Applications of Satellite-Based Applications of Satellite-Based Microwave Data to Tropical Cyclone Microwave Data to Tropical Cyclone

AnalysisAnalysis(Microwave Imagery and Scatterometer)(Microwave Imagery and Scatterometer)

byby

Roger T. EdsonRoger T. EdsonScience and Operations Officer Science and Operations Officer

NOAA/NWS WFO GuamNOAA/NWS WFO Guam

11stst TC-TRCG Technical Workshop , Jeju Island, ROK , May2009 TC-TRCG Technical Workshop , Jeju Island, ROK , May2009

INTRODUCTIONINTRODUCTION

• Microwave Microwave Data in the TropicsData in the Tropics

• Passive (SSMI) vs Active (‘Scat’) Passive (SSMI) vs Active (‘Scat’)

• Characteristics of MI imagery Characteristics of MI imagery patternspatterns

• QuikSCAT ScatterometerQuikSCAT Scatterometer

• Examples of uses in the Tropics Examples of uses in the Tropics and Mid-Latitudesand Mid-Latitudes

• Combined or Integrated UsesCombined or Integrated Uses

------OPTIONAL ------OPTIONAL (in back)(in back)--------------• (Suggested QuikSCAT Procedures)(Suggested QuikSCAT Procedures)

• TC Life Cycle in Microwave ImageryTC Life Cycle in Microwave Imagery

Passive MicrowavePassive Microwave(SSMI/AMSR-E/CloudSAT/WindSAT/AMSU/TR(SSMI/AMSR-E/CloudSAT/WindSAT/AMSU/TR

MM)MM)

Information given by naturallyOccurring Microwave radiation

Why Use Microwave Data?Why Use Microwave Data?

Three views of Super Typhoon Podul125-140kts

Positioning in Microwave ImageryPositioning in Microwave Imagery

37 Ghz color 85 Ghz color

Try to position in the rain-free dry area—out of the convection

Positioning, Intensify and Genesis of a Positioning, Intensify and Genesis of a Tropical Cyclone: All from Microwave Tropical Cyclone: All from Microwave

Data!Data!37 Ghz color 85 Ghz color

Circular‘blue region’Weak Rain/CU lines Vis

Dvorak IR

Where’s the Center? Help with Dvorak IR

IR Center

Dvorak IR

Where’s the Center? Unenhanced IR

IR Center

85 Center

Where’s the Center? TRMM 85h GHz

85 Center

Visible Center

85 Center

Now, where’s the Center? TMI 37 GHz**

Dvorak IR

IR Center

**Actually, COMBINEDReconnaissance gives the highest degree of Confidence**

ADVANTAGES OF USING 85 GHz AND 37 GHz ADVANTAGES OF USING 85 GHz AND 37 GHz Microwave ImageryMicrowave Imagery

• ‘‘Sees’ through cloudsSees’ through clouds• Positioning of TCs in difficult situations Positioning of TCs in difficult situations

(especially in EARLY stages of development)(especially in EARLY stages of development)– ‘‘try’ animation of multiple 37GHz polar passestry’ animation of multiple 37GHz polar passes

• View of convective rain bands is more View of convective rain bands is more DIRECTLY related to intensification of the TCDIRECTLY related to intensification of the TC

• Less delay in seeing Less delay in seeing changeschanges in intensification in intensification• Lower altitude of Lower altitude of TRMM/AMSR-E/WindSAT TRMM/AMSR-E/WindSAT has has

increased resolution in BOTH 85 and 37 GHz increased resolution in BOTH 85 and 37 GHz • Can still use in conjunction with existing Can still use in conjunction with existing

techniquestechniques

Sourcesof

Microwave ImageryFor

Tropical Cyclone Analysis

Tropical Cyclone LifecycleTropical Cyclone Lifecyclein Microwave Imageryin Microwave Imagery

(see optional section in back)(see optional section in back)

I.I. TC Genesis Stage TC Genesis Stage ~~25-30kt25-30kt

II.II. Early Intensification and Early Intensification and Development Development~~30-45kt30-45kt

III.III. Continued Intensification and Mature Continued Intensification and Mature Stage Stage

IV.IV. Peaking and Initial Weakening Stage Peaking and Initial Weakening Stage

V.V. Dissipation and Extratropical Dissipation and Extratropical Transition Transition

EVALUATIONS OF CAT5/SUPER TYPHOONS EVALUATIONS OF CAT5/SUPER TYPHOONS (85h) VIEWS: Double eyes (red inner (85h) VIEWS: Double eyes (red inner eye)eye)

STY Saomai 140kt STY Billis 135kt STY Ivan 155kt STY Shanshan 125kt

TC Paul 125kt STY Bart 140kt

All cyclones in this categoryare going in or out of eye cycle.Intensification is near max. Anychange dependent upon red inouter eye. Red in inner eye most important for evaluatingcurrent intensity.

Physics and Interpretation

of

Microwave Imagery

Storm Convection or Exposed Ocean? (85 Storm Convection or Exposed Ocean? (85 GHz)GHz)

Convection ??

Sea Surface ?

or

85 GHz PCT Correction 85 GHz PCT Correction (color)(color)

Ambiguity ResolvedAmbiguity Resolved

Convection

Sea Surface

Lower levelRain Bands

Some times the 87 GHz Imagery is not enough: Where’s the Eye of the Storm?

Another case for Using the 37 GHz: Eye Revealed

SSM/I Resolution and FootprintsSSM/I Resolution and Footprints

Channel Frequency FOV ResolutionChannel Frequency FOV Resolution (GHz)/Polarization (GHz)/Polarization km x km)km x km)19.35 V,H19.35 V,H 69 x 4369 x 4322.235 V22.235 V 60 x 4060 x 4037.0 V,H37.0 V,H 37 x 2937 x 29

85.5 V,H (highest resolution)15 x 1385.5 V,H (highest resolution)15 x 13

85 GHz37 GHz

22 GHz

19 GHz

Microwave Physical CharacteristicszMicrowave Physical Characteristicsz85GHz vs 37GH85GHz vs 37GH

RAIN RATE mm/h

Exti

ncti

on

Ice Extinctionis relatively low in

37GHz(rain is larger)

85GHz is VERY sensitive

toIce Extinction

(rain is smaller)85GHz more

Sensitive to BOTH rain and ice rates

than 37GHz

Properties of Microwaves Properties of Microwaves Imagery for Tropical Imagery for Tropical

Cyclones Cyclones • 85 GHz85 GHz

THINGS THAT APPEAR THINGS THAT APPEAR COLDCOLD::

- Sea Surface and High portions of - Sea Surface and High portions of deep convection with where there are deep convection with where there are large ice phase precip (e.g., snow)large ice phase precip (e.g., snow)

THINGS THAT APPEAR THINGS THAT APPEAR WARMWARM::

- Land and Low-cloud fields- Land and Low-cloud fields

Properties of Microwave Properties of Microwave Imagery for Tropical Imagery for Tropical

CyclonesCyclones• 37 GHz37 GHzTHINGS THAT APPEAR THINGS THAT APPEAR COLDCOLD:: - Sea Surface, but not deep - Sea Surface, but not deep

convection: 37 GHz signal largely passes convection: 37 GHz signal largely passes through ice (except when exceptionally through ice (except when exceptionally dense).dense).

THINGS THAT APPEAR THINGS THAT APPEAR WARMWARM:: - Land and rain at low level (rain very - Land and rain at low level (rain very

warm due to absorption versus 85 GHz).warm due to absorption versus 85 GHz).

Microwave ImageryMicrowave ImageryViewing Interpretation--Viewing Interpretation--OceansOceans

85h 37v(IR)

OCEAN

ColdCool WarmWarm

Cold

Cold

Cool

Cool

*Oceans Appears Cool in 85h

*Oceans Appears Cold in 37v

Cold

Dry Moist

Raindrops

Ice Crystals EffectiveLevel of

hydrometeors

85 GHz Parallax

Hail/Graupel

Freezing level

X Y

Raindrops

Ice CrystalsEffectiveLevel of

hydrometeorsHail/Graupel

Freezing level

X Y

37 GHz Parallax

85 GHz

37 GHz

Advantages of 85 GHzAdvantages of 85 GHz1. Identify peripheral low-level cloud bands, giving

information about center of circulation.2. Distinguish deep (cold) convection (heavy

precipitation) from lightly-raining (warm) low cloud features.

3. Identify cirrus-covered eyes.4. High Spatial Resolution

Limitations of 85 GHzLimitations of 85 GHz1. Cold Ocean may “look like” deep convection: Use 85 GHz Color Composite as a correction.2. Parallax Error (10-20 km).3. Saturates (no detail) in storm cores, misses

structure.

Advantages of 37 GHzAdvantages of 37 GHz1. Identify cirrus-covered eyes.2. Resolve detail within the storm core missed by 85

GHz, sometimes can see eyes missed by 85 GHz.3. Shows regions of low-level clouds/rain.4. Little Parallax error compared to 85 GHz.

Limitations of 37 GHzLimitations of 37 GHz

1. Does not show distinguish convection from low clouds bands. Eyes are sometimes poorly defined or not detectable. False eyes are common*.

2. Suffers from poor spatial resolution on SSM/I, SSM/IS, better on TMI, WindSAT and AMSR-E

3. Not available on AMSU-B

Active MicrowaveActive Microwave(Scatterometer)(Scatterometer)

Return pulse gives information

ADVANTAGES OF USING Microwave DataADVANTAGES OF USING Microwave Data

• ‘‘Sees’ through clouds (Sees’ through clouds (passive and activepassive and active))• View of convective rain bands is more DIRECTLY View of convective rain bands is more DIRECTLY

related to intensification of the TCrelated to intensification of the TC• Positioning of TCs in difficult situations (especially in Positioning of TCs in difficult situations (especially in

EARLY and LATE stages of development)EARLY and LATE stages of development)• Less delay in seeing Less delay in seeing changeschanges in intensification in intensification• Lower altitude of TRMM/AMSR-E has increased Lower altitude of TRMM/AMSR-E has increased

resolution in BOTH 85 and 37 GHz Imagery resolution in BOTH 85 and 37 GHz Imagery

• Can still use in conjunction with existing Can still use in conjunction with existing techniques (active and passive)techniques (active and passive)

• Can detect winds on the ocean surface Can detect winds on the ocean surface (active)***(active)***

Passive MI Wind Measurements

WindSAT SSM/I

RECENT/FUTURE SCATTEROMETERS

SENSOR/SAT SCAT NSCAT SEAWINDS SEAWINDS ASCAT ERS 1 / 2 ADEOS1 QUICKSCAT ADEOS2 METOP1AGENCY ESA JPL JPL JPL ESA  LAUNCH May 91 Aug 96 Jun 99 Late 2002 Jun 2006 /Apr 95

SWATH (KM) 500 2x600 1800 1800 2x550 GAP (KM) N/A 320 0 0 600  ANT 3 6 CIRCU CIRCU 6   RESOLUTION(KM) 50 (25) 25 25 (12.5) 25 25km  SPEED (KT)/ 6-40 5-60 5-80 5-80 5-60? ACCURACY(rms) 4 OR 10% 2 OR 10% 2 or 10% 2 or 10% 2 or 10% DIRECTION (rms) 360 +/- 20 360 +/- 15 360 +/- 15 360 +/- 15 360 +/- 15 FREQ (GHZ) 5.3 (C-BAND) 14.0 (Ku-BAND) 13.4 13.4 5.6 COVRG (90%) ~4 Days ~2 Days ~1 Day ~1 Day ~2 Days

ASND NODE (LST) 10PM 10PM 6AM 6AM 10PM

Sourcesof

Scatterometer Data

NOAA/NESDIS Storm Page (3-views)

Wind Vectors

Ambiguity Solutions

o V-pol forward

NRCS

(2 deg grid)

Build time?

ASCAT(NOAA/NESDIS site)

Which are the correct pair?

Physical Processes of Scatterometery

Gravity-capillary waves-Wavelength in centimeters-Respond almost instantaneously to the strength of the local wind-Microwave (Bragg) Scattering strongly depends on the amplitude-Caps of these waves tend to align perpendicular to the local wind dir-Sharp shape of leeward side of the capillary wave results in a different ocean radar return upwind (more) than in downwind (less) direction

Wind Direction(downwind example)

MoreLess

Bragg Scattering--NOT ocean waves!

= I (incidence angle)

QuikSCAT:QuikSCAT: SeaWinds MeasurementsSeaWinds Measurements

From Dr. M. Freilich, Oregon State University

V-pol H-pol

i = 54 degi = 46 deg

i = Incidence Angle

zz

SeaWinds: Swath Geometry (3-views)SeaWinds: Swath Geometry (3-views)

From Dr. M. Freilich, Oregon State University

Red = V-pol

Blue = H-pol

Edge View (2 solns) V-pol only

Subtrack View (4 solns,but small angle var)

Ideal View(4 solns, 90 deg var)

Forward Look

Backward Look

Towards Cross Away Cross (from sensor)

o

(Relative View Angle)

Wind Speed(less)

(approx equal)

More towards More towards the sensorthe sensor

15 m/s

05 m/s

10 m/s

(cause of rain orientation)

Ambiguity Probability Solution

Wind Retrieval ProcessWind Retrieval Process(Inverse of Radar Cross-Section Equation)(Inverse of Radar Cross-Section Equation)

4- View ‘possible’ Solutions4- View ‘possible’ Solutions

QUIKSCAT RANKING SELECTION(FROM A.C. VOORRIPS, DEC, 1999: QUIKSCAT PROGRESS REPORT,ROYAL NETHERLANDS METEOROLOGICAL INSTITUTE)

1

1

RANKS

RANKS

# SOLUTIONS IN 5 ORBITS (solid line)

# SOLUTIONS CLOSEST TO NWP WIND VELOCITY

(dashed line)

RATIO

* Top #1 Rank dominates solution selection

Normalized Radar Cross-Section (NRCS)

--Thank you, Dr David Long (BYU)

Towards Cross Away Cross (from sensor)

o

(Relative View Angle)

Wind Speed(less)

(approx equal)

More towards More towards the sensorthe sensor

15 m/s

05 m/s

10 m/s

Large Eye/Eyewall CycleLarge Eye/Eyewall Cycle

Some Problem AreasSome Problem Areas (But….most can (have been) solved!)(But….most can (have been) solved!)

--Very High and Very Low winds--Very High and Very Low winds

--Rain Areas--Rain Areas

--Direction Confusion --Direction Confusion (i.e. Ambiguity Selection – not the (i.e. Ambiguity Selection – not the instrument!)instrument!)

**MUST be Examined before Discarding!****MUST be Examined before Discarding!**

6161

QuikSCAT and TC Maximum WindsQuikSCAT and TC Maximum Winds• Comparison of QuikSCAT maximum wind to best track and Comparison of QuikSCAT maximum wind to best track and

Dvorak intensity estimates shows limited skillDvorak intensity estimates shows limited skill– Lowest bias/MAE in tropical storms and weak hurricanesLowest bias/MAE in tropical storms and weak hurricanes– Some low bias values due to cancellation errors of opposite Some low bias values due to cancellation errors of opposite

signsign

• Large positive bias in TD stage likely due to rain enhanced Large positive bias in TD stage likely due to rain enhanced backscatterbackscatter– Weak winds at surface overwhelmed by effects of rainWeak winds at surface overwhelmed by effects of rain

• Negative bias at high winds due to attenuation from rain, Negative bias at high winds due to attenuation from rain, saturation of signal and limited resolutionsaturation of signal and limited resolution

• QuikSCAT winds QuikSCAT winds mustmust be used with care for intensity be used with care for intensity analysis analysis – Interpretation ambiguous at bestInterpretation ambiguous at best– Lack of co-located rain rate information Lack of co-located rain rate information – TRMM PR (or 37Ghz) can be used occasionally to get rain rate TRMM PR (or 37Ghz) can be used occasionally to get rain rate

infoinfo

Edge of Swath Retrievals- Edge of Swath Retrievals- comparisoncomparison

Pass over TD9 at 0842 UTC 28 September

Typical edge of swath

retrieval in current

algorithm

Improved wind

direction and

circulation better

resolved in new retrieval

Correct ambiguities

chosen

1) The radar signal is attenuated by the rain as it travels to and from the Earth’s surface σ0

2) The radar signal is scattered by the raindrops. Some of this scattered energy returns to the instrument σ0

3) The roughness of the sea surface is increased because of the splashing due to raindrops σ0

3 Rain Effects3 Rain Effects

Rain-enhanced (Light) WindsRain-enhanced (Light) Winds--Always check up and --Always check up and

downstreamdownstream

RAIN EFFECTS-Direction selection RAIN EFFECTS-Direction selection problemproblem(Rain Blocks--Perpendicular to Swath)(Rain Blocks--Perpendicular to Swath)

Bad direction selection—Speeds are ‘good’.

The “Rain Block”

Swath Orientation

Watch out for“False Center”!

Rain-enhanced (Light Wind) Directions

Rain-enhanced (Heavy Wind) Directions --not so bad

Ambiguity Format

Ambiguity Solutions

RAIN EFFECTSRAIN EFFECTS(Wind and ambiguity solutions perpendicular to (Wind and ambiguity solutions perpendicular to

swath)swath)

Wind field discontinuity

Wind field perpendicular to swath angle

2-solution (some 3-) ambiguities perpendicular to swath (usually ‘rain-flagged’)

Note: ‘True’ rain-affected area smaller than indicated in wind vector field

Uses of QuikSCAT data for Tropical Cyclone Analysis

• Positioning and Motion• Minimum (at least) maximum wind• Structure and Structure Change (Wind Radii)

• Genesis and (Surface) Genesis processes• Extratropical Transition and Dissipation

Where is the center of this tropical Where is the center of this tropical storm?storm?

Where is the center now?Where is the center now?

Major Changes (since Major Changes (since 2007**) 2007**)

• Refinement of model function Refinement of model function (backscatter-wind relationship—higher (backscatter-wind relationship—higher wind speeds!)wind speeds!)

• Retrieval algorithm modificationRetrieval algorithm modification

• Development of new rain impact flag Development of new rain impact flag

• Improved edge of swath retrievalsImproved edge of swath retrievals

• Reduced land mask for 12.5-km Reduced land mask for 12.5-km retrievalretrieval

**Seen in ‘Test’ mode, as of Sept 2007

Ultra Hi-Res Wentz Ultra Hi-Res

Diagnostic of NWP initial Diagnostic of NWP initial conditionsconditions

GFS – 3 hour forecast of wind speed 12.5 km QuikSCAT

Maximum Wind speed 20 knots Maximum Wind speed 40 knots

A GALE warning was issued!

kts

Extratropical Transition Extratropical Transition IntensityIntensity

Ex-Typhoon Bavi14Oct2002

Scatterometer Winds over the Ocean (up to 100 kt!)

Hurricane Force Extratropical Hurricane Force Extratropical CycloneCyclone

Intense, non-tropical cyclones with hurricane force winds

Feb 09, 2007, North Atlantic

kts

Hurricane Force Extratropical Cyclones ObservedHurricane Force Extratropical Cyclones ObservedData from the NOAA/NWS Ocean Prediction CenterData from the NOAA/NWS Ocean Prediction Center

119

23

14

24 23

15

22

37

33 3134

64

51

0

5

10

15

20

25

30

35

40

45

50

55

60

65

Num

ber o

f eve

nts

1995-96 1996-97 1997-98 1998-99 1999-00 2000-01 2001-02 2002-03 2003-04 2004-05 2005-06 2006-07

Sep through May 2000-07 (except Dec through April 2000-01)Atlantic

Pacific

Combined or IntegratedAnalysis of Microwave Imagery

andScatterometer Data

Hur Fabian(10 L)

~17.5N 49.9W105kt

Streamlines shifted westward 31Aug0214 IR

Scatterometer Winds over the Ocean-Contribution to theOcean wave model-Determining Swell

Typhoon Sonca

Wind overlay over NRCS and 37Ghz data--Look for low wind and low rain region

OverlayOverlay QuikSCAT winds and QuikSCAT winds and ambiguities over MI - 37Ghz ambiguities over MI - 37Ghz

imageryimagery

X

35kt

35kt

50kt

65kt+

Questions?

PROCEDURES TO

EVALUATE

QUIKSCAT SOLUTIONS(extra)

Scatterometer Procedures Guidefor Tropical Cyclone

Reconnaissance(JTWC guide)

• TASK 1: Evaluation of Potential Suspect Area and Meteorological

Environment (Preliminary Steps)

• TASK 2: Use Scatterometer Wind and Ambiguity Data to Obtain a TC Position

• TASK 3: Use Normalized Radar Cross-Section (NRCS) Image to

Refine TC Position

• TASK 4: Comparison with Microwave and other Remote Sensing

Data

• TASK 5: Reconciliation of Positions and Possible Re-Evaluation

• TASK 6: Determine Strongest Wind Speed(s) from Scatterometer Data

Scatterometer Procedures Guidefor Tropical Cyclone

Reconnaissance

• TASK 7: Obtain TC Outer Wind Radii from Scatterometer Data

• TASK 8: Determining Scatterometer Fix Position Accuracy

• TASK 9: Complete Scatterometer Worksheet and Include

Fix into ATCF

5 Appendices

A. Points of Contacts and Reference Web Sites

B. QuikSCAT Problem Areas and Solutions

C. Acronyms, Abbreviations and Terminology

D. Scatterometer Worksheet

E. Example

Step 4: Perform a wind speed (isotach) analysis in the region determined above.

- Look for a potential center in the lightest winds that are in close proximity to the highest winds in the analysis (may not exist for very small circulation centers).

-- Avoid wind speeds that appear excessively enhanced by rain.

- For very small circulation centers, a minimum wind speed vector may not exist. In this case look for the area within the highest wind speeds that best fits the cyclonic flow.

- In large asymmetric and in sheared situations, the strongest winds may be on one side of the center. In this case, look for a center along the cyclonic side of the highest wind speeds (versus in the geometric center).

- Trough Axis Solution. In weaker systems (circulation less developed) look for a position in the lighter winds (usually within or near a trough axis) that could be considered on the cyclonic side of the highest wind speeds.

-- Especially important to avoid wind speeds that appear excessively

enhanced by rain

Isotach Solution

“ISOTACH SOLUTION”

Center found inlocal ‘min’ ofisotach ring.

DMSP “Color”02 Mar 1728Z

Eye

This is NOT used in sheared situations. A center can often be found within a local minimum inside the highest isotach. Use in conjunction with available satellite imagery

40kt

60kt

50kt

“Trough-Axis” No (or incorrect) circulation

center Trough Axis Solution. In weaker systems, look in lighter winds (near a trough axis), on the cyclonic side of the highest wind speeds. Avoid wind speeds that appear excessively enhanced by rain .

This situation occurs in small systems or when the equatorial westerlies are weak, or when the NWP mistakes the equatorial trough axis for the TC circulation center common in Atlantic and South Indian Oceans.

Ambiguity Streamline Strategy

Step 5:Perform a streamline analysis with the ambiguity plots.

- Use the higher confidence, 2-direction (line) solutions to assist with the correct environmental wind flow away from the center.

- Use the 3-direction, “Y-shaped”, solutions (assisted by common color- coded wind speeds with similar directions) and the 2-direction, with curved orientation, to follow the flow into the center.

- Try to streamline without using the lowest confidence areas; however for a rain-affected wvc, try to use the alternate 3rd and 4th choice when possible especially if these choices show a bias from one side of the circulation to the other.

- Adjust center to best fit with the position identified by the

isotach analysis

Ambiguity Plotting Convention

Ambiguity plotting convention: 1-4 possible wind directions are plotted from the center of the wind vector cell (wvc) OUTWARDS and towards the direction of the flow (this is opposite of conventional meteorological wind vector plotting routines).

(SH Circulation)

High confidence (2-way) solutions primarily away from the center

Step 5:Step 5:

“Key” 2- and 3- way solutions near center

Step 5:Step 5:

Primary Steps – Obtain corresponding NRCS image from NOAA/NESDIS QuikSCAT Storm Page. Check date/time/grid/orbital path. Look for NRCS patterns. If reliable center found, try to verify this position with previous position found with the wind and ambiguity data.

Task 3

Steps, continued: Overlay scatterometer winds and ambiguities on to the NRCS image. Do all positions coincide? Check for position of dark band with respect to the radial extent into the suspect area center region (almost all the way: wind directions and speeds are reliable in this area—over 35kt). See alternate solutions (circled).

Task 3(b)

Tropical Cyclone LifecycleTropical Cyclone Lifecyclein Microwave Imageryin Microwave Imagery

I.I. TC Genesis Stage TC Genesis Stage ~~25-30kt25-30kt

II.II. Early Intensification and Early Intensification and Development Development~~30-45kt30-45kt

III.III. Continued Intensification and Mature Continued Intensification and Mature Stage Stage

IV.IV. Peaking and Initial Weakening Stage Peaking and Initial Weakening Stage

V.V. Dissipation and Extratropical Dissipation and Extratropical Transition Transition

TC LIFE CYCLE IN MICROWAVE IMAGERY TC LIFE CYCLE IN MICROWAVE IMAGERY

MI STAGES 1 2 3(pre-stage 0)

 

    

Developmental patterns in Dvorak as compared Developmental patterns in Dvorak as compared with the first 3 Stages of MI developmentwith the first 3 Stages of MI development ..

The Beginning?….no The Beginning?….no classificationclassification

TRMM 37 color TRMM 85h

IR

Stage 1Stage 1(Pre-Typhoon Francesco-(Pre-Typhoon Francesco-25kts25kts))18 Sep 120018 Sep 1200

Tropical Storm Erin (06L) 45kts-- Stage 203Sep1200

STY Mitag (02W) (Mar 2002)STY Mitag (02W) (Mar 2002)---MI Stages 0 – 3---MI Stages 0 – 3 (85 GHz H) (85 GHz H)

Stage 0 – Pre-genesis

Stage 1 – Genesis

Stage 2 -Early Intensification

and Development

25 Feb 1046Z

**Initial development in low level cloud structure and (blue) moisture increase, deep banding

structure not well defined.

Stage 3 -BandingStructure

26 Feb 1001Z 25kt

27 Feb 0947Z 35kt

Signs for Rapid Intensification‘PLUS’

Ring hasFormed!

37GHz

EVALUATIONS OF CAT5/SUPER TYPHOONS EVALUATIONS OF CAT5/SUPER TYPHOONS (85h) VIEWS: Double eyes (red inner (85h) VIEWS: Double eyes (red inner eye)eye)

STY Saomai 140kt STY Billis 135kt STY Ivan 155kt STY Shanshan 125kt

TC Paul 125kt STY Bart 140kt

All cyclones in this categoryare going in or out of eye cycle.Intensification is near max. Anychange dependent upon red inouter eye. Red in inner eye most important for evaluatingcurrent intensity.

EVALUATIONS OF CAT5/SUPER TYPHOONS EVALUATIONS OF CAT5/SUPER TYPHOONS (85h) VIEWS: Time changes in red inner (85h) VIEWS: Time changes in red inner

eyeseyes

TC Susan 70kt -26hr TC Susan 95kt -13hr TC Susan 120kt -06hr

STY Zeb 95kt -24hr STY Zeb 140kt -00hr

‘PLUS’

TC Dianne-Jery (21S)

07Apr230065kt

09Apr0753 90kt11Apr0000

60kt

85 GHz

Peaking and Initial Weakening StagePeaking and Initial Weakening Stage

‘MINUS’

Ex- TYPHOON KATE (04W) Weakening Stage

TRMM 37V

TRMM 85H

Sample T/ST#sT3.0/4.0

T2.0/2.0 ?T1.5/2.5T2.5/3.5

TRMM 37v