The effect of vertically resolved soil biogeochemistry and alternate soil C and N models on C dynamics of CLM4

Koven, Charles D.; Riley, William J.; Subin, Z. M.; Tang, Jinyun; Torn, M. S.; Collins, William D.; Bonan, G. B.; Lawrence, David M.; Swenson, S. C.

doi:10.5194/bg-10-7109-2013

Cited by 423 publications

(506 citation statements)

References 88 publications

(104 reference statements)

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“…Monthly CO 2 output is sampled during midday (10-18 LST), averaged across all Alaskan land grid points (55°N to 72°N, 170°W to 140°W), and binned vertically into the ML and FT. We run CO 2 experiments based on two configurations of the Community Land Model, version 4.5 (CLM4.5) (15)(16)(17). These experiments are described briefly below and in more detail in S2: Land and Atmospheric Simulations.…”

Section: Methodsmentioning

confidence: 99%

Detecting regional patterns of changing CO ₂ flux in Alaska

Parazoo

Commane

Wofsy

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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With rapid changes in climate and the seasonal amplitude of carbon dioxide (CO 2 ) in the Arctic, it is critical that we detect and quantify the underlying processes controlling the changing amplitude of CO 2 to better predict carbon cycle feedbacks in the Arctic climate system. We use satellite and airborne observations of atmospheric CO 2 with climatically forced CO 2 flux simulations to assess the detectability of Alaskan carbon cycle signals as future warming evolves. We find that current satellite remote sensing technologies can detect changing uptake accurately during the growing season but lack sufficient cold season coverage and near-surface sensitivity to constrain annual carbon balance changes at regional scale. Airborne strategies that target regular vertical profile measurements within continental interiors are more sensitive to regional flux deeper into the cold season but currently lack sufficient spatial coverage throughout the entire cold season. Thus, the current CO 2 observing network is unlikely to detect potentially large CO 2 sources associated with deep permafrost thaw and cold season respiration expected over the next 50 y. Although continuity of current observations is vital, strategies and technologies focused on cold season measurements (active remote sensing, aircraft, and tall towers) and systematic sampling of vertical profiles across continental interiors over the full annual cycle are required to detect the onset of carbon release from thawing permafrost.carbon cycle | permafrost thaw | climate | Earth system models | remote sensing T he future trajectory of carbon balance in the Arctic-Boreal Zone (ABZ) is of global importance because of the vast quantities of carbon sequestered in permafrost soils (1). Climate warming threatens to increase permafrost thaw and release soil carbon back to the atmosphere as a positive feedback promoting additional warming (2). It is unclear whether the observed intensification of the northern high-latitude carbon cycle is dominated by plant productivity or microbial decomposition, both of which seem to be increasing (3-6). Although warming temperatures and C/N fertilization promote greening and higher summer productivity during the short, intense growing season, these same factors also drive increased emissions during the long cold season (3-5).Detecting changes in ABZ carbon balance requires sustained observations over the full annual cycle. In the last decade, researchers have recognized the importance of year-round landatmosphere CO 2 flux observations (3-5). Synthesis studies of these data show that increasing growing season uptake has been offset by stronger winter respiration. Measurements of atmospheric CO 2 collected from in situ and remote sensing instruments provide spatially and temporally integrated constraints of net CO 2 exchange on regional to pan-Arctic scales. In situ observations have been limited primarily to a small network of surface towers and infrequent, short duration airborne campaigns designed primarily to detect the pan-Ar...

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Section: Methodsmentioning

confidence: 99%

Detecting regional patterns of changing CO ₂ flux in Alaska

Parazoo

Commane

Wofsy

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Despite the importance of deep soil carbon, to date only one LSM (CLM4) incorporates mechanisms for the vertical mixing and subsequent stabilization of carbon (Koven et al, 2013). The representation of SOC in LSMs is generally highly simplified, with a single-layer box modeling approach and without representation of a soluble pool of carbon (ToddBrown et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

ORCHIDEE-SOM: modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe

et al. 2018

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Abstract. Current land surface models (LSMs) typically represent soils in a very simplistic way, assuming soil organic carbon (SOC) as a bulk, and thus impeding a correct representation of deep soil carbon dynamics. Moreover, LSMs generally neglect the production and export of dissolved organic carbon (DOC) from soils to rivers, leading to overestimations of the potential carbon sequestration on land. This common oversimplified processing of SOC in LSMs is partly responsible for the large uncertainty in the predictions of the soil carbon response to climate change. In this study, we present a new soil carbon module called ORCHIDEE-SOM, embedded within the land surface model ORCHIDEE, which is able to reproduce the DOC and SOC dynamics in a vertically discretized soil to 2 m. The model includes processes of biological production and consumption of SOC and DOC, DOC adsorption on and desorption from soil minerals, diffusion of SOC and DOC, and DOC transport with water through and out of the soils to rivers. We evaluated ORCHIDEE-SOM against observations of DOC concentrations and SOC stocks from four European sites with different vegetation covers: a coniferous forest, a deciduous forest, a grassland, and a cropland. The model was able to reproduce the SOC stocks along their vertical profiles at the four sites and the DOC concentrations within the range of measurements, with the exception of the DOC concentrations in the upper soil horizon at the coniferous forest. However, the Published by Copernicus Publications on behalf of the European Geosciences Union. 938M. Camino-Serrano et al.: ORCHIDEE-SOM model was not able to fully capture the temporal dynamics of DOC concentrations. Further model improvements should focus on a plant-and depth-dependent parameterization of the new input model parameters, such as the turnover times of DOC and the microbial carbon use efficiency. We suggest that this new soil module, when parameterized for global simulations, will improve the representation of the global carbon cycle in LSMs, thus helping to constrain the predictions of the future SOC response to global warming.

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“…CLM has been evaluated against observations from a wide range of sources, and these evaluations have resulted in improved model performance (Bauerle et al, 2012;Bonan et al, 2011Bonan et al, , 2012Koven et al, 2013;Lawrence et al, 2011;Mao et al, 2012aMao et al, , b, 2013Oleson et al, 2008;Randerson et al, 2009;Riley et al, 2011;Shi et al, 2011Shi et al, , 2013Shi et al, , 2015Thornton et al, 2007). Nevertheless, little attention has been paid to CLM's ability to replicate short-term manipulative experiments, which provide an avenue for exploring and validating model response to sudden, large changes in environmental drivers that control physiological and ecological responses (Amthor et al, 2001;Bonan et al, 2013;Shi et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Community Land Model in a pine stand with shading manipulations and <sup>13</sup>CO<sub>2</sub> labeling

et al. 2016

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Abstract. Carbon allocation and flow through ecosystems regulates land surface-atmosphere CO 2 exchange and thus is a key, albeit uncertain, component of mechanistic models. The Partitioning in Trees and Soil (PiTS) experimentmodel project tracked carbon allocation through a young Pinus taeda stand following pulse labeling with 13 CO 2 and two levels of shading. The field component of this project provided process-oriented data that were used to evaluate terrestrial biosphere model simulations of rapid shifts in carbon allocation and hydrological dynamics under varying environmental conditions. Here we tested the performance of the Community Land Model version 4 (CLM4) in capturing short-term carbon and water dynamics in relation to manipulative shading treatments and the timing and magnitude of carbon fluxes through various compartments of the ecosystem. When calibrated with pretreatment observations, CLM4 was capable of closely simulating stand-level biomass, transpiration, leaf-level photosynthesis, and pre-labeling 13 C values. Over the 3-week treatment period, CLM4 generally reproduced the impacts of shading on soil moisture changes, relative change in stem carbon, and soil CO 2 efflux rate. Transpiration under moderate shading was also simulated well by the model, but even with optimization we were not able to simulate the high levels of transpiration observed in the heavy shading treatment, suggesting that the BallBerry conductance model is inadequate for these conditions. The calibrated version of CLM4 gave reasonable estimates of label concentration in phloem and in soil surface CO 2 after 3 weeks of shade treatment, but it lacks the mechanisms needed to track the labeling pulse through plant tissues on shorter timescales. We developed a conceptual model for photosynthate transport based on the experimental observations, and we discussed conditions under which the hypothesized mechanisms could have an important influence on model behavior in larger-scale applications. Implications for future experimental studies are described, some of which are already being implemented in follow-on studies.

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The effect of vertically resolved soil biogeochemistry and alternate soil C and N models on C dynamics of CLM4

Cited by 423 publications

References 88 publications

Detecting regional patterns of changing CO ₂ flux in Alaska

Detecting regional patterns of changing CO ₂ flux in Alaska

ORCHIDEE-SOM: modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe

Evaluating the Community Land Model in a pine stand with shading manipulations and <sup>13</sup>CO<sub>2</sub> labeling

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The effect of vertically resolved soil biogeochemistry and alternate soil C and N models on C dynamics of CLM4

Cited by 423 publications

References 88 publications

Detecting regional patterns of changing CO 2 flux in Alaska

Detecting regional patterns of changing CO 2 flux in Alaska

ORCHIDEE-SOM: modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe

Evaluating the Community Land Model in a pine stand with shading manipulations and &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; labeling

Contact Info

Product

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About

Detecting regional patterns of changing CO ₂ flux in Alaska

Detecting regional patterns of changing CO ₂ flux in Alaska

Evaluating the Community Land Model in a pine stand with shading manipulations and <sup>13</sup>CO<sub>2</sub> labeling