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Preliminary Performance of the ASAR Wave Level WVS and WVW Product Frank Melger ARGOSS. WVS (Level 1b) product. ASA_WVS_1PNPDK20021117_091558_000013202011_00179_03740_0161.N1 ASA_WVS_1PNPDK20021117_094531_000020842011_00179_03740_0160.N1 - PowerPoint PPT Presentation
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Page 1ASAR Validation Workshop - ESRIN – 11-12 December 2002
Preliminary
Performance of the ASAR Wave Level WVS and WVW Product
Frank Melger
ARGOSS
Page 2ASAR Validation Workshop - ESRIN – 11-12 December 2002
WVS (Level 1b) product
ASA_WVS_1PNPDK20021117_091558_000013202011_00179_03740_0161.N1 ASA_WVS_1PNPDK20021117_094531_000020842011_00179_03740_0160.N1 ASA_WVS_1PNPDK20021117_102031_000002552011_00179_03740_0159.N1 ASA_WVS_1PNPDK20021117_120010_000002552011_00180_03741_0164.N1. ASA_WVS_1PNPDK20021117_130545_000007802011_00181_03742_0168.N1
Page 3ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVS_1PNPDK20021117_091558/_094531/_102031/_120010/_130545
Retrieved wave energy against ECMWF WAM wave energy SPRA scheme, preliminary results
Page 4ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVS_1PNPDK20021117_091558/094531/102031/120010/130545
Retrieved wave energy against ECMWF WAM wave energy SPRA scheme, preliminary results
Page 5ASAR Validation Workshop - ESRIN – 11-12 December 2002
Summary WVS (Level 1) product No problems found in the WVS product examples. Representative but limited dataset, (large variation sea
states, different oceans)
Page 6ASAR Validation Workshop - ESRIN – 11-12 December 2002
WVW (Level 2) product
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Page 7ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Retrieved wave energy against ECMWF WAM wave energy
Page 8ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Retrieved wave energy against ECMWF WAM wave energy
Page 9ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Retrieved wind velocity against ECMWF WAM wind velocity
slightly underestimated unresolved wind speed
below ~ 4m/s
Page 10ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Retrieved and ECMWF WAM wind velocity
Page 11ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Retrieved ocean wave spectra
Page 12ASAR Validation Workshop - ESRIN – 11-12 December 2002
WVW inversion scheme
Estimate azimuth cut-off wave number (Kc) Use Kc to estimate
inverse wave age quasi-linear mapping relations
Estimate ocean wave spectrum within quasi linear mapping area
Ocean wave energy outside linear mapping area is not included in the WVW product.
Page 13ASAR Validation Workshop - ESRIN – 11-12 December 2002
Azimuth wave number
Expected problems at high sea states
Page 14ASAR Validation Workshop - ESRIN – 11-12 December 2002
WVW
Relation azimuth cut_off wave number and shift variance
Wind direction is set to dummy value of 45 degrees relative to range direction
Without true wind (wave) direction information 45 degrees gives smallest average errors
Propagation direction short waves unknown
Page 15ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Correlation normalised wave age-1 and retrieved wind velocitycorrelation coefficient: 0.9077
Page 16ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Relative low phase velocity
Page 17ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1
Retrieved wave height relative to wave height wind waves
Dominating swell energy Relative low wind speeds Relative young
seas( duration fetch length)
Page 18ASAR Validation Workshop - ESRIN – 11-12 December 2002
WVW or Level 2 product
ASA_WVW_2PXPDE20020708_195148_000014542007_00300_01857_0003.N1
Page 19ASAR Validation Workshop - ESRIN – 11-12 December 2002
ASA_WVW_1PXPDE20020708_195148_000014542007_00300_01857_0003.N1
Retrieved ocean wave spectra
Page 20ASAR Validation Workshop - ESRIN – 11-12 December 2002
Remarks WVW (level 2) product Current dataset not representative: long waves energy
dominates. With ERS data the best results were always found in the Pacific.
Applicability of retrieved wind speed and wave age is questionable. Development of a procedure to add (missing) wind sea energy from retrieved wind vector is not trivial.
Performance is expected to deteriorate at high sea states. Additional validation is needed to evaluate the performance
for various sea states at various locations. Dataset is too limited for definite conclusions.
Page 21ASAR Validation Workshop - ESRIN – 11-12 December 2002
Summary WVW product Initial problems with WVW and WVS product have already
been solved. ESA scheme has performed well on this limited dataset but
much more validation is needed.
Page 22ASAR Validation Workshop - ESRIN – 11-12 December 2002
What next ? Organisation and infrastructure for validation is operational.
WVS, WVW, ECMWF, BUOY data easily accessible. Because the data stream has just started we have not really
be able to benefit from these facilities. The next year will be crucial for the validation of wave mode
products.
Page 23ASAR Validation Workshop - ESRIN – 11-12 December 2002
Thank you for listening to my presentation
Frank Melger
ARGOSSP.O. Box 618325 ZH VOLLENHOVEthe NetherlandsTelnr.: +31-527-242299Faxnr.: +31-527-242016E-mail: [email protected]
WWW.ARGOSS.NL
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