Fasham, Ducklow$and$McKelvie(1990) · · 2014-12-22– Oxygencycle$ – Iron$cycle$(HNLC)$ –...

Dec 13, 2014 Ocean Biogeochemistry in CMIP5

Fasham, Ducklow and McKelvie (1990)

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Dec 13, 2014 Ocean Biogeochemistry in CMIP5 2

Fasham, Ducklow and McKelvie (1990)


A variety of OBGCMs are now in use Steina

cher et a

l. (201

0; Biogeoscien

ces)


Diversity of Ocean BGC in CMIP5

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Bopp et al. (2013)


What’s happened since 1990? •  Global applicaPon •  IncorporaPon of other elemental cycles

–  Carbon Cycle (OCMIP2) –  Oxygen cycle –  Iron cycle (HNLC) –  Silicic Acid (diatoms) –  CalcificaPon (forams, coccoliths) –  Nitrogen-‐Phosphorus interacPons

•  River, atmosphere and N2 fixaPon supply •  Water Column and sediment denitrificaPon

•  Improved processes –  Phytoplankton K/R strategies and size structure –  MechanisPcally moPvated sinking –  Dissolved organic ma[er

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Typical OBGCMs applicaPons 1.  How much anthropogenic carbon uptake has occurred? 2.  How will anthropogenic carbon uptake change under climate change? 3.  How will the natural carbon cycle change under climate change? 4.  How will ecosystems change under climate change? …limiting uncertainties representing ocean circulation and sensitivity to change. Biogeochemical uncertainties include mechanistic controls on:

•  Euphotic zone nutrient consumption and degree of residual nutrient •  Controls on POM/DOM passive and active transport •  Deviations in stoichiometry from Redfield (e.g. N2 fixation) •  Remineralization scales through the twilight zone

Ecological uncertainties include: •  Physiology (general controls, functional traits, adaptation limits) •  Biodiversity (predictability, phenology, niche gaps, etc) •  Ecological interactions


Philosophies for Ocean BGC Modeling

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•  Challenge: the vast complexity of natural systems versus the limited, imperfect ability to mathemaPcally represent those processes.

•  Seek fundamental rules and constraints of energy, mass, and biogeochemistry

•  RepresentaPon of phytoplankton via: •  SenPnal species (i.e. Prochlorococcus, Trichodesmium, and T. weissflogii, E. huxleya)

•  CalibraPon to best-‐known constraints, but leaves vast biogeochemical gaps •  Phytoplankton funcPonal groups (CO2-‐fixers, N2-‐fixers, silicifiers, calcifiers)

•  CalibraPon to parPcular funcPons, leaving other funcPons missing •  Empirical biogeochemical funcPon (CO2-‐fxaPon, N2-‐fixaPon, silicificaPon, calcificaPon)

•  CalibraPon to overall biogeochemical impact

•  Assessment and a[ribuPon of biases •  PrioriPzaPon of process study sites, field observaPons, vs satellite esPmates for ‘truth’ •  A[ribuPon to deficiencies in ocean physics? Atmospheric physics? •  If a[ribuPon to biology, is it external inputs, physiology, ecology, or biogeochemistry? •  Depending on a[ribuPon, decision-‐making on possibiliPes to change assumpPons.


Removal

GFDL’s Tracers of Phytoplankton with Allometric Zooplankton (TOPAZ)

Small phyto.

Large phyto.

ProJst Filter feeder

semilabile semirefract. DOM Detritus New

nutrients

Recycled nutrients

N2-‐fixer DOM cycling

ParJcle sinking

Gas exchange

Atm. DeposiJon

River Input

Sediment Input Scavenging

Carbon Oxygen Phosphorus

CaCO3

Nitrogen Iron Alkalinity Lithogenic Silicon

Biogeochemistry Phytoplankton ecology

Diatoms and Other Large Phytoplankton Flexible N:P:Si:Fe:Chl Aragonite and Calcite

Heterotrophs

30 Tracers

Dunne et al. (2005;2013)


Many groups are exploring alternaJve verJcal coordinates

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Dunne et al. (2012, 2013); Winton et al. (2013); Hallberg et al. (2013); Froelicher et al. (submiXed)

Soil 1339

Atmosphere 607

VegetaJon 1003

Surface Ocean 874

DOC 697

Intermediate and Deep Ocean 36855

SedimentaJon

81 141 60

0

82 Rivers 0.12

85 85

72

8

0.10

0.12 Weathering

2

66 76

60

GFDL-‐ESM2M Soil 1341

Atmosphere 607

VegetaJon 997

Surface Ocean 883

DOC 695

Intermediate and Deep Ocean 37231

SedimentaJon

82 143 61

0

68 Rivers 0.12

85 85

61

5

0.04

0.12 Weathering

2 45 53

61

GFDL-‐ESM2G

Reservoirs in PgC Fluxes in PgC a-‐1

Reservoirs in PgC Fluxes in PgC a-‐1

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Biota 1.1 Biota 1.2

2

z ρ

z* (MOM4.1): -‐  Depth-‐based verJcal coordinate -‐  Over 40 years of experience

ρ (GOLD): -‐  Density-‐based verJcal coordinate -‐  Easy to preserve water masses


Taylor Diagrams of CMIP5 X-‐Y Pa[erns

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SST

pH NPP

O2

Models get SST, under esJmate pH variability, and vary widely on NPP Bopp et al. (2013)


‘Labile’ DOC in CMIP5 (Anderson et al 2015)

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Carbon a Key CMIP5 ContribuPon

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Hoffman et al., 2014


Southern Ocean Key to Carbon

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Frölicher, T., J. Sarmiento, J. Dunne, D. Paynter, M. Winton, in press: Heat and carbon uptake in the CMIP5 models: The dominance of the Southern Ocean.


ESM ensembling and inter-‐comparison provide powerful constraints insofar as the models agree (i.e. SST and pH changes)

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Bopp, L., L. Resplandy, J. C. Orr, S. C. Doney, J. P. Dunne, M. Gehlen, P. Halloran, C. Heinze, T. Ilyina, R. Séférian, J. Tjiputra, and M. Vichi, 2013: MulJple stressors of ocean ecosystems in the 21st century: projecJons with CMIP5 models, Biogeosciences, 10, 6225-‐6245, doi:10.5194/bg-‐10-‐6225-‐2013.

RCP8.5 at 2100 -‐ SPppling indicates sign agreement among models


Major challenges remain in resolving areas where ESM’s disagree

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RCP8.5 at 2100 -‐ SPppling indicates sign agreement among models

Bopp, L., L. Resplandy, J. C. Orr, S. C. Doney, J. P. Dunne, M. Gehlen, P. Halloran, C. Heinze, T. Ilyina, R. Séférian, J. Tjiputra, and M. Vichi, 2013: MulJple stressors of ocean ecosystems in the 21st century: projecJons with CMIP5 models, Biogeosciences, 10, 6225-‐6245, doi:10.5194/bg-‐10-‐6225-‐2013.


Largest Ocean AcidificaPon in Tropical Mode Waters

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ESM2M Pacific SecJon (190°E)

Resplandy, L. L. Bopp, J. Orr, and J. Dunne (2013)

The achievement in GFDL’s ESMs illustrates the importance of including dynamical, chemical and biogeochemical interacJons


Digging into Mechanisms: Without CirculaJon Change, Heat Uptake Would Look Much Like Carbon Uptake

Winton et al., 2013

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ΔTemp

ΔDIC


Pugng the puzzle pieces together: Mechanisms of Ocean Biogeochemical Change in CMIP5 ESMs

•  Warming increases straJficaJon –  Ven;la;on and nutrient supply decreases globally –  Increase in maximum rates, shi@ to microbial loop

•  Poleward expansion and slow-‐down of subtropical gyres –  Shoaling nutricline in the subtropical gyres –  Enhanced nutrients, hypoxia and acidifica;on in some areas

•  Intensified hydrological cycle reduces North AtlanJc overturning –  Shoaling Northern Subpolar Atlan;c and deepening tropics

•  and many more pieces… Overall, a changing balance of processes creates intense regional structure.

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Moving forward with GFDL’s ESMs •  ApplicaJon: MulP-‐member ensembles for detecPon and a[ribuPon, centennial-‐millennial scales, idealized sensiPvity, diverse impacts applicaPon.

•  Comprehensiveness: beyond closing the CO2 cycle to fully comprehensive and self consistent representaPon of aerosol, Fe, CH4 and N cycles, and ecosystems

•  ResoluJon: Resolving regional atmosphere-‐land interacPons and the ocean mesoscale for improved base state and change, and the human and marine applicaPons

•  PredicJon: IntegraPon with seasonal-‐decadal climate predicPon effort, exploring opportuniPes for experimental biogeochemistry predicPon

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Pushing the envelope: Decadal high resoluJon prototype with next generaJon biogeochemisty

Satellite

ESM2.6-‐COBALT ESM2M

1.5 1 0.5 0

Chlorophyll (mg Chl m-‐3)

California Current Upwelling Signature vastly improved from 1° to 1/10° ResoluJon

Fasham, Ducklow$and$McKelvie(1990) · · 2014-12-22– Oxygencycle$ – Iron$cycle$(HNLC)$ –...

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