fluorescence line height (flh)
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Fluorescence Line Height (FLH)
Ricardo Letelier,Mark Abbott,
Jasmine NahorniakOregon State University
Outline
• FLH basic alghorithm• Comparison between field
measurements and MODIS FLH• FLH and [chl a]• Chlorophyll Fluorescence Efficiency
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)
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
400 450 500 550 600 650 700
Wavelength, nm
Lu/E
s
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
400 450 500 550 600 650 700
Wavelength, nm
Lu/E
s
Chlorophyll absorption
Increase in fluorescence
F = PAR x ([chl] x a*) x f
MODIS FLH bands: avoid oxygen absorbance at 687 nm
Weighting factor used to compensate for off-center FLH
0
2
4
6
8
10
12
650 670 690 710 730 750 770
0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
Rad
ianc
e, W
m-2
µm
-1 sr
-1
Nor
mal
ized
ban
d tr
ansm
itta
nce10 mg
0.01 mg
Wavelength, nm
650 670 690 710 730 750 7700.00
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
Field Observations
-In situ open ocean - MOBY - HOT cruises
-In situ Coastal - GLOBEC - COAST
- Southern Ocean
Optical Drifters
- 29 off Oregon- 12 in the Southern Ocean- Noth Atlantic (John Cullen’s group)
http://picasso.coas.oregonstate.edu/ORSOO/
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0 0.05 0.1 0.15 0.2 0.25
Oregon Drifters FLH, W m-2 m-1 sr-1
MO
DIS
Terr
a F
LH,
W m
-2
m-1 s
r-1
From Hoge et al.
Testing the MODIS FLH Algorithm
FLH vs. chlorophyll
FLH vs. CDOM
In situ chlorophyll, mg m-3
FLH
, W
m-2 µ
m-1 s
r-1
GLOBEC NEP AUGUST 2002
[chl] = .021 + 43.4 FLH1.866
All cruise dataOnly pixels of passes within 5 hrs of sampling time
chlFLH empirical(this study)
chlFLH 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)
GLOBEC NEP AUGUST 2002 (July 31st – August 19th)
In situ chl a, mg m-3 MODIS chl a_2, mg m-3
In Situ Observations of F/[chl] suggest it can be a proxy for f
Initial slope proportional to F
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 3rd 2001
From OSU-COAS EOS DB Station
Southern Ocean Temp. Test
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
3/15/00 10/1/00 4/19/01 11/5/01 5/24/02 12/10/02 6/28/03
Date
Ch
l a, m
g m
-3
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
FL
H, W
m-2
m
-1 s
r-1
Chl a 3
FLH
Seasonal patterns of FLH and chl a
Southern Ocean
Indian Ocean
0.02
0.03
0.04
0.05
0.06
0.07
0.08
3/15/00 10/1/00 4/19/01 11/5/01 5/24/02 12/10/02 6/28/03
Date
Ch
l a, m
g m
-3
0.05
0.07
0.09
0.11
0.13
0.15
0.17
0.19
0.21
0.23
0.25
FL
H, W
m-2
m
-1 s
r-1
MODIS ARP Huot & Cullen ARPusing in situ chl to
Derive an average f
chlFLH empirical(this study)
0 0.005 0.01 0.015 0.02 0.025 0.030
500
1000
1500
2000
2500
3000
# oc
cure
nces
CFE, non dimensional
Range covering mostoceanic regions(Gordon, 1979)
Mean oceanic value according to Fischer and Kronfeld (1990)
GLOBEC NEP AUGUST 2002
MODIS CFE using MODIS ARP
MODIS CFE using Huot & Cullen ARP
chlFLH empirical(this study)
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Fv/
Fm
, n.d
.9
AM
CF
E, r
.u.
/max , n.d.
Thalassiosira weissflogii Chemostat results 2001-2002
After 3 days of constant cell counts
After 14 days
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.
FLH working group
• Charlie Yentsch ([email protected]), • Dave Siegel ([email protected]), • Greg Leptoukh ([email protected]), • Richard Sikorski ([email protected]), • Chuck McClain ([email protected]), • Heidi Dierssen ([email protected]), • Chuanmin Hu ([email protected]), • Paula Bontempi ([email protected]), • Alex Cunningham ([email protected]), • Mike Behrenfeld ([email protected]),• Ricardo Letelier ([email protected])