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. Chlorophyll absorption Increase in fluorescence F = PAR x ([chl] x a*) x  f

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

6. Radiance, W m -2 µm -1 sr -1 Normalized band transmittance 10 mg 0.01 mg Wavelength, nm 650 670 690710730750770 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0 2 4 6 8 10 12 13 14 15 FLH (10 mg) Negative FLH due to TOA curvature needs to be corrected empirically

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

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

12. In situ chlorophyll, mg m -3 FLH, W m -2 µm -1 sr -1 GLOBEC NEP AUGUST 2002 [chl] =.021 + 43.4 FLH 1.866 All cruise data Only pixels of passes within 5 hrs of sampling time

13. chl FLH empirical (this study) chl FLH semi-analytical (Huot & Cullen assuming  f = 0.006) In situ chl GLOBEC NEP AUGUST 2002 -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 31 st – August 19 th ) 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  f Initial slope proportional to  F

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

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

22. MODIS ARP Huot & Cullen ARP using in situ chl to Derive an average  f chl FLH empirical (this study)

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

24. GLOBEC NEP AUGUST 2002 MODIS CFE using MODIS ARP MODIS CFE using Huot & Cullen ARP chl FLH empirical (this study)

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

26. Where do we stand? Field observations suggest that MODIS FLH is a robust product. Comparison of [chl] field vs FLH MODIS 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.

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