climate-driven trends in contemporary ocean productivity
DESCRIPTION
Robert O’MalleyJorge SarmientoWayne Esaias Don SheaGene FeldmanRobert Frouin Dave SiegelAllen MilliganCompton Tucker Emmanuel BossRicardo LetelierDorota Kolber Toby WestberryJames RandersonNathan Pollack Chuck McClainChristopher FieldStephane Maritorena - PowerPoint PPT PresentationTRANSCRIPT
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
or
“The World According to SeaWiFS”
• Biospheric NPP increased 6 Pg from 1997 El Nino to 1999 La Nina, with clearest response in oceans
• In most central ocean gyres, chlorophyll concentrations decreased between 1997 and 2003
• Declines in mid-ocean gyres chlorophyll associated with increases in sea surface temperature
7 December 2006 Vol. 444 Nature
Tidbits
• Based on Vertically Generalized Production Model (VGPM)
• Initial increase = 1,930 TgC/yr
• Subsequent decrease = 190 TgC/yr
• Global trends dominated by changes in permanently stratified ocean regions (ann. ave. SST < 15oC)
global> 15oC
-200
-150
-100
-50
0
50
100
150 -0.9
-0.7
-0.5
-0.3
-0.1
0.2
0.4
0.6
0.8
1.0
1.2
*
* Multivariate ENSO Index
Low
Latitu
de
SS
T A
nom
aly
SS
T C
han
ges
( 0C
) +3
-1
+2
-2
+1
-3
0
0
-30
+60
-60
+30
NP
P C
han
ges (
%) b
a
cN
PP
NP
PS
ST
SS
T
Tidbits
• 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
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
-200
-150
-100
-50
0
50
100
150
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
-200
-150
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-50
0
50
100
150
Year1998 2000 2002 2004 2006
Year1998 2000 2002 2004 2006
global> 15oC
< 15oC
…are there alternative explanations?L
ow
Latitu
de
SS
T A
nom
aly
‘98-200
-150
-100
-50
0
50
100
150 -0.9
-0.7
-0.5
-0.3
-0.1
0.2
0.4
0.6
0.8
1.0
1.2‘99‘97 ‘00 ‘01 ‘02 ‘03 ‘04 ‘05 ‘06
Year
• Nutrient-driven changes in NPP
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
• Photo-oxidation of cDOM
• Light-driven changes in photoacclimation
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.
Measurement Maturity Index
Des
ired
Tra
ject
ory
1 2 3 4 5 6 7 81
2
3
4
5
6
7
8
Mea
sure
men
t Q
ualit
y In
dex
CZCS (1978-1985)
SeaWiFS(1997 - )
MODIS (2002 - )
VIIRS(2009 - )
AdvancedMission(2013 - )
Ins
uff
icie
nt
for
Cli
ma
te D
ata
Re
co
rd Current trajectory
Cli
ma
te D
ata
R
ec
ord
Qu
ali
ty
KeyFew science products
Extensive science products
* NOTE: MODIS Aqua climate-quality ocean biology data have only been achieved because SeaWiFS data were available for comparison
*
measured operationally
approaches limits on
performance
no known use for measurement
potential science return
SW
IRN
IRV
isib
le
CZ
CS
Se
aW
iFS
MO
DIS
VII
RS
SWIR NIR Visible Ultraviolet
5 nm resolution (335 – 865 nm) 17 aggregate bands
2 SWIRbands
Backup Slides
Su
rface C
hlo
rop
hyll A
nom
aly
(Tg
)
Year1998 2000 2002 2004 2006
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
> 15oC
Contemporary Changes in Ocean Chlorophyll during the SeaWiFS Era
El Nino – La Nina changes
Chlsat vs Chleuphotic
Other NPP models
Chlorophyll and MEI
NPP and MEI update
Zonal temperature changes
Surface chlorophyll updates
The 2006 minimum
Credit really belongs to the Ocean Color Group at NASA Goddard Space Flight Center and Ocean Biology and Biogeochemistry Program at NASA Headquarters
• Biospheric NPP increased 6 Pg from 1997 El Nio to 1999 La Nia, with clearest response in oceans
(C)
(D)
0.01 0.1 1 10 100 1000
Chlorophyll Concentration
0.01 0.1 1 10 100 1000
Rela
tive F
requency
Dep
th-i
nte
gra
ted
Year
1998 2000 2002 2004 2006
-0.012
-0.008
-0.004
0
0.004
0.008
Su
rface C
hlo
rop
hyll
An
om
aly
(Tg
)
global> 15oC
Tidbits
• Three models: VGPM – polynomial VGPM – Eppley CbPM – Chl:C-based growth
• All show 2 primary trends
• 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
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-0.1
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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