Climate-driven Trends in Contemporary Ocean Productivity Michael Behrenfeld Oregon State University Robert O’Malley Jorge Sarmiento Wayne Esaias Don Shea Gene Feldman Robert Frouin Dave Siegel Allen Milligan Compton Tucker Emmanuel Boss Ricardo Letelier Dorota Kolber Toby Westberry James Randerson Nathan Pollack Chuck McClain Christopher Field Stephane Maritorena Paul Falkowski Sietse Los or “The World According to SeaWiFS”
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Climate-driven Trends in Contemporary Ocean Productivity
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Climate-driven Trends in Contemporary Ocean Productivity
Michael BehrenfeldOregon State University
Robert O’Malley Jorge Sarmiento Wayne EsaiasDon Shea Gene Feldman Robert FrouinDave Siegel Allen Milligan Compton TuckerEmmanuel Boss Ricardo Letelier Dorota KolberToby Westberry James Randerson Nathan PollackChuck McClain Christopher Field Stephane MaritorenaPaul Falkowski Sietse Los
• Six different coupled climate models• Ocean biological responses to climate warming from industrial revolution to 2050• Marginal sea-ice biome area decreases 42% (N) and 17% (S)• Expansion of low production permanently stratified ocean by 4% (N) to 9.4% (S)• Subpolar gyre biome expands 16% (N) and 7% (S)• Stratification decreases nutrient supply and thus productivity in permanently stratified oceans• Stratification, extended growing season, and sea ice retreat enhance production at high latitudes• Significant shifts in community composition
So, what do we really know?....• Satellites measure neither NPP or chlorophyll, they tell us about optics• SeaWiFS has recorded changes in ocean optical properties over vast regions• These changes are clearly linked to effects of climate variability on upper ocean temperature and stratification - not instrument or atmospheric artifacts
Spectral matching algorithms are a path to a solution…• Do not rely on the ‘bio-optic’ assumption – now known to be wrong• Would allow changes in cDOM photo-oxidation to be detected• Would allow changes in photoacclimation to be detected from Chl:C• Are not optimized with heritage ‘ocean color’ wavebands
Difference in chlorophyll estimates for standard wavelength-ratio and
spectral matching algorithms
cDOM from spectral matching algorithm
•Uncertainty in remote sensing products reflects inadequacy of heritage wavebands for separating different absorbing and scattering components.
• Biggest differences is in slope of initial El Nino – La Nina period
Chl
Chl
SS
TSS
TM
atc
hM
ism
atc
h
Chl
Chl
SS
TSS
TVGPM Polynomial
VGPM Eppley
matchup / mismatch
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0 20 40 60 80 100 120
-2.3
-1.3
-0.3
0.7
1.7
2.7
Year
1998 2000 2002 2004 2006
MEI
-0.8000
-0.6000
-0.4000
-0.2000
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
0 20 40 60 80 100 120
subpolar
subtropical
equatorial
global
SST c
hanges
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0 20 40 60 80 100
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 20 40 60 80 100
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 20 40 60 80 100
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 20 40 60 80 100
SeaWiFS time series – sequential months
Chlo
rophyll
anom
alie
s
All bins
Global
> 15C
< 15C
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0 20 40 60 80 100
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0 20 40 60 80 100
SeaWiFS time series – sequential months
Su
rface C
hlo
rop
hyll A
nom
aly
(Tg
)
Quality and Maturity DefinitionsQuality and Maturity Definitions
Measurement Maturity Index1 = No known operational use for measurement2 = Parameter identified as having potential for operational significance 3 = Operational significance demonstrated through simulations4 = Pathfinder mission launched. Need for long term record widely accepted 5 = Pilot decision support tool (DST) use of space-based measurements6 = Space ops over sustained period. Adds value to DSTs.7 = Ready for transfer to operational use 8 = Measured operationally. Used operationally in existing DSTs.
Measurement Quality Index1 = Measurement identified as potentially providing significant science return2 = Initial measurements produced and calibrated3 = Geophysical, biological, or chemical properties inferred or estimated from
calibrated measurements4 = Geophysical, biological, or chemical properties inferred or estimated from
calibrated measurements and validated5 = Significant improvement in calibration, spatial resolution, spectral resolution,
temporal revisit, and/or spatial coverage over initial measurements6 = Second significant improvement in calibration resolution, temporal revisit,
and/or spatial coverage over initial measurements7 = Further significant improvement in calibration resolution, temporal revisit,
and/or spatial coverage over initial measurements8 = Measurement approaches theoretical or practical limits on performance