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WES User Manual 3D/2D modelling suite for integral water solutions DELFT3D WES User Manual WES Wind Enhance Scheme for cyclone modelling User Manual Version: 3.01 SVN Revision: 68491 27 September 2021 WES, User Manual Published and printed by: Deltares telephone: +31 88 335 82 73 Boussinesqweg 1 fax: +31 88 335 85 82 2629 HV Delft e-mail: [email protected] P.O. 177 www: https://www.deltares.nl 2600 MH Delft The Netherlands For sales contact: For support contact: telephone: +31 88 335 81 88 telephone: +31 88 335 81 00 fax: +31 88 335 81 11 fax: +31 88 335 81 11 e-mail: [email protected] e-mail: [email protected] www: https://www.deltares.nl/software www: https://www.deltares.nl/software Copyright © 2021 Deltares All rights reserved. No part of this document may be reproduced in any form by print, photo print, photo copy, microfilm or any other means, without written permission from the publisher: Deltares. Contents Contents List of Figures v List of Tables vii 1 A Guide to the manual1 1.1 Changes with respect to previous versions..................1 2 Introduction 3 2.1 Functions and data flow of WES.......................3 2.2 Definition of the circular or the ‘spiderweb’ grid................4 2.3 Overview of the in- and output files......................5 3 Getting Started7 3.1 How to run WES...............................7 4 Files description9 4.1 The main Input file <∗.inp> file........................9 4.2 History points, <∗.xyn> file.........................9 4.3 Creating a track file <∗.trk> .........................9 4.4 Possible input parameters with respect to the tropical cyclone intensity....9 4.5 The diagnostic file.............................. 10 5 Conceptual description 11 5.1 Brief description of Holland’s model...................... 11 5.2 Further improvements to the original model.................. 12 5.3 Conversion factors.............................. 13 6 The approach in WES 15 6.1 Method 1: computing wind and pressure fields from Vmax, A and B ..... 15 6.2 Method 2: computing wind and pressure fields from Vmax, R35, R50 and R100 15 6.3 Method 3: computing wind and pressure fields from Vmax, pdrop and Rw ... 16 6.4 Method 4: computing wind and pressure fields from Vmax, pdrop (Rw is not known).................................... 16 6.5 Methods 5 and 6: Computing wind and pressure fields from Vmax and Rw (pdrop is not known)............................. 16 6.5.1 Method 5: Computing wind and pressure fields from Vmax and Rw (pdrop is not known), pdrop based on empirical model based on US hurricane statistics.......................... 16 6.5.2 Method 6: Computing wind and pressure fields from Vmax and Rw (pdrop is not known), pdrop based on empirical model for Indian tropical cyclones............................... 18 6.6 Method 7: computing wind and pressure fields from Vmax ........... 19 7 The approach in WES 21 7.1 Method 1: computing wind and pressure fields from Vmax, A and B ..... 21 7.2 Method 2: computing wind and pressure fields from Vmax, R35, R50 and R100 21 7.3 Method 3: computing wind and pressure fields from Vmax, Pdrop and Rw ... 22 7.4 Method 4: computing wind and pressure fields from Vmax, Pdrop (Rw is not known).................................... 22 7.5 Methods 5 and 6: Computing wind and pressure fields from Vmax and Rw (Pdrop is not known)............................. 22 7.5.1 Method 5: Pdrop based on empirical model based on US hurricane statistics............................... 22 7.5.2 Method 6: Pdrop based on empirical model for Indian tropical cyclones 23 Deltares iii WES, User Manual 7.6 Method 7: computing wind and pressure fields from Vmax ........... 24 8 Comparisons with observations 25 8.1 Comparison of Radius of Maximum Wind (Rw) and maximum wind speed.. 25 8.2 Comparison of Wind speed and direction with satellite data.......... 27 8.2.1 QuickSCAT winds........................... 27 8.2.2 ERS winds.............................. 30 8.2.3 Comparison of WES Winds with measured ground data........ 35 9 Comparison of different methods 37 10 Glossary of terms 39 References 41 A Description of used files 43 A.1 Description of the main input file for WES <∗.inp> .............. 43 A.2 History points, <∗.xyn> ........................... 44 A.3 Description of the cyclone parameters in the track file, <∗.trk> ........ 45 A.4 Spiderweb file................................. 46 A.5 Conversion Factors for wind speed...................... 46 A.6 Common Errors and Suggested Solutions in WES.............. 48 iv Deltares List of Figures List of Figures 2.1 Tropical cyclone winds on a circular grid....................4 2.2 Definition of the spiderweb grid........................4 3.1 Screen shot from WES requesting the name of the main input file.......7 3.2 Specifying the name of the main input file...................7 3.3 Screen shot from WES while processing...................8 3.4 Screen shot from WES showing error in running WES.............8 5.1 Example of calculated wind speed for given A and B values.......... 11 5.2 Asymmetric wind due to translation of the cyclone. Wind vectors jj~ajj > jj~bjj . 13 6.1 A and B value computed using two different methods............ 16 6.2 Left: Central pressure drop depicted agains maximum wind for 13 hurricanes in USA between 2000 – and 2005 data; Right: Comparison between the empirical relation to hurricane Ike data (data source: http://weather.unisys.com/hurricane)................. 17 6.3 Central pressure vs maximum wind for WES, HURDAT observations and Hol- lands’ P–W model and Dvorak for the dependent dataset (source: Holland (2008)).................................... 18 6.4 B as a function of Maximum wind speed (Vmax) for Indian tropical cyclones. 18 7.1 A and B value computed using two different methods............ 22 7.2 Left: Central pressure drop depicted agains maximum wind for 13 hurricanes in USA between 2000 – and 2005 data; Right: Comparison between the empir- ical relation to hurricane Ike data (data source: http://weather.unisys.com/hurricane). ........................................ 23 7.3 Central pressure vs maximum wind for WES, HURDAT observations and Hol- lands’ P–W model and Dvorak for the dependent dataset (source: Holland (2008)).................................... 24 7.4 B as a function of Maximum wind speed (Vmax) for Indian tropical cyclones. 24 8.1 (from top to bottom) Comparison between the observed and computed Radius of Maximum Wind and maximum wind speed for Vizag, Kakinada, and Orissa Cyclones................................... 26 8.2 QuickSCAT wind measured at 28/10/1999 (Orissa Cyclone - 05B). Black coloured wind barbs indicates rain contaminated data.................. 27 8.3 Comparison of WES winds and direction with derived winds from QuickSCAT satellite for 4 different sectors (Orissa Cyclone)................ 28 8.4 Comparison of WES winds and direction with derived winds from QuickSCAT satellite for 4 different sectors (Cuddalore Cyclone).............. 29 8.5 Comparison of ERS and parametric wind speeds and directions (Method A) on three radial cross sections on 28/10/1999 at 0400 Z. Triangles represent ERS data, crosses model data........................ 31 8.6 Comparison of ERS and parametric wind speeds and directions (Method B) on four radial cross sections on 28/10/1999 at 0400 Z. Triangles represent ERS data, crosses model data........................... 32 8.7 Comparison of ERS and parametric wind speeds and directions (Method A) on four radial cross sections on 28/11/2000 at 0400 Z. Triangles represent ERS data, crosses model data........................... 34 8.8 Comparison of ERS and parametric wind speeds and directions (Method B) on four radial cross sections on 28/11/2000 at 0400 Z. Triangles represent ERS data, crosses model data........................... 35 Deltares v WES, User Manual 8.9 Comparison of WES generated wind speed and direction with ground obser- vation..................................... 36 9.1 Computed Katrina wind speed on the 25th of August 2005 for 6 different meth- ods in WES.................................. 38 A.1 Gust factors for cyclone wind speed (Curve C) as a function of time (Krayer and Marshall, 1992).............................. 47 vi Deltares List of Tables List of Tables 5.1 Wind conversion factor from 1 minute (60 sec) average to 10 minutes (600 sec) average from Harper et al. (2010)..................... 13 Deltares vii WES, User Manual viii Deltares 1 A Guide to the manual This user manual provides detailed information on running of WES program, version 3.3. To make this manual more accessible we will briefly describe the contents of each chapter and appendices. Chapter 2: Introduction, provides an overview of the WES functions, area of applications and the software and hardware configurations of WES. Chapter 3: Getting Started, gives a brief overview of the input files required, data flow within the program, the output files of the program and finally, the steps executed byWES. Chapter 4: Files description, provides practical information of the model input files Chapter 5: Conceptual description, describes the equations in WES. Chapter 7: The approach in WES, describes a number of methods available in WES to generate the the wind and pressure fields. Chapter 8: Comparisons with observations, comparison of numerical results and obser- vations of 4 different tropical cyclones. Chapter 9: Comparison of different methods, comparison of wind and pressure fields generated with different methods in WES. Chapter 10: Glossary of terms, contains a list of terms and abbreviations used in this man- ual and their explanations. References, provides a list of publications referenced by this manual. Appendix A: Description of used files, gives a description of all the files that can be used in WES. This information is required for generating some files manually or by other means of other utility programs. 1.1 Changes with respect to previous versions Version Description 3.32.01 Output on history points can now be generated. 3.32.00 Default of radius of maximum wind Rmax is changed from 13.5 [nmi] to 25[nmi].
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