Evidence for interannual variability of the carbon cycle from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory Global Air Sampling Network

Conway, T. J.; Tans, Pieter P.; Waterman, Lee S.; Thoning, K. W.; Kitzis, Duane; Masarie, K. A.; Zhang, Ni

doi:10.1029/94jd01951

Cited by 761 publications

(597 citation statements)

References 46 publications

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“…Seasonal NEE fluxes are controlled by both the magnitude and timing of NPP and the temperature sensitivity of heterotrophic respiration (Kaminski et al, 2002;Randerson et al, 2002). Measurements of the annual cycle are a robust constraint at a large spatial scale on the combined set of processes regulating NEE because (1) ocean and fossil fuel fluxes contribute only weakly to seasonal variations in CO 2 in the northern hemisphere Heimann et al, 1998;Nevison et al, 2008) and (2) the CO 2 measurements are precise (Conway et al, 1994). These data-model comparisons are sensitive, however, to biases in the atmospheric model-particularly with respect to convection, planetary boundary layer mixing, and other processes that regulate vertical mixing (Stephens et al, 2007;Yang et al, 2007).…”

Section: The Annual Cycle Of Atmospheric Carbon Dioxidementioning

confidence: 99%

Systematic assessment of terrestrial biogeochemistry in coupled climate–carbon models

Randerson

Hoffman

Thornton

et al. 2009

Global Change Biology

349

300

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With representation of the global carbon cycle becoming increasingly complex in climate models, it is important to develop ways to quantitatively evaluate model performance against in situ and remote sensing observations. Here we present a systematic framework, the Carbon‐LAnd Model Intercomparison Project (C‐LAMP), for assessing terrestrial biogeochemistry models coupled to climate models using observations that span a wide range of temporal and spatial scales. As an example of the value of such comparisons, we used this framework to evaluate two biogeochemistry models that are integrated within the Community Climate System Model (CCSM) – Carnegie‐Ames‐Stanford Approach′ (CASA′) and carbon–nitrogen (CN). Both models underestimated the magnitude of net carbon uptake during the growing season in temperate and boreal forest ecosystems, based on comparison with atmospheric CO2 measurements and eddy covariance measurements of net ecosystem exchange. Comparison with MODerate Resolution Imaging Spectroradiometer (MODIS) measurements show that this low bias in model fluxes was caused, at least in part, by 1–3 month delays in the timing of maximum leaf area. In the tropics, the models overestimated carbon storage in woody biomass based on comparison with datasets from the Amazon. Reducing this model bias will probably weaken the sensitivity of terrestrial carbon fluxes to both atmospheric CO2 and climate. Global carbon sinks during the 1990s differed by a factor of two (2.4 Pg C yr−1 for CASA′ vs. 1.2 Pg C yr−1 for CN), with fluxes from both models compatible with the atmospheric budget given uncertainties in other terms. The models captured some of the timing of interannual global terrestrial carbon exchange during 1988–2004 based on comparison with atmospheric inversion results from TRANSCOM (r=0.66 for CASA′ and r=0.73 for CN). Adding (CASA′) or improving (CN) the representation of deforestation fires may further increase agreement with the atmospheric record. Information from C‐LAMP has enhanced model performance within CCSM and serves as a benchmark for future development. We propose that an open source, community‐wide platform for model‐data intercomparison is needed to speed model development and to strengthen ties between modeling and measurement communities. Important next steps include the design and analysis of land use change simulations (in both uncoupled and coupled modes), and the entrainment of additional ecological and earth system observations. Model results from C‐LAMP are publicly available on the Earth System Grid.

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Section: The Annual Cycle Of Atmospheric Carbon Dioxidementioning

confidence: 99%

Systematic assessment of terrestrial biogeochemistry in coupled climate–carbon models

Randerson

Hoffman

Thornton

et al. 2009

Global Change Biology

349

300

View full text Add to dashboard Cite

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“…The total amount of CO2 entering the atmosphere each year through these processes is relatively well quantified [Andres et al, 1996; Houghton, 1995], as is the rate of accumulation of atmospheric CO2 [Conway et al, 1994]. …”

Section: Introductionmentioning

confidence: 99%

Determination of the isotopic(¹³C/¹²C) discrimination by terrestrial biology from a global network of observations

Bakwin¹,

Tans²,

White³

et al. 1998

Global Biogeochemical Cycles

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103

116

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“…N20 , for example, with its photochemical destruction in the middle stratosphere and above, has a long history as a stratospheric tracer; it has been used to diagnose polar descent and mixing between middle latitudes and the polar vortices [Schoeberl et al, 1992;Strahan et al, 1994;Eluszkiewicz et al, 1995]. CO2 has the potential to be a good tracer because of its source function at the surface, which has a large secular increase (--• 1.5 ppm/yr) and a large-amplitude, latitudedependent seasonal cycle (> 15 ppm at high northern latitudes) [Conway et al, 1994]. In the middle and upper stratosphere, methane oxidation provides a small source for CO2, but this has a negligible effect on horizontal gradients in the lower stratosphere [Hall and Prather, 1993].…”

Section: Introductionmentioning

confidence: 99%

The CO₂ seasonal cycle as a tracer of transport

Strahan¹,

Douglass²,

Nielsen³

et al. 1998

J. Geophys. Res.

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Abstract. CO2 time series in the lower stratosphere have been constructed as a function of latitude and altitude using ER-2 aircraft observations. A seasonally varying signal derived from tropical surface CO 2 data was fit to these data in a manner similar to that of Boering et al. [1996]. This analysis shows how the tropospheric CO2 seasonal cycle in air entering the tropical lower stratosphere ascends and gradually loses amplitude. The midlatitude results show that in the 370-to 400-K range the tropical signal is transported poleward rapidly with only a small loss in amplitude. The signal also reaches the midlatitudes rapidly at higher altitudes but with markedly less amplitude. Above --•440 K the midlatitude CO 2 data best fit a line whose slope is the secular increase in CO2. This observational analysis is used as a basis for diagnosing transport in a CO2 simulation produced using GEOS-1 Data Assimilation System (DAS) winds in an off-line chemistry and transport model. The model is forced at the lowest levels by a 5-year zonal mean CO2 data set derived from surface observations. The analysis of model results as a function of height and latitude determines whether (1) the seasonally varying CO2 cycle forced in the troposphere survives in the tropical lower stratosphere and whether (2) the CO2 cycle in the tropical lower stratosphere propagates realistically to the midlatitudes. We find that the model transports a CO2 seasonal cycle from the surface to the tropical upper troposphere that agrees with the phase and amplitude of tropospheric aircraft measurements. The cycle input into the model tropical lower stratosphere attenuates with height in a reasonable way compared with observations. The phase and amplitude of the cycle transported from the tropics to the midlatitudes agree well with the data up to about 440 K, but above that the model transports more of the tropical signal to the midlatitudes than is suggested by the ER-2 data. Overall, there is remarkable consistency between the model and observations in the upper troposphere/lower stratosphere, which supports the use of assimilated winds in assessments of the effects of aircraft exhaust.

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Evidence for interannual variability of the carbon cycle from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory Global Air Sampling Network

Cited by 761 publications

References 46 publications

Systematic assessment of terrestrial biogeochemistry in coupled climate–carbon models

Systematic assessment of terrestrial biogeochemistry in coupled climate–carbon models

Determination of the isotopic(¹³C/¹²C) discrimination by terrestrial biology from a global network of observations

The CO₂ seasonal cycle as a tracer of transport

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Evidence for interannual variability of the carbon cycle from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory Global Air Sampling Network

Cited by 761 publications

References 46 publications

Systematic assessment of terrestrial biogeochemistry in coupled climate–carbon models

Systematic assessment of terrestrial biogeochemistry in coupled climate–carbon models

Determination of the isotopic(13C/12C) discrimination by terrestrial biology from a global network of observations

The CO2 seasonal cycle as a tracer of transport

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Product

Resources

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Determination of the isotopic(¹³C/¹²C) discrimination by terrestrial biology from a global network of observations

The CO₂ seasonal cycle as a tracer of transport