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Ocean NPP MOD 27 Status

Ocean NPP MOD 27 Status. Wayne E. Esaias Code 971, GSFC Kevin R. Turpie SAIC, GSC December 18, 2001. Outline. Product Summary Performance of Provisional - Version 3 Input Dependencies Comparison with SeaWiFS Quality Flags Remaining Issues Schedule for Promotion.

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Ocean NPP MOD 27 Status

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  1. Ocean NPP MOD 27 Status Wayne E. Esaias Code 971, GSFC Kevin R. Turpie SAIC, GSC December 18, 2001 Esaias MOD 27

  2. Outline Product Summary Performance of Provisional - Version 3 Input Dependencies Comparison with SeaWiFS Quality Flags Remaining Issues Schedule for Promotion Esaias MOD 27

  3. Esaias MOD 27

  4. Esaias MOD 27

  5. SCIENCE QUESTIONS (Ocean NPP) • This Product Derives Ocean Net Primary Production and Annual Export Production from Chlorophyll, Light (PAR), SST, and Mixed Layer Depth • Carbon fixed/m2/day - Needed to understand: • Magnitude and Variability of ONPP, and uncertainties. • Ecosystem dynamics (coupling with physical forcings) • Food chain effects (fisheries resources) • Carbon cycle (carbon export, pCO2 and hence air sea C flux) • (Ocean NPP is 40-50% of global total production. ONPP shows greater interannual variability than TNPP - Behrenfeld et al, 2000) • RELEVANT SCIENCE QUESTIONS for MODIS Oceans • Variability - How are global ecosystems changing? • Response - How do ecosystems respond to and affect global • environmental change and the carbon cycle? • Consequences - What are the consequences of climate and sea level • changes and increased human activities in the coastal regions? • Prediction - How well can cycling of carbon through the Earth system be • modeled, and how reliable are predictions… • WHAT IS THE PRESENT UNCERTAINTY OF ONPP? Esaias MOD 27

  6. Esaias MOD 27

  7. ONPP a Level 4 product P1 = Behrenfeld & Falkowski NPP = f(Chl a, PAR, Pb opt) Integrated over the Euphotic zone Pb opt = f (SST) 7th order polynomial P2 = Howard, Yoder, Ryan NPP = f (Chl a, PAR, Pmax) Integrated over the upper Mixed Layer Depth (MLD) Pmax (Platt) = f (SST) Eppley Peterson exponential Annual = Iverson/Esaias Empirical relationship Esaias MOD 27

  8. Input Dependencies • Chlorophyll • Current archive product uses Chlor_a_3. • Investigate differences with Chor_MODIS, Chlor_a_2. • Flags are independent, can account for some differences in test runs. • Freshwater, inland seas. • MLD • No comparisons - Carr PPARR • PAR • Comparisons with SeaWiFS, DAO, B-R PAR Products • Currently use the same PAR used by Land NPP • Spatial, Temporal resolution issues • May impact SeaWiFS/MODIS comparisons. Esaias MOD 27

  9. MODIS best quality MODIS coverage is greater due to Wider swath, greater duty cycle (50 vs 40 min/orbit), Less cloud obscuration (1 km pixels), morning orbit. Product dependent. Esaias MOD 27

  10. Weekly PAR December 10, 2000 Derived from GSFC Data Assimilation Office 3 hr retrievals. Esaias MOD 27

  11. OPP P1 December 10, 2000 Falkowski Behrenfeld depth integrated model calculates total euphotic zone productivity to 1% surface irradiance. Primary inputs are PAR, SST, Chlor_a_3. Units gm Carbon/m2/yr. Esaias MOD 27

  12. Mixed Layer Depth Dec. 10, 2000 Mixed Layer Depth is averaged from daily values retreived by Fleet Numerical Monterey Oceanographic Center’s (FNMOC) OTIS model, obtained through NOAA-Navy net by GES DAAC. Esaias MOD 27

  13. OPP P2 December 10, 2000 Howard Yoder Ryan model for productivity in the upper mixed layer. Esaias MOD 27

  14. QL=BEST This period is not highly impacted by Earth-sun double correction. Esaias MOD 27

  15. Percent Differences in NPP estimates From MODIS Chlorophylls and SeaWiFS Esaias MOD 27

  16. Steps to Validation • Algorithms are validated, published. • PGE 51 code computes the correct ONPP for given inputs. • Requires “validation” of Chlor_a_3, SST. • Acceptance” of higher global means from Chlor_a_3. • Investigating issues with how quality flags are propagated. • Can be accomplished in 1 month from a stable input. • Expect to meet spring schedule for code readiness. • Initial uncertainties will be based on: • Heritage (SeaWiFS and Published Literature) • Consistency • Comparison with Ocean Time Series • Participant in PP Round Robin - M.E. Carr, JPL. • Expect a validated status ~ 1 month after Chlor_a_3. Esaias MOD 27

  17. Developments that have been Deferred P1 Evolution to Behrenfeld Photo-Acc approach Prod. Efficiency = f(MLD, Nut, Fe) Run at daily scales coverage is better than expected, less filling/extrap is needed major processing load MODIS PAR Esaias MOD 27

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