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  • 1. IOP Algorithm Workshop @ OOXIX
  • 2. Fri / Sat workshop generic agenda: 9:00 start 10:30 break 12:30 lunch 13:30 resume 15:30 break 17:30 end 22:00 group dinner (Fri)
  • 3.
    • focus topics:
    • overview
    • end-user perspectives
    • operational implementation strategies
    • relationships between Rrs and IOPs
    • regional adjustment of SAA parameterization
    • new directions
    • summary, recommendations, & steps forward
  • 4. topic 1 - overview (mod by Jeremy) topics: summarize goals, approaches, evaluation process, & limitations goals: clear understanding of workshop goals agreement on evaluation process & metrics agreement on accuracy of SAA summaries recognition of overlap amongst approaches
  • 5.
    • what we’re (NASA, anyway) looking to do:
    • extend the IOCCG SAA survey by
    • evaluating application of SAA algorithms to satellite radiometry
    • reviewing & consolidating SAA construction
    workshop motivation & goal: achieve community consensus on an effective algorithmic approach for producing global -scale, remotely sensed SAA IOP products what we’re (NASA, anyway) looking for: combination of accuracy and geographic coverage flexible, multi-sensor implementation computational efficiency to support operational environment open source software and accompanying LUTs associated SAA uncertainties
  • 6. algorithm “shoot out” you’ve been warned:
  • 7. topic 1 - overview (mod by Jeremy) topics: summarize goals, approaches, evaluation process, & limitations goals:  clear understanding of workshop goals  agreement on evaluation process & metrics agreement on accuracy of SAA summaries recognition of overlap amongst approaches
  • 8. process: SAA identification: literature review (IOCCG report 5); community solicitation open community dialog SAA consolidation: identification of (dis)similarities software accumulation: standalone versions & l2gen (SeaDAS) import evaluation prep: define metrics; design analyses; identify test data sets “ validation” analyses sensitivity studies workshop: consolidate recom-mendations; ideas
  • 9.
    • pre-workshop achievements - overview
    • process: a philosophy & a path forward
    • software: l2gen (msl12) & l3gen & IDL, Matlab, C, etc.
    • dialog: public record of (forum for) issues & ideas
    • shared analyses (evaluation, sensitivity, etc.)
  • 10.
    • pre-workshop achievements - dialog & discussion
    • air-sea transmission, Rrs  rrs(0 - )
    • calculation of Rrs (bandpass correction, f/Q)
    • temperature & salinity dependence of aw & bbw
    • spectral data products to be considered (adg, bb, etc.)
    • evaluation metrics & SAA failure conditions
    • inversion methods & linearization issues
    • calculation of uncertainties
    • SAA product validation & sensitivity analyses
    • strategies to produce level-3 products
    • http://oceancolor.gsfc.nasa.gov/forum/oceancolor/board_show.pl?bid=24
  • 11.
    • pre-workshop achievements - analyses
    • in situ-to-in situ & satellite-to-in situ match-ups
    • global (level-3) comparisons
    • spatial coverage (level-2) comparisions
    • sensitivities to parameterization & noisy input
    • sensitivity to inversion method
    • level-2 vs. level-3 inversion
    • http://oceancolor.gsfc.nasa.gov/MEETINGS/OOXIX/IOP/analyses.html
  • 12. available metrics: posted analyses … ( for 400 <  < 700 ) Rrs(  ) > 0 adg(  ) & a  (  ) > -0.005 bbp(  ) > -0.0001 coverage … retrieval quality / comparison … available metrics: level-3 flagging … ( for 400 <  < 600 ) Rrs(  ) > 0 ( ? ) - 0.95 aw(  ) < a(  ) < 5 -0.05 aw(  ) < adg(  ) < 5 -0.05 aw(  ) < a  (  ) < 5 - 0.95 bbw(  ) < bb(  ) < 0.015 -0.05 bbw(  ) < bbp(  ) < 0.015
  • 13. topic 1 - overview (mod by Jeremy) topics: summarize goals, approaches, evaluation process, & limitations goals: clear understanding of workshop goals  agreement on evaluation process & metrics  agreement on accuracy of SAA summaries recognition of overlap amongst approaches
  • 14. anatomy of a semi-analytical algorithm (SAA): many approaches are similarly constructed & parameterized next, I’ll deconstruct the SAAs to illustrate similarities & differences the goal is to convince you that most SAAs fall within 2 / 3 categories of construction & that most have interchangeable parts
  • 15. satellite provides R rs (  ) a (  ) and b b (  ) are desired products total a and b b are sums of coefficients for all components in seawater each coefficient expressed as product of magnitude and spectral shape
  • 16.  
  • 17. GSM, HL, BR Gordon quad; Lee trans inversion  variable S variable simultaneous: nonlinear (L-M), matrix inversion a  variable system of 5/6 equations with 3 unknowns
  • 18. a  = a - a w - a dg LUT calculate a empirical a (555) iteration  a (  i ,  j ) estimate a dg (  i ) using S ,  adg (  i ,  j ), and  a  (  i ,  j ) QAA PML, NIWA Gordon quad; Lee trans  variable calculate a 
  • 19. solution b b and a both from K d , b w / b , and solz LUT LAS calculate K d LUT
  • 20. GSM, HL, BR Gordon quad; Lee trans a  = a - a w - a dg inversion  variable S variable simultaneous: nonlinear (L-M), matrix inversion a  variable LUT calculate a empirical a (555) iteration  a (  i ,  j ) estimate a dg (  i ) using S ,  adg (  i ,  j ), and  a  (  i ,  j ) QAA solution b b and a both from K d , b w / b , and solz PML, NIWA Gordon quad; Lee trans  variable calculate a  LUT LAS calculate K d LUT
  • 21. agp(443) bbp(443) current state-of-the-art:
  • 22. algorithm #1 algorithm #2 difference global deep water adg(555) retrievals adg(555) difference
  • 23. topic 1 - overview (mod by Jeremy) topics: summarize goals, approaches, evaluation process, & limitations goals: clear understanding of workshop goals agreement on evaluation process & metrics  agreement on accuracy of SAA summaries   recognition of overlap amongst approaches 
  • 24. GSM (standard) QAA (standard)
  • 25. GSM (QAA  , QAA S, Bricaud a  ) QAA (standard)
  • 26. GSM (standard) QAA (GSM  , GSM S)
  • 27. GSM (standard) QAA (GSM  , GSM S, GSM a(555))
  • 28. topic 2 - end-user perspectives (mod by Mike) topics: desired products & their uses accuracy / behavior uncertainty requirements goals: list(s) near- & long-term needs (with attention to what’s available) list(s) of data product hierarchy / priority
  • 29. topic 3 - operational implementation strategies (mod by Bryan) topics: L2 Rrs - l2gen, f/Q & normalization, bandpass corrections L3 IOPs - masks, geometry, calc @ L2 vs L3, other strategies goals: consensus understanding of L2 Rrs generation agreeement on SAA flags & their use in L3 product generation discussion of (dis)advantages of product generation at L2 vs. L3
  • 30. topic 4 - relationships b/w Rrs and IOPs (mod by Emmanuel) topics: IOP shape functions; inversion procedures; uncertainties; ambiguity goals: discussion of sensitivities of shape functions & inversion procedures & how they impact product accuracies & geographic coverage discussion of methods for uncertainty determination
  • 31. topic 5 - regional adjustment of SAA params (mod by Mark/Tim) topics: Dowell/Moore optical water type classification approach; others? goals: consensus (dis)agreement of need to pursue such approaches
  • 32. topic 6 - new directions (mod by Samantha) topics: GlobColour; fluorescence; f/Q & normalization(s); others? goals: illumination
  • 33. backup slides
  • 34.
    • questions to be answered:
    • SAAs predefine spectral shapes for the IOP products of interest. What are the key components & can their sensitivities, uncertainties, & relative priority be defined?
    • How critical / sensitive is the optimization or inversion method used?
    • How does spectral resolution effect the retrievals?
    • How do the SAAs perform:
    • a. relative to in situ IOPs using in situ Rrs?
      • b. relative to in situ IOPs using satellite Rrs (from a match-up data set)?
      • c. on various satellite level-2 & level-3 scenes
    • Do the conclusions of #1-4 vary by trophic level or bioregime?
    • What are the remediations to failure?
    • What is the most appropriate implementation strategy for operational satellite data processing (e.g., level-2 Rrs normalization, masking & binning at level-3?
  • 35. topic 2 - end-user perspectives (mod by Mike) recommendations:
  • 36. topic 3 - operational implementation strategies (mod by Bryan) recommendations:
  • 37. topic 4 - relationships b/w Rrs and IOPs (mod by Emmanuel) recommendations:
  • 38. topic 5 - regional adjustment of SAA params (mod by Mark/Tim) recommendations:
  • 39. topic 6 - new directions (mod by Samantha) recommendations:
  • 40. (dis)advantages of various modeling approaches: empirical straightforward (Rrs  product) & computationally efficient biased to in situ database & degrades with optical complexity SAA / quasi-SAA configurable form & simultaneous output of multiple products only as representative as model assumptions (including empirical functions) LUT based on exact RTE calculations & simultaneous output of products only as representative and flexible as RTE model assumptions
  • 41. attendees: Antoine Mangin (ACRI) Odile Hembise Fanton d’Andon (ACRI) Bryan Franz (NASA) Paula Bontempi (NASA) Catherine Brown (LOV) Samantha Lavender (U. Plymouth) Emmanuel Boss (U. Maine) Sean Bailey (NASA) Gene Feldman (NASA) Stephane Maritorena (UCSB) Hubert Loisel (U. Littoral) Takafumi Hirata (PML) Jeremy Werdell (NASA) Tim Moore (NURC) Jill Schwarz (NIWA) Tim Smyth (PML) Mark Dowell (JRC) Yannick Huot (LOV) Mike Behrenfeld (OSU) ZhongPing Lee (MSU) unable to attend: Andre Morel (LOV), Paul Lyon (NRL)
  • 42.  
  • 43.  
  • 44.