Variability in the Variability in the ocean - from ocean - from modewater modewater
biogeochemistry to biogeochemistry to SSTSST
Holger BrixHolger Brix
UCLA, JIFRESSE and Dept. of UCLA, JIFRESSE and Dept. of Atmospheric and Oceanic Atmospheric and Oceanic
SciencesSciences
JPL, 16 September 2008JPL, 16 September 2008
AcknowledgementsAcknowledgements
Curtis Deutsch, UCLACurtis Deutsch, UCLA
Nicolas Gruber, ETH, ZNicolas Gruber, ETH, Zürichürich
Scott Doney, Ivan Lima, WHOIScott Doney, Ivan Lima, WHOI
Crews and scientists of NOAA, UH, Crews and scientists of NOAA, UH,
BBSR, and other research vesselsBBSR, and other research vessels
Dimitris Menemenlis, JPLDimitris Menemenlis, JPL
OutlineOutline Mode water biogeochemistryMode water biogeochemistry
Global Carbon Cycle PerturbationsGlobal Carbon Cycle Perturbations Carbon and the OceanCarbon and the Ocean Why mode waters (and what are they Why mode waters (and what are they anyway)?anyway)?
Mode water variability - time-Mode water variability - time-scales and placesscales and places
Modeling the gapsModeling the gaps Sea surface temperatures and Sea surface temperatures and heat flux variability in ECCO2 heat flux variability in ECCO2 and beyondand beyond
OutlineOutline Mode water biogeochemistryMode water biogeochemistry
Global Carbon Cycle PerturbationsGlobal Carbon Cycle Perturbations Carbon and the OceanCarbon and the Ocean Why mode waters (and what are they Why mode waters (and what are they anyway)?anyway)?
Mode water variability - time-Mode water variability - time-scales and placesscales and places
Modeling the gapsModeling the gaps Sea surface temperatures and Sea surface temperatures and heat flux variability in ECCO2 heat flux variability in ECCO2 and beyondand beyond
The Global Carbon The Global Carbon CycleCycle
Sarmiento & Gruber, 2002
deforestation
tropicsextra-tropics
1.5
2000-2006
CO2 f
lux
(Pg
C y-1
)Si
nkSo
urce
Time (y)Le Quéré, unpublished; Canadell et al. 2007, PNAS
Perturbation of Global Carbon Budget (1850-2006)
deforestation
fossil fuel emissions 7.6
1.5
2000-2006
CO2 f
lux
(Pg
C y-1
)Si
nkSo
urce
Time (y)Le Quéré, unpublished; Canadell et al. 2007, PNAS
Perturbation of Global Carbon Budget (1850-2006)
fossil fuel emissions
deforestation
7.6
1.5
2000-2006
CO2 f
lux
(Pg
C y-1
)Si
nkSo
urce
Time (y)Le Quéré, unpublished; Canadell et al. 2007, PNAS
Perturbation of Global Carbon Budget (1850-2006)
fossil fuel emissions
deforestation
7.6
1.5
4.1
2000-2006
CO2 f
lux
(Pg
C y-1
)Si
nkSo
urce
Time (y)
atmospheric CO2
Le Quéré, unpublished; Canadell et al. 2007, PNAS
Perturbation of Global Carbon Budget (1850-2006)
atmospheric CO2
fossil fuel emissions
deforestation
ocean
7.6
1.5
4.1
2.2
CO2 f
lux
(Pg
C y-1
)Si
nkSo
urce
Time (y)
2000-2006
Le Quéré, unpublished; Canadell et al. 2007, PNAS
Perturbation of Global Carbon Budget (1850-2006)
atmospheric CO2
ocean
land
fossil fuel emissions
deforestation
7.6
1.5
4.1
2.22.8
2000-2006
CO2 f
lux
(Pg
C y-1
)Si
nkSo
urce
Time (y)Le Quéré, unpublished; Canadell et al. 2007, PNAS
Perturbation of Global Carbon Budget (1850-2006)
OutlineOutline Mode water biogeochemistryMode water biogeochemistry
Global Carbon Cycle PerturbationsGlobal Carbon Cycle Perturbations Carbon and the OceanCarbon and the Ocean Why mode waters (and what are they Why mode waters (and what are they anyway)?anyway)?
Mode water variability - time-Mode water variability - time-scales and placesscales and places
Modeling the gapsModeling the gaps Sea surface temperatures and Sea surface temperatures and heat flux variability in ECCO2 heat flux variability in ECCO2 and beyondand beyond
Sea-air COSea-air CO22 Flux Flux
N. Gruber, 2002
The Biogeochemical loopThe Biogeochemical loop
Marine PhytoplanktonMarine Phytoplankton
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
From top left: Diatoms, Radiolaria, Dinoflagellateshttp://www.amonline.net.au/exhibitions/beyond/phytoplnkton/
N. Gruber, 2002
The Biogeochemical loopThe Biogeochemical loop
Production
Export
CO2Corg
Phytopl.
Zoopl.Bacteria
Respiration (Heterotrophic)
Photosynthesis “Net Primary Production (NPP)”
Rh
NPP
Export Production
Production, Respiration, Production, Respiration, ExportExport
Net Community Production:
NCP = NPP - Rh
N. Gruber, 2002
The Biogeochemical loopThe Biogeochemical loop
Production
Export(=NCP)
NPP
NPP-NCP-POC at HOTNPP-NCP-POC at HOT(Hawaii Ocean Time-Series)(Hawaii Ocean Time-Series)
Brix et al., 2006POC: Particulate Organic Carbon
Spatial patterns in ∆pCO2 due to biology and temperature are also mostly opposing each other!
Anthropogenic COAnthropogenic CO22
Gruber (2002)
OutlineOutline Mode water biogeochemistryMode water biogeochemistry
Global Carbon Cycle PerturbationsGlobal Carbon Cycle Perturbations Carbon and the OceanCarbon and the Ocean Why mode waters (and what are they Why mode waters (and what are they anyway)?anyway)?
Mode water variability - time-Mode water variability - time-scales and placesscales and places
Modeling the gapsModeling the gaps Sea surface temperatures and Sea surface temperatures and heat flux variability in ECCO2 heat flux variability in ECCO2 and beyondand beyond
The Ocean ConveyorThe Ocean Conveyor
Waters will move mostly along surfaces of constant density.
Surface density, isopycnal Surface density, isopycnal outcropsoutcrops
What Are Mode Waters?Definitions after Hanawa and Talley (2001)
Homogeneity of water properties (such as temperature, salinity, oxygen)
Thickening of isopycnal layer - substantial volume
At a single vertical profile, mode water appears as low vertical density gradient (pycnostad) between high gradients (seasonal and main pycnocline)
Mode water is found well beyond its outcropping areas as a result of advection
Formation or maintenance usually associated with wintertime convective mixing
Mode WatersExample: 18o Mode Water
Subtropical Mode Water (STMW) in the North Atlantic
Potential Temperature
Why are we interestedin Mode Waters?
Mode waters can take up anthropogenic CO2 and hide it from the atmosphere (buffer capacity)
After a time delay (years to decades) mode waters re-emerge at (possibly distant) regions
And where do we find them? In all ocean basins “Descending” on isopycnals from outcrop regions
Mode Waters
Talley, 1999
Intermediate Waters
Talley, 1999
AAIW
LSWNPIW
OutlineOutline Mode water biogeochemistryMode water biogeochemistry
Global Carbon Cycle PerturbationsGlobal Carbon Cycle Perturbations Carbon and the OceanCarbon and the Ocean Why mode waters (and what are they Why mode waters (and what are they anyway)?anyway)?
Mode water variability - time-Mode water variability - time-scales and placesscales and places
Modeling the gapsModeling the gaps Sea surface temperatures and Sea surface temperatures and heat flux variability in ECCO2 heat flux variability in ECCO2 and beyondand beyond
U.S. JGOFS Time-series U.S. JGOFS Time-series SitesSites
DIC at BATS (Bermuda)DIC at BATS (Bermuda)
Bates et al., 2001
Chlorophyll in the Chlorophyll in the NAtl.NAtl.
Lévy, 2005; Palter et al., 2005
Apparent Oxygen Apparent Oxygen UtilizationUtilization
Figure prepared by Niki Gruber
AOU = OAOU = O2,SAT2,SAT - O - O22 (measure of respiration) (measure of respiration)
Johnson &Gruber, Prog. Oceanography, 2007
AAIW
MED
LAB
AAIW
NADW
MED
STMW
NADW
LAB
SPMW
SPMW
AOU = [O2sat] - [O2]
APPARENT
OXYGEN
UTILIZATION
Johnson &Gruber, Prog. Oceanography, 2007
AOU CHANGES 2003-1993
Johnson &Gruber, Prog. Oceanography, 2007
AOU AND DIC
CHANGES
2003-1993
Expected change from anthropogenic CO2: max 0-8 mol/kg
OO22 anomaly at HOT anomaly at HOT (Hawaii)(Hawaii)
Deutsch, 2006
Observed AOU Observed AOU differences North differences North
PacificPacific
Deutsch et al. (2006)
OutlineOutline Mode water biogeochemistryMode water biogeochemistry
Global Carbon Cycle PerturbationsGlobal Carbon Cycle Perturbations Carbon and the OceanCarbon and the Ocean Why mode waters (and what are they Why mode waters (and what are they anyway)?anyway)?
Mode water variability - time-Mode water variability - time-scales and placesscales and places
Modeling the gapsModeling the gaps Sea surface temperatures and Sea surface temperatures and heat flux variability in ECCO2 heat flux variability in ECCO2 and beyondand beyond
Case study ICase study IThe North The North PacificPacific
Modeled AOU differences Modeled AOU differences North PacificNorth Pacific
Deutsch et al. (2006)
Surface COSurface CO22 Flux Flux VarianceVariance
Components of Components of VariabilityVariability
Changes in AOU can be decomposedinto components:
AOU = AOUbiol + AOUvent + AOUcirc
Using: Multiple simulations with climatological OUR (OUR = dAOU/dt) and/or preformed climatological AOU fields
Total Circulation
Ventilation
Biology
OO22 change, 1990’s-1980’s, change, 1990’s-1980’s, = 26.6= 26.6
Deutsch et al. (2006)Deutsch et al. (2006)
Origin of OOrigin of O22 anomalies anomalies1990s - 1980s1990s - 1980s
b
c
d
a a,b: ventilationc,d: circulation
a,d: decadal trendsb,c: interannual perturbations
Deutsch et al. (2006)
Case study IICase study IIThe North The North AtlanticAtlantic
A16N Repeat A16N Repeat HydrographyHydrography
Johnson & Gruber, Prog. Oceanography, 2007
∆AOU: 2003 - 1993 Mean 40o-60oN
Apparent Oxygen Utilization (AOU):Apparent Oxygen Utilization (AOU):AOU = OAOU = O2,SAT2,SAT - O - O22 (measure of respiration) (measure of respiration)
Modeled AOU Modeled AOU (standard deviation)(standard deviation)
UCLA CCSM model runs
Components of Components of VariabilityVariability
Changes in AOU can be decomposedinto components:
AOU = AOUbiol + AOUvent + AOUcirc
Using: A single simulation analyzing nutrient concentrations and the (de-)coupling of C and O2
Components of Components of VariabilityVariability
Changes in AOU can be decomposed into components:
AOU = AOUbiol + AOUvent+AOUcirc
AOUbiol can be approximated using a constant stochiometic O2:PO4 ratio:
AOU = rO2:PO4 · PO4 + AOU*
AOU* can be analyzed using the (de-)coupling of C and O2
AOU
=
rO2:PO4·PO4
+
AOU*
– Total
Biology
– Physics
Biology / Physics Correlation DIC-AOU
Components of Components of VariabilityVariability
Modewater Modewater Observations and Observations and
ModelingModeling Mode and Intermediate Waters are Mode and Intermediate Waters are “hotspots” of oxygen, carbon and “hotspots” of oxygen, carbon and nutrient variability in mid-latitudesnutrient variability in mid-latitudes
Formation regions of these Mode Waters Formation regions of these Mode Waters also show substantial surface also show substantial surface variability variability
Analyses of components of Analyses of components of biogeochemical variability require biogeochemical variability require either:either: Multiple model simulations Multiple model simulations Multi-tracer correlationsMulti-tracer correlations
OutlineOutline Mode water biogeochemistryMode water biogeochemistry
Global Carbon Cycle PerturbationsGlobal Carbon Cycle Perturbations Carbon and the OceanCarbon and the Ocean Why mode waters (and what are they Why mode waters (and what are they anyway)?anyway)?
Mode water variability - time-Mode water variability - time-scales and placesscales and places
Modeling the gapsModeling the gaps Sea surface temperatures and Sea surface temperatures and heat flux variability in ECCO2 heat flux variability in ECCO2 and beyondand beyond
SST variability in SST variability in ECCO2 and beyond….ECCO2 and beyond….
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are needed to see this picture.
ECCO2 AVHRR-AMSRE ROMS model satellite data model
SST variability in SST variability in ECCO2 and beyond….ECCO2 and beyond….
Mixed layer heat budget Mixed layer heat budget governs SSTgoverns SST
This project will investigate the components of mixed layer heat budget and its associated errors as a function of region, spatial scale, and frequency.
Thank you!!!Thank you!!!