ADT – Advanced Dvorak Technique
Tim Olander
and
Chris Velden
University of Wisconsin – Madison
Cooperative Institute for Meteorological
Satellite Studies (CIMSS)
International Workshop on
Satellite Analysis of Tropical Cyclones
Honolulu, Hawaii
13 – 16 April, 2011
Advanced Dvorak Technique
Acknowledgements
We wish to acknowledge the inputs from those whom have
provided valuable feedback regarding the ADT over the years,
specifically Mike Turk and Greg Gallina at NESDIS/SAB, Andrew
Burton at the Australian Bureau of Meteorology, numerous
forecasters and specialists at the NOAA/National Hurricane
Center and the Joint Typhoon Warning Center, past and present
(too many to name here).
Special thanks to Jeff Hawkins and the Naval Research
Laboratory and Office of Naval Research for the support towards
the development and continued advancement of the ADT!
Advanced Dvorak Technique
Presentation Overview
•
•
•
•
•
Brief Historical Overview
Latest Advancements
Validation
Current Status and Availability
Looking Towards the Future
Advanced Dvorak Technique
Presentation Overview
•
•
•
•
•
Historical Overview
Latest Advancements
Validation
Current Status and Availability
Looking Towards the Future
Advanced Dvorak Technique
ADT History: The ODT
Step One:
Creating the initial Objective Dvorak Technique (ODT)
Advanced Dvorak Technique
ADT History: The ODT
Why develop an objective Dvorak Technique (DvT)?
• Reduce subjectivity
– Analyst subjectivity can be introduced in assessing scene
type, applying certain DvT parameters and rules, and
determining TC storm center locations
• Promote uniformity
-- Given the above, significant variation in DvT
estimates
can sometimes exist between Operational Forecast
Centers (OFCs), as documented by IBTrACS
-- Provide objectively-based estimates as a guidance
tool
• Original Goal
Advanced Dvorak Technique
ADT History: The ODT
Examples of wide intensity
estimate variations between
Operational Forecast Centers
landfall
Regions of Note
Advanced Dvorak Technique
ADT History: The ODT
• Retain DvT “roots”, but amend a little
– Implement as much of original DvT technique as possible
• Keep familiarity for analysts/forecasters (e.g. EIR branch)
• Output that includes T# and CI# values
• Utilize same scene type classifications
• Integrate DvT steps/rules (e.g. DvT Rule 9 for weakening)
– Implement a time averaging scheme
• Operate the ODT at hourly (or even 30-min.) increments
• Utilize a “history file” to store critical information for each analysis
• Employ 6-h (now 3-h) running average of T# estimates to smooth
minor fluctuations from estimate to estimate, apply to final CI#
– Implement additional features requested by users
• Add user position or scene override functionality
• ODT applications limited to TCs > T3.5 (strong tropical
storms and higher)
Advanced Dvorak Technique
ADT History: The ODT
Development of an objective scheme to estimate
tropical cyclone intensity from digital geostationary
satellite infrared imagery
Chris Velden, Tim Olander and Ray Zehr
Weather and Forecasting, 1998, Vol. 13, pp. 172-186
Advanced Dvorak Technique
ADT History: The AODT
Step Two:
The Advanced Objective Dvorak Technique (AODT)
Advanced Dvorak Technique
ADT History: The AODT
• Expand and Improve the ODT
– Increase analysis intensity range and precision
• Allow for analysis of all ranges of intensities at/above TD stage
• Addition of new scene type classifications and analysis scheme
– Curved Band using 10° Log Spiral technique
– Additional Eye scene types
– Modified cloud region temperature calculation (to help identify cloud symmetry)
• Integrate modified DvT Rule 8 intensity growth/decay constraints
– Provide completely automated analysis capability
• Remove final subjective element of ODT technique: the storm center
determination/selection (replace analyst positioning using a
mouse/curser with an objective Laplacian-based technique to search
for localized and correlated bi-directional Tb gradients)
– Implement latitude bias adjustment for final MSLP estimates
• Regression-based on relationship of the change of tropopause height
(and cloud top temps) with latitude (Kossin and Velden, 2004, MWR)
Advanced Dvorak Technique
ADT History: The ADT
Step Three:
The Advanced Dvorak Technique (ADT)
Advanced Dvorak Technique
ADT History: The ADT
• Improve existing AODT methodology, and advance
the algorithm beyond scope of the DvT
– Integrate new intensity relationships
• Derive regression-based equations for eye and central dense overcast
(CDO) scene types (discard look-up tables)
– Identify new environmental variables for regression equations
• Implement “Scene Score” calculation to determine current scene type
using previous scene type and other environmental values
– Helps eliminate unrealistic scene type jumps
– Utilize new automated storm center determination process
• Implement forerunner to Wimmers/Velden ARCHER scheme (2010, JAMC)
– Examines spiral band structure of entire IR cloud top temperature field
– Searches for eye features using advanced ring fitting analysis scheme
– Can identify and discard most “false eye” situations
• Scheme works primarily in T# range 3.5 and greater
– Defaults to interpolation of OFC track forecast at weaker intensities
Advanced Dvorak Technique
ADT History: The ADT
The Advanced Dvorak Technique: Continued
development of an objective scheme to estimate
tropical cyclone intensity using geostationary infrared
satellite imagery
Timothy Olander and Christopher Velden
Weather and Forecasting, 2007, Vol. 22, pp. 287-298
Advanced Dvorak Technique
ADT History: The ADT
• New: Exploit additional satellite sensor information
– Utilize externally-derived Passive Microwave (PMW) Intensity
“Score” values during CDO events
• ADT intensities typically level out during CDO events until eye feature appears
in IR imagery
• PMW imagery can often identify the organization of eye features below cirrus
shield in the developing TC stages
• PMW score is determined from objectively analyzed TC structure using 85GHz,
and based on empirically-derived thresholds, can result in the over-ride of the
ADT-based T# (depending on score, two different T# intensity estimates can be
assigned (either T# = 4.3 or 5.0))
• Additional logic in ADT algorithm “merges” new PMW-derived T# values into
existing history file to eliminate unnatural intensity jumps (linear extrapolation
back 12 hours from PMW estimate point). New logic also linearly increments
the PMW value forward in proportion to DvT model Tnum expected growth.
Advanced Dvorak Technique
Presentation Overview
•
•
•
•
•
Historical Overview
Latest Advancements
Validation
Current Status and Availability
Looking Towards the Future
Advanced Dvorak Technique
Presentation Overview
• Historical Overview
• Latest Advancements
– Automated Storm Centering
– PMW Score
– Knaff/Courtney/Zehr Wind>Pressure
• Validation
• Current Status and Availability
• Looking Towards the Future
Advanced Dvorak Technique
Automated Storm Centering
Storm center determination
• Utilize IR-Window Imagery (No VIS yet)
• Spiral Centering
» First guess interpolated from official TC forecast
» Fits 5° log spiral to grid points within search radius around
first guess position
» Calculates Tb gradients along spiral; determines position
and rotation where minimum exists
• Ring Fitting
» Spiral Centering position serves as first guess
» Fits series of rings with different radii at grid points within
search region
» Searches for single ring that fits maximum Tb gradients
Advanced Dvorak Technique
Automated Storm Centering
Spiral Centering
• Fits 5° log spiral vector field
to the IR image
• Calculates a grid of scores
that indicates the alignment
between the spiral field and
the IR Tb gradients
(maximum at the spiral
center
Ring Fitting
• Calculates a grid of
scores that indicates the
best fit to a range of
possible ring positions
and diameters
(maximum at the eye
center)
Advanced Dvorak Technique
Automated Storm Centering
Advanced Dvorak Technique
Presentation Overview
• Historical Overview
• Latest Advancements
– Automated Storm Centering
– PMW Score
– Knaff/Courtney/Zehr Wind>Pressure
• Validation
• Current Status and Availability
• Looking Towards the Future
Advanced Dvorak Technique
PMW Intensity Estimate “Score”
Summary
• As briefly mentioned earlier, a recent major ADT algorithm
improvement utilizes external passive microwave (PMW) information
to aid in detection of tropical cyclone eye/eyewall formation when the
ADT objective scene identification scheme (relying on IR alone)
cannot discern developing eye features due to high-level overcast.
• ADT algorithm can struggle with this scenario and the T#s often
“plateau”. Coincident PMW data can view through much of the
overcast and in many cases discern an organizing eye structure.
• Based on the amount of eyewall organization (wrap) and strength, a
PMW “score” is calculated.
• If the score exceeds pre-determined thresholds, the value is passed
to the ADT, where it is converted to a T# and over-rides the IR-based
T#.
• Currently this scheme is only utilized in the developing stages of TCs
Advanced Dvorak Technique
PMW Intensity Estimate Score
• Uses
Eyewall temperatures
the 85GHz brightness
temperature signal to deduce the
vigor and organization of the
developing eyewall/eye, and
calculate an intensity score
• Successful in loosely
differentiating between storms
• Greater than ~72 knots
• Greater than ~90 knots
Warmest eye pixel
Hurricane Dolly, 23 July 2008 1126 UTC
DMSP SSM/I 85GHz (H) brightness temperature
• If thresholds are exceeded,
PMW scores are converted to
either T# of 4.3 or 5.0 in the ADT
• The scheme has been
operating in the ADT since 2008
Advanced Dvorak Technique
PMW Intensity Estimate Score
More intense;
Closer to Best Track
More accurate during
rapid intensification
Advanced Dvorak Technique
PMW Intensity Estimate Score
Eliminated false intensity
“plateau”; Closer to Best Track
More closely follows rapid
intensification; More
accurate maximum intensity
resulted
Advanced Dvorak Technique
Presentation Overview
• Historical Overview
• Latest Advancements
– Automated Storm Centering
– PMW Score
– Courtney/Knaff Wind>Pressure
• Validation
• Current Status and Availability
• Looking Towards the Future
Advanced Dvorak Technique
Courtney/Knaff Wind>Pressure
• Based on Courtney and Knaff (2009)
– Adapting the Knaff and Zehr wind-pressure relationship for operational use
in Tropical Cyclone Warning Centres, Australian Meteorological and
Oceanographic Journal, 58, pp. 167-179
• ADT final MSLP estimate: Starts with the derived
T# and Vmax, then utilizes information from realtime ATCF CARQ files provided by OFCs (NHC or
JTWC)
– R34 = Average of ATCF RAD1-RAD4 wind radii (in nmi) for 34 knot wind
threshold (gale radius)
– MSLP = Pressure (in mb) of outermost closed isobar (ATCF POUTER value)
– ROCI = Radius of outermost closed isobar (ATCF ROUTER value, in nmi) to
estimate R34 value if no 34-knot wind radii are available
• R34est = (0.354 * ROCI) + 13.3
– ADT also uses climatological storm speed value of 11 knots
– Andrew Burton will discuss C/K methodology in greater detail later…
Advanced Dvorak Technique
Presentation Overview
•
•
•
•
•
Historical Overview
Latest Advancements
Validation
Current Status and Availability
Looking Towards the Future
Advanced Dvorak Technique
ADT Validation (Vmax, vs. Recon)
Comparison of latest ADT version (v8.1.3, with PMW) and previous version (v7.2.3, w/o PMW)
7.2.3 Mean Error
7.2.3 Bias
8.1.3 Mean Error
8.1.3 Bias
Intensity range affected most by
PMW “eye score” addition
Advanced Dvorak Technique
ADT Validation: Comparisons with SAB DvT
• NORTH ATLANTIC – 2010 TC Season
– Independent comparisons between ADT and SAB intensity estimates
– ADT and SAB estimates w/in +/- 30 minutes
– Closest NHC Best Track intensity (co-located w/ aircraft
reconnaissance in situ measurement w/in 2 hours)
106 total matches (homogeneous)
bias
aae
stdv
SAB:CI# -0.22
0.48
0.57
SAB:Win -1.40
7.77
10.23
SAB:MSL
5.01
8.20
9.78
ADT:CI# -0.02
0.58
0.73
ADT:Win
2.59
8.22
10.47
ADT:MSL
2.22
8.94
11.35
Note: SAB analysts do have access to, or
awareness of, the recon reports. While this
influence is difficult to quantify, it offers a
stringent comparison test for the ADT.
Advanced Dvorak Technique
ADT Validation: Comparisons with SAB DvT
• EAST/CENTRAL PACIFIC – 2010 TC Season
– Independent comparisons between ADT and SAB intensity estimates
– ADT and SAB estimates w/in +/- 30 minutes
– Closest NHC Best Track intensity
126 total matches (homogeneous)
SAB:CI#
SAB:Win
SAB:MSL
ADT:CI#
ADT:Win
ADT:MSL
bias
-0.05
0.48
0.08
-0.07
-0.38
0.88
aae
0.33
5.91
4.59
0.28
5.94
3.81
stdv
0.43
8.54
6.73
0.36
7.73
5.36
Note: NHC is using the ADT increasingly,
especially in the EPAC. While difficult to
quantify, their BT may reflect ADT influences.
Advanced Dvorak Technique
Presentation Overview
•
•
•
•
•
Historical Overview
Latest Advancements
Validation
Current Status and Availability
Looking Towards the Future
Advanced Dvorak Technique
Current Status and Availability
• Current ADT Status and Availability
– Routinely utilized by several OFCs from CIMSS web site
• http://tropic.ssec.wisc.edu/real-time/adt/
– Version 8.1.3 will be active on the CIMSS web site
starting 1 May, 2011
– Efforts underway at SAB to integrate this version into
operations there, to provide estimates via ATCF.
• Completion date uncertain
– Portable version now available (license req.)
Advanced Dvorak Technique
Current Status and Availability
ADT real-time homepage : http://tropic.ssec.wisc.edu/real-time/adt
Advanced Dvorak Technique
Current Status and Availability
****************************************************
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm
Date :
Lat :
----- Current Analysis ----28 AUG 2005
Time :
154500 UTC
26:14:25 N
Lon :
88:20:05 W
http://tropic.ssec.wisc.edu/real-time/adt
CI# /Pressure/ Vmax
6.8 / 926.0mb/134.8kt
Final T#
6.7
Adj T#
6.7
Raw T#
6.7
Latitude bias adjustment to MSLP :
-0.6mb
Estimated radius of max. wind based on IR : 33 km
Center Temp : +20.2C
ADT real-time homepage
Cloud Region Temp : -69.9C
Scene Type : EYE
Positioning Method : RING/SPIRAL COMBINATION
Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC
Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : OFF
****************************************************
ADT
Current Intensity
“Bulletin”
Advanced Dvorak Technique
Current Status and Availability
=====
ADT real-time homepage
http://tropic.ssec.wisc.edu/realtime/adt
ADT
History
File
Listing
Time
Date
(UTC)
2005AUG28 104500
ADT-Version 8.1.3 =====
--------Intensity------- -Tno Values-- ---Tno/CI Rules--Time
Final/MSLPLat/Vmax
Fnl Adj Ini
Cnstrnt Wkng Rpd
Date
(UTC)
CI MSLP /BiasAdj/(kts) Tno Raw Raw
Limit Flag Wkng
2005AUG23 211500 2.0 1009.0/ +0.0 / 30.0 2.0 2.0 2.0 NO LIMIT OFF OFF
2005AUG23 214500 2.1 1008.2/ +0.0 / 31.0 2.1 2.2 2.6 0.2T/hour OFF OFF
2005AUG23 221500 2.1 1008.2/ +0.0 / 31.0 2.1 2.2 2.5 0.2T/hour OFF OFF
2005AUG23 224500 2.1 1008.2/ +0.0 / 31.0 2.1 2.3 2.3 NO LIMIT OFF OFF
2005AUG23 231500 2.2 1007.4/ +0.0 / 32.0 2.2 2.4 2.7 0.2T/hour OFF OFF
2005AUG23 234500 2.2 1007.4/ +0.0 / 32.0 2.2 2.3 2.3 NO LIMIT OFF OFF
2005AUG24 001500 2.2 1007.4/ +0.0 / 32.0 2.2 2.3 2.3 NO LIMIT OFF OFF
2005AUG24 004500 2.2 1007.4/ +0.0 / 32.0 2.2 2.3 2.3 NO LIMIT OFF OFF
<records deleted>
2005AUG27 154500 4.8 973.5/ -0.1 / 84.8 4.6 4.9 4.9 NO LIMIT
ON OFF
2005AUG27 161500 4.8 973.5/ -0.1 / 84.8 4.7 5.0 5.0 NO LIMIT
ON OFF
2005AUG27 164500 4.8 973.5/ -0.1 / 84.8 4.8 5.1 5.1 NO LIMIT OFF OFF
2005AUG27 171500 4.8 973.5/ -0.1 / 84.8 4.8 5.0 5.0 NO LIMIT OFF OFF
2005AUG27 174500 4.8 973.5/ -0.1 / 84.8 4.8 4.6 4.6 NO LIMIT OFF OFF
2005AUG27 181500 4.8 973.4/ -0.2 / 84.8 4.8 4.5 4.5 NO LIMIT OFF OFF
2005AUG27 184500 4.8 973.5/ -0.1 / 84.8 4.8 5.1 5.1 NO LIMIT OFF OFF
2005AUG27 191500 4.8 973.5/ -0.1 / 84.8 4.8 4.7 4.7 NO LIMIT OFF OFF
2005AUG27 194500 4.8 973.5/ -0.1 / 84.8 4.8 4.7 4.7 NO LIMIT OFF OFF
<records deleted>
2005AUG28 104500 6.7 929.0/ -0.4 /132.2 6.7 6.8 6.8 NO LIMIT OFF OFF
2005AUG28 111500 6.7 929.0/ -0.4 /132.2 6.7 6.7 6.7 NO LIMIT OFF OFF
2005AUG28 114500 6.8 926.1/ -0.4 /134.8 6.8 6.8 6.8 NO LIMIT OFF OFF
2005AUG28 121500 6.8 926.1/ -0.4 /134.8 6.7 6.7 6.7 NO LIMIT
ON OFF
2005AUG28 124500 6.8 926.1/ -0.5 /134.8 6.7 6.7 6.7 NO LIMIT
ON OFF
2005AUG28 131500 6.8 926.1/ -0.5 /134.8 6.7 6.8 6.8 NO LIMIT
ON OFF
2005AUG28 134500 6.8 926.1/ -0.5 /134.8 6.7 6.8 6.8 NO LIMIT
ON OFF
2005AUG28 141500 6.8 926.1/ -0.5 /134.8 6.7 6.7 6.7 NO LIMIT
ON OFF
2005AUG28 144500 6.8 926.0/ -0.6 /134.8 6.7 6.8 6.8 NO LIMIT
ON OFF
2005AUG28 151500 6.8 926.0/ -0.6 /134.8 6.7 6.6 6.6 NO LIMIT
ON OFF
<records deleted)
2005AUG29 084500 6.3 938.8/ -1.4 /122.2 5.8 6.2 6.2 NO LIMIT
ON OFF
2005AUG29 091500 6.3 938.8/ -1.4 /122.2 5.9 6.2 6.2 NO LIMIT
ON OFF
2005AUG29 094500 6.3 938.8/ -1.4 /122.2 5.9 6.2 6.2 NO LIMIT
ON OFF
2005AUG29 101500 6.3 938.7/ -1.5 /122.2 6.0 6.0 6.0 NO LIMIT
ON OFF
2005AUG29 104500 6.3 938.7/ -1.5 /122.2 6.0 5.8 5.8 NO LIMIT
ON OFF
2005AUG29 111500 0.0
0.0/ +0.0 / 0.0 0.0 0.0 0.0
N/A N/A
2005AUG29 114500 6.3 938.6/ -1.6 /122.2 6.0 5.6 5.6 NO LIMIT
ON OFF
2005AUG29 121500 6.3 938.6/ -1.6 /122.2 5.8 5.5 5.5 NO LIMIT
ON OFF
2005AUG29 124500 6.3 938.5/ -1.7 /122.2 5.7 5.5 5.5 NO LIMIT
ON OFF
2005AUG29 131500 6.3 938.5/ -1.7 /122.2 5.6 5.6 5.6 NO LIMIT
ON OFF
2005AUG29 134500 0.0
0.0/ +0.0 / 0.0 0.0 0.0 0.0
N/A N/A
2005AUG29 141500 6.3 938.5/ -1.7 /122.2 5.5 5.7 5.7 NO LIMIT
ON FLG
2005AUG29 144500 0.0
0.0/ +0.0 / 0.0 0.0 0.0 0.0
N/A N/A
Utilizing history file /home/tlo/odt/ADTV8.1.3WV/history/2005KATRINA.ODT
Successfully completed listing
--------Intensity------- -Tno Values-- ---Tno/CI Rules--Final/MSLPLat/Vmax
Fnl Adj Ini
Cnstrnt Wkng Rpd
CI MSLP /BiasAdj/(kts) Tno Raw Raw
Limit Flag Wkng
6.7 929.0/ -0.4 /132.2 6.7 6.8 6.8 NO LIMIT OFF OFF
-TemperatureCntr
Mean
Region Cloud
-4.76 -35.41
5.84 -34.85
5.84 -33.57
3.84 -34.04
0.04 -34.42
6.74 -33.37
13.54 -32.66
14.74 -30.82
Scene EstRMW
MW
Type
(km) Score
CRVBND
N/A
N/A
CRVBND
N/A
N/A
CRVBND
N/A
N/A
CRVBND
N/A
N/A
CRVBND
N/A
N/A
CRVBND
N/A
N/A
CRVBND
N/A
N/A
CRVBND
N/A
N/A
-53.56
-53.86
-60.06
-62.66
-68.36
-67.06
-65.36
-68.76
-68.36
-68.93
-68.15
-69.29
-69.35
-70.79
-69.50
-71.15
-73.14
-73.25
EMBC
EMBC
EMBC
EMBC
UNIFRM
UNIFRM
EMBC
UNIFRM
UNIFRM
19.64
19.44
19.74
18.54
18.54
19.64
20.24
19.94
19.34
20.64
-70.90
-71.08
-71.74
-71.46
-71.12
-72.01
-71.25
-70.71
-70.99
-69.05
EYE
EYE
EYE
EYE
EYE
EYE
EYE
EYE
EYE
EYE
30
31
30
31
32
32
32
31
31
32
13.04
15.34
12.54
13.84
14.44
99.50
12.54
14.34
11.84
11.94
99.50
-1.56
99.50
-66.90
-66.15
-66.08
-63.94
-61.50
99.50
-59.59
-58.01
-59.13
-60.14
99.50
-61.88
99.50
EYE
EYE
EYE
EYE
EYE
LAND
EYE
EYE
EYE
EYE
LAND
EYE
LAND
-TemperatureCntr
Mean
Region Cloud
19.64 -70.90
Scene
Type
EYE
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Storm Location
Lat
Lon
23.25
75.44
23.28
75.49
23.30
75.54
23.33
75.58
23.36
75.63
23.39
75.68
23.41
75.72
23.43
75.77
Fix
Mthd
FCST
FCST
FCST
FCST
FCST
FCST
FCST
FCST
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
24.49
24.50
24.51
24.53
24.64
24.76
24.68
24.60
24.63
85.25
85.31
85.49
85.67
85.75
86.03
85.85
85.57
85.61
SPRL
SPRL
SPRL
SPRL
SPRL
SPRL
SPRL
SPRL
SPRL
IR
IR
IR
IR
IR
IR
IR
IR
IR
IR
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
25.74
25.68
25.73
25.76
25.88
25.90
25.93
25.97
26.11
26.26
87.56
87.64
87.72
87.78
87.81
87.97
88.02
88.08
88.15
88.22
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
28 IR
28 IR
28 IR
29 IR
30 IR
N/A
30 IR
31 IR
29 IR
30 IR
N/A
27 IR
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
28.81
28.92
29.03
29.14
29.25
29.37
29.49
29.67
29.74
29.81
30.00
30.00
30.32
89.54
89.54
89.54
89.54
89.54
89.54
89.43
89.54
89.55
89.55
89.56
89.45
89.56
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
COMBO
EstRMW
MW
(km) Score
30 IR N/A
Comments
Storm Location Fix
Lat
Lon
Mthd
25.74
87.56 COMBO
Advanced Dvorak Technique
Current Status and Availability
ADT Time Series Intensity Plot
Advanced Dvorak Technique
Presentation Overview
•
•
•
•
•
Historical Overview
Latest Advancements
Validation
Current Status and Availability
Looking Towards the Future
Advanced Dvorak Technique
Looking Towards the Future
• Address current ADT biases and weaknesses
–
–
–
–
Shear scenes (weaker systems)
Curved Band analyses (employ regression approach?)
Weak bias in storms with Vmax >130kts
Passage over land and re-emergence
• Exploit additional satellite sensor information
– Differencing of Infrared and Water Vapor imagery
shows promise in multiple areas
• Correlation improvements for CDO and other scene type intensity
estimates through regression analysis
• Can aid in automated storm center determination
• Shows potential in rapid intensification prediction
Advanced Dvorak Technique
IR-WV Channel Differencing
Note similarities
between derived IR-WV
image and NWS radar
identifying strongest
convective regions
Recon Center
IR-WV selected
storm center
Interpolated
NHC forecast
IR Image
Stretched Enh IR Image
IR-WV product correctly
identifies possible
forming eye region
(IR-WV locations only)
Uniform CDO
in IR-Window
covering storm center
IR Image (w/ BD enh)
Derived IR-WV Image
NOAA/NWS Radar
Advanced Dvorak Technique
IR-WV Channel Differencing
Tropical cyclone convection and intensity analysis
using differenced infrared and water vapor imagery
Timothy Olander and Christopher Velden
Weather and Forecasting, 2009, Vol. 24, pp. 1558-1572
Advanced Dvorak Technique
Other ADT Research Avenues
• Expand ADT to initiate and operate on “Invest”
systems
– I.E., attempt to objectively identify DvT T#1.0-1.5
convective disturbances
– Test and possibly integrate a new objective algorithm
developed by Chris Hennon et al. at North Carolina State
Univ. which detects and tracks tropical cloud clusters
related to tropical cyclogenesis
– Implementation and initial testing will begin this summer