VORTRAC

Overview

The Vortex Objective Radar Tracking and Circulation software is a collection of radar algorithms designed to provide real-time or post-analysis information about hurricane location and structure from a single Doppler radar. These algorithms are written in C++ and combined with a graphical user interface (GUI) that allows the user to control the software operation and display critical storm parameters for use in an operational environment. The primary display shows a timeline of estimated central surface pressure and the radius of maximum wind (RMW) that updates as new radar volumes are processed. Additional information about the radar data and program operation is also displayed to the user, including a constant altitude plan-position indicator (CAPPI), maximum velocity, storm signal, status light, operation log, and progress bar. This development was funded under a grant from the NOAA Joint Hurricane Testbed program from 2005 – 2007.

Copyright, License, and Patent

The VORTRAC code is governed under two copyrights and licenses, and contains a patented algorithm.

The majority of the code is licensed under the Apache License Version 2.0, with the exception of the code in the NRL subdirectory. The code in the NRL subdirectory has contributions from Paul Harasti at the Naval Research Laboratory and is governed by a separate license. The Generalized Velocity Track Display (GVTD) algorithm was patented in 2010 as “Method for generating a representation of an atmospheric vortex kinematic structure” – US Patent No. 7728760 B2

Main code copyright and license

Copyright 2005 - 2018, Colorado State University and University Corporation for Atmospheric Research

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

References

• Cha, T.-Y., and Bell, M. M., 2020: Comparison of Single Doppler and Multiple Doppler Wind Retrievals in Hurricane Matthew (2016), Atmos. Meas. Tech. Discuss. [preprint], https://doi.org/10.5194/amt-2020-240, in review, 2020.
• Harasti, P.R., 2014: An Expanded VVP Technique to Resolve Primary and Environmental Circulations in Hurricanes. J. Atmos. Oceanic Technol., 31, 249–271.

• Jou, B. J.-D., W.-C. Lee, S.-P. Liu, and Y.-C. Kao, 2008: Generalized VTD retrieval of atmospheric vortex kinematic structure. Part I: Formulation and error analysis. Mon. Wea. Rev., 136 (3), 995–1012, doi: 10.1175/2007MWR2116.1.

• Lee, W.-C. and F. D. Marks, 2000: Tropical cyclone kinematic structure retrieved from single-Doppler radar observations. Part II: The GBVTD-Simplex center finding algorithm. Mon. Wea. Rev., 128 (6), 1925–1936, doi: 10.1175/1520-0493(2000)128<1925:TCKSRF>2.0.CO;2.

• Lee, W.-C., B. J.-D. Jou, P.-L. Chang, and S.-M. Deng, 1999: Tropical cyclone kinematic structure retrieved from single-Doppler radar observations. Part I: Interpretation of Doppler velocity patterns and the GBVTD technique. Mon. Wea. Rev., 127 (10), 2419–2439, doi: 10.1175/1520- 0493(1999)127<2419:TCKSRF>2.0.CO;2.

Running VORTRAC

1. Create several folders in the same directory as the xml file:

• cappi
• center
• choosecenter
• radar
• pressure
• vtd

2. Put the radar files in the radar folder.

If you select to use NetCDF pregridded data, make sure to convert the raw file format to CfRadial using RadxConvert then grid the data on Cartesian coordinate using Radx2Grid.

3. Edit the xml file and configure the information.

   • Descriptions of the xml file can be found below: Configuration.

   • The xml example file can be found here: myconfig.xml

   Important Note: Current vortrac_radarList.xml file only has the United States NEXRAD radar information. If the user would like to use other radar outside of the United States, you will have to manually insert the radar configuration in the vortrac_radarList.xml file under the Resources directory.

4. To initiate a new run, execute VORTRAC using the following command:

/path/to/lrose/install/bin/vortrac

Click “File”, and open the configured xml file. Then, the user can initiate the analysis with the “Run” button on the bottom right.

5. After VORTRAC finishes all the analysis, the program will generate four files:

• {TC_name}_{Radar_name}_{Year_of_the_TC}_coefficientlist.csv
• {TC_name}_{Radar_name}_{Year_of_the_TC}_simplexlist.xml
• {TC_name}_{Radar_name}_{Year_of_the_TC}_vortexlist.xml
• VORTRAC_status_{The_time_of_analysis}.log

TC_name, Radar_name, and Year_of_the_TC will be generated based on the configured xml file, and The_time_of_analysis depends on the time when the user initiates a new run.

6. Convert the retrieved coefficients into a netCDF file with the coefficintlist and log files by using the following command:

/path/to/lrose/install/bin/vo2nc -c {TC_name}_{Radar_name}_{Year_of_the_TC}_coefficientlist.csv -l VORTRAC_status_{The_time_of_analysis}.log -o output.nc

From here, you can read in the netCDF file using Julia, Python, or other programming languages for further analysis.

Configuration

Edit the configuration in the XML file. Each section in the XML file is explained by the following:

vortex

XML Label: name (default: New Hurricane)

• Input: Vortex Name
• Description: This parameter holds the name of the tropical cyclone that VORTRAC is tracking. This parameter is used internally for labeling and also for labeling various output files.

XML Label: lat (default: 0 deg)

• Input: Vortex Latitude
• Range: [-90, 90] deg

XML Label: lon (default: 0 deg)

• Input: Vortex Longitude
• Range: [-180, 180] deg
• Description: These parameters hold the first observation latitude and longitude of the tropical cyclone. The latitude and longitude of the storm given here should correspond with the time shown in “Time of Above Observation” so that VORTRAC can accurately locate the tropical cyclone. VORTRAC accepts latitude (longitude) in a decimal format where a negative value is in the Northern (Western) hemisphere and a positive value is in the Southern (Eastern) hemisphere. Initializing the VORTRAC analysis with an accurate storm location and time is required for a successful run and the accuracy of these parameters affects VORTRAC’s ability to follow the storm as it evolves.

XML Label: direction (default: 0 deg)

• Input: Direction of Vortex Movement (Degrees clockwise from North)
• Range: [0, 359.9] deg

XML Label: speed (default: 0 m/s)

• Input: Speed of Vortex Movement (Degrees clockwise from North)
• Range: [0, 100] m/s
• Description: These parameters should hold the direction and speed of the initial storm movement. These measurements should correspond with the time set in “Time of Above Observation” so that VORTRAC can accurately follow the tropical cyclone. While these parameters are not required for a successful run, it is highly recommended that the user obtain this information about the storm. These parameters are particularly useful when the initial observation (observation time, latitude and longitude on the VORTEX panel) is outside of the range of the Doppler radar. When the initial observation is outside Doppler range VORTRAC will linearly interpolate the initial position based on direction of storm movement and storm speed until the circulation enters the Doppler range of the radar.

XML Label: obsdate (default: current date UTC)

• Input: Time of Above Observation
• Range: Any Valid Date (format: YYYY-MM-DD)

XML Label: obstime (default: current time UTC)

• Input: Time of Above Observation
• Range: Any Valid UTC Time (format: HH:MM:SS)
• Description: These parameters are used to set the time of the initial observation which is described by Vortex Latitude, Vortex Longitude, Vortex Speed and Vortex Direction parameters contained in this panel. If this time of observation occurs before the starting time in RADAR CONFIGURATION PANEL, then VORTRAC will attempt to interpolate a starting location that is in the Doppler domain after the indicated initial time in the RADAR CONFIGURATION PANEL.

XML Label: dir (default: ‘default’ sets to current working directory at run time)

• Input: Working Directory
• Range: Any directory where the user has permission to read and write files
• Description: This parameter holds the location of the working directory which will contain many of the products and temporary files that VORTRAC uses during a run. When other directories in the configuration are left on the default setting they will default to subdirectories of this working directory. It is recommended that the user not change the working directory once a run has begun processing because this can cause difficulties in locating data products and intermediates. The working directory is also important when restarting an old run, since VORTRAC will search the working directory for traces of previous runs to restart.

XML Label: centers (optional, data format: YYYY-MM-DD:HH:MM,lat,lon)

• Input: Center file directory
• Range: Any directory where the user has permission to read and write files
• Description: This parameter should hold the directory of the csv file that contains the centers information. VORTRAC can use the csv file as a first guess to perform the simplex algorithm or as a final center to perform the GBVTD/GVTD algorithm. It is optional to include the center file, and the center format is YYYY-MM-DD:HH:MM,lat,lon.

radar

XML Label: name (default: WSR-88D)

• Input: Radar Name
• Range: Any four letters (preferably radar call letters)
• Description: This parameter is intended to hold the radar call letters for WRS-88D radar that is being used to observe the storm. The drop down box in the RADAR CONFIGURATION PANEL can be used to select from several existing radars near the Atlantic and Gulf coasts. Additionally the user may choose to add new radars to this list by clicking ‘Other Radar …’ and entering or editing parameters as necessary. The radar call letters entered here are used for identifying radar volume data, in addition to internal labeling and naming data products, so entering these correctly is highly recommended.

XML Label: lat (default: 0 deg)

• Input: Radar Latitude (deg)
• Range: [-90, 90] decimal degrees

XML Label: lon (default: 0 deg)

• Input: Radar Longitude (deg)
• Range: [-180, 180] decimal degrees

XML Label: alt (default: 0 m)

• Panel Label: Radar Altitude (meters)
• Range: [-999, 999]
• Description: These three parameters describe the location of the radar in latitude, longitude and altitude. They will be automatically set when a radar is selected from the radar name drop box. These can be manually adjusted in the panel or in the radar list dialog which can be accessed by choosing ‘Other Radar …’ in the Radar Name drop box. These three parameters are all required to successfully run VORTRAC.

XML Label: dir (default: ‘default’)

• Input: Radar Data Directory -Range: Any existing directory where the user has read permissions
• Description: This parameter should hold the name of the directory that contains the level II radar data from the radar specified in this panel. The level II data in this directory should be the same format as that selected in the format drop box on this panel. Additionally, the level II data should be named in the following format: KXXXyyyyMMdd_hhmmss

where KXXX is the station call letters specified in the radar name parameter. The call letters are followed by the UTC time stamp of the volume in the above format. This parameter will default to the working directory if no other directory is given.

XML Label: format (default: LEVELII)

• Input: Data Format
• Range: [LDMLEVELII, NCDCLEVELII,NETCDF]
• Description: This parameter is used to select the radar data format of the files contained in the directory specified in dir. These formats are explained in greater detail in Sec 1A. This is a required parameter, selecting a format that doesn’t correspond with the files located in the Radar Data Directory will cause VORTRAC to run improperly.

XML Label: startdate (default: current date UTC, format: YYYY-MM-DD)

XML Label: starttime (default: current time UTC, format: HH:MM:SS)

• Input: Start Date and Time
• Range: Any valid date and time
• Description: These date and time parameters indicate the earliest time stamp that a volume of level II radar data may have in order to be processed by VORTRAC. This parameter is intended to help the user control which volumes are read in by VORTRAC for each analysis.

XML Label: enddate (default: current date UTC + 3 days, format: YYYY-MM-DD)

XML Label: endtime (default: current time UTC, format: HH:MM:SS) -Panel Label: End Date and Time

• Range: Any valid date and time -Description: These date and time parameters indicate the latest time stamp that a volume of level II radar data may have in order to be processed by VORTRAC. This parameter is intended to help the user control which volumes are read in by VORTRAC for each analysis.

cappi

XML Label: dir (default: default)

• Input: CAPPI Output Directory -Range: Any directory where the user has read and write permission
• Description: This directory will be used to store CAPPI output files in the .asi format. More information on the .asi format can be found in Sec 1A. When the xml parameter dir is set to ‘default’ this directory will default to subdirectory of the working directory selected in the VORTEX CONFIGURATION PANEL. If such a subdirectory does not exist, one will be created. The user can also choose to adjust this directory independent of the main working directory.

XML Label: xdim (default: 150)

• Input: Grid Dimension in X Direction
• Range: [0, no maximum limit]

XML Label: ydim (default: 150)

• Input: Grid Dimension in Y Direction
• Range: [0, no maximum limit]

XML Label: zdim (default: 3)

• Input: Grid Dimension in Z Direction
• Range: [0, no maximum limit]
• Description: These three parameters allow the user to adjust the size of the CAPPI used in the analysis. The default dimensions are intended to meet the needs of the ‘average’ circulation, but these parameters can be adjusted to meet specific needs. Larger grids provide more data for analysis, but they also increase processing times considerably.

XML Label: xgridsp (default: 1.0 km)

• Input: X Grid Spacing (km)

XML Label: ygridsp (default: 1.0 km)

• Input: Y Grid Spacing (km)

XML Label: zgridsp (default: 1.0 km)

• Input: Z Grid Spacing (km)
• Description: These values control the grid spacing of the CAPPI. Currently these value are fixed at 1 km, but VORTRAC’s functionality may be expanded later to allow adjustments in these parameters.

XML Label: interpolation (default: cressman)

• Input: Interpolation
• Range: [cressman]
• Description: This parameter contains the interpolation method used for mapping data from the level II radar volume to the CAPPI for further processing. Currently Cressman interpolation is the only option for interpolating.

center

XML Label: dir (default: ‘default’)

• Input: Center Output Directory
• Range: Any directory where the user has read and write permission -Description: This parameter stores the directory where the results of each simplex search will be stored. These files are intermediates which are only valuable to the advanced user, but if they are discarded the user will be unable to restart the VORTRAC run. A list of these files are stored in the working directory (file ending in simplexList.xml). This directory will default to use or create a center subdirectory in the working directory if its value is not altered.

XML Label: skipsimplex (default: false)

• Input: skip the simplex to find the center
• Range: [false,true]
• Description: This parameter determines whether to perform the center finding algorithm for the VORTRAC analysis. The user can put predetermined centers into a file (in the vortex section) and use them for the VORTRAC analysis.

XML Label: geometry (default: GBVTD)

• Input: Geometry
• Range: [GBVTD,GVTD]
• Description: This parameter holds the geometry for the VORTRAC analysis. Currently only the GBVTD geometry is implemented so this parameter should not be changed.

XML Label: closure (default: original)

• Input: Closure
  
• Range: [original]
• Description: This parameter holds the closure assumption to be used in the VORTRAC analysis. Currently only the original closure assumption is available for use. This closure assumption is used in the simplex search for the vorticity center. For more about closure assumptions see Sec. 3A Algorithm Overview.

XML Label: reflectivity (default: DZ)

• Input: Reflectivity
• Range: [DZ]
• Description: This parameter holds the letters that identify the reflectivity data within the radar volumes. There is currently only one option for this parameter but it may be expanded later to suit user needs.

XML Label: velocity (default: VE)

• Input: Velocity
• Range: [VE] -Description: This parameter holds the letters that identify the velocity data within the radar volumes. There is currently only one option for this parameter but it may be expanded later to suit user needs.

XML Label: bottomlevel (default: 1 km)

• Input: Bottom Level (km) -Range: [0, 5] km

XML Label: toplevel (default: 3)

• Input: Top Level (km)
• Range: [2, 20] (km)
• Description: These two parameters control which height range within the CAPPI is used in the SIMPLEX search algorithms. The user can adjust these parameters, but the total number of levels used cannot exceed 20 due to memory constraints. Examining a greater number of levels may provide greater accuracy, but at the cost of computation time. The default values for these parameters should be appropriate for most cases. The user should also be cautioned that trying to examine levels outside of those contained in the CAPPI could yield undesirable results due to absent data.

XML Label: innerradius (default: 10)

• Input: Inner Radius (km)
• Range: [1, 120] XML Label: outerradius (default: 35)
• Input: Outer Radius (km)
• Range: [2, 150]
• Description: These two parameters control the range that the SIMPLEX algorithm searches for a circulations radius of maximum wind. These parameters should be adjusted based on outside information on the approximate radius of the tropical cyclone. If a cyclone’s RMW is not enclosed in this range SIMPLEX is unlikely to accurately locate a center. These are required parameters, they should also be adjusted if the storm changes size during the analysis. The SIMPLEX radius search range is displayed on the CAPPI DISPLAY once VORTRAC has completely processed a volume. This visual display should help the user locate the best radius range for subsequent simplex searches.

XML Label: ringwidth (default: 1.0 km)

• Input: Width of Search Rings (km)
  
• Range: [0.01, 10.00] km
• Description: This parameter controls the width of the search ring for each radius search preformed by the SIMPLEX algorithm. This parameter does not change the ring spacing (SIMLEX will search in 1 km increments between the Inner Radius and the Outer Radius). This parameter controls the thickness of the annuli of data points from the CAPPI that are used for each search. It may be useful to increase this value when data in the region of interest is very sparse. However, increasing this value significantly may cause greater uncertainty in the radius of maximum wind.

XML Label: search (default: MAXVT0)

• Input: Center Finding Criteria
• Range: [MAXVT0]
• Description: This parameter contains the criteria that simplex searches for when attempting to locate the tropical cyclone center. Currently the only available option is MAXVT0. This selection indicates that the SIMPLEX search will attempt to locate the tropical cyclone based on the greatest primary circulation wind that it can locate during its search.

XML Label: influenceradius (default: 4.0)

• Input: Radius of Influence (km) * Range: [2, 10] km
• Description: This parameter controls the initial spacing of points in the SIMPLEX search algorithm. While this parameter can be adjusted to begin searching smaller or greater areas based on user needs, it is recommended that this parameter only be adjusted by advanced users.

XML Label: convergence (default: 0.05)

• Input: Convergence Requirements
• Range: [0.001, 2.000]
• Description: This parameter controls the extent of the convergence of centers required by the SIMPLEX algorithm for agreement between separate searches. While this parameter can be adjusted to require more or less convergence based on user needs, it is recommended that this parameter only be adjusted by advanced users.

XML Label: maxiterations (default: 60)

• Input: Maximum Iterations for Process
• Range: [10, 100]
• Description: This parameter sets the maximum number of iterations possible within a SIMPLEX search. Increasing this parameter may increase computation time. It is recommended that this parameter only be adjusted by advanced users.

XML Label: boxdiameter (default: 12.0 km)

• Input: Width of Search Zone (km)
• Range: [9, 25]

XML Label: numpoints (default: 16, recommended the number can be a square of an integer)

• Input: Number of Center Points
• Range: [1, 25]
• Description: These two parameters control the distribution of initial SIMPLEX searches that are independently run to locate the circulation center. The Width of Search Zone parameter controls the width of the initial range where SIMPLEX searches are started. The Number of Center Points parameter controls the number of starting points distributed within this box. It is recommended that these parameters only be changed by advanced users, the defaults should perform well for most cases.

XML Label: maxwavenum (default: 1)

• Input: Maximum Wave Number of TC
• Range: [0, no maximum limit]

XML Label: maxdatagap (default: 0 deg)

• Input: Wave #
• Range: [0, 359] deg
• Description: These parameters control how much data can be missing within a ring of analysis at each wave number. The Maximum Wave Number controls the order of the Fourier fit used to calculate the winds at each ring. The SIMPLEX CONFIGURATION PANEL will hold multiple Wave # boxes corresponding to the value assigned maxwavenum. The maximum data gap for each wave number should be assigned based on an understanding of how missing data affects the quality of the fit. The defaults should work well form most cases.

choosecenter

XML Label: dir (default: ‘default’)

• Input: Choosecenter Output Directory
• Description: This parameter designates a directory where the user has read and write permissions to store choose center intermediate outputs and diagnostics. This parameter is not currently implemented.

XML Label: startdate (default: current date UTC, format: YYYY-MM-DD)

XML Label: starttime (default: current time UTC, format: HH:MM:SS)

• Input: Start Date and Time
• Range: Any valid date and time
• Description: These date and time parameters indicate the earliest time stamp that a volume of radar data may have in order to be included in the polynomial fit. This parameter is intended to help the user control which results are used to guide the center finding algorithm for future volumes. We recommend excluding volumes where the circulation center is near the edge of the radar range.

XML Label: enddate (default: current date UTC + 3 days, format: YYYY-MM-DD)

XML Label: endtime (default: current time UTC, format: HH:MM:SS)

• Input: End Date and Time
• Range: Any valid date and time
• Description: These date and time parameters indicate the latest time stamp that a volume of radar data may have in order to be included in the polynomial fit. This parameter is intended to help the user control which results are used to guide the centering algorithm for future volumes. We recommend excluding volumes where the circulation center is near the edge of the radar range.

XML Label: min_volumes (default: 6)

• Input: Number of Volumes Required to Begin Curve Fitting
• Range: [3, 100]
• Description: This parameter controls the minimum number of volumes that must process successfully before curve fitting begins. The user can avoid curve fitting by setting this parameter higher than the number of volumes he expects to process.

XML Label: wind_weight (default: 0.20)

• Input: Maximum Wind Score Weight

XML Label: stddev_weight (default: 0.60)

• Input: Standard Deviation Score Weight

XML Label: pts_weight (default: 0.20)

• Input: Number of Converging Centers Score Weight
• Range: [0.0, 1.0]
• Description: This set of weights determines the mean centers and the radius of maximum wind on each level of the CAPPI from the centers located by the SIMPLEX algorithm. The sum of all three of these weights should add to one. Adjusting these weights allows the user to put greater emphasis on a specific characteristic when determining the location of the circulation center and corresponding radius of maximum wind. It is recommended that these parameters only be adjusted by the advanced user.

XML Label: position_weight (default: 0.40)

• Input: Distance Score Weight

XML Label: rmw_weight (default: 0.40)

• Input: Radius of Maximum Wind Score Weight

XML Label: vt_weight (default: 0.20)

• Input: Maximum Velocity Score Weight
• Range: [0.0, 1.0]
• Description: This set of weights determines the fitted center and radius of maximum wind on each level of the CAPPI based on information from previously processed volumes. The sum of all three of these weights should add to one. A polynomial fit is constructed based no the position, radius of maximum wind, and the maximum wind from all previous volumes included in the fit to determine the best circulation center of those located by simplex. Adjusting these parameters will effect which characteristics are given a greater emphasis is determining the best center, it is recommended that these parameters only be adjusted by the advanced user.

XML Label: stats (default: 95)

• Input: fTest Precision
• Range: {95, 99} %
• Description: This parameter determines the statistical significance level required to increase the order of the polynomial curve fits used to constrain the selected centers. The higher significance level results in a stricter requirement, and therefore most likely a lower order fit. It is recommended that this parameter only be adjusted by the advanced user.

VTD

XML Label: dir (default: ‘default’)

• Input: VTD Output Directory -Range: Any directory where the user has read and write permission -Description: This parameter stores the directory where the results of the final GBVTD search will be stored. These files are intermediates which are only valuable to the advanced user, but if they are discarded the user will be unable to restart the VORTRAC run. A list of these files are stored in the working directory (file ending in vortexList.xml). This directory will default to use or create a center subdirectory in the working directory if its value is not altered.

XML Label: geometry (default: GBVTD)

• Input: Geometry
• Range: [GBVTD, GVTD] Description: This parameter holds the geometry for the VORTRAC analysis. Currently only the GBVTD geometry is implemented so this parameter should not be changed. This parameter controls the same functionality as the parameter of the same name in the SIMPLEX Configuration Panel, but is only used in the final calculation of the circulation winds.

XML Label: closure (default: original_hvvp)

• Input: Closure
  
• Range: [original, original_hvvp]
• Description: This parameter holds the closure assumption to be used in the VORTRAC analysis. Selecting the ‘original’ closure assumption assumes the component of the environmental wind perpendicular to the radar’s line of view to the storm is negligible. Selecting ‘original_hvvp’ allows VORTRAC to use the HVVP algorithm to calculate this environmental wind component. This closure assumption is used in the GBVTD final analysis of the selected vorticity center. For more about closure assumptions see Sec. 3A Algorithm Overview. This parameter controls the same functionality as the parameter of the same name in the SIMPLEX CONFIGURATION PANEL, but is only used in the final calculation of the circulation winds. The ‘original_hvvp’ closure assumption is not available in the simplex search because it increases calculation times considerably.

XML Label: reflectivity (default: DZ)

• Input: Reflectivity
• Range: [DZ]
• Description: This parameter holds the letters that identify the reflectivity data within the radar volumes. There is currently only one option for this parameter but it may be expanded later to suit user needs. This parameter controls the same functionality as the parameter of the same name in the SIMPLEX CONFIGURATION PANEL, but is only used in the final calculation of the circulation winds.

XML Label: velocity (default: VE)

• Input: Velocity
• Range: [VE] -Description: This parameter holds the letters that identify the velocity data within the radar volumes. There is currently only one option for this parameter but it may be expanded later to suit user needs. This parameter controls the same functionality as the parameter of the same name in the SIMPLEX CONFIGURATION PANEL, but is only used in the final calculation of the circulation winds.

XML Label: bottomlevel (default: 1 km)

• Input: Bottom Level (km) -Range: [0, 5] km

XML Label: toplevel (default: 3)

• Input: Top Level (km)
• Range: [2, 20] (km)
• Description: These two parameters control which height range within the CAPPI is used in the final calculation of the circulation winds. The user can adjust these parameters, but the total number of levels used cannot exceed 15 due to memory constraints. Examining a greater number of levels may provide greater accuracy, but at the cost of computation time. The default values for these parameters should be appropriate for most cases. The user should also be cautioned that trying to examine levels outside of those contained in the CAPPI and those processed by SIMPLEX could yield undesirable results due to absent data.

XML Label: innerradius (default: 1)

• Input: Inner Radius (km) -Range: [1, 100]

XML Label: outerradius (default: 60)

• Input: Outer Radius (km) -Range: [2, 150]
• Description: These two parameters control the range of radii that are included in the pressure deficit calculation using the final circulation winds. These parameters should be adjusted to encompass as much of the circulation as possible without exceeding memory limitations (current memory limitations are 150 rings). These are required parameters, they should also be adjusted if the storm changes size during the analysis. It is highly recommended that the user leave the inner radius at the 1 km default. The Outer VTD radius is displayed on the CAPPI DISPLAY once VORTRAC has completely processed a volume. This visual display should help the user locate the best radius range for analysis of subsequent volumes.

XML Label: ringwidth (default: 1.0 km)

• Input: Width of Search Rings (km)
  
• Range: [0.01, 10.00] km
• Description: This parameter controls the width of the search ring for each radius analysis preformed in the final calculation of circulation winds. This parameter does not change the ring spacing (VTD will extract information on circulation winds in 1 km increments between the Inner Radius and the Outer Radius). This parameter controls the thickness of the annuli of data points from the CAPPI that are used for each search. It may be useful to increase this value when data in the region of interest is very sparse. However, increasing this value significantly may cause greater uncertainty in the radius of maximum wind.

XML Label: maxwavenum (default: 1)

• Input: Maximum Wave Number of TC
• Range: [0, no maximum limit]

XML Label: maxdatagap (default: 0 deg)

• Input: Wave #
• Range: [0, 359] deg
• Description: These parameters control how much data can be missing within a ring of analysis at each wave number. The Maximum Wave Number controls the order of the Fourier fit used to calculate the winds at each ring. The VTD CONFIGURATION Panel will hold multiple Wave # boxes corresponding to the value assigned maxwavenum. The maximum data gap for each wave number should be assigned based on an understanding of how missing data affects the quality of the fit. The defaults should work well form most cases.

hvvp

Currently, HVVP is not used in the VORTRAC analysis, so the user can leave it as default setting.

pressure

XML Label: dir (default: default)

• Input: Directory Containing Pressure Data
• Range: Any directory where the user has read permissions
• Description: This parameter is used to specify the directory that holds files containing the pressure anchor data for the tropical cyclone that is currently being processed. This directory will be repeatedly checked for any additional pressure data files while the algorithm is running.

XML Label: format (default: AWIPS)

• Input: Data Format
• Range: [AWIPS, Hwind]
• Description: This parameter indicates the format of the incoming pressure data that is found in the directory specified by the Directory Containing Pressure Data parameter. More information about the expected input format is found in Sec. 4B.

XML Label: height (default: 1 km)

• Input: Height at which Pressure Gradient is Calculated (km)
• Range: [1, 20] km
• Description: This parameter is used to specify the height that will be used when the pressure deficit is calculated. The height is measured in km above the radar. Best results are obtained when examining the lowest level containing viable data. Usually this is 1 km but in some circumstances the user may want to adjust this parameter.

XML Label: maxobstime (default: 59 min)

• Input: Discard Pressure Observations After (minutes)
• Range: [1, 1000] minutes
• Description: This parameter indicates the maximum number of minutes which can elapse between the time a volume is created and time of the external pressure observation used to anchor the VORTRAC pressure calculation. VORTRAC requires external pressure anchors to accurately calculate the central pressure of the circulation. The algorithm will use near by pressure observations in conjunction with the pressure gradient of the storm to calculate the central pressure. The pressure observations used to anchor the calculation of the central pressure for each volume are limited to those which were recorded maxobstime minutes before the volume.

XML Label: maxobsdist (default: 50 km)

• Input: Maximum Distance (km)
• Range: [1, 1000]
• Description: External pressure observations used to anchor the VORTRAC central pressure estimate are also weighted by the distance of the external observation from the tropical storm. This parameter specifies the maximum distance between a pressure measurement and the tropical cyclone being examined which permits the measurement to be used in the anchoring calculation. External pressure observations beyond this distance will not be used as part of the anchor pressure calculation.

XML Label: maxobsmethod (default: ring)

• Input: Maximum Distance to Pressure Observations. Measure from TC Center or measure from Edge of Analysis
• Range: [ring, center]
• Description: Checking one of the two radio buttons in this box will set the method for deciding which pressure estimates should be used as anchors in the VORTRAC pressure calculation. If ‘Measure from TC Center’ is down only pressure within the Maximum Distance parameter value of the tropical cyclone center are used to calculate the anchor pressure for the VORTRAC central pressure estimate. If ‘Measure from Edge of Analysis’ is down then the pressure observations used in this calculation must be less than the Maximum Distance parameter value from the edge of the VORTRAC analysis domain (described in VTD Configuration Panel in the Outer Radius parameter).

XML Label: av_interval (default: 8)

• Input: Number of Volumes Averaged
• Range: [3, 12]
• Description: This parameter holds the number of volumes that will be averaged together to determine the rate of change in central pressure for the tropical cyclone. The Storm Signal on the VORTRAC display will indicate when there has been a significant change in the pressure trend of the storm being analyzed. In order to avoid signals based on small volume to volume fluctuations several volumes are averaged and compared to radar volumes collected during the previous hour to diagnose the rate of change of storm central pressure.

XML Label: rapidlimit (default: 3)

• Input: Pressure Change for Warnings (mb/hr)
• Range: [1, 10] mb/hr
• Description: This value sets the rate of change in the tropical cyclone central pressure that will trigger a change in the Storm Signal on the VORTRAC display. This parameter is used in conjunction with the Number of Volumes Averaged parameter to determine the thresholds for displaying pressure change warnings.

graphics

XML Label: autolimits (default: on)

• Input: Parameters for Graph Display (radio button)
• Range: {on, off}
• Description: This box of items is used to manually adjust the scale and parameters of the radius of maximum wind (RMW) and pressure display in the GUI. The Pressure/RMW Display is set to automatically adjust the scales to include the results from every successfully processed volume. Should the user want to adjust these parameters, the xml autolimits parameter can be turned off (by checking the Parameters for Graph Display box), making available a number of adjustment parameters.

XML Label: pressmin (default: 900.00 mb)

• Input: Minimum Pressure (mb). Only available when “Parameters for Graph Display” is checked
• Range: [0, 1000] mb
• Description: This value is the user defined minimum pressure measurement that will be displayed on the Pressure/RMW Display. Any pressure measurements below this value will not be displayed on the graph.

XML Label: pressmax (default: 1020 mb)

• Input: Maximum Pressure (mb). Only available when “Parameters for Graph Display” is checked
• Range: [700, 1100] mb
• Description: This value is the user-defined maximum pressure measurement that will be displayed on the Pressure/RMW Display. Any pressure measurements above this value will not be displayed on the graph.

XML Label: rmwmin (default: 0 km)

• Input: Minimum RMW (km). Only available when “Parameters for Graph Display” is checked
• Range: [0, 200]
• Description: This value is the user-defined minimum radius of maximum wind (RMW) measurement that will be displayed on the Pressure/RMW Display. Any RMW measurements above this value will not be displayed on the graph.

XML Label: rmwmax (default: 60 km)

• Input: Maximum RMW (km). Only available when “Parameters for Graph Display” is checked
• Range: [0, 200]
• Description: This value is the user-defined maximum radius of maximum wind (RMW) measurement that will be displayed on the Pressure/RMW Display. Any RMW measurements above this value will not be displayed on the graph.

XML Label: startdate (default: current date UTC, format: YYYY-MM-DD)

XML Label: starttime (default: current time UTC, format: HH:MM:SS) -Input: First Graph Display Time. Only available when “Parameters for Graph Display” is checked * Range: Any valid date and time -Description: This is the user-defined minimum time for pressure and RMW measurements that will be displayed on the Pressure/RMW Display. This value should be within the period of currently processed radar data.

XML Label: enddate (default: current date UTC + 3 days, format: YYYY-MM-DD)

XML Label: endtime (default: current time, format: HH:MM:SS)

• Input: Final Graph Display Time. Only available when “Parameters for Graph Display” is checked
• Range: Any valid date and time -Description: This time is the user-defined maximum time for pressure and RMW measurements that will be displayed on the Pressure/RMW Display. This value should be within the period of currently processed radar data