Carbon Fluxes Across Regions: Observational Constraints at Multiple Scales

Law, B. E.; Turner, Dave; Campbell, John L.; Lefsky, M. A.; Guzy, Michael; Sun, Osbert Jianxin; Tuyl, Steve Van; Cohen, Warren B.

doi:10.1007/1-4020-4663-4_9

Cited by 44 publications

(48 citation statements)

References 27 publications

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“…In our Biome-BGC modeling, we addressed this issue by use of ecoregion-level parametrization based on (1) observations (e.g., foliar nitrogen concentration) and (2) parameter optimization (with reference to FIA observations). In Law et al (2006), we further discuss our use of eddy covariance flux tower observations, FIA data, ecological field plot measurements, and associated Monte Carlo analyses, to characterize multiple aspects of Biome-BGC model uncertainty.…”

Section: Modeling Limitationsmentioning

confidence: 99%

Regional carbon cycle responses to 25 years of variation in climate and disturbance in the US Pacific Northwest

et al. 2016

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Variation in climate, disturbance regime, and forest management strongly influence terrestrial carbon sources and sinks. Spatially distributed, process-based, carbon cycle simulation models provide a means to integrate information on these various influences to estimate carbon pools and flux over large domains. Here we apply the Biome-BGC model over the four-state Northwest US region for the interval from 1986 to 2010. Landsat data were used to characterize disturbances, and forest inventory data were used to parameterize the model. The overall disturbance rate on forest land across the region was 0.8 % year -1 , with 49 % as harvests, 28 % as fire, and 23 % as pest/pathogen. Net ecosystem production (NEP) for the 2006-2010 interval on forestland was predominantly positive (a carbon sink) throughout the region, with maximum values in the Coast Range, intermediate values in the Cascade Mountains, and relatively low values in the Inland Rocky Mountain ecoregions. Localized negative NEPs were mostly associated with recent disturbances. There was large interannual variation in regional NEP, with notably low values across the region in 2003, which was also the warmest year in the interval. The recent (2006)(2007)(2008)(2009)(2010) net ecosystem carbon balance (NECB) was positive for the region (14.4 TgC year -1 ). Despite a lower area-weighted mean NECB, public forestland contributed a larger proportion to the total NECB because of its larger area. Aggregated forest inventory data and inversion modeling are beginning to provide opportunities for evaluating model-simulated regional carbon stocks and fluxes.

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Section: Modeling Limitationsmentioning

confidence: 99%

Regional carbon cycle responses to 25 years of variation in climate and disturbance in the US Pacific Northwest

et al. 2016

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“…It can help improve our understanding of the feedbacks between the terrestrial biosphere and atmosphere (Law et al, 2006) and provide critical information to studying long-term biosphere interactions with other components of the Earth system (Potter et al, 2007). The Intergovernmental Panel on Climate Change (IPCC) reported that the continent of North America has been identified as a significantly large fraction of global carbon budget in terms of both source and sink of atmospheric CO 2 (Pacala et al, 2001;Gurney et al, 2002;IPCC, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…However, since the environmental limitation for simulating carbon fluxes is estimated with specific algorithms driven by uncertain environmental variables, biases between the observed and estimated environmental status can introduce uncertainty. In addition, terrestrial biogeochemical model simulations are uncertain due to lacking of large-scale disturbance data (Canadell et al, 2000;Law et al, 2006). Remotely sensed data provide globally consistent and near real-time observations of numerous surface variables as well as the information of the timing, distribution, spatial extent or severity of disturbances at regional and global scales .…”

Section: Introductionmentioning

confidence: 99%

Quantification of terrestrial ecosystem carbon dynamics in the conterminous United States combining a process-based biogeochemical model and MODIS and AmeriFlux data

et al. 2011

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Abstract. Satellite remote sensing provides continuous temporal and spatial information of terrestrial ecosystems. Using these remote sensing data and eddy flux measurements and biogeochemical models, such as the Terrestrial Ecosystem Model (TEM), should provide a more adequate quantification of carbon dynamics of terrestrial ecosystems. Here we use Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI), Land Surface Water Index (LSWI) and carbon flux data of AmeriFlux to conduct such a study. We first modify the gross primary production (GPP) modeling in TEM by incorporating EVI and LSWI to account for the effects of the changes of canopy photosynthetic capacity, phenology and water stress. Second, we parameterize and verify the new version of TEM with eddy flux data. We then apply the model to the conterminous United States over the period 2000-2005 at a 0.05 • × 0.05 • spatial resolution. We find that the new version of TEM made improvement over the previous version and generally captured the expected temporal and spatial patterns of regional carbon dynamics. We estimate that regional GPP is between 7.02 and 7.78 Pg C yr −1 and net primary production (NPP) ranges from 3.81 to 4.38 Pg C yr −1 and net ecosystem production (NEP) varies within 0.08-0. were captured by the model. Our study provides a new independent and more adequate measure of carbon fluxes for the conterminous United States, which will benefit studies of carbon-climate feedback and facilitate policy-making of carbon management and climate.

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“…To quantify the spatial pattern of ecosystem processes in the Changbai Mountain Nature Reserve in China, this study provides an example of upscaling ecophysiological and geophysical processes from the patch level to the entire landscape by integrating simulation modeling, GIS, remote sensing, and field-based observations. While the general scaling approach is similar to those used in other studies (e.g., King 1991;Wu 1999;Law et al 2006), this research has resulted in new findings that are particularly useful for understanding the structure and functioning of the CMNR landscape as well as unraveling problems and challenges in scaling up ecosystem processes across heterogeneous landscapes.…”

Section: Discussionmentioning

confidence: 93%

“…In spatial extrapolation through modeling, we explicitly considered the interactions of each patch with the atmosphere and soil, but horizontal interactions between patches were not explicitly considered. This is essentially the ''direct extrapolation'' method that has been widely used in landscape ecology, particularly for simulating ecosystem productivity (King 1991;Law et al 2006;Wu and Li 2006). The vegetation and soil characteristics of CMNR exhibited relatively discrete patches (Ge et al 1990), which made the hierarchical patch dynamic approach quite appropriate.…”

Section: Patch-level Model Validation and Upscaling Schemementioning

confidence: 99%

Scaling up ecosystem productivity from patch to landscape: a case study of Changbai Mountain Nature Reserve, China

Zhang

et al. 2006

Landscape Ecol

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Scaling up ecosystem processes from plots to landscapes is essential for understanding landscape structure and functioning as well as for assessing ecological impacts of land use and climate change. This study illustrates an upscaling approach to studying the spatiotemporal pattern of ecosystem processes in the Changbai Mountain Nature Reserve in northeastern China by integrating simulation modeling, GIS, remote sensing data, and field-based observations. The ecosystem model incorporated processes of energy transfer, plant physiology, carbon dynamics, and water cycling. Using a direct extrapolation scheme, the patch-level ecosystem model was scaled up to quantify the landscape-level pattern of primary productivity and the carbon source-sink relationship. The simulated net primary productivity (NPP) for the entire landscape, consisting of several ecosystem types, was 0.680 kg C m -2 yr -1 . The most widely distributed ecosystem type in this region was the mixed broad-leaved and Korean pine (Pinus koraiensis) forest, which had the highest NPP (1.084 kg C m -2 yr -1 ). The total annual NPP for all ecosystem types combined was estimated to be 1.332 Mt C yr -1 . These results suggest that the Changbai Mountain landscape as a whole was a carbon sink, with a net carbon sequestration rate of about 0.884 Mt C yr -1 for the study period. The simulated NPP agreed reasonably well with available field measurements at a number of locations within the study landscape. Our study provides new insight into the relationship between landscape pattern and ecosystem processes, and useful information for improving management practices in the Changbai Mountain Nature Reserve, which is one of the most important forested landscapes in China. Several research needs are discussed to further refine the modeling approach and reduce prediction uncertainties.

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Carbon Fluxes Across Regions: Observational Constraints at Multiple Scales

Cited by 44 publications

References 27 publications

Regional carbon cycle responses to 25 years of variation in climate and disturbance in the US Pacific Northwest

Regional carbon cycle responses to 25 years of variation in climate and disturbance in the US Pacific Northwest

Quantification of terrestrial ecosystem carbon dynamics in the conterminous United States combining a process-based biogeochemical model and MODIS and AmeriFlux data

Scaling up ecosystem productivity from patch to landscape: a case study of Changbai Mountain Nature Reserve, China

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