Skip to main content

DAAC Home > Get Data > Field Campaigns > NACP (North America) > Data Set Documentation
NACP Site: Terrestrial Biosphere Model and Aggregated Flux Data in Standard Format

Get Data
Revision Date: September 10, 2013

Summary:

This data set provides standardized output variables for gross primary productivity (GPP), net ecosystem exchange (NEE), leaf area index (LAI), ecosystem respiration (Re), latent heat flux (LE), and sensible heat flux (H) from 24 terrestrial biosphere models for 47 eddy covariance flux tower sites in North America. Each model used standardized input data for each flux tower site (i.e., gap-filled, locally observed weather; land use history; and other site specific data) and followed standard model setup and spinup procedures. The files also contain gap-filled observations and total uncertainty estimates. The data set was compiled for the North American Carbon Program (NACP) Site-Level Synthesis for use in model inter-comparison and assessment of how well the models simulate carbon processes across vegetation types and environmental conditions in North America.

There is one compressed (.zip) file with this data set. When expanded, the .zip file contains model output data for one variable at one site. The model output and observations are available at the native half-hourly time step, or in daily, monthly, and annual aggregations, in comma-separated text (.csv) format.

NEE graph


Figure 1. Example of plots displaying the diurnal growing season averages for the six output variables for each of the 47 modeled sites. Plots are included as companion files. This plot shows the modeled output for the diurnal cycle of growing season (defined as June, July and August) net ecosystem exchange (NEE) at the Lethbridge grassland site in Alberta, Canada. Plotted values are the outputs from the 11 models that submitted hourly or finer temporal resolution data for the site. Also shown are the ensemble mean of these 11 models (thick red line) and the gap-filled observations from the eddy covariance site (thick black line). The legend includes an entry for each of the 15 participating models; however, 4 models that did not submit results for this site are not represented on the plot. Models that reported a coarser temporal resolution (e.g. daily or monthly) are not included in either the legend or the plot.


NEE  comparison charts


Figure 2. Example of plots displaying the annual seasonal averages for the six output variables for each of the 47 modeled sites. Plots are included as companion files. This plot shows the modeled output for the seasonal cycle of net ecosystem exchange (NEE) at the Lethbridge grassland site in Alberta, Canada. In the top panel, 11 models with hourly or finer temporal resolution are plotted along with the ensemble mean of all 15 models that submitted results for this site (thick red line) and the gap-filled observations from the eddy covariance site (thick black line). The legend includes an entry for each participating model that submitted hourly or finer temporal resolution; however, 4 models that did not submit results for this site are not represented on the plot. In the bottom panel, 5 models with daily or coarser temporal resolution are shown along with the ensemble mean of all 15 models (thick red line) and the gap-filled observations from the eddy covariance site (thick black line). The legend includes an entry for each participating model that submitted daily or coarser temporal resolution; however, 3 models that did not submit results for this site are not represented on the plot.


Data and Documentation Access:

Get Data: http:daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1183

Links to Related Data Products:

NACP Site: Tower Meteorology, Flux Observations with Uncertainty, and Ancillary Data [http:daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1178]
NACP Site: Terrestrial Biosphere Model Output Data in Original Format

Supplemental Information:

The Protocol for the NACP Site-level Interim Synthesis Model-Data Comparison (Site Synthesis), Version 7, is included as a companion file. See Site_Synthesis_Protocol_v7.pdf.

Plots displaying the diurnal growing season and annual seasonal averages for the six output variables for each of the 47 modeled sites are included as companion files. The captions for Figures 1 and 2  describe the plotted data and legends. See the companion file, figures.zip.

Data Citation:

Cite this data set as follows:

Ricciuto, D.M., K. Schaefer, P.E. Thornton, K. Davis, R.B. Cook, Shishi Liu, R. Anderson, M.A. Arain, I. Baker, J.M. Chen, M. Dietze, R. Grant, C. Izaurralde, A.K. Jain, A.W. King, C. Kucharik, Shuguang Liu, E. Lokupitiya, Y. Luo, C. Peng, B. Poulter, D. Price, W. Riley, A. Sahoo, H. Tian, C. Tonitto, and H. Verbeeck. 2013. NACP Site: Terrestrial Biosphere Model and Aggregated Flux Data in Standard Format. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA. http://dx.doi.org/10.3334/ORNLDAAC/1183

 

Table of Contents:

 

1. Data Set Overview:

Project: North American Carbon Project (NACP)

The North American Carbon Program (NACP) (Denning et al., 2005; Wofsy and Harriss, 2002) is a multidisciplinary research program to obtain scientific understanding of North America's carbon sources and sinks and of changes in carbon stocks needed to meet societal concerns and to provide tools for decision makers. Successful execution of the NACP has required an unprecedented level of coordination among observational, experimental, and modeling efforts regarding terrestrial, oceanic, atmospheric, and human components. The project has relied upon a rich and diverse array of existing observational networks, monitoring sites, and experimental field studies in North America and its adjacent oceans. It is supported by a number of different federal agencies through a variety of intramural and extramural funding mechanisms and award instruments.

MAST-DC organized several synthesis activities to evaluate and inter-compare biosphere model outputs and observation data at local to continental scales for the time period of 2000 through 2005. The synthesis activities have included three component studies, each conducted on different spatial scales and producing numerous data products: (1) site-level synthesis that examined process-based model estimates and observations at over 30 AmeriFlux and Fluxnet-Canada tower sites across North America; (2) a regional, mid-continent intensive study centered in the agricultural regions of the United States and focused on comparing inventory-based estimates of net carbon exchange with those from atmospheric inversions; and (3) a regional and continental synthesis evaluating model estimates against each other and available inventory-based estimates across North America. A number of other NACP syntheses are underway, including ones focusing on non-CO2 greenhouse gases, the impact of disturbance on carbon exchange, and coastal carbon dynamics. The Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) is the archive for the NACP synthesis data products.

NACP Site Synthesis

This data set is part of the NACP Site Synthesis which is divided into three separate data components: model driver data and observations (Data Set 1), the processed model output (Data Set 2), and the original model output (Data Set 3).

This data set (Data Set 2) provides the processed outputs of 24 terrestrial biosphere models (Schwalm et al., 2010) for model inter-comparison and assessment of how well the models simulate carbon process across vegetation types and environmental conditions at 47 eddy covariance flux tower sites in North America. Standardized files have been generated from the models for the following output variables: gross primary productivity (GPP), net ecosystem exchange (NEE), leaf area index (LAI), ecosystem respiration (Re), latent heat flux (LE), and sensible heat flux (H). Each file contains output from the models for one variable at one site. These files also contain gap-filled observations and total uncertainty estimates from Barr et al. (2009; 2013b) and Schaefer et al. (2012). The data files are available at the native half-hourly time step, or in daily, monthly, and annual averages. The files are in ASCII format.

 

Authors:

Contact Model Model Short Name Email
Dan M. Ricciuto     ricciutodm@ornl.gov
Kevin Schaefer combined Simple Biosphere-Carnegie_Ames_Stanford_Approach (SiBCASA) Model SiBCASA kevin.schaefer@nsidc.org
Peter E. Thornton     thorntonpe@ornl.gov
Ken Davis     davis@meteo.psu.edu
Robert B. Cook     cookrb@ornl.gov
Shishi Liu     carol.shishi@gmail.com
Ryan Anderson BIOME_BGC (BioGeochemical Cycles) BIOME-BGC ryan.anderson@ntsg.umt.edu
M. Altaf Arain Carbon and Nitrogen (CN) Canadian Land Surface Scheme (CLASS) CN-CLASS arainm@mcmaster.ca
Ian Baker Simple Biosphere model v 3 SiB3 baker@atmos.colostate.edu
Jing Ming Chen Boreal Ecosystems Productivity Simulator BEPS chenj@geog.utoronto.ca
Michael Dietze Ecosystem Demography Model v 2 ED2 dietze@bu.edu
Robert Grant Ecosys terrestrial ecosystem model ecosys Robert.Grant@afhe.ualberta.ca
Cesar Izaurralde Erosion-Productivity Impact Calculator (EPIC) model EPIC cesar.Izaurralde@pnl.gov
Atul K. Jain Integrated Science Assessment Model ISAM jain@atmos.uiuc.edu
Anthony W. King Local Terrestrial Ecosystem Carbon (LoTEC) model - Data Assimilation (DA) mode LoTEC_DA kingaw@ornl.gov
Chris Kucharik Agro-Integrated BIosphere Simulator Agro-IBIS kucharik@wisc.edu
Shuguang Liu Eddy Covariance (EC)-Light Use Efficiency (LUE) Erosion–Deposition-Carbon-Model (EDCM) ECLUEEDCM sliu@usgs.gov
Erandi Lokupitiya coupled Simple Biosphere (SiB) - crop phenology model (SiBcrop) SiBcrop erandi@atmos.colostate.edu
Yiqi Luo Terrestrial ECOsystem (TECO) model TECO yluo@ou.edu
Changhui Peng TRIPLEX generic hybrid model of forest growth and carbon and nitrogen dynamics CLASS-CTEM (TRIPLEX-Flux) peng.changhui@uqam.ca
Ben Poulter Lund-Potsdam-Jena Dynamic Global Vegetation Model, Swiss Federal Research Institute WSL modification LPJ-wsl ben.poulter@pik-potsdam.de
David Price Canadian Integrated BIosphere Simulator Can-IBIS David.Price@NRCan-RNCan.gc.ca
William Riley Isotope Land Surface Model ISOLSM wjriley@lbl.gov
Alok Sahoo Simplified Simple Biosphere (SSiB) model SSIB2 aksahoo2004@gmail.com
Hanqin Tian Dynamic Land Ecosystem Model DLEM tianhan@auburn.edu
Christina Tonitto Denitrification-Decomposition (DNDC) biogeochemical model DNDC ct244@cornell.edu
Hans Verbeeck Organizing Carbon and Hydrology in Dynamic Ecosystems ORCHIDEE Hans.Verbeeck@UGent.be

Note: See Table 2 in Schaefer et al. (2012) for a summary of model characteristics and references.

2. Data Description:

This data set contains standardized, processed output from 24 terrestrial biosphere models for 47 flux tower sites in North America. The output variables are: gross primary productivity (GPP), net ecosystem exchange (NEE), leaf area index (LAI), ecosystem respiration (Re), latent heat flux (LE), and sensible heat flux (H). The data files also contain gap-filled observations and total uncertainty estimates from Barr et al. (2009) and Schaefer et al. (2012). Data are provided at the native half-hourly time step, daily, monthly, and annual averages. The data files are in comma-separated text (.csv) format.

2.1. Spatial Coverage

Site: North America

Site boundaries: (All latitude and longitude given in decimal degrees)

Site (Region) Westernmost Longitude Easternmost Longitude Northernmost Latitude Southernmost Latitude
North America -170 -50 84 10

2.2. Spatial Resolution

Point (lat/lon) centered around flux tower

2.3. Temporal Coverage

1998-2007

2.4. Temporal Resolution

Half-hourly, daily, monthly, and annual aggregations

2.5. Time Variable

Standardized files are in local standard time (LST) with the timestamp representing the beginning of the averaging period. To match this standard, model output has been time-shifted when necessary

2.6. Data File Information

Table 1. Data Files

FILE AND FOLDER NAMES
COMPRESSED FILE NAME FILE FOLDER NAMES DATA FILE FOLDER NAMES FOR EACH SITE DATA FILES FOR EACH SITE
NACP_Site_Model_Flux_Std_Fmt.zip GPP_47_site_model_output *_GPP *_GPP_annual.txt
*_GPP_daily.txt
*_GPP_halfhourly.txt
*_GPP_monthly.txt
H_47_site_model_output *_H *_H_annual.txt
*_H_daily.txt
*_H_halfhourly.txt
*_H_monthly.txt
LAI_47_site_model_output *_LAI *_LAI_annual.txt
*_LAI_daily.txt
*_LAI_halfhourly.txt
*_LAI_monthly.txt
LE_47_site_model_output *_LE *_LE_annual.txt
*_LE_daily.txt
*_LE_halfhourly.txt
*_LE_monthly.txt
NEE_47_site_model_output *_NEE *_NEE_annual.txt
*_NEE_daily.txt
*_NEE_halfhourly.txt
*_NEE_monthly.txt
Re_47_site_model_output *_Re *_Re_annual.txt
*_Re_daily.txt
*_Re_halfhourly.txt
*_Re_monthly.txt

Note: * represents the 6-character tower codes used in the site lists (see Tables 3 and 4).

2.7. Companion File Information

Table 2. Companion Files

FILE NAME DESCRIPTION
NACP_uncertainty_analysis.pdfMethodology of estimating uncertainty
Richardson_gap_filling_2009.pdfExplanation of algorithmic uncertainties in GPP/RE partitioning and gap filling of NEE, at annual and half-hourly time scales
site_information_basic.csvBasic information about each flux tower site (site code, name, PI, affiliation, email, address, references, priority, biome, etc.)
site_information_extended.pdfSummarizes site code, name, PI, affiliation, email, address, references, priority, biome, etc.
site_location_summary.csvSummarizes all site location information required as input to all models: latitude, longitude, elevation, instrument height, biome, start and stop years, time zone shift to local standard time, and the flux time averaging period
site_synthesis_protocol_v7.pdfDescribes standardized site synthesis protocol
figures.zipPlots representing diurnal and seasonal averages for the six output variables for each of the 47 modeled sites.
figures_readme.pdfExamples of plots from figures.zip with plot and legend descriptions. The examples provided are Figures 1 and 2 in this document.

 

3. Data Application and Derivation:

This data product contributes to a multidisciplinary research program to obtain scientific understanding of North America's carbon sources and sinks and of changes in carbon stocks needed to meet societal concerns and to provide tools for decision makers. The data were generated as part of a NACP site-level synthesis to evaluate and inter-compare models and observation measurements across North America.

This data set contains standardized, processed outputs of 24 terrestrial biosphere models and was used to inter-compare model simulations and assess how well terrestrial biosphere models simulate carbon processes across vegetation types and environmental conditions at 47 eddy covariance flux tower sites in North America.

4. Quality Assessment:

The modeling teams used standard model input data derived from local observations, simulation setup procedures, model outputs, and analysis techniques to ensure a valid and fair comparison of model results against observations. Using standardized input, output, and analysis techniques also minimized setup and analysis time and allowed investigators to accurately gauge model and data uncertainty with minimal error and bias.

Overall, there was a very large spread in model performance. See discussions on model inter-comparisons and model-data comparisons in Dietze et al. (2011), Richardson et al. (2012), Schaefer et al. (2012), and Schwalm et al. (2010).

light use efficiency curve

Figure 3. GPP Annual Bias, as shown in this light use efficiency (LUE) curve for the US-Me2 Flux Tower Site (Schaefer et al., 2012). The slope of the LUE curve drives the annual bias.

 

5. Data Acquisition Materials and Methods:

5.1 Participating Flux Tower Sites

Participating eddy flux covariance towers in the Site Synthesis were divided into a Priority 1 and a Priority 2 list. The Priority 1 sites represent a broad range of vegetation types and geographic regions to test each model’s performance under the fullest range of expected conditions across North America. No more than three Priority 1 sites were chosen to represent each of the major biome types in North America as defined by the IGBP biome classification.

The Priority 1 list represents the minimum number of tower sites required to evaluate model performance in North America. The Priority 2 list expands the site selection to include towers required for specialized analyses. Each participating site provided data as input to models and for comparison with model output, as described below.

An additional 11 flux tower sites that lacked ancillary and biological data were identified as third-priority sites (see Figure 4) but were not used as part of the model-data comparison.

For each site we used the unique FLUXNET code CC-XXX, where CC is a two letter country code and XXX is a three letter site code. The site codes are a unique identifier for each site and a convenient naming convention for all model input and output files.

NACP sites

Figure 4. Flux Tower Site Locations: First-priority sites (36 sites) and Second-priority sites (11 chronosequence sites) were used for the model-data comparison. The third-priority sites (11 sites) were not used as part of the model-data comparison.

 

Table 3. NACP Site-Level Synthesis - First-priority sites (36 sites). These sites have forcing and flux with uncertainty data but not all sites provided ancillary data.

FLUXNET Site CodeFull Name Period of Record1Flux w/ Uncertainty Data Ancillary Data State/Prov Type2
US-ARM ARM – Southern Great Plains 2000-2006 yes yesOK CRO
US-Ne1 Mead – Irrigated maize 2001-2006 yesyes NECRO
US-Ne2 Mead – Irrigated maize/soybean 2001-2006 yesyes NECRO
US-Ne3 Mead – Rainfed maize/soybean 2001-2006 yesyes NECRO
US-IB1 Fermi Lab – Maize/soybean rotation 2005-2007 yesyes ILCRO
CA-Let Lethbridge Grassland 1997-2006 yesyes ABGRA
US-Var Vaira Ranch 2001-2007 yesyes CAGRA
US-Shd Shidler 1997-2001 yesyes OKGRA
US-IB2 Fermi Lab – Prairie 2004-2007 yesyes ILGRA
CA-Oas BERMS – Old Aspen 1997-2006 yesyes SKDBF
US-Ha1 Harvard Forest – EMS Tower 1991-2006 yesyes MADBF
US-Dk2 Duke Forest – Hardwood 2003-2005 yesyes NCDBF
US-UMB University of Michigan Biological Station (UMBS) 1998-2006 yesyes MIDBF
US-MMS Morgan Monroe State Forest 1999-2006 yesyes INDBF
US-WCr Willow Creek 1998-2006 yes no WIDBF
US-MOz Missouri Ozark 2004-2007 yesyes MODBF
CA-Man BOREAS – Northern Study Area, Old Black Spruce 1994-2006 yesyes MBENFB
CA-Obs BERMS – Old Black Spruce 2000-2006 yesyes SKENFB
CA-Ojp BERMS – Old Jack Pine 2000-2006 yesyes SKENFB
CA-Qfo Quebec – Mature Black Spruce 2004-2006 yesyes QBENFB
CA-Ca1 Campbell River – Mature Douglas-fir 1998-2006 yesyes BCENFT
US-Dk3 Duke Forest – Loblolly Pine 1998-2005 yesyes NCENFT
US-Ho1 Howland Forest – Main Tower 1996-2004 yesyes MEENFT
US-Me2 Metolius – Intermediate-aged Ponderosa Pine 2002-2007 yesyes ORENFT
US-NR1 Niwot Ridge 1998-2007 yesyes COENFT
CA-TP4 Turkey Point – Mature 2002-2007 yesyes ONENFT
US-PFa Park Falls / WLEF 1997-2005 yesyes WIMF
US-Syv Sylvania Wilderness Area 2001-2006 yesyes MIMF
CA-Gro Groundhog River Station 2004-2006 yesyes ONMF
US-Ton Tonzi Ranch 2001-2007 yesyes CAWSA
US-SO2 Sky Oaks – Old 1998-2006 yesyes CASHR
US-Brw Barrow 1998-2006 yesyes AKTUN
US-Atq Atqasuk 1999-2006 yesyes AKTUN
CA-Mer Eastern Peatland – Mer Bleue 1999-2006 yesyes ONWET
US-Los Lost Creek 2000-2006 yes no WIWET
CA-WP1 Western Peatland – LaBiche River 2003-2007 yes no ABWET

Table 4. NACP Site-Level Synthesis - Second-priority sites (11 chronosequence sites). All second-priority sites have forcing data but not all sites have flux with uncertainty data and none provided ancillary data.

FLUXNET Site CodeFull Name Period of Record1Flux w/ Uncertainty Data Ancillary Data State/Prov Type2
CA-SJ1BERMS – Jack Pine, 1994 harvest 2002-2005 yes no SK ENFB
CA-SJ2BERMS – Jack Pine, 2002 harvest 2003-2006 yes no SK ENFB
CA_SJ3BERMS – Jack Pine, 1975 harvest 2004-2005 yes no SK ENFB
CA-Ca2Campbell River – Douglas-fir clearcut 2001-2006 yes no BC ENFT
CA-Ca3Campbell River – Douglas-fir juvenile 2002-2006 yes no BC ENFT
US-Me3Metolius – Ponderosa Pine, young #2 2004-2005 yes no OR ENFT
US-Me4Metolius – Ponderosa Pine, old-growth 1996-2000 no no OR ENFT
US-Me5Metolius – Ponderosa Pine, Young #1 1999-2002 yes no OR ENFT
CA-TP1Turkey Point – Young 2003-2007 no no ON ENFT
CA-TP2Turkey Point – Seedling 2003-2007 no no ON ENFT
CA-TP3Turkey Point – Middle-aged 2003-2007 no no ON ENFT

Notes (apply to both tables):

1Start-end years in the gap-filled weather data. Partial years (from flux data record) have been extended to complete years of surface weather data to simplify model forcing. 2Types were assigned for convenience in this project, to identify combination of vegetation type and climate zone as an aid in site selection. These type names are not intended to match the IGBP classification assigned in other databases. Class: CRO = crop; GRA = grassland; ENFB = evergreen needleleaf forest – boreal; ENFT = evergreen needle leaf forest – temperate; DBF = deciduous broadleaf forest; MF = mixed (deciduous/evergreen) forest; WSA = woody savanna; SHR = shrubland; TUN = tundra; and WET = wetland. An additional 11 flux tower sites, which lack ancillary and biological data templates, were identified as third-priority sites (see Figure 4) but were not used as part of the model-data comparison.

5.2 Site Synthesis Protocol

Participating modeling teams followed the NACP Site Synthesis Protocol (Site_Synthesis_Protocol_v7.pdf) which covers procedures, plans, and infrastructure for the site-level analyses. MAST-DC provided each modeling team with standardized model input data for each flux tower site. The input data included: gap-filled, locally observed weather; remotely-sensed phenology; land use history; and site description data. The input data are described and provided in a related data set, NACP Site: Tower Meteorology, Flux Observations with Uncertainty, and Ancillary Data (10.3334/ORNLDAAC/1178). To ensure consistency, each modeling team followed standard model setup and spinup procedures (see the NACP Site Synthesis Protocol). All models used their standard values for various biophysical parameters except LoTEC, which used optimized parameter values obtained through data assimilation (Ricciuto et al., 2011).

5.3 Model Output

Included here is the latest version of processed model output (mid-December 2009). GPP, NEE, and Re files have been further updated in November 2012 to provide total uncertainty estimated by Schaefer et al. (2012). However, LE and H have not been updated, and only contain the random and u* threshold uncertainty summed in quadrature. Plots representing diurnal and seasonal averages for these output variables are also provided in the companion file figures.zip.

6. Data Access:

This data set is available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Data Archive Center:

Contact for Data Center Access Information:
E-mail: uso@daac.ornl.gov
Telephone: +1 (865) 241-3952


7. References:

Barr, A.G., D.M. Ricciuto, K. Schaefer, A. Richardson, D. Agarwal, P.E. Thornton, K. Davis, B. Jackson, R.B. Cook, D.Y. Hollinger, C. van Ingen, B. Amiro, A. Andrews, M.A. Arain, D. Baldocchi, T.A. Black, P. Bolstad, P. Curtis, A. Desai, D. Dragoni, L. Flanagan, L. Gu, G. Katul, B.E. Law, P. Lafleur, H. Margolis, R. Matamala, T. Meyers, H. McCaughey, R. Monson, J.W. Munger, W. Oechel, R. Oren, N. Roulet, M. Torn, and S. Verma. 2013. NACP Site: Tower Meteorology, Flux Observations with Uncertainty, and Ancillary Data. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA http://dx.doi.org/10.3334/ORNLDAAC/1178

Barr, A.G., A.D. Richardson, D.Y. Hollinger, D. Papale, M.A. Arain, T.A. Black, G. Bohrer, D. Dragoni, M.L. Fischer, L. Gu, B.E. Law, H.A. Margolis, J.H. McCaughey, J.W. Munger, W. Oechel, K. Schaeffer. 2013b. Use of change-point detection for friction–velocity threshold evaluation in eddy-covariance studies. Agricultural and Forest Meteorology, 171–172: 31-45 http://dx.doi.org/10.1016/j.agrformet.2012.11.023

Barr, A.G., D. Hollinger, and A. D. Richardson. 2009. CO2 flux measurement uncertainty estimates for NACP. Eos Transactions SGU, 90(52), Fall Meeting, Abstract B54A-04.

Denning, A.S., et al. 2005. Science implementation strategy for the North American Carbon Program: A Report of the NACP Implementation Strategy Group of the U.S. Carbon Cycle Interagency Working Group. U.S. Carbon Cycle Science Program, Washington, DC. 68 pp.

Dietze, M.C., R. Vargas, A.D. Richardson, P.C. Stoy, A.G. Barr, R.S. Anderson, M.A. Arain, I.T. Baker, T.A. Black, J.M. Chen, P. Ciais, L.B. Flanagan, C.M. Gough, R.F. Grant, D. Hollinger, C. Izaurralde, C.J. Kucharik, P. Lafleur, S. Liu, E. Lokupitiya, Y. Luo, J.W. Munger, C. Peng, B. Poulter, D.T. Price, D.M. Ricciuto, W.J. Riley, A.K. Sahoo, K. Schaefer, A.E. Suyker, H. Tian, C. Tonitto, H. Verbeeck, S.B. Verma, W. Wang, and E. Weng. 2012.  Characterizing the performance of ecosystem models across time scales: A spectral analysis of the North American Carbon Program site-level synthesis. Journal of Geophysical Research: Biogeosciences 116: G04029. doi:10.1029/2011JG001661

Ricciuto, D.M., A.W. King, D. Dragoni, and W.M. Post. 2011. Parameter and prediction uncertainty in an optimized terrestrial carbon cycle model: Effects of constraining variables and data record length, J. Geophys. Res. 116: G01033. doi:10.1029/2010JG001400

Richardson, A.D., R.S. Anderson, M.A. Arain, A.G. Barr, G. Bohrer, G. Chen, J.M. Chen, P. Ciais, K.J. Davis, A.R. Desai, M.C. Dietze, D. Dragoni, S.R. Garrity, C.M. Gough, R. Grant, D.Y. Hollinger, H.A. Margolis, H. McCaughey, M. Migliavacca, R.K. Monson, J.W. Munger, B. Poulter, B.M. Raczka, D.M. Ricciuto, A.K. Sahoo, K. Schaefer, H. Tian, R. Vargas, H. Verbeeck, J. Xiao, and Y. Xue. 2012. Terrestrial biosphere models need better representation of vegetation phenology:  Results from the North American Carbon Program site synthesis. Global Change Biology 18(2): 566-584. doi:10.1111/j.1365-2486.2011.02562.x

Schaefer, K., C. Schwalm, C. Williams, M.A. Arain, A. Barr, J. Chen, K.J. Davis, D. Dimitrov, T.W. Hilton, D.W. Hollinger, E. Humphreys, B. Poulter, B.M. Raczka, A.D. Richardson, A. Sahoo, P.E. Thornton, R. Vargas, H. Verbeeck, R. Anderson, I. Baker, T.A. Black, P. Bolstad, Jiquan Chen, P. Curtis, A.R. Desai, M. Dietze, D. Dragoni, C. Gough, R.F. Grant, L. Gu, A. Jain, C. Kucharik, B. Law, S. Liu, E. Lokipitiya, H.A. Margolis, R. Matamala, J.H. McCaughey, R. Monson, J.W. Munger, W. Oechel, C. Peng, D.T. Price, D. Ricciuto, W.J. Riley, N. Roulet, H. Tian, C. Tonitto, M. Torn, E. Weng, X. Zhou 2012. A model-data comparison of gross primary productivity: Results from the North American Carbon Program site synthesis. Journal of Geophysical Research: Biogeosciences 117: G03010. doi:10.1029/2012JG001960

Schwalm, C., C.A. Williams, K. Schaefer, R. Anderson, M.A. Arain, I. Baker, A. Barr, T.A. Black, G. Chen, J.M. Chen, P. Ciais, K.J. Davis, A. Desai, M. Dietze, D. Dragoni, M.L. Fischer, L.B. Flanagan, R. Grant, L. Gu, D. Hollinger, R.C. Izaurralde, C. Kucharik, P. Lafleur, B.E. Law, L. Li, Z. Li, S. Liu, E. Lokupitiya, Y. Luo, S. Ma, H. Margolis, R. Matamala, H. McCaughey, R.K. Monson, W.C. Oechel, C. Peng, B. Poulter, D.T. Price, D.M. Riciutto, W. Riley, A. Kumar Sahoo, M. Sprintsin, J. Sun, H. Tian, C. Tonitto, H. Verbeeck, and S.B. Verma. 2010. A model-data intercomparison of CO2 exchange across North America: Results from the North American Carbon Program site synthesis.  Journal of Geophysical Research: Biogeosciences 115: G00H05. doi:10.1029/2009jg001229

Wofsy, S.C., and R.C. Harriss. 2002. The North American Carbon Program (NACP). Report of the NACP Committee of the U.S. Interagency Carbon Cycle Science Program. U.S. Global Change Research Program, Washington, DC. 56 pp.

Additional Sources of Information:

Keenan, T.F., I. Baker, A. Barr, P. Ciais, K. Davis, M. Dietze, D. Dragoni, C.M. Gough, R. Grant, D. Hollinger, K. Hufkens, B. Poulter, H. McCaughey, B. Rackza, Y. Ryu, K. Schaefer, H. Tian, H. Verbeeck, M. Zhao, and A.D. Richardson. 2012. Terrestrial biosphere model performance for inter-annual variability of land-atmosphere CO2 exchange. Global Change Biology 18(6): 1971–1987. doi:10.1111/j.1365-2486.2012.02678.x

Li H., M. Huang, M.S. Wigmosta, Y. Ke, A.M. Coleman, L.Y.R. Leung, A. Wang, and D.M. Ricciuto. 2011. Evaluating runoff simulations from the Community Land Model 4.0 using observations from flux towers and a mountainous watershed. Journal of Geophysical Research: Atmospheres 116:  D24120.  doi:10.1029/2011JD016276

Sulman, B.N., A.R. Desai, N.M. Schroeder, D. Ricciuto, A. Barr, A.D. Richardson, L.B. Flanagan, P.M. Lafleur, H. Tian, G. Chen, R.F. Grant, B. Poulter, H. Verbeeck, P. Ciais, B. Ringeval, I.T. Baker, K. Schaefer, Y. Luo, and E. Weng. 2012. Impact of hydrological variations on modeling of peatland CO2 fluxes: Results from the North American Carbon Program site synthesis. Journal of Geophysical Research: Biogeosciences 117: G01031. doi:10.1029/2011JG001862