A NEW SAR RETRIEVAL METHOD FOR HURRICANE WIND PARAMETERS REMOTE - - PowerPoint PPT Presentation

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

A NEW SAR RETRIEVAL METHOD FOR HURRICANE WIND PARAMETERS

Antonio Reppucci, Susanne lehner, Johannes Schulz-Stellenfleth

German Aerospace Center (DLR) Oberpfaffenhofen 82234 Wessling, Germany.

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati *A * B

Hurricane Katrina

Radius of Maximum Wind (70 m/s). Radius of Hurricane force Wind (33 m/s). Strong Convective Cell

Buoys wind speed : A: Measured=14.4 m/s SAR Retrieved =13.3 m/s B: Measured=15.8 m/s SAR Retrieved =17.1 m/s

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

• Measurement of Tropical

Cyclone Intensity

• Wind Speed Error
• New procedure to estimate TC

intensity using SAR data

• NRCS attenuation in hurricane
• Conclusion.

Overview

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

The technique utilizes the difference between the temperature of the warm eye and the surrounding cold cloud tops from IR images and the fact that cyclones of similar intensity tend to have certain characteristic

• features. From these measurements a Current Intensity (CI) value is

assigned to the storm.

[Dvorak, V., 1984: Tropical cyclone intensity analysis using satellite data. NOAA Tech. Report NESDIS 11. Available from NOAA/NESDIS, 5200 Auth Rd., Washington DC, 20233, 47pp. ] 921 140 7,0 906 155 7,5 935 127 6,5 948 115 6,0 1009 30 2.0

• - -

25 1.5 MSLP (hPa) MWS (kts) CI number 960 102 5,5 970 90 5,0 979 77 4,5 987 65 4,0 994 55 3,5 890 170 8,0 1000 45 3,0 1005 35 2,5

• - -

25 1.0

Dvorak Technique

Operational since 1973

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

NOAA P3 and G4 research aircraft

Airplane Measurement

Hurricane Katrina 28/08/2005

GPS dropwindsondes: pressure humidity temperature wind direction and speed Stepped-Frequency Microwave Radiometer Wind speed Rain Rate

[Uhlhorn, Eric W., Peter G. Black, James L. Franklin, Mark Goodberlet, James Carswell, Alan S. Goldstein, 2007 : Hurricane Surface Wind Measurements from an Operational Stepped Frequency Microwave Radiometer, Monthly Weather Review, In press]

Operational

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

m/s

SeaWinds Hurricane Katrina 29-08-2005 (c) JPL ASAR Hurricane Katrina 28-08-2005

Active Microwave Wind Speed Measurements

Ku band C band

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Rain in Tropical Cyclones

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Rain Rate by HOAPS

Image courtesy UNI Hamburg, MPI

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

SFMR rain rate measurements NOAA HRD Hurricane Katrina 28/08/2005

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Rain attenuation

Ku band C band

[Ulaby F.T., More R.K., Fung A.K, 1981, Microwave Remote Sensing: Active and Passive (MA: Addison-Wesley), vol. 1.] [Z.S. Haddad, David A. Short, Stephen L. Durden, Eastwood Im,Scott Hensley, Martre B. Grable, and Robert

• A. Black,(1997). A New Parametrization of the Rain Drop

Size Distribution, IEEE Trans. Geosci. Remote Sensing,

• vol. 29,pp. 690–703, Sept. 1997.]

Undisturbed NRCS Undisturbed NRCS Delta NRCS Delta NRCS

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

NRCS err. on wind speed retrieval

Simulation of NRCS for different wind speed and direction Attenuation

• f the simulated

NRCS of 0.5 dB Retrieval of wind speed using attenuated NRCS

CMOD-5

[Hersbach H., 2003, CMOD5 an improved geophysical model function for ERS C- band scatterometry, Internal report, European Centre for Medium- Range Weather Forecast, no. 395. ]

Wind speed [m/s] Wind direction [deg]

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Wind Speed error

Wind speed [m/s] Wind speed [m/s] Wind speed [m/s] NRCS [dB] CMOD5 Inc.=25° Cross wind CMOD5 Inc.=25° Cross wind Att.=0.5 dB First Solution Second Solution CMOD5 Inc.=25° Up wind Att.=0.5 dB CMOD5 Inc.=25° Up wind Wind speed [m/s] NRCS [dB] Wind speed [m/s] Wind speed [m/s]

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Error Map

Wind speed [m/s] Wind speed [m/s] Wind direction [deg] Wind direction [deg]

• Inc. Angle

35°

• Inc. Angle

25°

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Holland Model

Simulation of Katrina Wind Field

[G.J. Holland, 1980, An Analytic model of the wind and pressure profiles in Hurricanes, Mon. Weather Rev., vol. 108, pp. 1212–1218. ]

2 2 1 4 2 2 exp

/

f r f r B r c p n p B A r V

B r A

⋅ − ⋅ + ⋅ − ⋅ ⋅ =

⎥ ⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ − ⎟ ⎠ ⎞ ⎜ ⎝ ⎛

ρ

pc = Central Pressure pn = Environment pressure r = distance from the center f = Coriolis parameter ρ = Air Density A,B = Scaling Parameter related to Rmws

Wind speed [m/s] Wind speed [m/s]

AOML-HRD Wind Field

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Holland simulated NRCS Measured NRCS

Along Track Cut

Radius maxmimum wind speed

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Holland fitted wind speed CMOD5 Retrieved wind speed

tropical storm force winds

New Method to Estimate the Maximum Hurricane Wind Speed

Holland Model(pc,vM) CMOD5 (θ,φ)

( ) ( )

M c

• v

p , σ

( ) ( )

M c

• v

p , σ = Holland simulated NRCS

• i

σ = Measured NRCS

pc= central pressure vM = maximum wind speed

( ) ( )

[ ] [ ]

2 2

, ,

• i
• i

M c

• i

i M c

v p v p J σ σ σ − = ∑

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

New Method to Estimate the Maximum Hurricane Wind Speed

28.8° N, 128.4°E 29.4°N, 124.2°E 18.3° N, 131° E 23.5° N, 85.5°W 26,1° N, 87.7°W Image center Coordinates 06-09-04 13:23 11-09-05 01:46 09-09-05 01:11 22-09-05 03:45 28-08-05 15:50 Acquisition Time 930 mb 945 mb 60 m/s 55 m/s Typhoon Kiko 946 mb 945 mb 40 m/s 44 m/s Typhoon Songda 950 mb 955 mb 48 m/s 45 m/s Typhoon Kiko 890 mb 897 mb 70 m/s 75 m/s Hurricane Rita 901 mb 905 mb 68 m/s 70 m/s Hurricane Katrina SAR Retrieved Central Pressure Measured Central Pressure SAR Retrieved Max Wind Speed Measured Max Wind Speed

Measured Max Wind Speed SAR Retrieved Max Wind Speed Measured Central Pressure SAR Retrieved Central Pressure

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

NRCS att. Katrina 28-08 2005

Wind speed [m/s] NRCS [dB] NRCS meas [dB] Delta NRCS [dB]

• Inc. Angle:

33.9°

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

NRCS att. Kiko 09-09 2005

Wind speed [m/s] NRCS [dB] NRCS meas [dB] Delta NRCS [dB]

• Inc. Angle:

37°

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Conclusions and future steps

• Wind Speed retrieval in Hurrican force winds shows a Limited

skill in intensity analysis.

• Rain contamination can partly explain the strong damping but

also the foam layer must be taken into account.

• A new Procedure for the estimation of Tropical Cyclone

Intensity using SAR data and parametric model results has been developed.

• First analysis of the NRCS predicted by the CMOD5 GMF

seems not agree with SAR measurements for high wind speed conditions.

• Validation of the

developed algorithm using more SAR Hurricane images.

• Estimation of a possible correction to apply to the GMF

CMOD5 for Tropical Cyclones conditions.

• Application to extratropical Cyclones.

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Thanks for your Attention

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

200 m Wind Speed ~ 46 m/s 200 m Wind speed ~28m/s

Ocean Surface in a Hurricane

Images courtesy NOAAA HRD

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Rain Attenuation

[J. Tournadre, Y. Quilfen, 2003]

Attenuation Coefficient Volume Backscattering Coefficient Reflectivity Factor

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Objective

• Estimation of TC parameter using

SAR data.

• Improve the existing models

for the wind speed retrieval In Tropical Cyclones conditions.

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Experimental techniques

Objective Estimation of Tropical Cyclone Wind Structure from Infrared Satellite Data.

KIMBERLY J. MUELLER, MARK DEMARIA, JOHN KNAFF, JAMES P. KOSSIN, THOMAS H. VONDER HAAR. WEATHER AND FORECASTING,dec 2005.

Observational Analyses

• f North Atlantic

Tropical Cyclones from NOAA Polar-Orbiting Satellite Microwave Data

Christopher S. Velden, Journal of Applied Meteorology, Volume 28, Issue 1 (January 1989). [Katsaros K. B., Vachon P. W., Black P. G., Dodge P. P.,. Uhlhorn E. W., 2000, Wind Fields from SAR: Could They Improve Our Understanding of Storm Dynamics?, Johns Hopkins APL Technical Digest, vol 21, No. 1]

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Wind Speed error

CMOD5 Inc.=35° Cross wind CMOD5 Inc.=35° Cross wind Att.=0.5 dB CMOD5 Inc.=35° Up wind CMOD5 Inc.=35° Up Att.=0.5 dB Wind speed [m/s] NRCS [dB] Wind speed [m/s] Wind speed [m/s] NRCS [dB] Wind speed [m/s] Wind speed [m/s] Wind speed [m/s]

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Along Track Cut

Holland simulated NRCS Measured NRCS

Strong Nrcs Attenuation inside the Tropical Storm force winds area Possible explanation:

• Strong Rain
• Foam Layer on the sea surface

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Rain Attenuation 20 mm/h 30 mm/h 40 mm/h 50 mm/h

C-Band Ku-Band

Sigma Naugth [dB] Attenuation [dB]

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Holland Fitting

Wind Speed [m/s] Holland wind speed Retrieved wind speed

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Holland Fitting

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Conclusion and Future Steps

• Wind Speed retrieval In Hurrican force winds

using the Scatterometer GMF is not accurate.

• Rain can partly explain the strong damping

but also the foam and layer must be taken into account.

• Estimates of Hurricanes wind field can be

made fitting an appropriate Holland profile that match the retrieved wind speed in the range below 17 m/s.

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

Thanks for Your Attention

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

REMOTE SENSING TECHNOLOGIES INSTITUTE SEASAR 2008, Frascati

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