# Presentation: 794854

## Objective method to determine the Typhoon intensityusing IR1 images

- 20/03/2007 NESDIS
- Japan Meteorological Agency
- Koji Kato

## Today’s Topic

- Preliminary objective approach to determine the typhoon intensity.
- Input the position of typhoons and IR1 image of typhoon then get the typhoon intensity automatically!

- Analysis
- Program

- 960[hPa]
-  MAX103[kt]

## Example

- Comparison between and manual result
- 2004 TC0024(Japan)

## Procedure

- Brief introduction of conventional method
- Introduction of objective hurricane analysis method.

## What is Dvorak Technique?

- Tropical storm analysis method using IR (11μm) image of meteorological satellites.
- (*Especially minimum pressure and maximum wind velocity)
- At the JMA, we have no operational objective method for Typhoon analysis.

## 1

- “CSCの決定”

- 雲パターンによる解析
- (不可能ならStep3も考慮する。)

- BANDパターン
- (10°logスパイラルを適合して
- 弧の長さを測定)

- SHEARパターン
- (CSC位置と濃密な雲域まで
- の距離を測定)

- EYEパターン
- (バンド状眼パターンのときは
- 平均バンド幅を測定)

- EMBEDパターン
- (CSCの埋没距離が0.4°以上)

- 全ての湾曲した雲列または雲バンドにより
- ”CSC”を決定する。初期の発達(TI)に対しては、Step1A(本文)を参照

- 雲パターンが2A~2Eに適合しない場合、
- Step3~6を先に実施し、指示」された場合Step2に戻る

- 【眼の明瞭さによる調整】
- 1)大きな眼あるいは細長い眼に対しては、対角線の右側の値のみを使う。
- 2)E数が4.5以上である細長い眼に対しては、他に惹かれていなければ0.5を引く

| WMG | (Warm Medium Gray) | >+9°C |
| --- | --- | --- |
| OW | (Off White) | +09°C≧ ≧-30°C |
| DG | (Dark Gray) | -31°C≧ ≧-41°C |
| MG | (Medium Gray) | -42°C≧ ≧-53°C |
| LG | (Light Gray) | -54°C≧ ≧-63°C |
| B | (Black) | -64°C≧ ≧-69°C |
| W | (White) | -70°C≧ ≧-75°C |
| CMG | (Coldest Medium Gray) | -76°C≧ ≧-80°C |
| CDG | (Coldest Dark Gray) | ≦-81°C |

|  | WMG | OW | DG | WG | LG | B | W |
| --- | --- | --- | --- | --- | --- | --- | --- |
| OW | 0.0 | -0.5 |  |  |  |  |  |
| DG | 0.0 | 0.0 | -0.5 |  |  |  |  |
| MG | 0.0 | 0.0 | -0.5 | -0.5 |  |  |  |
| LG | +0.5 | 0.0 | 0.0 | -0.5 | -0.5 |  |  |
| B | +1.0 | +0.5 | 0.0 | 0.0 | -0.5 | -0.5 |  |
| W | +1.0 | +0.5 | +0.5 | 0.0 | 0.0 | -1.0 | -1.0 |
| CMG | +1.0 | +0.5 | +0.5 | 0.0 | 0.0 | -0.5 | -1.0 |

- 測定階調「W」のときはDT数に0.5を加える。スパイラル長が1.0以上のときは「2C(バンド状眼)」で解析する

- 24時間前のT数
- ≧2.0

- 12時間前のT数
- ≧3.5

- Step2A or 4へ

- 眼調整(Eadj)

- CF数決定
- CF=E+Eadj

- BF調整(BF)

- DT数決定
- DT=CF+BF

- DT1.5±0.5                         DT2.5                            DT3.0                           DT3.5

- Step4へ

- Step4へ

| 最狭バンド幅 | ≧.5° | ≧.5 ° | ≧.5 ° | ≧.4 ° | ≧.4 ° | ≧.3 ° | ≧.3 ° |
| --- | --- | --- | --- | --- | --- | --- | --- |
| バンドの階調 | CMG | W | B | LG | MG | DG | OW |

- E6.5           E6.0         E5.5          E5.0        E4.5         E4.5           E4.0

- Step2A or 4へ

| 最狭バンド幅 | ≧.6° | ≧.6 ° | ≧.5 ° | ≧.5 ° | ≧.4 ° | ≧.4 ° |
| --- | --- | --- | --- | --- | --- | --- |
| バンドの階調 | ≦W | B | LG | MG | DG | OW |

- CF5.0     CF5.0     CF4.5       CF4.0     CF4.0     CF3.5

- 階調コード(BDコード)

-                    眼階調             ⇒ 冷

- 眼を一周する最も冷たいリングの階調

- YES

- YES

- NO

- NO

- 2

- 2A

- 2B

- 2C

- 2D

## How to do? Part1

- TY 05 2005/07/15日12UTC

- TY 05 2005/07/15 12 UTC

- Special
- Coloring

- IR

- Determine the pattern

## How to do? Part2

- Tropical Number = 3.5

## How to do? Part3

| CI | Max Wind [kt] | Min Pressure [hPa] |
| --- | --- | --- |
| 1.0  | 25 | --- |
| 1.5  | 25 | --- |
| 2.0  | 30 | 1009 |
| 2.5  | 35 | 1005 |
| 3.0  | 45 | 1000 |
| 3.5  | 55 | 994 |
| 4.0  | 65 | 987 |
| 4.5  | 77 | 979 |
| 5.0  | 90 | 970 |
| 5.5  | 102 | 960 |
| 6.0  | 115 | 948 |
| 6.5  | 127 | 935 |
| 7.0  | 140 | 921 |
| 7.5  | 155 | 906 |
| 8.0  | 170 | 890 |

## Weak point of Dvorak Technique

- 1. Depend on forecaster’s skill.
- 2. Improvement of satellite sensor doesn’t
-     contribute the accuracy.
- 3. Get intensities in 6 hours interval.

## Pattern determination

- EYE Patter or Band Pattern ?

## Weak point of Dvorak Technique

- 1. Depend on forecaster’s skill.
- 2. Improvement of satellite sensor doesn’t
-     contribute the accuracy.
- 3. Get intensities in 6 hours interval.

- Why?

## Can we see the difference?

## How to overcome the problems?

## Objective Hurricane Analysis method

- ODT (Objective Dvorak Technique)
- 	(Velden, Zehr 1998)
- AODT (Advanced ODT)
- 	(Olander, Velden 2002-present)

## What is AODT?

- National Hurricane Center and Wisconsin university group developed AODT. Only one objective method to determine the hurricane intensities.
- Input the center position of the hurricane and the IR(10 μm) image, then output the hurricane intensity.
- _Algorithm is not open!_
- Output the intensity every hour!

## Slide 17

## I want an objective method!I am envious of them.But I can’t get the AODT............!!Make by myself!

## My method

- 1.Use IR picture and center position of typhoon.

- 2. Divide typhoon area into concentric circles.

- 3. Classify the typhoon using maximum temperature, minimum ring temperature and variance.

- Tropical Number

## Procudure1

- TCenter

- TRing

- Divide into rings (0.05°width) to 1.5°radius.
- And find the minimum temperature ring and calculate the variance of temperatures.

## Procedure2

- From the temperature distribution classify the typhoon automatically

| Ultra EYE |
| --- |
| Active Cb |
| Low Cloud |
| Weak EYE |
| Flat EYE |

## Procedure3

| Ultra EYE | Very clear EYE with very cold ring! |
| --- | --- |
| Active Cb | Active clouds but not have definite shape |
| Low Cloud | Decayed typhoon with high temperature cloud |
| Weak EYE | EYE pattern but not so clear like Ultra EYE |
| Flat EYE | Typhoon which is near to have EYE |

## Procedure4

- Ultra EYE

- Active Cb

- Low Cloud

- Weak EYE

- Flat EYE

- unknown

- Tropical
- Number

- Determine the Tropical number using tendency and previous Tropical number.

## Example

- Ultra EYE

- Active Cb

- Low Cloud

## Ultra EYE

- Very low temperature

- Warm area in the center area

- Smooth ring (low variance)

## Active Cb

- Totally low temperature

- Very low temperature around the center

- Temperature distribution is rough spatially-temporally

## Low cloud

- Low Cloud

- High temperature area

- High temperature around the center

- Asymmetric shape

## Condition 1

- Ultra EYE
- TBBMAX-TBBMIN>=30[K]
- σTBBMIN<=8[K]
- TBBMAX>=240[K]
- TBBMIN<=220[K]

## Condition 2

- Active Cb	-α
- TBBMIN<230[K]
- TBBMAX<=8[K]
- σTBBMIN>20[K]
- 	Or Average6(TBBMIN)>16[K]

## Condition 2.1

- Active Cb	-β
- TBBMAX-TBBMIN< 7[K]
- σTBB1.5Ring≧20[K]

## Condition 2.3

- Active Cb	-γ
- TBBMIN<230[K]
- Ave3(σTBB0.25)-AvePre3(σTBB0.25)

## Condition 3.1

- Low Cloud - α
- TBBMAX≧260[K]
- TBBMIN≧240[K]

## Condition 3.2

- Low Cloud – β
- TBB0.25≧230[K]
- TBBMAX≧260[K]
- σTBB0.25≧15[K]

## Condition 4

- Weak EYE
- TBBMAX-TBBMIN>=15[K]
- σTBBMIN<=10[K]
- TBBMIN<=230[K]

## Condition 5

- Flat EYE
- TBBMAX-TBBMIN≦5[K]
- Ave3(σTBBMIN)<=8[K]
- TBBMIN<=210[K]

## Data

- Period	2004 TC0004-TC0040
- Satellite	IR1(GOES-9)
- Using regression analysis to determine the T-number

- Data Resolution
- 0.05°	10bit

## Is this method is valid?

- Introduce 5 examples.
- TC0007	TC0009	TC0013	TC0021	TC0024

## TC0007

## TC0009

## TC0013

- Expect the typhoon to become more stronger!

## TC0021

- Human error

## TC0024

## Features

- In T≧4.5 (under 979[hPa]),
- 	comparable to human
- In T<4.0 (over 987[hPa]),
- 	Auto classification doesn’t work well.

## Further Study

- Improve the recognition ability especially in the developing and decaying stage
- Reduce biases between satellites

## TC0517

- Different Satellite! (MTSAT-1R)
- Bad Result!

## Thank you for your attention!

- Sorry, I stopped developing these tools.
- But I’d like to try again someday!

- Thank you for
- your attention!

## Fin