Download or read book Detecting Tropical Cyclone Secondary Eyewalls with a Microwave Based Scheme written by Alex Cheung and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intense tropical cyclones (TCs) often form secondary eyewalls, triggering a process known as an eyewall replacement cycle (ERC). This can lead to short-term fluctuations in intensity and an increase in the size of the TC wind field. When occurring near landfall, the short-term variations can dramatically alter coastal watch, warning, and storm surge forecasts, potentially altering pre-storm preparation plans, including evacuations. However, documenting these events can be a time-consuming, subjective, and sometimes difficult task. Here, we use 89 --92 GHz microwave imagery from the NOAA Cooperative Institute for Research in the Atmosphere's Tropical Cyclone PRecipitation, Infrared, Microwave, and Environmental Dataset (TC PRIMED) to develop image-based variables to identify concentric structures related to deep convection. The image-based variables are combined with various environmental and storm variables (e.g, deep-layer shear magnitude, current maximum wind speed, 24-h difference in radius of 5 kt (1 kt = 0.514 m s--1) winds, and 24-h difference in infrared brightness temperature), to create a probabilistic secondary eyewall classification scheme using a machine learning classifier (linear discriminant analysis). This classification scheme is trained and tested using subjectively created secondary eyewall labels (2016--2019) of storms from the North Atlantic, East Pacific, West Pacific, and Southern Hemisphere basins. We trained the classifier using 36 storms and retained 16 storms for testing. From the classifier output, we calculate the probability of detection, false alarm ratios, skill scores, and bias ratio for various probability thresholds. Using the best default probability threshold (50%), the model produced a secondary eyewall probability of detection of about 64% with a false alarm ratio of 34% and a Peirce's Skill Score of 0.52, indicating fair skill in the model.
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 The Use of Satellite Microwave Rainfall Measurements to Predict Eastern North Pacific Tropical Cyclone Intensity written by Derek A. West and published by . This book was released on 1998 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proposed study examines the potential use of satellite passive microwave rainfall measurements derived from Special Sensor Microwave/Imager (SSM/I) radiometers onboard the Defense Meteorological Satellite Program (DMSP) constellation to improve eastern North Pacific Ocean tropical cyclone intensity change forecasting techniques. Relationships between parameters obtained from an operational SSM/I-based rainfall measuring algorithm and 12-, 24-, 36-, 48-, 60- and 72-hour intensity changes from best track data records are examined in an effort to identify statistically significant predictors of intensity change. Correlations between rainfall parameters and intensity change are analyzed using tropical cyclone data from three years, 1992 to 1994. Stratifications based upon tropical cyclone intensity, rate of intensity change, climatology, translation, landfall and synoptic-scale environmental forcing variables are studied to understand factors that may affect a statistical relationship between rainfall parameters and intensity change. The predictive skill of statistically significant rainfall parameters is assessed by using independent tropical cyclone data from another year, 1995. In addition, case studies on individual tropical cyclones are conducted to gain insight on predictive performance and operational implementation issues.
Download or read book Tropical Cyclone Dynamics Prediction and Detection written by Anthony Lupo and published by BoD – Books on Demand. This book was released on 2016-11-02 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, tropical cyclones continue to bring destruction, as well as disruption, to societies that are exposed to their threat. This book represents a compilation of recent cutting-edge research on tropical cyclones and their impacts from researchers at many institutions around the world. This book contains new looks at tropical cyclone dynamics, the use of satellite-based remote sensing in the detection and climatology of tropical cyclones, and the modeling and prediction of tropical cyclones as well as their associated impacts. This book would make a nice addition to any course on tropical meteorology highlighting topics of interest in recent research on this topic.
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 Secondary Eyewall Formation as a Response to Evolving Tropical Cyclone Wind Structure written by Rohini Bhimsen Shivamoggi and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The third chapter of the thesis describes work using an axisymmetric numerical model (Cloud Model 1) to establish a dynamical relationship between secondary eyewall formation and wind broadening in the outer region of a tropical cyclone. In these simulations, secondary eyewall formation is a means by which the inner region of a tropical cyclone adjusts to growth in the outer wind field. While some past studies have used quasi-steady frameworks for studying secondary eyewall formation, the results from Chapters 2 and 3 of this work emphasize the importance of examining secondary eyewall formation in frameworks in which the tropical cyclone's wind structure is evolving.
Download or read book Microwave Observations of Mesoscale Convective Systems During Tropical Cyclone Genesis in the Western North Pacific written by David Milot and published by . This book was released on 1998-03-01 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: A better understanding of the role mesoscale convective systems (MCS) play in the genesis stages of tropical cyclones will increase the ability to predict their formation. This thesis employs polar-orbiter microwave and geostationary infrared satellite imagery to document MCS structure and evolution during tropical cyclone genesis. Microwave imagery at frequencies of 19.35 GHz and 85.5 GHz are used to define convective and stratiform cloud areal amounts, percent coverage, and time-integrated rain rates. Collocations with geostationary infrared images are used to calibrate that imagery so that the hourly values may be calculated until another microwave image is available. Specifically, seven MCSs in two disturbances that eventually developed into tropical cyclones were analyzed. Two MCSs in non-developing storms are also described for contrast.
Download or read book Satellite based Tropical Cyclone Intensity Estimation Using NOAA KLM Series Advanced Microwave Sounding Unit AMSU Data written by Kurt Frederick Brueske and published by . This book was released on 2001 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Introduction to Boundary Layer Meteorology written by Roland B. Stull and published by Springer Science & Business Media. This book was released on 1988-07-31 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: Part of the excitement in boundary-layer meteorology is the challenge associated with turbulent flow - one of the unsolved problems in classical physics. An additional attraction of the filed is the rich diversity of topics and research methods that are collected under the umbrella-term of boundary-layer meteorology. The flavor of the challenges and the excitement associated with the study of the atmospheric boundary layer are captured in this textbook. Fundamental concepts and mathematics are presented prior to their use, physical interpretations of the terms in equations are given, sample data are shown, examples are solved, and exercises are included. The work should also be considered as a major reference and as a review of the literature, since it includes tables of parameterizatlons, procedures, filed experiments, useful constants, and graphs of various phenomena under a variety of conditions. It is assumed that the work will be used at the beginning graduate level for students with an undergraduate background in meteorology, but the author envisions, and has catered for, a heterogeneity in the background and experience of his readers.
Download or read book A Numerical and Observational Study of the Genesis of Concentric Eyewall Hurricanes written by Shangyao Nong and published by . This book was released on 1999 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Tropical Cyclones Using Microwave Data from the Special Sensor Microwave Imager written by Hongwei Zhao and published by . This book was released on 1994 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Atmospheric Sciences written by Board on Atmospheric Sciences and Climate and published by National Academies Press. This book was released on 1998-11-05 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technology has propelled the atmospheric sciences from a fledgling discipline to a global enterprise. Findings in this field shape a broad spectrum of decisions--what to wear outdoors, whether aircraft should fly, how to deal with the issue of climate change, and more. This book presents a comprehensive assessment of the atmospheric sciences and offers a vision for the future and a range of recommendations for federal authorities, the scientific community, and education administrators. How does atmospheric science contribute to national well-being? In the context of this question, the panel identifies imperatives in scientific observation, recommends directions for modeling and forecasting research, and examines management issues, including the growing problem of weather data availability. Five subdisciplines--physics, chemistry, dynamics and weather forecasting, upper atmosphere and near-earth space physics, climate and climate change--and their status as the science enters the twenty-first century are examined in detail, including recommendations for research. This readable book will be of interest to public-sector policy framers and private-sector decisionmakers as well as researchers, educators, and students in the atmospheric sciences.
Download or read book Microwave Radiometry and Remote Sensing of the Earth s Surface and Atmosphere written by 0 Pampaloni and published by CRC Press. This book was released on 2023-06-14 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains a selection of refereed papers presented at the 6 Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment held in Florence, Italy on March 15-18, 1999. Over the last two decades, passive microwave remote sensing has made considerable progress, and has achieved significant results in the study of the Earth's surface and atmosphere. Many years of observations with ground-based and satellite-borne sensors have made an important contribution to improving our knowledge of many geophysical processes of the Earth's environment and of global changes. The evolution in microwave radiometers aboard satellites has increased steadily over recent years. At the same time, many investigations have been carried out both to improve the algorithms for the retrieval of geophysical parameters and to develop new technologies. The book is divided into four main sections: three of these are devoted to the observation of the Earth's surface and atmosphere, and the fourth, to future missions and new technologies. The first section deals with the study of sea and land surfaces, and reports recent advances in remote sensing of ocean wind, sea ice, soil moisture and vegetation biomass, including electromagnetic modelling and the assimilation of radiometric data in models of land surface processes. The following two sections are devoted to the measurement of atmospheric quantities which are of fundamental importance in climatology and meteorology, and, since they influence radio-wave propagation, they also impact on several other fields, including geodesy, navigational satellite and radioastronomy. The last section presents an overview of new technologies and plans for future missions.
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 Tropical Cyclone Intensity Analysis Using Satellite Data written by Vernon F. Dvorak and published by . This book was released on 1984 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Encyclopedia of Hurricanes Typhoons and Cyclones New Edition written by David Longshore and published by Infobase Publishing. This book was released on 2010-05-12 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a detailed encyclopedia of named hurricanes, typhoons and cyclones, descriptions of storm activity, definitions of meteorological terms, and more.
Download or read book Tropical Cyclone Structure and Intensity Change Related to Eyewall Replacement Cycles and Annular Storm Formation Utilizing Objective Interpretation of Satellite Data and Model Analyses written by James P. Kossin and published by . This book was released on 2009 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project aims toward increasing our understanding of the dynamics of secondary eyewalls in tropical cyclones and our ability to forecast their formation and associated intensity changes. This is being accomplished through a synergistic combination of theoretical, empirical, and numerical modeling approaches. We expect to apply our results to the construction of objective algorithms that will be transitioned to operations to provide forecasters with new tools for improved forecasting of tropical cyclone structure and intensity.
