Regional CO2 Flux Estimates for North America

through data assimilation of NOAA CMDL trace gas observations

Wouter Peters Lori Bruhwiler John B. Miller Pieter Tans

Adam Hirsch Kevin Schaefer Arlyn AndrewsAnna Michalak Maarten KrolJeff Whitaker

Wouter Peters Lori Bruhwiler John B. Miller Pieter Tans

Adam Hirsch Kevin Schaefer Arlyn AndrewsAnna Michalak Maarten KrolJeff Whitaker

NOAA- CMDL

ICDC7-September 27th-2005

MotivationMany new (continuous) CO2 observations from North America are coming in over the next few years

From these, we want to study carbon cycle behavior

This requires a framework that efficiently links atmospheric CO2 observations to surface processes

The framework should include high detail of spatial and temporal variability

Fire Flux Fire Flux ModuleModule

SEAT-A

ObservatioObservationsns

Biosphere Biosphere Flux Flux

ModuleModule

Fossil Fuel Fossil Fuel FluxFlux

ModuleModule

Ocean Flux Ocean Flux ModuleModule

Insights...?

System forEnsembleAssimilation ofTracers in theAtmosphere

ICDC7Sept 2005

TM5 atmospheric transport TM5 atmospheric transport model + Ensemblemodel + Ensemble

Kalman FilterKalman Filter

FiresFires

SEAT-A

ObservatioObservationsns

BiosphereBiosphere

Fossil FuelsFossil Fuels

OceansOceans

Fire Fire ModuleModule

Biosphere Biosphere ModuleModule

Fossil FuelFossil FuelModuleModule

Ocean Ocean ModuleModule

System forEnsembleAssimilation ofTracers in theAtmosphere

Insights...?Peters, W., J.B. Miller, J. Whitaker, A.S. Denning, A. Hirsch, M.C. Krol, Peters, W., J.B. Miller, J. Whitaker, A.S. Denning, A. Hirsch, M.C. Krol, D. Zupanski, L. Bruhwiler, and P.P. TansD. Zupanski, L. Bruhwiler, and P.P. Tans, An ensemble data assimilation , An ensemble data assimilation

system to estimate COsystem to estimate CO22 surface fluxes from atmospheric trace gas surface fluxes from atmospheric trace gas observations, observations, J. Geophys. Res.J. Geophys. Res., , submittedsubmitted, 2005., 2005.

Flux Modules

Simple parameterizations of flux behavior (for now...)

Include carbon cycle ‘auxiliary’ information

Fill in details we cannot see from atm. CO2

..., weather, NDVI, pCO2, biosphere maps, fire counts, chlorophyl, ...

Straightforward extension to more tracers, isotopes

optimizable parameters to constrain net flux

Diagnosing parameters can inform on modulesICDC7Sept 2005

clim. pCO2 in sea water (Takahashi, 2002)

Clim. SST and salinity for saturation vapor pressure, solubility, gas transfer

TM5 3-hourly winds for quadratic gas transfer

TM5 3-hourly surface pressure to scale pCO2 in air (Kettle & Merchant, 2005)

TM5 daily sea ice mask

11 scalar multipliers for TransCom region net fluxes

Ocean Module

Ocean Ocean ModuleModule

ICDC7Sept 2005

soon: VPRM by Wofsy, Pathmathevan, Matross

Now: similar to Olsen and Randerson, 2004

monthly mean CASA NEP (neutral biosphere)

GPP=2*NPP distributed with solar radiation

R=Q10 relationship with 2 meter temperature

R scaled to match NEP

1ºx1º spatial, 3-hourly temporal T2m and radiation (TM5 ->ECMWF)

11 Transcom land regions subdivided into 19 possible biome types (Olson v1.3)

135 ‘biome regions’ with each one scalar to be optimized

Scalar multiplies the net-flux

Biosphere Module

Biosphere Biosphere ModuleModule

ICDC7Sept 2005

Fluxes for June 2004no data assimilation

Daily averagesocean: dark is uptake, light is emissionLand: green is uptake, red is emissionICDC7

Sept 2005

D.A.

BiosphereBiosphereBiospherBiosphere Modulee Module

Ocean Ocean ModuleModule

50-100 obs/week

TimeICDC7

Sept 2005

TM5 TM5 +Ensemble+Ensemble

Kalman FilterKalman Filter

146 146 parameters/wparameters/w

eekeek

Insights

Preliminary 2001 Annual Mean biosphere fluxes in

µmol/m2/s

(52x) 24 (52x) 24 parameters!parameters!

(52x) 111+11 (52x) 111+11 parameters!parameters!

++

--

+-

-0.59± 0.56 -0.59± 0.56 PgC/yrPgC/yr

ICDC7Sept 2005

QuickTime™ and aTIFF (Uncompressed) decompressor

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Conclusions

CMDL has a working CO2 data assimilation framework

Allows many observations, many unknowns

Auxiliary information included through flux modules

Short-term improvements:

more sophisticated modules

more CO2 observations

Covariances and model-data mismatch

First flux estimates for validation in progressICDC7

Sept 2005

Seasonal CycleNorth America Temperate

QuickTime™ and aTIFF (Uncompressed) decompressor

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10

0

-152000.0 2002.5

PgC/yr