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Fluorescence Line Height (FLH)

Fluorescence Line Height (FLH). Ricardo Letelier, Mark Abbott, Jasmine Nahorniak Oregon State University. Outline. FLH basic alghorithm Comparison between field measurements and MODIS FLH FLH and [chl a] Chlorophyll Fluorescence Efficiency. Acknowledgments.

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Fluorescence Line Height (FLH)

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  1. Fluorescence Line Height (FLH) Ricardo Letelier, Mark Abbott, Jasmine Nahorniak Oregon State University

  2. Outline • FLH basic alghorithm • Comparison between field measurements and MODIS FLH • FLH and [chl a] • Chlorophyll Fluorescence Efficiency

  3. Acknowledgments • Mark Abbott, Jasmine Nahorniak (OSU) • Dennis Clark (NOAA) • Wayne Esaias, Frank Hoge (NASA) • Bob Evans, Kay Kilpatrick, Howard Gordon, Ed Kearns (Univ. Miami) • Ken Carder (USF) • John Cullen & Yannick Huot (Dalhousie)

  4. 0.016 0.016 0.014 0.014 0.012 0.012 0.01 0.01 0.008 0.008 Lu/Es Lu/Es 0.006 0.006 0.004 0.004 0.002 0.002 0 0 400 400 450 450 500 500 550 550 600 600 650 650 700 700 Wavelength, nm Wavelength, nm Chlorophyll absorption Increase in fluorescence F = PAR x ([chl]x a*) x Ff

  5. MODIS FLH bands: avoid oxygen absorbance at 687 nm Weighting factor used to compensate for off-center FLH

  6. 12 0.12 FLH (10 mg) 10 0.10 10 mg 8 0.08 0.01 mg Radiance, W m-2 µm-1 sr-1 6 0.06 Normalized band transmittance 4 0.04 Negative FLH due to TOA curvature needs to be corrected empirically 2 0.02 0 0.00 650 690 710 730 750 770 670 l13 l14 l15 Wavelength, nm

  7. Field Observations • In situ open ocean • - MOBY • - HOT cruises • -In situ Coastal • - GLOBEC • - COAST • - Southern Ocean

  8. Optical Drifters • 29 off Oregon • 12 in the Southern Ocean • Noth Atlantic • (John Cullen’s group)

  9. http://picasso.coas.oregonstate.edu/ORSOO/

  10. MODIS Terra FLH, W m-2mm-1 sr-1 Oregon Drifters FLH, W m-2mm-1 sr-1

  11. Testing the MODIS FLH Algorithm FLH vs. chlorophyll FLH vs. CDOM From Hoge et al.

  12. All cruise data Only pixels of passes within 5 hrs of sampling time GLOBEC NEP AUGUST 2002 FLH, W m-2 µm-1 sr-1 [chl] = .021 + 43.4 FLH1.866 In situ chlorophyll, mg m-3

  13. GLOBEC NEP AUGUST 2002 chlFLH semi-analytical (Huot & Cullen assuming ff = 0.006) chlFLH empirical (this study) In situ chl • Both FLH derived chl algorithms appear to slightly overestimate chl a fields. • They do not seem to reproduce the low values observed in situ. • Some of the differences between in situ and FLH derived could be due to time differences and sampling depth (in situ = 5 m depth)

  14. GLOBEC NEP AUGUST 2002 (July 31st – August 19th) In situ chl a, mg m-3 MODIS chl a_2, mg m-3

  15. In Situ Observations of F/[chl] suggest it can be a proxy for ff Initial slope proportional to F

  16. MODIS Terra L2 1 km resolution scene from October 3rd 2001 Sea Surface Temperature Chl a Chl Fluorescence Line Height (°C) (mg m-3) (W m-2mm-1 sr-1) From OSU-COAS EOS DB Station

  17. Seasonal patterns of FLH and chl a Southern Ocean Indian Ocean

  18. chlFLH empirical (this study) Huot & Cullen ARP using in situ chl to Derive an average ff MODIS ARP

  19. Mean oceanic value according to Fischer and Kronfeld (1990) Range covering most oceanic regions (Gordon, 1979) # occurences CFE, non dimensional

  20. GLOBEC NEP AUGUST 2002 chlFLH empirical (this study) MODIS CFE using Huot & Cullen ARP MODIS CFE using MODIS ARP

  21. Fv/Fm, n.d. 9 AM CFE, r.u. m/mmax , n.d. Thalassiosira weissflogii Chemostat results 2001-2002 After 3 days of constant cell counts After 14 days

  22. Where do we stand? • Field observations suggest that MODIS FLH is a robust product. • Comparison of [chl]field vs FLHMODIS suggest that FLH may prove of use to derive [chl] in turbid waters. However, and as expected, there is no single relation between FLH and [chl a]. (See also K Carder poster). • CFE validation requires that of FLH and ARP. • In order to interpret CFE we need field and laboratory based work that explores the effect of environmental variability and phytoplankton specific composition.

  23. FLH working group • Charlie Yentsch (CSYentsch@aol.com), • Dave Siegel (davey@icess.ucsb.edu), • Greg Leptoukh (Gregory.Leptoukh@nasa.gov), • Richard Sikorski (sikorski@raytheon.com), • Chuck McClain (Charles.R.McClain@nasa.gov), • Heidi Dierssen (heidi.dierssen@uconn.edu), • Chuanmin Hu (hu@seas.marine.usf.edu), • Paula Bontempi (paula.s.bontempi@nasa.gov), • Alex Cunningham (a.cunningham@strath.ac.uk), • Mike Behrenfeld (Mike.Behrenfeld@nasa.gov), • Ricardo Letelier (letelier@coas.oregonstate.edu)

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