North American Carbon Program

Kevin Robert Gurney

Colorado State University Scott Denning , Chair NACP Science Implementation Subcommittee US Carbon Cycle Science Steering Group

NACP Questions

1. What is the carbon balance of North America and adjacent oceans? What are the geographic patterns of fluxes of CO CO 2 , CH 4 2 , CH 4 , and CO? How is Attribution /

Diagnosis

, and CO, and how do the controls

Processes

3. Are there potential surprises (could sources ”) 2. What processes control the sources and sinks of ”) increase or sinks disappear)? (“ (“

Decision support

”)

Prediction

”) 4. How can we enhance and manage long-lived carbon sinks ("sequestration"), and provide resources to support decision makers?

NACP Integration Strategy

experiments observing networks model/data fusion diagnostic models maps of variable fluxes and stocks predictive models decision support Scientific understanding Needs of stakeholders • Process studies and manipulative experiments inform improved models • Systematic observations used to evaluate models • Innovative model-data fusion techniques produce optimal estimates of time mean and spatial and temporal variations in fluxes and stocks • Improved models predict future variations, tested against ongoing diagnostic analyses • Predictive models and continuing analyses used to enhance decision support

Hierarchical Terrestrial Measurements

for integration

“Wall-to-wall” remote sensing and other spatial data … 10 7 Extensive inventories ( Forest and Cropland )………………..

10 5 – More than 170,000 sites at 5-10 yr intervals – Complementary networks in Canada & Mexico Intermediate intensity sampling scaling from local fluxes to regional modeling with RS/GIS (new) at many sites - facilitate …………………………………………………………………..

10 3 Very intensive investigation of processes……………………..

10 2 ~ 100 flux towers, long-term ecological research sites, etc

Ocean Observations and Modeling

• Coastal carbon burial and export to the open ocean • River-dominated margins and coastal upwelling regions merit special attention due to their dominant role in coastal carbon budgets • Coordination with US Ocean Carbon & Climate Change program

Atmospheric CO

2

Observations ~2000

Atmospheric CO

2

Observations ~2006

Orbiting Carbon Observatory

(Planned August 2007 launch) • Estimated accuracy for single column ~1.6 ppmv • 1 x 1.5 km IFOV • 10 pixel wide swath • 105 minute polar orbit • 26º spacing in longitude between swaths • 16-day return time

Potential Satellite CO

2

Observations

• One day’s worth of column retrieval (Jul 2, no cloud mask ) • Joint NIR/Thermal IR retrieval using both AIRS (2003) & OCO (2007) sensors

1 Day of North American OCO Data

• Three very narrow (10 km) swaths over N. America per day • Most of domain will be outside of strongest influence of observations • Spatial autocorrelation length scale?

• Are tomorrow’s fluxes the same?

• Need to handle temporal covariance

Inverse Modeling

Air Parcel transport Air Parcel Sources Sinks transport Air Parcel Sample concentration (observe) transport (model) sources and sinks (solve for) Sample

Top-down Integration

using atmospheric inverse models

• Standard synthesis transport and small regions tied to process characterization inversion using high-resolution • Newer approaches using Lagrangian particle dispersion, adjoint transport, variational methods (e.g., 4DVAR), or Ensemble Kalman Filter (EnKF) • Combination from airborne and flask sampling with continuous data of periodic large-scale constraint • Inclusion of satellite • Multi-gas data inversions for source attribution

Capacity Building

 TransCom community resources  Education  Code  Datasets  Control experiments http://transcom.colostate.edu; [email protected]

Spatially Distributed Process Modeling

bottom-up integration

• Models of terrestrial ecosystem fluxes, calibrated and tested against local data • “Slow” ecosystem dynamics: disturbance, succession, soil carbon biogeochemistry (Spatial mapping of carbon stocks) • Agroecosystem modeling ( irrigation, fertilization, harvest , etc) • Coastal upwelling, air-sea fluxes , sedimentation • Fossil fuel emissions (new process-based approach)

Process-based Fossil Fuel CO

2 Complementing the downscaling of fossil fuel sales/consumption information through surrogates…… ………Build from the history of the Air Quality effort Emissions databases/models for regulated pollutants

• CO, O 3 , NOx, SOx, particulates, Pb • Stack monitoring, geocoded, process-based

Long developmental history in the US

Critical for bottom-up and top-down – Gurney et al., in press JGR Errors in “background” fields are aliased into target fluxes NASA funded project starting soon

“CONCEPT” Emissions Model

EMS undergoing fundamental updating to become “CONCEPT”, open-source based code (postgres SQL).

• LADCO, ENVIRON, Applied Geophysics, UC Riverside Combines inventory data and process attributes to construct detailed space and time dependent emissions of criteria pollutants.

Database/model

has three classes of inputs: • Point sources – powerplants, for example • Mobile sources – vehicle emissions • Area sources – residential sources, for example

Modules Area source Point source Vehicle Biogenic nonroad

Resolution:

36 km, hourly

Model-Data Fusion

(a.k.a. Data Assimilation)

• Analogous to weather forecasting • Uses best process-based, deterministic models of key carbon fluxes and pools • Identification of key parameters uncertainty in final maps that control • Optimization of parameters according to all available observations (space and time) • Produces analyzed fields of fluxes and stocks that are optimally consistent with disparate observations and process understanding

Diagnostic Analyses

optimal process-based estimates at highest appropriate space/time resolution

• Photosynthesis, respiration, decomposition • Combustion emissions (CO diurnal and weekly cycles • Storage of carbon in forests, grasslands, crops, fuel, rivers, reservoirs, estuaries, sediments • Transfers among pools • Net fluxes of CO 2 , CO, CH 2 4 , CO, CH 4 ) including to the atmosphere • Finely resolved 3D grids of CO atmosphere at hourly intervals 2 , CO, CH 4 in the

North American Carbon Budget

(Gt C/year)

Inverse • 1990s: TransCom3: -0.7 ± 0.5 (total uncertainty) Rodenbeck: -0.9 ± 0.2

• 1980s: TransCom3: -1.2 ± 0.5 Inventory • 1980s: Houghton: -0.15 to -0.35 (US) (direct) Pacala: -0.3 to -0.6 (US) (d and i) Birdsey: -0.31 (US) (forest) Remote Sensing • Myneni (1995 to 1999), -0.2 (woody bio only)

North American Interannual (T3)

Gurney et al., in preparation

Convergence

Source IPCC 1 a IPCC 2 b T3 (22) c

flux

-1.8 -1.7 -1.6

80s

0.8 0.6 0.7

Ocean unc flux

-1.9 -2.4 -1.9

90s Unc

0.7 0.7 0.9

a IPCC estimates adjusted by Le Quere et al., 2003 b IPCC estimates adjusted by Plattner et al., 2002 c River transport corrected (0.6 Gt C/year) Flux 80s

-0.3 -0.4 -0.5

unc

0.9 0.7 0.8

Land flux

-1.2 -0.7 -1.2

90s unc

0.9 0.8 0.9 Gurney et al., in preparation

NACP Intensive Field Campaigns

• Motivation: evaluate integrated observing/modeling/assimilation system in a “testbed” for which all relevant variables are “oversampled” • Several IFCs may be required, to test various aspects of coupled analysis system – Crops & managed carbon fluxes with atmospheric sampling and inversion – Forest management, tiered sampling, biomass inventories – Combustion emissions inventory downscaling with detailed downwind trace gas measurements – Synoptic and cloud-scale meteorology and trace gas transport • Goal is a well-tested observing and analysis system with documented uncertainties that we understand

First NACP IFC

• Mid-continent focus: smaller areas 2005-2006 • Upper Midwestern United States – eastern South Dakota, eastern Nebraska, eastern Kansas, northern Missouri, Iowa, southern Minnesota, southern Wisconsin, and Illinois – Some elements of experiment may include larger or • Reconcile estimates of sources and sinks derived from atmospheric models using measurements of trace gas concentrations with based on field measurements, inventories, regional geographic information, and remote sensing • Attribution of sources and sinks to processes and human activities direct estimates ecosystem within the region

Free Air Carbon Enrichment (FACE)

• Fumigation rings maintain steady levels of elevated CO 2 in canopies under changing weather conditions • Control and replicated treatments test effects of CO 2 , water, N, etc

FACE Sites

• Many types of ecosystems around the world • Most only in place for a few years so far

Research Elements: Question 1

Diagnosis of Current Carbon Budgets

• A hierarchical approach for large-scale,

distributed terrestrial measurements

• Substantially improved

fossil fuel emissions inventories with high resolution downscaling in time and space, and methods for evaluating these inventories using atmospheric measurements

• Hydrologic transfers of carbon

over land, and sequestration in sediments

• Ocean measurements and modeling • An

atmospheric observing system

• Spatially-distributed modeling

, both in the coastal zone and the open ocean, in coordination with the OCCC consisting of ground stations, aircraft and measurements from towers of carbon cycle processes

• Model-data fusion • Interdisciplinary

and data assimilation to produce optimal estimates of spatial and temporal variations that are consistent with observations and process understanding intensive field campaigns designed to evaluate major components of the model-data fusion framework

Research Elements: Question 2

Processes Controlling Carbon Budgets

• Terrestrial carbon response to changes in atmospheric CO tropospheric ozone, nitrogen deposition, and climate • Responses of terrestrial ecosystems to changes in disturbance regimes, forest management, and land use • Responses of terrestrial ecosystems to agricultural and 2 , range management • The impacts of lateral flows of carbon in surface water from land to fresh water and to coastal ocean • Coastal marine ecology and sedimentation • Human institutions inference from timeseries environments • Estuarine biogeochemical transformations; ; • Air-sea exchange and marine carbon transport; and and economics: use this research and modeling, or develop new research in this element?

• Clearly acknowledge different approaches: manipulation vs

Program Elements: Question 3

Predictive Modeling

• Transfer of synthesized information from process studies into prognostic carbon-cycle models • Retrospective analyses models • Evaluation systems • Development of to evaluate the spatial and temporal dynamics of disturbance regimes simulated by prognostic of predictions of interannual variations with predictive models against continued monitoring using observational networks and diagnostic model-data fusion scenarios of future changes in driving variables of prognostic models • Application and comparison of prognostic models to evaluate the sensitivity of carbon storage into the future • Incorporation of prognostic models into coupled models of the climate system

Program Elements: Question 4

Decision Support

• North American contribution to the State of the Carbon Cycle Report (SOCCR) • Analysis of the vulnerabilities longevity of sinks • Assessment of sequestration options scientific evaluation of present and future behavior of carbon cycling • Provide scientific understanding to inform management of the carbon cycle understanding, diagnosis, and prediction • Early detection of carbon cycle risks and • Scenario development given best given improved for simulation of future climate

Atmospheric Observing System

• Existing global flask network provides seasonal/latitude background • Outer “ring” of buoy-based and airborne sampling documents variations in continental inflow and outflow • Continuous analyzers on tall towers • Continental airborne sampling 2x/week • Calibrated [CO 2 ] at flux towers (VTT) • Satellite [CO 2 ], [CO] , and [CH 4 ] • Upward-looking FTIR spectrometers

NACP Question 1: Diagnosis of current carbon budgets

NACP Atmospheric [CO

2

] Network

Atmospheric Modeling

• Propagation of surface fluxes of CO2, CO, and CH4 estimated by from data using process-based models into atmosphere • Realistic transport at high resolution • Detailed comparison to atmospheric observations • Evaluation of mismatches, attribution of error to process characterization • Relationship of high-res efforts over NA to global obs and models

NACP Question 1: Diagnosis of current carbon budgets

Important Gaps

for bottom-up scaling • High-resolution weather data respiration calculations at native resolution of imagery and other spatial data to drive daily GPP and – current 1 km MODIS products use 1-degree weather!

• Historic land-use/land management data calculations of carbon storage due to successional changes to drive • Carbon flux and storage data for urban/suburban landscapes • Irrigation quantified in space and time?

NACP Question 1: Diagnosis of current carbon budgets

Important Gaps

for Top-Down Scaling and Model-data fusion

• Very high resolution meteorological drivers for tracer transport modeling – NCEP analyses currently ~2.5º at 6 hr intervals – Eta analyses higher resolution but limited area – Lateral boundaries – Mass conservation – Near-surface processes (e.g., PBL turbulence) – Cloud transports • Applied mathematics for assimilation into coupled models of carbon processes • Computational needs

Sources, Sinks, and Processes

atmosphere ocean forests farms cities industry foresters farmers citizens industrialists ocean economics institutions policy • Carbon exchanges with the atmosphere over North America are managed by people • Understanding and predicting these exchanges will require quantification of management effects