development and maintenance of tropical cyclones are treated comprehensively, and illustrated with both qualitative and quantitative examples. The role of the planetary boundary layer, cumulus convection and radiation are all discussed in detail. Progress in numerical simulation of tropical cyclones is carefully reviewed. Modern, three-dimensional models succeed in simulating observed features such as the eye and spiral rain bands and in predicting storm motion over time intervals of three days. Current capabilities to predict and modify hurricanes and tropical cyclones are fully examined. The methods and difficulties of operational forecasting, the economic aspects of storm predictions, and the trends in accuracy of offical forecasts are all considered. The potential benefits and scientific problems associated with hurricane modification are discussed as part of a review of experimental and theoretical results on the consquences of seeding hurricane clouds. A unique feature of the book is a thorough treatment of the interactions between storm and ocean, with both observations and thery being integrated to provide a complete description.

Book Tropical cyclone intensity and structure changes  Theories  observations  numerical modeling and forecasting

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:

Book Uncertainties and Limitations in Simulating Tropical Cyclones

Download or read book Uncertainties and Limitations in Simulating Tropical Cyclones written by Asuka Suzuki-Parker and published by Springer Science & Business Media. This book was released on 2012-01-05 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis work was in two major parts: development and testing of a new approach to detecting and tracking tropical cyclones in climate models; and application of an extreme value statistical approach to enable assessment of changes in weather extremes from climate models. The tracking algorithm applied a creative phase-space approach to differentiate between modeled tropical cyclones and their mid-latitude cousins. A feature here was the careful attention to sensitivity to choice of selection parameters, which is considerable. The major finding was that the changes over time were relatively insensitive to these details. This new approach will improve and add confidence to future assessments of climate impacts on hurricanes. The extremes approach utilized the Generalized Pareto Distribution (one of the standard approaches to statistics of extremes) applied to present and future hurricane distributions as modeled by a regional climate model, then applied the changes to current observations to extract the changes in the extremes. Since climate models cannot resolve these extremes directly, this provides an excellent method of determining weather extremes in general. This is of considerable societal importance as we are most vulnerable to such extremes and knowledge of their changes enables improved planning and adaptation strategies.

Book How Vertical Wind Shear Affects Tropical Cyclone Intensity Change  An Overview

Download or read book How Vertical Wind Shear Affects Tropical Cyclone Intensity Change An Overview written by Levi Thatcher and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Multiscale Convection coupled Systems in the Tropics

Download or read book Multiscale Convection coupled Systems in the Tropics written by Robert G. Fovell and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This monograph was inspired by the life and work of Professor Michio Yanai, a seminal figure and dedicated mentor in tropical meteorology. Conceived initially at the Michio Yanai Symposium held in January 2011 as 'lessons' organized around the principal research areas that attracted Yanai's attention and passion, this collection represents both a lasting tribute to the Professor and his legacy, and a useful reference for scientists in all stages of their careers. Among the many topics included in this volume are reviews of tropical clouds and convection, equatorial waves, tropical cyclones, monsoon flows, Madden-Julian oscillation, multiscale modeling and analyses, and the role of the Tibetan Plateau on climate. Also included are personal reminiscences from Professor Taroh Matsuno and a biographical sketch of Professor Yanai's life led by Professor Steven Esbensen, one of Professor Yanai's earliest students during his forty-year career at UCLA."--Provided by publisher.

Book Tropical Cyclone Development and Intensification Under Moderate to Strong Vertical Wind Shear

Download or read book Tropical Cyclone Development and Intensification Under Moderate to Strong Vertical Wind Shear written by Debra K. Smith and published by . This book was released on 1994 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to understand the physical mechanisms by which a tropical cyclone is able to develop and be maintained under moderate to strong vertical wind shear. The general approach was to describe case studies of three tropical cyclones in the western North Pacific that developed and/or intensified in the lee of another tropical cyclone. The data resources include high temporal and spatial resolution visible and infrared satellite imagery, operational subjective and objective analyses, plus special Tropical Cyclone Motion (TCM-90) high resolution (50 km) analyses and multi-quadric analyses. The three tropical cyclones developed and/or intensified under moderate to strong vertical wind shear that exceeded threshold values. The vertical wind shear was time dependent due to complex interactions with the leading tropical cyclone outflow, adjacent tropical upper tropospheric trough, and large-scale environment. Diurnal variability in strength of convection and outflow against the impinging flow led to fully exposed, partially exposed, or covered middle to lower tropospheric cyclonic circulation. Special characteristics of the monsoon trough circulation must create and sustain the tropical cyclone circulation against the tendency for the vertical wind shear to ventilate the vertical thermal and convective structure. Tropical cyclone, Vertical wind shear.

Book The Tropical Cyclone Response to Structural and Temporal Variability in the Environmental Wind Profile

Download or read book The Tropical Cyclone Response to Structural and Temporal Variability in the Environmental Wind Profile written by Matthew J Onderlinde and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this dissertation is to attain a better understanding of how tropical cyclones (TCs) respond to variations in the three-dimensional environmental wind field. Much attention has been given to the impact of environmental wind shear in the 850 -- 200 hPa layer on tropical cyclones. However, even with the same magnitude of shear, helicity in this layer can vary significantly. A new parameter is presented, the tropical cyclone-relative environmental helicity (TCREH). Positive TCREH leads to a tilted storm that enhances local storm scale helicity in regions of convection within the TC. Initially we proposed that this enhanced local scale helicity may allow for more robust and longer lasting convection which is more effective at generating latent heat and subsequent TC intensification. Further investigation shows that this is a secondary influence on TC intensity and that variations in the azimuthal and radial position of convection in the TC play a stronger role. Vertical tilt of the vortex is often attributed to wind shear. Different values of helicity modulate this tilt and certain tilt configurations are more favorable for development or intensification than others, suggesting that mean positive environmental helicity is more favorable for development and intensification than mean negative helicity. Idealized modeling simulations demonstrate the impact of environmental helicity on TC development and intensification. Results show that wind profiles with the same 850-200 hPa wind shear but different values of helicity lead to different rates of development. TCREH also is computed from Era-Interim reanalysis (1979 -- 2011) and GFS analyses (2004 -- 2011) to determine if a significant signal exists between TCREH and TC intensification. Mean annular helicity is averaged over various time periods and correlated with the TC intensity change during those periods. Results suggest a weak but statistically significant correlation between environmental helicity and TC intensity change with positive helicity being more favorable for intensification. Another goal of this dissertation is to identify the mechanisms that lead to the observed variations in intensification rate. Results suggest that the difference in intensification rate between TCs embedded in positive versus negative TCREH primarily results from the position of convection and associated latent heat fluxes relative to the wind shear vector. When TCREH is positive, convection is more readily advected upshear and air parcels that experience larger fluxes are more frequently ingested into the TC core. Trajectories computed from high resolution simulations demonstrate the recovery of equivalent potential temperature downwind of convection, latent heat flux near the TC core, and parcel routes through updrafts in convection. Trajectory characteristics show that low-level unstable air is lofted into deep convection near the radius of maximum winds more frequently when TCREH is positive. Contoured frequency-by-altitude diagrams (CFADs) show that convection is distributed differently around TCs embedded in environments characterized by positive versus negative TCREH. They also show that the nature of the most intense convection differs only slightly between cases of positive and negative TCREH. Finally, the implications of time-varying environments around TCs are examined. Until now, idealized numerical simulations of the tropical cyclone (TC) response to time-varying wind shear have applied instantaneous changes in the TC environment. A new modeling framework allows for smoothly transitioning environmental wind states: time-varying point-downscaling (TVPDS). TVPDS is an enhancement of the point-downscaling technique (Nolan 2011) developed for the Weather Research and Forecast (WRF) model. It uses analysis nudging to smoothly transition between different environmental vertical wind (and/or temperature and moisture) profiles while coordinating the point-downscaling method such that the environment remains in balance. Using this new framework, results from previous studies are reexamined to test whether the instantaneous 'shock' to the environment has implications for TC intensity evolution. Results suggest that instantaneous changes to the TC environment indeed do lead to an unrealistic response to an increase in shear. TVPDS simulations of quasi-steady state, moderately intense (~50 ms-1) TCs show that the response to increasing wind shear is a steady reduction in intensity without a recovery to the pre-shear intensity. TVPDS simulations also show that the rate at which the TC weakens depends on how rapidly the environment transitions from low to high shear. Analyses of surface fluxes and regions of convection are presented to determine how the time-varying shear affects the TC.

Book Environmental Influences on Rapid Intensity Changes in Tropical Cyclones   a Case Study

Download or read book Environmental Influences on Rapid Intensity Changes in Tropical Cyclones a Case Study written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hurricane Bret underwent a rapid intensification (RI) and subsequent weakening between 1200 UTC August 21 and 1200 UTC August 22, 1999, before it made landfall as a category 3 hurricane on the Texas coast 12 h later. Its minimum sea-level pressure dropped 35 hPa from 979 to 944 hPa within 24 h. During this period, aircraft of the National Oceanographic and Atmospheric Administration (NOAA) flew several research missions that sampled the environment and inner core of the storm. These data sets combined with gridded data from the National Centers for Environmental Prediction's (NCEP) Global Model and the National Center for Atmospheric Research (NCAR) reanalyses are used to document the atmospheric and oceanic environments of the tropical cyclone (TC) as well as their relation to the observed structural and intensity changes. Bret's RI was linked to movement over a warm ocean eddy and high sea surface temperatures (SSTs) in the Gulf of Mexico coupled with a simultaneous decrease in vertical wind shear. SSTs at the beginning of the storm2s RI were approximately 29 degrees Celcius and steadily increased to 30 degrees Celcius as it moved northward. The vertical wind shear relaxed to less than 10 kt during this time. Mean values of oceanic heat content (OHC) beneath the storm were about 20 % higher at the beginning of the RI period than 6 h before. Cooling of near-coastal shelf waters (to between 25 and 26 degrees Celcius) by pre-storm mixing combined with an increase in vertical wind shear were responsible for the weakening of the storm. The available observations suggested that intrusion of dry air into the circulation core did not contribute to the intensity evolution. In order to quantitatively describe the influence of environmental conditions on the intensity forecast, sensitivity studies with the Statistical Hurricane Intensity Prediction Scheme (SHIPS) model were conducted. Four different cases with modified vertical wind shear and/or SSTs were studied. Differences between all cases were relatively small due to the model design, but much cooler prescribed SSTs resulted in the greatest intensity changes. Model runs with idealized environmental conditions demonstrated the model2s general lack of capability to forecast RIs and also stressed the need of more accurate SST observations in the coastal shelf regions when predicting the intensity of landfalling TCs.

Book Global Perspectives on Tropical Cyclones

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.

Book El Ni  o Southern Oscillation in a Changing Climate

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.

Book Dynamics and Predictability of Tropical Cyclones Under Vertical Wind Shear

Download or read book Dynamics and Predictability of Tropical Cyclones Under Vertical Wind Shear written by Dandan Tao and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation explores the formation and predictability of sheared tropical cyclones (TCs) through a series of convection-permitting ensemble simulations using the Weather Research and Forecasting (WRF) model with different environmental vertical wind shear, sea-surface temperature (SST), and ambient moisture conditions. Small-amplitude random moisture perturbations are introduced in the lower troposphere as the initial-condition uncertainties to generate the ensembles under different environmental conditions. Both the composites and members of ensemble sets are analyzed in this study to examine the mean dynamics of sheared TCs as well as the predictability of tropical cyclone rapid intensification onset. From the ensemble-mean aspect, it is found that the environmental shear can significantly affect the timing of tropical cyclone formation by influencing the spatial distribution of convection and subsequently changing the positive feedback between diabatic heating and the TC vortex primary circulation. Except for the initial spin-up periods, the larger the vertical wind shear, the farther and weaker the convection from the TC center, which leads to a weakening TC vortex circulation and more time is needed to start the onset of rapid intensification (RI). The simulated tropical cyclones cannot start rapid intensification during a 9-day simulation if the shear between 200 hPa and 850 hPa approaches 7.5 m or higher for a constant SST of 27 °C. Increasing SST to 29 °C reduces the tilt magnitude and thus shortens the RI onset time because of faster generation of diabatic heating at the very beginning which strengthens vortex column to resist shear effect. Reduction in the environmental moisture content will eventually lead to weakened convection and delayed or failed precession in the later stages if the TC forms at all. In summary, the development of tropical cyclones is largely depending on the magnitude of vertical wind shear and diabatic heating, which can be further altered by other environmental conditions, such as the sea-surface temperature and ambient moisture content.From the ensemble aspect, it is found that the intrinsic predictability of the RI onset time is getting worse with increasing shear magnitude until the shear magnitude is large enough to prevent the TC formation. Based on ensemble sensitivity and correlation analysis, the RI onset timing within one set is largely related to the vortex tilt magnitude, the diabatic heating distribution and the strength of the vortex primary circulation. It appears that systematic differences amongst the ensemble members begin to arise right after the initial burst of moist convection associated with the incipient vortex. This difference from the randomness inherent in moist convection first changes the TC vortex structure subtly and then leads to the deviations in systematic scales and eventually in the development of the TC vortices. On average, a higher SST has a positive effect on the TC formation and reduces the uncertainty of development under all shear conditions, while a drier environment has a negative impact on the TCs development and either broadens the ensemble spread of RI onset time or prevents the storm from forming when the shear-induced tilt is large. It is also found that the shear modulation is quite significant that the effect of randomness of moist convection at the very beginning is overwritten by the difference in shear magnitudes.

Book A Literature Review  Effect of Climate Change on Tropical Cyclones

Download or read book A Literature Review Effect of Climate Change on Tropical Cyclones written by Kopal Arora and published by GRIN Verlag. This book was released on 2014-06-11 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Essay from the year 2011 in the subject Geography / Earth Science - Meteorology, Aeronomy, Climatology, grade: 11.0, University of Exeter, language: English, abstract: Since tropical cyclones(TCs) are one of the major geophysical cause of loss of life and property, it is important to understand if there is any change in the frequency and intensity of TCs due to anthropogenic climate change. IPCC considers 0.25-0.5 C increase in warming over tropical oceans over the past few decades due to increase in greenhouse gas concentration over past 50years. During 6th International Workshop on Tropical Cyclones, a statement was released on the connection between the TCs and anthropogenic climate change. The statement was in response to the increase in number of recent high-impact TC events which includes, 10 land falling Tcs in Japan in 2004, 5 TCs affecting the Cook island in a five week period during 2005, cyclone Gafilo in Madagascar in 2004, cyclone Larry in Australia in 2006, typhoon Saomai in China in 2006, and violently active Atlantic TC season during the period of 2004 to 2005, including the catastrophic socioeconomic impact of Hurricane Katrina. A few recent articles [1] have noted a large increase in TC’s intensity, frequency and wind-speeds in some regions during past 5 decades, which could be attributed to the increase in the concentration of green house gases in past 50years. However, other studies explain this noticed increase as a result of better observations made and instruments used, making it easier to detect TCs. Consensus statement by the International workshop on TC-6 reported uncertain conclusions about the influence of climate change on TC after taking into account evidence both for and against. It was concluded that no TC could be solely attributed to the anthropogenic climate change. Model and theory predicts 3-5% increase in wind speed per degree C increase in SST. But, there is inconsistency between the small change in wind speed projected by theory and modelling versus large variations reported by some observational studies. Significant limitation of measurements over some regions make detection of trends difficult. It was suggested that if increase in SST continues, susceptibility to TC storm surge flooding would strengthen.