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Preliminary Performance of the ASAR Wave Level WVS and WVW Product Frank Melger ARGOSS

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

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Preliminary Performance of the ASAR Wave Level WVS and WVW Product Frank Melger ARGOSS

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  1. Preliminary Performance of the ASAR Wave Level WVS and WVW Product Frank Melger ARGOSS

  2. 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

  3. ASA_WVS_1PNPDK20021117_091558/_094531/_102031/_120010/_130545ASA_WVS_1PNPDK20021117_091558/_094531/_102031/_120010/_130545 Retrieved wave energy against ECMWF WAM wave energy • SPRA scheme, preliminary results

  4. ASA_WVS_1PNPDK20021117_091558/094531/102031/120010/130545 Retrieved wave energy against ECMWF WAM wave energy • SPRA scheme, preliminary results

  5. Summary WVS (Level 1) product • No problems found in the WVS product examples. • Representative but limited dataset, (large variation sea states, different oceans)

  6. WVW (Level 2) product ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1

  7. ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1 Retrieved wave energy against ECMWF WAM wave energy

  8. ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1 Retrieved wave energy against ECMWF WAM wave energy

  9. ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1 • slightly underestimated • unresolved wind speed below ~ 4m/s Retrieved wind velocity against ECMWF WAM wind velocity

  10. ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1 Retrieved and ECMWF WAM wind velocity

  11. ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1 Retrieved ocean wave spectra

  12. 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.

  13. Azimuth wave number • Expected problems at high sea states

  14. WVW • 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 Relation azimuth cut_off wave number and shift variance

  15. ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1 Correlation normalised wave age-1 and retrieved wind velocity correlation coefficient: 0.9077

  16. ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1 Relative low phase velocity

  17. ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1ASA_WVW_1PXPDE20020627_203722_000022492007_00143_01700_0045.N1 • Dominating swell energy • Relative low wind speeds • Relative young seas( duration fetch length) Retrieved wave height relative to wave height wind waves

  18. WVW or Level 2 product ASA_WVW_2PXPDE20020708_195148_000014542007_00300_01857_0003.N1

  19. ASA_WVW_1PXPDE20020708_195148_000014542007_00300_01857_0003.N1ASA_WVW_1PXPDE20020708_195148_000014542007_00300_01857_0003.N1 Retrieved ocean wave spectra

  20. 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.

  21. 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.

  22. 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.

  23. Thank you for listening to my presentation Frank Melger ARGOSS P.O. Box 61 8325 ZH VOLLENHOVE the Netherlands Telnr.: +31-527-242299 Faxnr.: +31-527-242016 E-mail: info@argoss.nl WWW.ARGOSS.NL

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