COS: A new tracer to constrain photosynthetic CO2 fluxes

COS: A new tracer to constrain photosynthetic CO2 fluxes

Dan Yakir1,

Max Berkelhammer2, Hulin Chen2 J. Miller3 1Environmental Sciences and Energy Research, Weizmann Institute

NOAA-GMD, Boulder, 3CIREES, UC Boulder

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A greatest sources of uncertainty for future climate predictions Is the response of the global carbon cycle to climate change

…our mass balance analysis shows that net global carbon uptake has increased significantly by about 0.05 Gt C per year and that g lobal carbon uptake doubled, from 2.4±0.8 to 5.0±0.9 Gt per year between 1960 and 2010… Ballantyne et al 2012

NEE  =  GPP  +  Re  

GPP   Re  

Net  CO2  flux  

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A major limitation: we cannot measure photosynthesis above the leaf scale

Soil uptake (74-180)

Anthropogenic, direct/indirect (90-266)

Direct COS (110-190) Indirect CS2, DMS (149-330)

Unknown (~600)

Stratosphere COSàSO2 OH uptake (82-110)

Global COS Budget (Gg S a-1; Kettle et al., 2002; Montzka et al., 2007; Berry et al., 2013 )

Mean atmospheric concentration ~500 ppt!

Leaf uptake (730-1500)

?

Global ocean

BB, wetland (81-119)

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COS Uptake by Leaf During Photosynthesis

COS  

CO2  

COS  and  CO2    are  taken  up  through  leaf  stomata  during  

photosynthesis  

CO2  

COS  

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Exiting new technological advances (Quantum cascade, mid IR lasers, Mobile lab….

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GPP

Ra

NPP

CO2 into leaves

Rh

NEE COS

Changes in ratio of COS to CO2 uptake across scales

Soil exchange? ARU=COSseasonal_drawdownCO2sessonal_drawdown

![CO2][COS]

~1.6±0.2

~Constant across species and conditions

Near zero

LRU

COS into leaves

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LRU = AcosAco2

[CO2]a[COS]a

GPP =Fcos [CO2a][COSa]! 1LRU

GPP/NEE= 1.9 to 2.2

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200

300

400

500

600

2000 2001 2002 2003 2004

Mix

ing

ratio

(pp

t)

mlokumnwrlefhfmbrwaltbrw, monthlykum, monthlyhfm, monthly

Montzka et al., 2007

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The signature of the Terrestrial Biosphere

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Huilin Chen

Atmospheric caveats…

416±18

489±21

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y = 5.77x + 0.00R2 = 0.89

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

-0.01 0.00 0.01 0.02 0.03 0.04 0.05 0.06

CO2 (Spring - Fall) / mean

COS

(Spr

ing

- Fal

l) / m

ean

LEF

ALT

BRW

NWR

MLO

KUM

CGO

HFM

MHD

SPO

SMO

Signature of GPP: COS/CO2 seasonal draw-down

Montzka et al., 2007 Asaf et al., 2013

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The atmospheric COS/CO2 “continuum”

NH continental sites

NH coastal sites

Leaf LRU

C3 max

C4 max

SH (ocean)

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Terrestrial &agricultural sites: Wisconsin; Iowa; S. Carolina ARU approaches LRU C4 effects

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C4 distribution and impact on surface [CO2]

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Mauder & Eder, unpublished

Ceilometer, two consecutive days

Wind Lidar:

Perspective from the Planetary Boundary Layer (PBL)

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Perspective from canopy air measurements: Diurnal surface concentration measurements

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Linking events in the surface layer to the PBL

Equations for both CO2 and COS with measured NEE and surface Cs solved for k and Ctrop

•  COS is a useful tracer of CO2 exchange with the terrestrial ecosystems and will add a powerful tool to a very limited arsenal..

•  There is no alternative “observational” means to directly

estimate GPP on global scale (new sun fluorescence is also developing)

•  Incorporating the use of several tracers controlled by

different processes (such as COS and CO2 and its stable isotopes) provide additional insights to the biosphere response to global change

Conclusions

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Thank you