DOCSLIB.ORG

The Role of Vortex Structure in Tropical Cyclone Motion

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Role of Vortex Structure in Tropical Cyclone Motion :A 9o943-R00fe NAVAL POSTIiRADUATE SCHOOL Monterey, California DISSERTATION THE ROLE OF VORTEX STRUCTURE IN TROPICAL CYCLONE MOTION by Michael Fiorino December 1987 Dissertation Supervisor: R.L. Elsberry Approved for public release; distribution is unlimited T238908 IJJRITY CLASSIFICATION OF THIS PAGE REPORT DOCUMENTATION PAGE 8REP0RT SECURITY CLASSIFICATION lb RESTRICTIVE MARKINGS JNCLASSIFIED aSECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION /AVAILABILITY OF REPORT Approved for public release; / : DECLASSIFICATION DOWNGRADING SCHEDULE distribution is unlimited. ERFORMING ORGANIZATION REPORT NUM8ER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S) INAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION (If applicable) uval Postgraduate School 63 Naval Postgraduate School l^DORESS {City, State, and ZIP Code) 7b. ADDRESS {City, State, and ZIP Code) /.mterey, California 93943-5000 Monterey, California 93943-5000 iNAME OF FUNDING /SPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If applicable) :.\DORESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT ELEMENT NO. NO. NO ACCESSION NO. TITLE (Include Security Classification) e Role of Vortex Structure in Tropical Cyclone Motion »ERSONAL AUTHOR(S) Fiorino, Michael TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year, Month, Day) IS. PAGE COUNT .D. Dissertation FROM TO 1987 December 371 UPPLEMENTARY NOTATION COSATl CODES 18. SUBJECT TERMS {Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Tropical cyclone motion, Barotropic model. Tropical cyclones. Circulation analysis, Beta drift ABSTRACT {Continue on reverse if necessary and Identify by block number) The role of vortex structure in tropical cyclone motion is studied using .moving-grid, nondivergent barotropic model on a beta plane in a no-flow vironment. Initial condition sensitivity tests reveal that the northwest- rd "beta" drift of the vortex is controlled by the symmetric circulation the r = 300 - 800 km "critical" annulus. Enhanced cyclonic or anticyclon- flow in this critical annulus leads to long-term cyclonic or anticyclonic rning motions. The dynamics of the motion process is examined in terms of e symmetric and asymmetric circulations. When the vortex is moving in a asi-steady manner, the asymmetric flow appears as a pair of large-scale, unter-rotating gyres with a broad "ventilation" flow through the vortex nter. A second much smaller pair of gyres is also found near the center. is the interaction between these two sets of gyres and the symmetric flow at governs the motion process as revealed by a streamfunction tendency lOlSTRIBUTION/ AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION )(UNCLASSIFIED/UNLIMITED D SAME AS RPT. Q DTIC USERS UNCLASSIFIED NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code) -:2c. OFFICE SYMBOL R.L. Elsberry (408)-646-2373 63 Es 83 APR edition may be used until exhausted. :F0RM 1473, 84 MAR SECURITY CLASSIFICATION OF THIS PAGE All other editions are obsolete ft U.S. Governmtnt Printlns Office: 1986—«06-24. 1 SECURITY CLASSIFICATION OF TmIS PAGC rVian Dmtm Bntt94) 19. cont. analysis and dynamical sensitivity tests in which the model equation is modified during the integration. Beta drift can be described as a balancing process between linear Rossby disper- sion which generates the asymmetric gyres and nonlinear advec- tion that moves the vortex to limit gyre development. Vortex structure is the key to this balance as it determines both the linear generation of the asymmetric forcing and the nonlinear interaction between the symmetric and asymmetric circulations. S N 0102- LP- 014- 6601 ^ SeCURITY CLASSIFICATION OF THIS P kGt.(WhM% Dmtm Snffd) Approved for public release; distribution is unlimited The Role of Vortex Structure in Tropical Cyclone Motion by Michael Fiorino B.S., Pennsylvania State University, 1975 M.S., Pennsylvania State University, 1978 Submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY IN METEOROLOGY from the NAVAL POSTGRADUATE SCHOOL December 1987 -Xt ,- r ABSTRACT The role of vortex structure in tropical cyclone motion is studied using a moving-grid, nondivergent barotropic model on a ^ plane in a no-flow environment. Initial condition sensitivity tests reveal that the northwestward "beta" drift of the vortex is controlled by the symmetric circulation in the r = 300 - 800 km "critical" annulus. Enhanced cyclonic or anticyclonic flow in this critical annulus leads to long-term cyclonic or anticyclonic turning motions. The dynamics of the motion process is examined in terms of the symmetric and asymmetric circulations. When the vortex is moving in a quasi-steady manner, the asymmetric flow appears as a pair of large-scale, counter- rotating gyres with a broad "ventilation" flow through the vortex center. A second much smaller pair of gyres is also found near the center. It is the interaction between these two sets of gyres and the symmetric flow that governs the motion process as revealed by a streamfunction tendency analysis and dynamical sensitivity tests in which the model equation is modified during the integration. Beta drift can be described as a balancing process between linear Rossby dispersion which generates the asymmetric gyres and nonlinear advection that moves the vortex to limit gyre development. Vortex structure is the key to this balance as it determines both the linear generation of the asymmetric forcing and the nonlinear interaction between the symmetric and asymmetric circulations. TABLE OF CONTENTS I. INTRODUCTION 19 A. CURRENT UNDERSTANDING 20 B. RESEARCH GOALS 25 II. THE MODEL AND NUMERICAL PROCEDURES 28 A. ANALYTICAL FORMULATION 28 B. NUMERICAL FORMULATION 30 1. Boundary Conditions 31 2. Moving Grid 31 3. Vortex Center Definition 3 2 4. Summary 33 C. NUMERICAL PRECISION 33 1. Radius of Maximum Wind Test 34 2. Horizontal Resolution Effects 36 3. Domain Size Effects 44 D. SUMMARY 46 III. DEPENDENCE OF VORTEX MOTION ON THE INITIAL SYMMETRIC FLOW 48 A. VORTEX STRUCTURE 48 B. VORTEX SPECIFICATION 51 1. Combining Two Profiles 52 2. Forcing a Zero in a Profile 54 C. EXPERIMENT DESIGN 56 D. TRACK RESULTS WITH THE BASIC PROFILES 57 E. THE INNER-OUTER STRENGTH CHANGE PROFILES 61 F. SYMMETRIC PERTURBATIONS 66 G. FAR OUTER FLOW 69 H. SPEED OF MOTION AS A FUNCTION OF STRENGTH 72 I. SUMMARY AND DISCUSSION 72 IV. EVOLUTION OF THE SYMMETRIC AND ASYMMETRIC CIRCULATIONS -77 A. SYMMETRIC/ASYMMETRIC SEPARATION PROCEDURE -78 B. SYMMETRIC WIND PROFILE — 82 C. THE ASYMMETRIC CIRCULATION —— -86 1. Growth of the Asymmetric Gyres 94 2. The Asymmetric Flow — 100 D. DESCRIPTION OF THE DYNAMICS OF BETA DRIFT 106 1. Overview 107 2. Discussion 111 E. STREAMFUNCTION TENDENCY ANALYSIS 116 1. Total Tendency Analysis 124 2. Symmetric and Asymmetric Tendencies 146 a. Weakening of the Maximum Wind 146 b^ Formation of the Asymmetric Gyres 152 c. Nonlinear Effects 156 d. Rotation of the Large-scale Asymmetric Gyres 172 e. Westward Component of Beta Drift 17 3 F. VENTILATION FLOW VECTOR 17*3 G. SUMMARY OF THE DYNAMICS OF BETA DRIFT 177 V. DYNAMICAL SENSITIVITY 181 A. VENTILATION FLOW DYNAMICS 182 1. The Hypothesized Ventilation Speed Function — • — 183 2. Experiment Design 184 3. Linear Solutions -•— 185 4. Results with Varying a/b Ratios 189 5. The Calculated Ventilation Speed Function 197 6. Summary 203 B. NONLINEAR-ONLY INTEGRATIONS AFTER LINEAR FORCING 204 1. Experiment Design 204 2. Track Results -205 3. The Asymmetric Streamfunction • 211 4. Very Long Integrations 226 5. Tangential Wind Profiles 231 6. Smnmary 231 C. MODIFYING THE SYMMETRIC/ASYMMETRIC NONLINEAR INTERACTIONS 236 1. Symmetric/Asymmetric Form of the Model Equation 237 2. Experiment Design 238 3. Setting ASVA to Zero 239 4. Setting AAVS to Zero 240 5. Modifying AAVS 253 6. Modifying ASVA 261 7. Summary 261 D. SUMMARY AND CONCLUSIONS 268 VI. ULTRA-LONG INTEGRATIONS 271 A. TRACK RESULTS 271 B. TANGENTIAL WIND PROFILES 274 C. DISCUSSION AND SUMMARY 274 VII. CONTRIBUTION TO THE MOTION BY DIFFERENT SCALES IN THE INITIAL VORTEX 280 A. THE FOURIER TRANSFORM PROCEDURE 280 B. EXPERIMENT DESIGN 283 C. PERFORMANCE CHARACTERISTICS OF THE FOURIER FILTER 285 D. TRACK RESULTS 306 E. IMPLICATIONS FOR VORTEX SPECIFICATION IN TRACK FORECAST MODELS AND TROPICAL CYCLONE ANALYSIS 328 F. SUMMARY 335 VIII. SUMMARY AND CONCLUSIONS 3 37 A. RESEARCH APPROACH 337 B. NUMERICAL EFFECTS 338 C. DEPENDENCE ON THE INITIAL SYMMETRIC VORTEX — 338 1. Radius of Maximum Wind 339 2. Inner/Outer Changes 339 3. Symmetric Perturbations 339 4. Far Outer Flow 340 D. EVOLUTION OF THE SYMMETRIC AND ASYMMETRIC FLOW 340 1. The Asymmetric Flow —= 340 2. Circulation Tendency Analysis • 341 E. DYNAMICAL SENSITIVITY —^— 342 1. Balance between Motion and Ventilation Flow Generation —— —-= 342 2. Nonlinear-only Integrations after Initialization with a Linear Solution 343 3. Modification of the Symmetric/Asymmetric Tendencies 344 F. ULTRA-LONG INTEGRATIONS 345 G. CONTRIBUTION TO THE MOTION BY DIFFERENT SCALES IN THE INITIAL VORTEX 346 H. SUMMARY OF STRUCTURE DEPENDENCE 347 I. SUMMARY OF NEW FINDING REGARDING THE DYNAMICS OF BETA DRIFT 347 J. APPLICATIONS TO FUTURE THEORETICAL STUDIES AND FORECAST MODELS 348 APPENDIX A: DERIVING THE TANGENTIAL WIND PROFILE AND VORTEX PARAMETERS FROM THE SYMMETRIC STREAMFUNCTION 351 APPENDIX B: DERIVING THE INITIAL 2-D STREAMFUNCTION FROM AN ANALYTICAL TANGENTIAL WIND PROFILE 354 APPENDIX C: THE MODEL TENDENCY EQUATION IN THE
Load more

Recommended publications
  • Deliverable D-4.01
    WakeNet3-Europe Grant Agreement No.: ACS7-GA-2008-213462 Deliverable D-4.01 Report 1 from Link activities and Trips Prepared by: Elsa FREVILLE (EUROCONTROL) Work Package: .............. 4 Dissemination level: ..... PU Version: ......................... Final Report Issued by: ...................... EUROCONTROL Reference: ..................... v1 Date: .............................. 12th March 2010 Number of pages: ......... 41 Project acronym: .............. WakeNet3-Europe Project full title: ................ European Coordination Action for Aircraft Wake Turbulence Project coordinator: ......... Airbus Operations S.A.S (*) Beneficiaries: A-F Airbus Operations S.A.S (*) TR6 Thales Air Systems THAv Thales Aerospace DLR Deutsches Zentrum für Luft- und Raumfahrt NLR Nationaal Lucht- en Ruimtevaartlaboratorium DFS DFS Deutsche Flugsicherung GmbH ONERA Office National d’Etudes et Recherches Aérospatiale NERL NATS En-Route Plc. UCL Université catholique de Louvain TUB Technische Universität Berlin ECA European Cockpit Association TU-BS Technische Universität Braunschweig A-D Airbus Operations GmbH (*) pending formal change of contract. This document has been produced under EC FP7 project 213462 (WakeNet3-Europe) 12 March 2010 Page 1 of 41 Document Revisions Version Date Modified Modified Comments page(s) section(s) 0.1 5th Feb 2010 Initial draft for review 0.2 22nd Feb 2010 7, 9, 33, 37- 2.1, 3, and Updates from A-D: 44 10 - Minor corrections for sections 2.1 and 3 - Section 10 is replaced by an inserted “pdf” file at the end of section 5.3.
    [Show full text]
  • METR 2603 Section 900 – Severe and Unusual Weather Fall 2012 Edition
    METR 2603 Section 900 – Severe and Unusual Weather Fall 2012 Edition Instructor: Mr. Ryan Sobash E-mail: [email protected] Meeting Times: MW 4:30pm - 5:45pm SEC A235 Office Hours: After class or by appointment (e-mail me!) Course Description Provides non-majors and majors a detailed descriptive account of the physical processes important in the formation of various severe and unusual weather phenomena including: thunderstorms, tornadoes, hail storms, lightning, hurricanes, mid- latitude snowstorms, lake effect snows, atmospheric optical effects, and global climate change. Textbook Required: Severe and Hazardous Weather: An introduction to high impact meteorology (4th edition) by Robert M. Rauber, John Walsh, and Donna Charlevoix. Book website: http://severewx.atmos.uiuc.edu/ I will inform you of the readings in the text that correspond to the material presented in class. I will frequently use questions and problems from the text for quizzes and exam questions, but I won’t expect you to know anything from the book that is not covered in the lectures. Desire2Learn Course announcements, lecture notes, homework assignments, and grades will be posted on the course page in the Desire2Learn system (learn.ou.edu). You can log into the system using your OU 4x4. Homework Assignments There will be 6 homework assignments due throughout the semester that provide an opportunity to apply your knowledge of the lecture material (often to meteorological events that occurred in Oklahoma). You will have 2 weeks to complete each assignment. I encourage you to start soon after they are assigned, to provide plenty of time for questions as they arise.
    [Show full text]
  • NWI Monthly Newsletter
    June 2017 — Issue 95 Letter from the Interim Director One of the most appreciated services NWI provides to our faculty affiliates is gap funding: When an existing grant has expired and a new one hasn’t come in, we make sure that graduate students, research associates, and technicians will be paid without interruption. By doing so, our researchers are able to maintain their capacity to execute the grants when they are awarded, as well as laying groundwork for future proposals. Such an “insurance policy” reflects the collective strength of the Institute, giving researchers extra confidence that they would not have oth- erwise as individuals. Due to budget cuts to multiple research and education programs, essential functions/ supports such as gap funding are at risk of being reduced or eliminated. Our leadership, working with advisory board members, are actively looking for creative ways to reorganize staff, increase efficiency, and raise funds from additional sources. One area in which we have been more engaged in lately is philanthropy. We are building a close relationship with the Office of Corporation and Daan Liang, Ph.D., P.E., Interim Director, NWI. Foundation Relations of Texas Tech University System which is extremely helpful in making contact with potential donors and project sponsors. Two visits are being planned this fall by major energy companies who have expressed a keen interest in our ex- panding footprint in renewable energy (wind, solar, battery, power grid) and robust educational programs (BSWE, Ph.D., continuing education). In addition, we receive legislative assistance from the federal relation team to be more proactive in applying for federal funding.
    [Show full text]
  • The Coastal Convective Interactions Experiment
    The Coastal Convective Interactions Experiment Joshua Stephen Soderholm BSc (Hons) A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in 2016 School of Geography, Planning and Environmental Management i Abstract Prediction of convective storm environments relies principally upon the broad-scale meteorology (e.g., synoptic boundaries and air masses) in contrast to local-scale (2 – 20 km) processes within the planetary boundary layer (PBL). Diurnal heating of the Earth’s heterogeneous surface at these finer scales forces circulations (e.g., sea breezes, valley winds, urban heat island circulations) which have been related to trends in the meteorological and climatological activity of storms; however, a quantitative understanding of their interactions with deep convection is limited. This is especially true for physical settings which support a variety of PBL circulations that challenge our understanding of storm characteristics and evolution. This thesis presents results from the Coastal Convective Interactions Experiment (CCIE), which incorporates meteorological and climatological analyses to provide a comprehensive understanding of how a complex coastal setting influences the convective storm environment. An 18-year radar-derived storm climatology (July 1997 – June 2015) is developed for Southeast Queensland (SEQ), Australia, supporting the operational planning and findings of Australia’s first thunderstorm field campaign. The following thesis presents the experimental design and findings of the CCIE to establish the drivers of storm activity in a coastal setting. Results from the CCIE climatology confirmed not only the hailstorm hotpots recognised by experienced local forecasters, but also a correlation between the storm frequency and sea breezes. To investigate the meteorology of hailstorm hotspots and interactions with the sea breeze further, climatological results were applied to coordinate a field measurement campaign.
    [Show full text]
  • Florida State University Libraries
    Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2019 A Climatology of U.S. Tropical Cyclone Rainfall, Its Use in a Statistical Forecasting Technique and an Analysis of Global Forecast System Tropical Cyclone Rainfall FTriostarne J. cHallst Environments Follow this and additional works at the DigiNole: FSU's Digital Repository. For more information, please contact [email protected] FLORIDA STATE UNIVERSITY COLLEGE OF ARTS & SCIENCES A CLIMATOLOGY OF U.S. TROPICAL CYCLONE RAINFALL, ITS USE IN A STATISTICAL FORECASTING TECHNIQUE AND AN ANALYSIS OF GLOBAL FORECAST SYSTEM TROPICAL CYCLONE RAINFALL FORECAST ENVIRONMENTS By TRISTAN HALL A Dissertation submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy 2019 Copyright c 2019 Tristan Hall. All Rights Reserved. Tristan Hall defended this dissertation on July 9, 2019. The members of the supervisory committee were: Henry E. Fuelberg Professor Directing Dissertation David Van Winkle University Representative Robert E. Hart Committee Member Vasubandhu Misra Committee Member Philip Sura Committee Member The Graduate School has verified and approved the above-named committee members, and certifies that the dissertation has been approved in accordance with university requirements. ii To Catherine and Ainsley. iii ACKNOWLEDGMENTS This dissertation could not have been completed without the help and guidance of Dr. Henry Fuelberg. He is a craftsman of words and logical thought. Additionally, this research could not have been completed without the help of Dr. Bob Hart. His knowledge of tropical cyclones is unmatched. I thank them both immensely for their acceptance of me to pursue my Ph.D.
    [Show full text]
  • National Windstorm Impact Reduction Program Biennial Progress Report to Congress for Fiscal Years 2015 and 2016
    NATIONAL WINDSTORM IMPACT REDUCTION PROGRAM BIENNIAL PROGRESS REPORT TO CONGRESS FOR FISCAL YEARS 2015 AND 2016 Disclaimer 1: Certain trade names or company products are mentioned in the text to specify experimental procedure and equipment used. In no case does such identification imply recommendation or endorsement by any of the agencies represented on the Interagency Coordinating Committee, nor does it imply that the equipment is the best available for the purpose. Disclaimer 2: In this document, we have provided link(s) to website(s) that may have information of interest to our users. The Interagency Coordinating Committee agencies do not endorse the views expressed or the facts presented on these sites. Further, Interagency Coordinating Committee agencies do not endorse any commercial products that may be advertised or available on these sites. This progress report for the National Windstorm Impact Reduction Program (NWIRP) is submitted to Congress by the Interagency Coordinating Committee of NWIRP, as required by the National Windstorm Impact Reduction Act of 2004 (Public Law 108-360, Title II), as amended by the National Windstorm Impact Reduction Act Reauthorization of 2015 (Public Law 114-52). Interagency Coordinating Committee Dr. Walter G. Copan - Chair Under Secretary of Commerce for Standards and Technology and Director National Institute of Standards and Technology U.S. Department of Commerce Dr. John Cortinas Director Office of Weather and Air Quality National Oceanic and Atmospheric Administration U.S. Department of Commerce Dr. Barry Johnson Acting Assistant Director Engineering Directorate National Science Foundation Mr. Michael Kratsios Deputy Assistant to the President, and Deputy U.S. Chief Technology Officer Executive Office of the President Mr.
    [Show full text]
  • Mesoscale Convective Vortex Formation in a Weakly Sheared Moist Neutral Environment
    MAY 2007 CONZEMIUS ET AL. 1443 Mesoscale Convective Vortex Formation in a Weakly Sheared Moist Neutral Environment ROBERT J. CONZEMIUS Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, and Windlogics, Inc., Grand Rapids, Minnesota RICHARD W. MOORE Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, and Institute for Atmospheric and Climate Science (IACETH), ETH-Zürich, Zurich, Switzerland MICHAEL T. MONTGOMERY Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, Department of Meteorology, Naval Postgraduate School, Monterey, California, and Hurricane Research Division, NOAA/AOML, Miami, Florida CHRISTOPHER A. DAVIS National Center for Atmospheric Research, Boulder, Colorado (Manuscript received 31 January 2006, in final form 31 July 2006) ABSTRACT Idealized simulations of a diabatic Rossby vortex (DRV) in an initially moist neutral baroclinic environ- ment are performed using the fifth-generation National Center for Atmospheric Research–Pennsylvania State University (NCAR–PSU) Mesoscale Model (MM5). The primary objective is to test the hypothesis that the formation and maintenance of midlatitude warm-season mesoscale convective vortices (MCVs) are largely influenced by balanced flow dynamics associated with a vortex that interacts with weak vertical shear. As a part of this objective, the simulated DRV is placed within the context of the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) field campaign by comparing its tangential velocity, radius of maximum winds, CAPE, and shear with the MCVs observed in BAMEX. The simulations reveal two distinct scales of development. At the larger scale, the most rapidly growing moist baroclinic mode is excited, and exponential growth of this mode occurs during the simulation.
    [Show full text]
  • The Role of Vortex and Environment Errors in Genesis Forecasts of Hurricanes Danielle and Karl (2010)
    232 MONTHLY WEATHER REVIEW VOLUME 141 The Role of Vortex and Environment Errors in Genesis Forecasts of Hurricanes Danielle and Karl (2010) RYAN D. TORN AND DAVID COOK Department of Atmospheric and Environmental Sciences, University at Albany, State University of New York, Albany, New York (Manuscript received 16 March 2012, in final form 2 July 2012) ABSTRACT An ensemble of Weather Research and Forecasting Model (WRF) forecasts initialized from a cycling ensemble Kalman filter (EnKF) system is used to evaluate the sensitivity of Hurricanes Danielle and Karl’s (2010) genesis forecasts to vortex and environmental initial conditions via ensemble sensitivity analysis. Both the Danielle and Karl forecasts are sensitive to the 0-h circulation associated with the pregenesis system over a deep layer and to the temperature and water vapor mixing ratio within the vortex over a comparatively shallow layer. Empirical orthogonal functions (EOFs) of the 0-h ensemble kinematic and thermodynamic fields within the vortex indicate that the 0-h circulation and moisture fields covary with one another, such that a stronger vortex is associated with higher moisture through the column. Forecasts of the pregenesis system intensity are only sensitive to the leading mode of variability in the vortex fields, suggesting that only specific initial condition perturbations associated with the vortex will amplify with time. Multivariate regressions of the vortex EOFs and environmental parameters believed to impact genesis suggest that the Karl forecast is most sensitive to the vortex structure, with smaller sensitivity to the upwind integrated water vapor and 200–850-hPa vertical wind shear magnitude. By contrast, the Danielle forecast is most sensitive to the vortex structure during the first 24 h, but is more sensitive to the 200-hPa divergence and vertical wind shear magnitude at longer forecast hours.
    [Show full text]
  • The Initiation of Moist Convection at the Dryline: Forecasting Issues from a Case Study Perspective
    1106 WEATHER AND FORECASTING VOLUME 13 The Initiation of Moist Convection at the Dryline: Forecasting Issues from a Case Study Perspective CONRAD L. ZIEGLER AND ERIK N. RASMUSSEN NOAA/National Severe Storms Laboratory, Norman, Oklahoma (Manuscript received 21 November 1997, in ®nal form 30 July 1998) ABSTRACT The processes that force the initiation of deep convection along the dryline are inferred from special mesoscale observations obtained during the 1991 Central Oklahoma Pro®ler Studies project, the Veri®cation of the Origins of Rotation in Tornadoes Experiment 1994 (VORTEX-94), and the VORTEX-95 ®eld projects. Observations from aircraft, mobile CLASS soundings, and mobile mesonets de®ne the ®elds of air¯ow, absolute humidity, and virtual temperature in the boundary layer across the dryline on the 15 May 1991, 7 June 1994, and 6 May 1995 case days. Film and video cloud images obtained by time-lapse cameras on the NOAA P-3 are used to reconstruct the mesoscale distribution of cumulus clouds by photogrammetric methods, permitting inferences concerning the environmental conditions accompanying cloud formation or suppression. The results of the present study con®rm the classical notion that the dryline is a favored zone for cumulus cloud formation. The combined cloud distributions for the three cases are approximately Gaussian, suggesting a peak expected cloud frequency 15 km east of the dryline. Deep mesoscale moisture convergence is inferred in cloudy regions, with either subsidence or a lack of deep convergence in cloud-free regions. The results document the modulating effect of vertical wind shear and elevated dry layers in combination with the depth and strength of mesoscale updrafts on convective initiation, supporting the notion that moist boundary layer air parcels must be lifted to their lifted condensation level and level of free convection prior to leaving the mesoscale updraft to form deep convection.
    [Show full text]
  • The Role of Vortex Structure in Tropical Cyclone Motion
    Calhoun: The NPS Institutional Archive Theses and Dissertations Thesis Collection 1987 The role of vortex structure in tropical cyclone motion. Fiorino, Michael. http://hdl.handle.net/10945/22465 :A 9o943-R00fe NAVAL POSTIiRADUATE SCHOOL Monterey, California DISSERTATION THE ROLE OF VORTEX STRUCTURE IN TROPICAL CYCLONE MOTION by Michael Fiorino December 1987 Dissertation Supervisor: R.L. Elsberry Approved for public release; distribution is unlimited T238908 IJJRITY CLASSIFICATION OF THIS PAGE REPORT DOCUMENTATION PAGE 8REP0RT SECURITY CLASSIFICATION lb RESTRICTIVE MARKINGS JNCLASSIFIED aSECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION /AVAILABILITY OF REPORT Approved for public release; / : DECLASSIFICATION DOWNGRADING SCHEDULE distribution is unlimited. ERFORMING ORGANIZATION REPORT NUM8ER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S) INAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION (If applicable) uval Postgraduate School 63 Naval Postgraduate School l^DORESS {City, State, and ZIP Code) 7b. ADDRESS {City, State, and ZIP Code) /.mterey, California 93943-5000 Monterey, California 93943-5000 iNAME OF FUNDING /SPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If applicable) :.\DORESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT ELEMENT NO. NO. NO ACCESSION NO. TITLE (Include Security Classification) e Role of Vortex Structure in Tropical Cyclone Motion »ERSONAL AUTHOR(S) Fiorino, Michael TYPE OF REPORT 13b. TIME COVERED
    [Show full text]
  • Mesoscale Convective Vortex Formation in a Weakly Sheared Moist Neutral Environment
    MAY 2007 CONZEMIUS ET AL. 1443 Mesoscale Convective Vortex Formation in a Weakly Sheared Moist Neutral Environment ROBERT J. CONZEMIUS Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, and Windlogics, Inc., Grand Rapids, Minnesota RICHARD W. MOORE Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, and Institute for Atmospheric and Climate Science (IACETH), ETH-Zürich, Zurich, Switzerland MICHAEL T. MONTGOMERY Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, Department of Meteorology, Naval Postgraduate School, Monterey, California, and Hurricane Research Division, NOAA/AOML, Miami, Florida CHRISTOPHER A. DAVIS National Center for Atmospheric Research, Boulder, Colorado (Manuscript received 31 January 2006, in final form 31 July 2006) ABSTRACT Idealized simulations of a diabatic Rossby vortex (DRV) in an initially moist neutral baroclinic environ- ment are performed using the fifth-generation National Center for Atmospheric Research–Pennsylvania State University (NCAR–PSU) Mesoscale Model (MM5). The primary objective is to test the hypothesis that the formation and maintenance of midlatitude warm-season mesoscale convective vortices (MCVs) are largely influenced by balanced flow dynamics associated with a vortex that interacts with weak vertical shear. As a part of this objective, the simulated DRV is placed within the context of the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) field campaign by comparing its tangential velocity, radius of maximum winds, CAPE, and shear with the MCVs observed in BAMEX. The simulations reveal two distinct scales of development. At the larger scale, the most rapidly growing moist baroclinic mode is excited, and exponential growth of this mode occurs during the simulation.
    [Show full text]
  • VORTEX a Stochastic Simulation of the Extinction Process
    Version 9.21 VORTEX A Stochastic Simulation of the Extinction Process User’s Manual Manual Written by: Philip S. Miller, Conservation Breeding Specialist Group (SSC/IUCN) Robert C. Lacy, Chicago Zoological Society Software Written by: Robert C. Lacy, Max Borbat, and JP Pollak A contribution of the IUCN/SSC Conservation Breeding Specialist Group in collaboration with the Chicago Zoological Society. VORTEX is provided at no cost, in order to further conservation and science. It is distributed without warranty of its suitability for any particular use, and neither the program or this manual is guaranteed to be free of errors, bugs, or potentially misleading information. It is the responsibility of the user to ensure that the software is appropriate for the uses to which it is put. VORTEX is owned and copyrighted by the Chicago Zoological Society. The software is not copy-protected. In addition to making back-up copies, individuals, not-for-profit organizations, and governmental agencies are hereby given licenses for making unlimited copies of VORTEX for the purpose of furthering conservation, teaching, and research. Distribution of VORTEX is restricted to: • distribution by the Chicago Zoological Society; • distribution by the IUCN/SSC Conservation Breeding Specialist Group; • downloading of the program from the Internet (http://www.vortex9.org/vortex.html) by individuals, not- for-profit organizations, and governmental agencies for their own research and conservation applications; • redistribution without charge of the unmodified executable program for the purposes described above. Unauthorized redistribution of VORTEX, in whole or in part by any for-profit organization or for any profit-making purposes is expressly forbidden.
    [Show full text]