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The Functionality of a New Radar Software Package: GRLevel2 Analyst Edition


The Functionality of a New Radar Software Package: GRLevel2 Analyst Edition Ted Keller Senior Meteorologist KOLR/KSFX-TV Springfield, Missouri I m from Springfield ... – PowerPoint PPT presentation

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Title: The Functionality of a New Radar Software Package: GRLevel2 Analyst Edition

The Functionality of a New Radar Software
Package GRLevel2 Analyst Edition
  • Ted Keller
  • Senior Meteorologist
  • Springfield, Missouri

  • Im from Springfield, Missouri

This Presentation
  • Why I decided to give this talk
  • Review of AE software capabilities
  • Using AE in real-time
  • Considerations for using AE on air
  • Establishment of a radar resource or dialog
    program (via a web site?)

My Radar Experience
  • WSR-57C (first hook echo)
  • Kavorus RADAC
  • WSI 1010N (level 3, NIDS)
  • Baron FasTrac Millennium

The NIDS Years
  • Useful for quick diagnostic storm attributes
  • NIDS images poor quality hard to see many
  • Storm attributes delayed from images
  • Storm attributes not perfect
  • The whole NIDS set up discouraged any detailed

Why This Talk?
  • Im excited! AE has opened a whole new world of
    radar analysis
  • I come from background with no live radar
  • Im certainly no radar expert but I believe I
    represent many of you with similar backgrounds
    and experiences
  • AE has improved severe weather coverage!

GR2 Analyst Edition (AE)
  • AE reads Level II data from the NWS 88D radar
    (real-time or archived)
  • It was designed as a volume-rendering tool
    allowing users to view radar data in three
    dimensions plus time (4D)
  • AE is also a very slick 2D radar viewer with lots
    of useful features

GR2 Analyst Edition (AE)
  • AE uses hail detection algorithms patterned after
    those developed by the National Severe Storms Lab
  • The environmental data used by the algorithms can
    be entered by hand or automatically input using
    RUC objective analysis data
  • AE generates two hail parameters
  • POSH, Probability of Significant Hail
  • MEHS, Maximum Estimated Hail Size

GR2 Analyst Edition (AE)
  • The user can input storm motion vectors used in
    the calculation of storm relative velocity (SRV)
  • AE calculates vertically integrated liquid (VIL)
    density (VILD)
  • VILD takes the entire storm height into
    consideration and uses all reflectivity
    (including hail) in its calculation

AE 2D Fields
  • Base reflectivity (BR)
  • Base Velocity (BV)
  • Storm Relative Velocity (SRV)
  • Spectrum Width (SW)
  • Echo Top (ET)
  • Vertically Integrated Liquid (VIL)
  • Vertically Integrated Liquid Density (VILD)
  • Probability of Significant Hail (POSH)
  • Maximum Expected Hail Size (MEHS)

2D Features
  • Elevation scan selection
  • Derived products
  • Screen markers
  • Storm motion vector
  • 2D slice
  • Placefiles and shapefiles
  • Exporting images

Place and Shape Files
  • Note the radar data is level 3 in this example

The Volume Rendering Engine
  • Four viewable fields
  • Base reflectivity
  • Base velocity
  • Storm relative velocity
  • Spectrum width
  • Allows storms to be viewed in three dimensions
  • Two modes
  • Lit Surface, uses an alpha table to produce
    semi-transparent dBZ surfaces
  • Isosurface, users can step through dBZ levels

Lit Surface Example
What is this?
  • Solid 50 dBZ surface (red)
  • Semi-transparent 45 dBZ shell (gold)

Isosurface Example
  • An externally produced animation showing
  • successive layers of dBZ being stripped away

3D Alpha Table
  • Users can select which dBZ levels are visible and
    their degree of transparency by manipulating an
    alpha color table

Solid above 50 dBZ
shell at about 45 dBZ
Strong Tornado
Where Are the Attributes?
  • At present, there are none in AE
  • The issues are what to offer and how to display
    it, not whether it should be done
  • Velocity data noisy data subject to aliasing

Current Cut-In Policy
  • Definite
  • At least one live cut-in for all tornado warnings
  • Subjective
  • Preemptive Strike a cut-in for a storm likely
    to become tornadic
  • Ongoing coverage of tornado warnings that fall
    short of wall-to-wall
  • Most severe thunderstorm warnings are not covered
    with a cut-in

Preemptive/Ongoing Tornado Coverage
  • Just using AE in 2D with Level II data is a huge
  • In 3D, features such as BWERs are plain to see
  • What about the tornado finger? (fickle finger
    of fate)
  • AE definitely aids the decision making process

Noteworthy 3D Features
  • Tornado tube
  • Hail cores
  • Bounded Weak Echo Regions (BWERs)
  • Overhangs
  • Triple Backscatter
  • Overshooting Tops

An Example of a Three Body Scatter Spike (TBSS)
Non-Tornadic Storms
  • Cut-in decision based on general storm intensity,
    weighed heavily by population density!
  • Can AE provide enough detailed storm information
    to justify more cut-ins for non-tornadic events?

Finding Hail Cores in 4D
  • AE makes it easier to visualize developing and
    descending hail cores using the volume rendering
  • AE also has sophisticated hail probability and
    estimated hail size algorithms

Extreme Hail Cores
Hail Size - MEHS
Tennis Ball (2.5) sized hail near Moody, MO AE
estimated 2.76 4 minutes before the reported
time of the hail
Using AE On-Air
  • It should first be stated that AE in its present
    form was not designed specifically for on-air use
  • If future builds lean in this direction, there
    are only two considerations
  • Would AE add meteorological value?
  • How does it look? Is it understandable?

Just the Facts
  • I tend to lean toward the Joe Friday approach
    to live cut-ins meaning I believe the public is
    best served by clear graphics which state what,
    where and when
  • On the other hand, this is TV and where would we
    be without a certain level of enthusiasm for new
    products and visualization techniques?

How Does it Look? Is it Understandable?
  • AE has done a great job giving the user graphical
    options to make the product look fantastic!
  • Will viewers understand what they are looking at?
  • Need accurate geographical reference points
  • Must be selective about what to show and careful
    in your explanation
  • For stations already committed to 3D radar views,
    AE is an improvement!

Would AE Add Meteorological Value?
  • This is a tougher question
  • A few candidates
  • Timing of hail core descent
  • Tornadic signatures
  • Other undiscovered signatures

Future Investigations and Projects
  • Database of hail size verification
  • New 3D structures or signatures?
  • New 3D velocity structures or signatures
  • Convincing management to invest in a stand alone
    computer for proper on-air testing
  • Establishing a radar resource web site

Helical Flow
  • Example of twisted inbound/outbound couplet in 3D
    velocity data
  • New signatures here? I dont know, Ive never
    seen images like this before, real-time or

Level 2 Radar Data(not a comprehensive list!)
  • Allison House (placefiles and data)
  • University of Iowa (non-commercial)
  • National Climate Data Center (archive only)